ことばの橋の作り方

# -*- coding: utf-8 -*-

# LICENSE.txt (unchanged text):
# 022 Word Bridge / ことばの橋
# Original code and pixel shapes: provided for the user's game project.
# Bundled Japanese bitmap glyphs were rendered from Noto Sans CJK Regular.
# Noto font data is licensed under SIL Open Font License 1.1.
# See assets/NOTO-LICENSE.txt for copyright and the complete license.
# Glyph generation: tools/build_font.py. Pillow is a development-only dependency.
# Runtime engine: Pyxel 2.9.9 (MIT license, installed separately by pip).
# No downloaded sprites, music, sound recordings, network services or LLM models.

# DISTRIBUTION_PERMISSION.txt (unchanged text):
# 022 ことばの橋：公開・教材配布の補足
# 記録日：2026年10月6日
# 
# この作品のコードと自作図形、および本講座用の段階教材は、プロジェクト所有者の承認に基づき、
# 「Pyxel入門 Pythonゲームの作り方」で学習・改造用のソース付き教材として配布しています。
# 教材をダウンロードし、内容を読んで学び、ご自身の制作のために変更して試すことができます。
# 
# 原納品物の LICENSE.txt は変更せずに同梱しています。
# この補足は今回の公開・教材配布と学習利用の許諾を記録するものであり、原LICENSEをMIT本文へ
# 置き換えたり、元からMITの記載があったものとして扱ったりするものではありません。
# 本作品と原作の権利表示を、ほかの作品の権利表示で上書きしないでください。
# 
# コード・図形と外部ライブラリー・字形データの条件は区別します。
# ・ゲームの図形は、Pyxelの矩形・線・円・三角形などで描いたものです。
# ・元の完成版の日本語字形はNoto Sans CJK Regular由来です。
#   SIL Open Font License 1.1の原文を assets/NOTO-LICENSE.txt に保持しています。
# ・Pyxelは別途インストールする外部ライブラリーです。Pyxel自身のライセンスが適用されます。
# ・段階教材の画面は標準ASCII描画を使い、Noto字形データの追加導入を必要としません。
# 
# 元コード・図形の提供に関する記載、外部由来の字形の著作権とライセンスは、原本のまま残しています。

"""022 Word Bridge: a standalone, incrementally runnable teaching stage.
Original notice: LICENSE.txt. Teaching distribution: DISTRIBUTION_PERMISSION.txt.
No image/font file is needed. Pyxel is imported only when the window starts.
"""
from dataclasses import dataclass, replace, asdict
from pathlib import Path
import json

STAGE = 1
STAGE_TITLE = 'TERRAIN AND COMPLEMENTARY RULES'
CONTROLS = ['ARROWS PROBE / SPACE LAB ASSIGNMENT', 'R RESET / Q TITLE / ESC QUIT / RELEASE EVERY KEY', 'CURSOR CAN INSPECT WATER; IT DOES NOT MOVE A PLAYER']
KEYS = {'UP', 'DOWN', 'LEFT', 'RIGHT', 'SPACE', 'R', 'Q'}

DIRECTIONS = {'UP': (0, -1), 'DOWN': (0, 1), 'LEFT': (-1, 0), 'RIGHT': (1, 0)}
MOVEMENT_PRIORITY = ('UP', 'DOWN', 'LEFT', 'RIGHT')
LIGHT_X = range(1, 6)

@dataclass(frozen=True)
class Level:
    width: int = 7
    height: int = 5
    dry: frozenset = frozenset(((0, 2), (6, 2)))
    light: frozenset = frozenset((x, 2) for x in LIGHT_X)
    heavy: frozenset = frozenset((x, 1) for x in (1, 2, 3))
    start: tuple = (0, 2)
    goal: tuple = (6, 2)

LEVELS = (Level(),)

def opposite(floating):
    return 'H' if floating == 'L' else 'L'

def rules(state):
    # The two complete assignments always contain one FLOAT and one SINK.
    return {'L': 'FLOAT' if state.floating == 'L' else 'SINK',
            'H': 'FLOAT' if state.floating == 'H' else 'SINK'}

def terrain(level, position):
    if position in level.dry:
        return 'DRY'
    if position in level.light:
        return 'LIGHT'
    if position in level.heavy:
        return 'HEAVY'
    return 'WATER'

def walkable(level, position, floating):
    return position in level.dry or position in (level.light if floating == 'L' else level.heavy)

INITIAL_FLOATING = 'L'
PROBE_START = (0, 2)

@dataclass(frozen=True)
class State:
    floating: str = INITIAL_FLOATING

class Game:
    """A terrain laboratory: the cursor is not the player."""
    def __init__(self):
        self.level = 0
        self.title = True
        self.reset(False)

    @property
    def layout(self):
        return LEVELS[self.level]

    def reset(self, gate=True):
        self.state = State()
        self.probe = PROBE_START
        self.gate = gate
        self.event = 'ready'

    def update(self, held, edges):
        if self.gate:
            if not (held | edges) & KEYS:
                self.gate = False
            return
        if self.title:
            if 'SPACE' in edges:
                self.title = False
                self.gate = True
            return
        if 'Q' in edges:
            self.title = True
            self.gate = True
            return
        if 'R' in edges:
            self.reset()
            return
        if 'SPACE' in edges:
            self.state = replace(self.state, floating=opposite(self.state.floating))
            self.event = 'assignment'
            return
        for key in MOVEMENT_PRIORITY:
            if key in edges:
                dx, dy = DIRECTIONS[key]
                x, y = self.probe
                self.probe = (max(0, min(self.layout.width - 1, x + dx)),
                              max(0, min(self.layout.height - 1, y + dy)))
                self.event = 'probe'
                break

class App:
    """Turn sampled keys into new edges; drawing cannot change the model."""
    def __init__(self):
        self.game = Game()
        self.previous = set()

    def feed(self, held):
        held = set(held)
        edges = held - self.previous
        self.previous = held
        self.game.update(held, edges)

    def draw(self, p):
        g = self.game
        level, state = g.layout, g.state
        editing = getattr(g, 'editing', False)
        paused = getattr(g, 'paused', False)
        p.cls(1)
        p.text(16, 12, '022 WORD BRIDGE / STAGE ' + str(STAGE), 10)
        p.text(16, 27, 'LAYOUT ' + 'ABC'[g.level] + ' / ' + STAGE_TITLE, 7)
        p.text(16, 45, 'L = LIGHT / H = HEAVY / S = START / G = GOAL', 6)
        cell, ox, oy = 36, (512 - level.width * 36) // 2, 70
        for y in range(level.height):
            for x in range(level.width):
                pos = (x, y)
                xx, yy = ox + x * cell, oy + y * cell
                p.rectb(xx, yy, cell, cell, 5)
                p.line(xx + 7, yy + 27, xx + 15, yy + 27, 5)
                if pos in level.dry:
                    p.rect(xx + 2, yy + 2, cell - 4, cell - 4, 4)
                    p.rectb(xx + 2, yy + 2, cell - 4, cell - 4, 9)
                    p.text(xx + 4, yy + 5, 'S' if pos == level.start else 'G' if pos == level.goal else 'ISLE', 10)
                elif pos in level.light | level.heavy:
                    category = 'L' if pos in level.light else 'H'
                    active = category == state.floating
                    color = 11 if category == 'L' else 15
                    if active:
                        p.rect(xx + 5, yy + 5, cell - 10, cell - 10, color)
                        p.text(xx + 15, yy + 14, category, 1)
                    else:
                        p.rectb(xx + 6, yy + 11, cell - 12, cell - 15, 5)
                        p.text(xx + 15, yy + 16, category, 6)
                    if editing:
                        if category == g.proposed:
                            for a in range(1, cell - 1, 4):
                                p.pset(xx + a, yy + 1, 10)
                                p.pset(xx + a, yy + cell - 2, 10)
                                p.pset(xx + 1, yy + a, 10)
                                p.pset(xx + cell - 2, yy + a, 10)
                        else:
                            p.text(xx + 26, yy + 3, 'v', 8)
        if STAGE == 1:
            x, y = g.probe
            xx, yy = ox + x * cell, oy + y * cell
            p.rectb(xx, yy, cell, cell, 7)
            p.rectb(xx + 1, yy + 1, cell - 2, cell - 2, 7)
            label = terrain(level, g.probe)
            allowed = walkable(level, g.probe, state.floating)
            p.text(16, 300, 'PROBE ' + str(g.probe) + ' / ' + label + ' / ' + ('WALKABLE' if allowed else 'BLOCKED'), 10)
        else:
            x, y = state.position
            xx, yy = ox + x * cell, oy + y * cell
            p.circ(xx + 18, yy + 17, 7, 8)
            p.pset(xx + 20, yy + 15, 7)
            p.rect(xx + 24, yy + 19, 6, 7, 10)
            p.text(16, 300, 'POS ' + str(state.position) + ' / MOVES ' + str(state.moves) + ' / CHANGES ' + str(state.changes), 7)
            if STAGE == 5:
                p.text(332, 300, 'HISTORY ' + str(len(g.history)), 6)
        current = rules(state)
        p.rectb(12, 319, 488, 62, 5)
        p.text(22, 329, 'CURRENT / L ' + current['L'] + ' / H ' + current['H'], 7)
        if editing:
            proposed = {'L': 'FLOAT' if g.proposed == 'L' else 'SINK',
                        'H': 'FLOAT' if g.proposed == 'H' else 'SINK'}
            p.text(22, 345, 'PROPOSED / L ' + proposed['L'] + ' / H ' + proposed['H'], 10)
            allowed = state.position in level.dry
            p.text(22, 363, 'DRY: CONFIRM ALLOWED' if allowed else 'ON STONE: CONFIRM WILL BE REJECTED', 11 if allowed else 8)
        else:
            p.text(22, 350, 'ONE FLOAT + ONE SINK / BOTH ROWS CHANGE TOGETHER', 6)
            p.text(22, 365, 'NO TIMER / NO LIVES / NO LANGUAGE MODEL', 6)
        status = 'PREVIEW ONLY: DOTS = WILL FLOAT / v = WILL SINK' if editing else EVENTS.get(g.event, g.event.upper())
        p.text(16, 395, status, 8 if g.event in ('bank', 'water', 'sunk') and not editing else 10)
        for i, line in enumerate(CONTROLS):
            p.text(16, 417 + i * 15, line, 7 if i == 0 else 6)
        if getattr(state, 'status', '') == 'success':
            p.rect(90, 130, 332, 74, 1)
            p.rectb(90, 130, 332, 74, 10)
            p.text(160, 148, 'DELIVERY COMPLETE', 10)
            p.text(108, 174, 'N NEXT / Z UNDO / R RETRY' if STAGE == 5 else 'R RETRY / Q TITLE / ESC QUIT', 7)
        if g.title:
            p.rect(40, 82, 432, 200, 1)
            p.rectb(40, 82, 432, 200, 10)
            lines = ['WORD BRIDGE / STAGE ' + str(STAGE), STAGE_TITLE,
                     'ARROWS INSPECT TILES; CURSOR IS NOT A PLAYER' if STAGE == 1 else 'WALK ONLY ON DRY LAND OR FLOATING STONES',
                     'TWO COMPLEMENTARY RULES: ONE FLOAT, ONE SINK',
                     'SPACE START / RELEASE BEFORE THE NEXT ACTION',
                     'LEFT RIGHT: CHOOSE A / B / C' if STAGE == 5 else 'THIS STAGE USES ONLY LAYOUT A',
                     'SAVE CODE, QUIT AND RERUN AFTER AN EDIT',
                     'R RESETS THE STATE; IT DOES NOT RELOAD CODE']
            for i, line in enumerate(lines):
                p.text(57, 102 + i * 22, line, 10 if i in (0, 4) else 7)
        if paused:
            p.rect(68, 144, 376, 75, 1)
            p.rectb(68, 144, 376, 75, 10)
            message = 'PAUSED STATE KEPT / SPACE START, THEN P RESUME' if g.title else 'PAUSED / RELEASE, PRESS P, RELEASE TO RESUME'
            p.text(88, 165, message, 10)
            p.text(88, 190, 'STATE AND HISTORY STAY UNCHANGED', 7)

def tap(app, key):
    app.feed({key})
    app.feed(set())

def snapshot(app):
    g = app.game
    result = {'stage': STAGE, 'level': g.level, 'state': asdict(g.state),
              'title': g.title, 'event': g.event, 'gate': g.gate,
              'scope': 'actual Pyxel Linux headless rendering with synthetic input'}
    for field in ('probe', 'editing', 'proposed', 'paused'):
        if hasattr(g, field):
            result[field] = getattr(g, field)
    if hasattr(g, 'history'):
        result['history'] = [asdict(state) for state in g.history]
    return result

def demo(app):
    tap(app, 'SPACE')
    if STAGE == 1:
        tap(app, 'RIGHT')
    elif STAGE == 2:
        tap(app, 'RIGHT')
        tap(app, 'RIGHT')
    elif STAGE == 3:
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'SPACE')
    elif STAGE == 4:
        tap(app, 'SPACE')
    else:
        tap(app, 'SPACE')
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'Z')

EVENTS = {'ready': 'READY', 'probe': 'INSPECTION ONLY', 'assignment': 'LAB ASSIGNMENT CHANGED',
          'move': 'MOVED ONE TILE', 'water': 'WATER OR OUTSIDE: STATE UNCHANGED',
          'sunk': 'SUNK STONE: STATE UNCHANGED', 'bank': 'SWAP REJECTED: STAND ON DRY LAND',
          'swap': 'BOTH RULES COMMITTED TOGETHER', 'success': 'DELIVERY COMPLETE',
          'invalid': 'INVALID ACTION OR RULE PAIR', 'terminal': 'ALREADY DELIVERED',
          'cancel': 'PREVIEW CANCELLED: STATE UNCHANGED', 'same': 'SAME ASSIGNMENT: STATE UNCHANGED',
          'undo': 'ONE ACCEPTED ACTION UNDONE'}

def main(headless=False, screenshot=None, state_json=None, checkpoint=False, case=None):
    import pyxel as p
    app = App()
    if case is not None:
        app.game.level = case
        app.game.reset(False)
    if checkpoint:
        demo(app)
    p.init(512, 480, title='022 Word Bridge / Stage ' + str(STAGE), fps=30,
           display_scale=1, headless=headless)
    keymap = {key: getattr(p, 'KEY_' + key) for key in KEYS}
    def update():
        if headless and p.frame_count >= 4:
            app.draw(p)
            if screenshot:
                p.screen.save(screenshot, 1)
            if state_json:
                with Path(state_json).open('x', encoding='utf-8') as stream:
                    json.dump(snapshot(app), stream, ensure_ascii=False, indent=2)
                    stream.write('\n')
            p.quit()
            return
        app.feed(set() if headless else {key for key, code in keymap.items() if p.btn(code)})
    p.run(update, lambda: app.draw(p))

if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser(description='Standalone Word Bridge teaching stage')
    parser.add_argument('--headless-smoke', action='store_true')
    parser.add_argument('--demo-checkpoint', action='store_true')
    parser.add_argument('--screenshot')
    parser.add_argument('--state-json')
    parser.add_argument('--case', choices=('A', 'B', 'C'))
    args = parser.parse_args()
    if (args.demo_checkpoint or args.screenshot is not None or args.state_json is not None or args.case) and not args.headless_smoke:
        parser.error('diagnostic options require --headless-smoke')
    if args.case and STAGE != 5:
        parser.error('--case is available only in stage 05')
    for field, suffix in (('screenshot', '.png'), ('state_json', '.json')):
        value = getattr(args, field)
        if value is not None:
            if not value.strip():
                parser.error('output path must not be empty')
            target = Path(value).absolute()
            if target.suffix.lower() != suffix or not target.parent.is_dir() or target.exists() or target.is_symlink():
                parser.error('output must be a new ' + suffix + ' in an existing directory')
            setattr(args, field, str(target))
    main(args.headless_smoke, args.screenshot, args.state_json, args.demo_checkpoint,
         'ABC'.index(args.case) if args.case else None)

# -*- coding: utf-8 -*-

# LICENSE.txt (unchanged text):
# 022 Word Bridge / ことばの橋
# Original code and pixel shapes: provided for the user's game project.
# Bundled Japanese bitmap glyphs were rendered from Noto Sans CJK Regular.
# Noto font data is licensed under SIL Open Font License 1.1.
# See assets/NOTO-LICENSE.txt for copyright and the complete license.
# Glyph generation: tools/build_font.py. Pillow is a development-only dependency.
# Runtime engine: Pyxel 2.9.9 (MIT license, installed separately by pip).
# No downloaded sprites, music, sound recordings, network services or LLM models.

# DISTRIBUTION_PERMISSION.txt (unchanged text):
# 022 ことばの橋：公開・教材配布の補足
# 記録日：2026年10月6日
# 
# この作品のコードと自作図形、および本講座用の段階教材は、プロジェクト所有者の承認に基づき、
# 「Pyxel入門 Pythonゲームの作り方」で学習・改造用のソース付き教材として配布しています。
# 教材をダウンロードし、内容を読んで学び、ご自身の制作のために変更して試すことができます。
# 
# 原納品物の LICENSE.txt は変更せずに同梱しています。
# この補足は今回の公開・教材配布と学習利用の許諾を記録するものであり、原LICENSEをMIT本文へ
# 置き換えたり、元からMITの記載があったものとして扱ったりするものではありません。
# 本作品と原作の権利表示を、ほかの作品の権利表示で上書きしないでください。
# 
# コード・図形と外部ライブラリー・字形データの条件は区別します。
# ・ゲームの図形は、Pyxelの矩形・線・円・三角形などで描いたものです。
# ・元の完成版の日本語字形はNoto Sans CJK Regular由来です。
#   SIL Open Font License 1.1の原文を assets/NOTO-LICENSE.txt に保持しています。
# ・Pyxelは別途インストールする外部ライブラリーです。Pyxel自身のライセンスが適用されます。
# ・段階教材の画面は標準ASCII描画を使い、Noto字形データの追加導入を必要としません。
# 
# 元コード・図形の提供に関する記載、外部由来の字形の著作権とライセンスは、原本のまま残しています。

"""022 Word Bridge: a standalone, incrementally runnable teaching stage.
Original notice: LICENSE.txt. Teaching distribution: DISTRIBUTION_PERMISSION.txt.
No image/font file is needed. Pyxel is imported only when the window starts.
"""
from dataclasses import dataclass, replace, asdict
from pathlib import Path
import json

STAGE = 2
STAGE_TITLE = 'SAFE GRID MOVEMENT'
CONTROLS = ['ARROWS MOVE ONE TILE / NO RULE SWAP IN STAGE 02', 'R RESET / Q TITLE / ESC QUIT / RELEASE EVERY KEY', 'STARTS WITH LIGHT FLOATING AS A MOVEMENT EXERCISE']
KEYS = {'UP', 'DOWN', 'LEFT', 'RIGHT', 'SPACE', 'R', 'Q'}

DIRECTIONS = {'UP': (0, -1), 'DOWN': (0, 1), 'LEFT': (-1, 0), 'RIGHT': (1, 0)}
MOVEMENT_PRIORITY = ('UP', 'DOWN', 'LEFT', 'RIGHT')
LIGHT_X = range(1, 6)

@dataclass(frozen=True)
class Level:
    width: int = 7
    height: int = 5
    dry: frozenset = frozenset(((0, 2), (6, 2)))
    light: frozenset = frozenset((x, 2) for x in LIGHT_X)
    heavy: frozenset = frozenset((x, 1) for x in (1, 2, 3))
    start: tuple = (0, 2)
    goal: tuple = (6, 2)

LEVELS = (Level(),)

def opposite(floating):
    return 'H' if floating == 'L' else 'L'

def rules(state):
    # The two complete assignments always contain one FLOAT and one SINK.
    return {'L': 'FLOAT' if state.floating == 'L' else 'SINK',
            'H': 'FLOAT' if state.floating == 'H' else 'SINK'}

def terrain(level, position):
    if position in level.dry:
        return 'DRY'
    if position in level.light:
        return 'LIGHT'
    if position in level.heavy:
        return 'HEAVY'
    return 'WATER'

def walkable(level, position, floating):
    return position in level.dry or position in (level.light if floating == 'L' else level.heavy)

INITIAL_FLOATING = 'L'

@dataclass(frozen=True)
class State:
    position: tuple
    floating: str
    moves: int = 0
    changes: int = 0
    status: str = 'playing'

@dataclass(frozen=True)
class Result:
    state: State
    event: str
    changed: bool = False

def initial(level):
    return State(level.start, INITIAL_FLOATING)

def transition(level, state, action):
    if state.status == 'success':
        return Result(state, 'terminal')
    if action not in DIRECTIONS:
        return Result(state, 'invalid')
    dx, dy = DIRECTIONS[action]
    destination = (state.position[0] + dx, state.position[1] + dy)
    if not walkable(level, destination, state.floating):
        event = 'sunk' if destination in level.light | level.heavy else 'water'
        return Result(state, event)
    end = destination == level.goal
    return Result(replace(state, position=destination, moves=state.moves + 1,
                          status='success' if end else 'playing'),
                  'success' if end else 'move', True)

class Game:
    def __init__(self):
        self.level = 0
        self.title = True
        self.reset(False)

    @property
    def layout(self):
        return LEVELS[self.level]

    def reset(self, gate=True):
        self.state = initial(self.layout)
        self.gate = gate
        self.event = 'ready'

    def act(self, action):
        result = transition(self.layout, self.state, action)
        self.event = result.event
        self.state = result.state
        if self.state.status == 'success':
            self.gate = True
        return result

    def update(self, held, edges):
        # Mode changes require an entirely neutral frame, including new edges.
        if self.gate:
            if not (held | edges) & KEYS:
                self.gate = False
            return
        if self.title:
            if 'SPACE' in edges:
                self.title = False
                self.gate = True
            return
        if 'Q' in edges:
            self.title = True
            self.gate = True
            return
        if 'R' in edges:
            self.reset()
            return
        if self.state.status == 'success':
            return
        for key in MOVEMENT_PRIORITY:
            if key in edges:
                self.act(key)
                break

class App:
    """Turn sampled keys into new edges; drawing cannot change the model."""
    def __init__(self):
        self.game = Game()
        self.previous = set()

    def feed(self, held):
        held = set(held)
        edges = held - self.previous
        self.previous = held
        self.game.update(held, edges)

    def draw(self, p):
        g = self.game
        level, state = g.layout, g.state
        editing = getattr(g, 'editing', False)
        paused = getattr(g, 'paused', False)
        p.cls(1)
        p.text(16, 12, '022 WORD BRIDGE / STAGE ' + str(STAGE), 10)
        p.text(16, 27, 'LAYOUT ' + 'ABC'[g.level] + ' / ' + STAGE_TITLE, 7)
        p.text(16, 45, 'L = LIGHT / H = HEAVY / S = START / G = GOAL', 6)
        cell, ox, oy = 36, (512 - level.width * 36) // 2, 70
        for y in range(level.height):
            for x in range(level.width):
                pos = (x, y)
                xx, yy = ox + x * cell, oy + y * cell
                p.rectb(xx, yy, cell, cell, 5)
                p.line(xx + 7, yy + 27, xx + 15, yy + 27, 5)
                if pos in level.dry:
                    p.rect(xx + 2, yy + 2, cell - 4, cell - 4, 4)
                    p.rectb(xx + 2, yy + 2, cell - 4, cell - 4, 9)
                    p.text(xx + 4, yy + 5, 'S' if pos == level.start else 'G' if pos == level.goal else 'ISLE', 10)
                elif pos in level.light | level.heavy:
                    category = 'L' if pos in level.light else 'H'
                    active = category == state.floating
                    color = 11 if category == 'L' else 15
                    if active:
                        p.rect(xx + 5, yy + 5, cell - 10, cell - 10, color)
                        p.text(xx + 15, yy + 14, category, 1)
                    else:
                        p.rectb(xx + 6, yy + 11, cell - 12, cell - 15, 5)
                        p.text(xx + 15, yy + 16, category, 6)
                    if editing:
                        if category == g.proposed:
                            for a in range(1, cell - 1, 4):
                                p.pset(xx + a, yy + 1, 10)
                                p.pset(xx + a, yy + cell - 2, 10)
                                p.pset(xx + 1, yy + a, 10)
                                p.pset(xx + cell - 2, yy + a, 10)
                        else:
                            p.text(xx + 26, yy + 3, 'v', 8)
        if STAGE == 1:
            x, y = g.probe
            xx, yy = ox + x * cell, oy + y * cell
            p.rectb(xx, yy, cell, cell, 7)
            p.rectb(xx + 1, yy + 1, cell - 2, cell - 2, 7)
            label = terrain(level, g.probe)
            allowed = walkable(level, g.probe, state.floating)
            p.text(16, 300, 'PROBE ' + str(g.probe) + ' / ' + label + ' / ' + ('WALKABLE' if allowed else 'BLOCKED'), 10)
        else:
            x, y = state.position
            xx, yy = ox + x * cell, oy + y * cell
            p.circ(xx + 18, yy + 17, 7, 8)
            p.pset(xx + 20, yy + 15, 7)
            p.rect(xx + 24, yy + 19, 6, 7, 10)
            p.text(16, 300, 'POS ' + str(state.position) + ' / MOVES ' + str(state.moves) + ' / CHANGES ' + str(state.changes), 7)
            if STAGE == 5:
                p.text(332, 300, 'HISTORY ' + str(len(g.history)), 6)
        current = rules(state)
        p.rectb(12, 319, 488, 62, 5)
        p.text(22, 329, 'CURRENT / L ' + current['L'] + ' / H ' + current['H'], 7)
        if editing:
            proposed = {'L': 'FLOAT' if g.proposed == 'L' else 'SINK',
                        'H': 'FLOAT' if g.proposed == 'H' else 'SINK'}
            p.text(22, 345, 'PROPOSED / L ' + proposed['L'] + ' / H ' + proposed['H'], 10)
            allowed = state.position in level.dry
            p.text(22, 363, 'DRY: CONFIRM ALLOWED' if allowed else 'ON STONE: CONFIRM WILL BE REJECTED', 11 if allowed else 8)
        else:
            p.text(22, 350, 'ONE FLOAT + ONE SINK / BOTH ROWS CHANGE TOGETHER', 6)
            p.text(22, 365, 'NO TIMER / NO LIVES / NO LANGUAGE MODEL', 6)
        status = 'PREVIEW ONLY: DOTS = WILL FLOAT / v = WILL SINK' if editing else EVENTS.get(g.event, g.event.upper())
        p.text(16, 395, status, 8 if g.event in ('bank', 'water', 'sunk') and not editing else 10)
        for i, line in enumerate(CONTROLS):
            p.text(16, 417 + i * 15, line, 7 if i == 0 else 6)
        if getattr(state, 'status', '') == 'success':
            p.rect(90, 130, 332, 74, 1)
            p.rectb(90, 130, 332, 74, 10)
            p.text(160, 148, 'DELIVERY COMPLETE', 10)
            p.text(108, 174, 'N NEXT / Z UNDO / R RETRY' if STAGE == 5 else 'R RETRY / Q TITLE / ESC QUIT', 7)
        if g.title:
            p.rect(40, 82, 432, 200, 1)
            p.rectb(40, 82, 432, 200, 10)
            lines = ['WORD BRIDGE / STAGE ' + str(STAGE), STAGE_TITLE,
                     'ARROWS INSPECT TILES; CURSOR IS NOT A PLAYER' if STAGE == 1 else 'WALK ONLY ON DRY LAND OR FLOATING STONES',
                     'TWO COMPLEMENTARY RULES: ONE FLOAT, ONE SINK',
                     'SPACE START / RELEASE BEFORE THE NEXT ACTION',
                     'LEFT RIGHT: CHOOSE A / B / C' if STAGE == 5 else 'THIS STAGE USES ONLY LAYOUT A',
                     'SAVE CODE, QUIT AND RERUN AFTER AN EDIT',
                     'R RESETS THE STATE; IT DOES NOT RELOAD CODE']
            for i, line in enumerate(lines):
                p.text(57, 102 + i * 22, line, 10 if i in (0, 4) else 7)
        if paused:
            p.rect(68, 144, 376, 75, 1)
            p.rectb(68, 144, 376, 75, 10)
            message = 'PAUSED STATE KEPT / SPACE START, THEN P RESUME' if g.title else 'PAUSED / RELEASE, PRESS P, RELEASE TO RESUME'
            p.text(88, 165, message, 10)
            p.text(88, 190, 'STATE AND HISTORY STAY UNCHANGED', 7)

def tap(app, key):
    app.feed({key})
    app.feed(set())

def snapshot(app):
    g = app.game
    result = {'stage': STAGE, 'level': g.level, 'state': asdict(g.state),
              'title': g.title, 'event': g.event, 'gate': g.gate,
              'scope': 'actual Pyxel Linux headless rendering with synthetic input'}
    for field in ('probe', 'editing', 'proposed', 'paused'):
        if hasattr(g, field):
            result[field] = getattr(g, field)
    if hasattr(g, 'history'):
        result['history'] = [asdict(state) for state in g.history]
    return result

def demo(app):
    tap(app, 'SPACE')
    if STAGE == 1:
        tap(app, 'RIGHT')
    elif STAGE == 2:
        tap(app, 'RIGHT')
        tap(app, 'RIGHT')
    elif STAGE == 3:
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'SPACE')
    elif STAGE == 4:
        tap(app, 'SPACE')
    else:
        tap(app, 'SPACE')
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'Z')

EVENTS = {'ready': 'READY', 'probe': 'INSPECTION ONLY', 'assignment': 'LAB ASSIGNMENT CHANGED',
          'move': 'MOVED ONE TILE', 'water': 'WATER OR OUTSIDE: STATE UNCHANGED',
          'sunk': 'SUNK STONE: STATE UNCHANGED', 'bank': 'SWAP REJECTED: STAND ON DRY LAND',
          'swap': 'BOTH RULES COMMITTED TOGETHER', 'success': 'DELIVERY COMPLETE',
          'invalid': 'INVALID ACTION OR RULE PAIR', 'terminal': 'ALREADY DELIVERED',
          'cancel': 'PREVIEW CANCELLED: STATE UNCHANGED', 'same': 'SAME ASSIGNMENT: STATE UNCHANGED',
          'undo': 'ONE ACCEPTED ACTION UNDONE'}

def main(headless=False, screenshot=None, state_json=None, checkpoint=False, case=None):
    import pyxel as p
    app = App()
    if case is not None:
        app.game.level = case
        app.game.reset(False)
    if checkpoint:
        demo(app)
    p.init(512, 480, title='022 Word Bridge / Stage ' + str(STAGE), fps=30,
           display_scale=1, headless=headless)
    keymap = {key: getattr(p, 'KEY_' + key) for key in KEYS}
    def update():
        if headless and p.frame_count >= 4:
            app.draw(p)
            if screenshot:
                p.screen.save(screenshot, 1)
            if state_json:
                with Path(state_json).open('x', encoding='utf-8') as stream:
                    json.dump(snapshot(app), stream, ensure_ascii=False, indent=2)
                    stream.write('\n')
            p.quit()
            return
        app.feed(set() if headless else {key for key, code in keymap.items() if p.btn(code)})
    p.run(update, lambda: app.draw(p))

if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser(description='Standalone Word Bridge teaching stage')
    parser.add_argument('--headless-smoke', action='store_true')
    parser.add_argument('--demo-checkpoint', action='store_true')
    parser.add_argument('--screenshot')
    parser.add_argument('--state-json')
    parser.add_argument('--case', choices=('A', 'B', 'C'))
    args = parser.parse_args()
    if (args.demo_checkpoint or args.screenshot is not None or args.state_json is not None or args.case) and not args.headless_smoke:
        parser.error('diagnostic options require --headless-smoke')
    if args.case and STAGE != 5:
        parser.error('--case is available only in stage 05')
    for field, suffix in (('screenshot', '.png'), ('state_json', '.json')):
        value = getattr(args, field)
        if value is not None:
            if not value.strip():
                parser.error('output path must not be empty')
            target = Path(value).absolute()
            if target.suffix.lower() != suffix or not target.parent.is_dir() or target.exists() or target.is_symlink():
                parser.error('output must be a new ' + suffix + ' in an existing directory')
            setattr(args, field, str(target))
    main(args.headless_smoke, args.screenshot, args.state_json, args.demo_checkpoint,
         'ABC'.index(args.case) if args.case else None)

# -*- coding: utf-8 -*-

# LICENSE.txt (unchanged text):
# 022 Word Bridge / ことばの橋
# Original code and pixel shapes: provided for the user's game project.
# Bundled Japanese bitmap glyphs were rendered from Noto Sans CJK Regular.
# Noto font data is licensed under SIL Open Font License 1.1.
# See assets/NOTO-LICENSE.txt for copyright and the complete license.
# Glyph generation: tools/build_font.py. Pillow is a development-only dependency.
# Runtime engine: Pyxel 2.9.9 (MIT license, installed separately by pip).
# No downloaded sprites, music, sound recordings, network services or LLM models.

# DISTRIBUTION_PERMISSION.txt (unchanged text):
# 022 ことばの橋：公開・教材配布の補足
# 記録日：2026年10月6日
# 
# この作品のコードと自作図形、および本講座用の段階教材は、プロジェクト所有者の承認に基づき、
# 「Pyxel入門 Pythonゲームの作り方」で学習・改造用のソース付き教材として配布しています。
# 教材をダウンロードし、内容を読んで学び、ご自身の制作のために変更して試すことができます。
# 
# 原納品物の LICENSE.txt は変更せずに同梱しています。
# この補足は今回の公開・教材配布と学習利用の許諾を記録するものであり、原LICENSEをMIT本文へ
# 置き換えたり、元からMITの記載があったものとして扱ったりするものではありません。
# 本作品と原作の権利表示を、ほかの作品の権利表示で上書きしないでください。
# 
# コード・図形と外部ライブラリー・字形データの条件は区別します。
# ・ゲームの図形は、Pyxelの矩形・線・円・三角形などで描いたものです。
# ・元の完成版の日本語字形はNoto Sans CJK Regular由来です。
#   SIL Open Font License 1.1の原文を assets/NOTO-LICENSE.txt に保持しています。
# ・Pyxelは別途インストールする外部ライブラリーです。Pyxel自身のライセンスが適用されます。
# ・段階教材の画面は標準ASCII描画を使い、Noto字形データの追加導入を必要としません。
# 
# 元コード・図形の提供に関する記載、外部由来の字形の著作権とライセンスは、原本のまま残しています。

"""022 Word Bridge: a standalone, incrementally runnable teaching stage.
Original notice: LICENSE.txt. Teaching distribution: DISTRIBUTION_PERMISSION.txt.
No image/font file is needed. Pyxel is imported only when the window starts.
"""
from dataclasses import dataclass, replace, asdict
from pathlib import Path
import json

STAGE = 3
STAGE_TITLE = 'ATOMIC SWAP ON DRY LAND'
CONTROLS = ['ARROWS MOVE / SPACE SWAP IMMEDIATELY ON DRY LAND', 'R RESET / Q TITLE / ESC QUIT / RELEASE EVERY KEY', 'ON A STONE, SPACE IS REJECTED WITH NO PENALTY']
KEYS = {'UP', 'DOWN', 'LEFT', 'RIGHT', 'SPACE', 'R', 'Q'}

DIRECTIONS = {'UP': (0, -1), 'DOWN': (0, 1), 'LEFT': (-1, 0), 'RIGHT': (1, 0)}
MOVEMENT_PRIORITY = ('UP', 'DOWN', 'LEFT', 'RIGHT')
LIGHT_X = range(1, 6)

@dataclass(frozen=True)
class Level:
    width: int = 7
    height: int = 5
    dry: frozenset = frozenset(((0, 2), (6, 2)))
    light: frozenset = frozenset((x, 2) for x in LIGHT_X)
    heavy: frozenset = frozenset((x, 1) for x in (1, 2, 3))
    start: tuple = (0, 2)
    goal: tuple = (6, 2)

LEVELS = (Level(),)

def opposite(floating):
    return 'H' if floating == 'L' else 'L'

def rules(state):
    # The two complete assignments always contain one FLOAT and one SINK.
    return {'L': 'FLOAT' if state.floating == 'L' else 'SINK',
            'H': 'FLOAT' if state.floating == 'H' else 'SINK'}

def terrain(level, position):
    if position in level.dry:
        return 'DRY'
    if position in level.light:
        return 'LIGHT'
    if position in level.heavy:
        return 'HEAVY'
    return 'WATER'

def walkable(level, position, floating):
    return position in level.dry or position in (level.light if floating == 'L' else level.heavy)

INITIAL_FLOATING = 'H'

@dataclass(frozen=True)
class State:
    position: tuple
    floating: str
    moves: int = 0
    changes: int = 0
    status: str = 'playing'

@dataclass(frozen=True)
class Result:
    state: State
    event: str
    changed: bool = False

def initial(level):
    return State(level.start, INITIAL_FLOATING)

def transition(level, state, action):
    if state.status == 'success':
        return Result(state, 'terminal')
    if action == 'SWAP':
        if state.position not in level.dry:
            return Result(state, 'bank')
        return Result(replace(state, floating=opposite(state.floating),
                              changes=state.changes + 1), 'swap', True)
    if action not in DIRECTIONS:
        return Result(state, 'invalid')
    dx, dy = DIRECTIONS[action]
    destination = (state.position[0] + dx, state.position[1] + dy)
    if not walkable(level, destination, state.floating):
        event = 'sunk' if destination in level.light | level.heavy else 'water'
        return Result(state, event)
    end = destination == level.goal
    return Result(replace(state, position=destination, moves=state.moves + 1,
                          status='success' if end else 'playing'),
                  'success' if end else 'move', True)

def apply_rules(level, state, light, heavy):
    if (light, heavy) not in (('FLOAT', 'SINK'), ('SINK', 'FLOAT')):
        return Result(state, 'invalid')
    target = 'L' if light == 'FLOAT' else 'H'
    if target == state.floating:
        return Result(state, 'same')
    return transition(level, state, 'SWAP')

class Game:
    def __init__(self):
        self.level = 0
        self.title = True
        self.reset(False)

    @property
    def layout(self):
        return LEVELS[self.level]

    def reset(self, gate=True):
        self.state = initial(self.layout)
        self.gate = gate
        self.event = 'ready'

    def act(self, action):
        result = transition(self.layout, self.state, action)
        self.event = result.event
        self.state = result.state
        if self.state.status == 'success':
            self.gate = True
        return result

    def update(self, held, edges):
        # Mode changes require an entirely neutral frame, including new edges.
        if self.gate:
            if not (held | edges) & KEYS:
                self.gate = False
            return
        if self.title:
            if 'SPACE' in edges:
                self.title = False
                self.gate = True
            return
        if 'Q' in edges:
            self.title = True
            self.gate = True
            return
        if 'R' in edges:
            self.reset()
            return
        if self.state.status == 'success':
            return
        if 'SPACE' in edges:
            self.act('SWAP')
            return
        for key in MOVEMENT_PRIORITY:
            if key in edges:
                self.act(key)
                break

class App:
    """Turn sampled keys into new edges; drawing cannot change the model."""
    def __init__(self):
        self.game = Game()
        self.previous = set()

    def feed(self, held):
        held = set(held)
        edges = held - self.previous
        self.previous = held
        self.game.update(held, edges)

    def draw(self, p):
        g = self.game
        level, state = g.layout, g.state
        editing = getattr(g, 'editing', False)
        paused = getattr(g, 'paused', False)
        p.cls(1)
        p.text(16, 12, '022 WORD BRIDGE / STAGE ' + str(STAGE), 10)
        p.text(16, 27, 'LAYOUT ' + 'ABC'[g.level] + ' / ' + STAGE_TITLE, 7)
        p.text(16, 45, 'L = LIGHT / H = HEAVY / S = START / G = GOAL', 6)
        cell, ox, oy = 36, (512 - level.width * 36) // 2, 70
        for y in range(level.height):
            for x in range(level.width):
                pos = (x, y)
                xx, yy = ox + x * cell, oy + y * cell
                p.rectb(xx, yy, cell, cell, 5)
                p.line(xx + 7, yy + 27, xx + 15, yy + 27, 5)
                if pos in level.dry:
                    p.rect(xx + 2, yy + 2, cell - 4, cell - 4, 4)
                    p.rectb(xx + 2, yy + 2, cell - 4, cell - 4, 9)
                    p.text(xx + 4, yy + 5, 'S' if pos == level.start else 'G' if pos == level.goal else 'ISLE', 10)
                elif pos in level.light | level.heavy:
                    category = 'L' if pos in level.light else 'H'
                    active = category == state.floating
                    color = 11 if category == 'L' else 15
                    if active:
                        p.rect(xx + 5, yy + 5, cell - 10, cell - 10, color)
                        p.text(xx + 15, yy + 14, category, 1)
                    else:
                        p.rectb(xx + 6, yy + 11, cell - 12, cell - 15, 5)
                        p.text(xx + 15, yy + 16, category, 6)
                    if editing:
                        if category == g.proposed:
                            for a in range(1, cell - 1, 4):
                                p.pset(xx + a, yy + 1, 10)
                                p.pset(xx + a, yy + cell - 2, 10)
                                p.pset(xx + 1, yy + a, 10)
                                p.pset(xx + cell - 2, yy + a, 10)
                        else:
                            p.text(xx + 26, yy + 3, 'v', 8)
        if STAGE == 1:
            x, y = g.probe
            xx, yy = ox + x * cell, oy + y * cell
            p.rectb(xx, yy, cell, cell, 7)
            p.rectb(xx + 1, yy + 1, cell - 2, cell - 2, 7)
            label = terrain(level, g.probe)
            allowed = walkable(level, g.probe, state.floating)
            p.text(16, 300, 'PROBE ' + str(g.probe) + ' / ' + label + ' / ' + ('WALKABLE' if allowed else 'BLOCKED'), 10)
        else:
            x, y = state.position
            xx, yy = ox + x * cell, oy + y * cell
            p.circ(xx + 18, yy + 17, 7, 8)
            p.pset(xx + 20, yy + 15, 7)
            p.rect(xx + 24, yy + 19, 6, 7, 10)
            p.text(16, 300, 'POS ' + str(state.position) + ' / MOVES ' + str(state.moves) + ' / CHANGES ' + str(state.changes), 7)
            if STAGE == 5:
                p.text(332, 300, 'HISTORY ' + str(len(g.history)), 6)
        current = rules(state)
        p.rectb(12, 319, 488, 62, 5)
        p.text(22, 329, 'CURRENT / L ' + current['L'] + ' / H ' + current['H'], 7)
        if editing:
            proposed = {'L': 'FLOAT' if g.proposed == 'L' else 'SINK',
                        'H': 'FLOAT' if g.proposed == 'H' else 'SINK'}
            p.text(22, 345, 'PROPOSED / L ' + proposed['L'] + ' / H ' + proposed['H'], 10)
            allowed = state.position in level.dry
            p.text(22, 363, 'DRY: CONFIRM ALLOWED' if allowed else 'ON STONE: CONFIRM WILL BE REJECTED', 11 if allowed else 8)
        else:
            p.text(22, 350, 'ONE FLOAT + ONE SINK / BOTH ROWS CHANGE TOGETHER', 6)
            p.text(22, 365, 'NO TIMER / NO LIVES / NO LANGUAGE MODEL', 6)
        status = 'PREVIEW ONLY: DOTS = WILL FLOAT / v = WILL SINK' if editing else EVENTS.get(g.event, g.event.upper())
        p.text(16, 395, status, 8 if g.event in ('bank', 'water', 'sunk') and not editing else 10)
        for i, line in enumerate(CONTROLS):
            p.text(16, 417 + i * 15, line, 7 if i == 0 else 6)
        if getattr(state, 'status', '') == 'success':
            p.rect(90, 130, 332, 74, 1)
            p.rectb(90, 130, 332, 74, 10)
            p.text(160, 148, 'DELIVERY COMPLETE', 10)
            p.text(108, 174, 'N NEXT / Z UNDO / R RETRY' if STAGE == 5 else 'R RETRY / Q TITLE / ESC QUIT', 7)
        if g.title:
            p.rect(40, 82, 432, 200, 1)
            p.rectb(40, 82, 432, 200, 10)
            lines = ['WORD BRIDGE / STAGE ' + str(STAGE), STAGE_TITLE,
                     'ARROWS INSPECT TILES; CURSOR IS NOT A PLAYER' if STAGE == 1 else 'WALK ONLY ON DRY LAND OR FLOATING STONES',
                     'TWO COMPLEMENTARY RULES: ONE FLOAT, ONE SINK',
                     'SPACE START / RELEASE BEFORE THE NEXT ACTION',
                     'LEFT RIGHT: CHOOSE A / B / C' if STAGE == 5 else 'THIS STAGE USES ONLY LAYOUT A',
                     'SAVE CODE, QUIT AND RERUN AFTER AN EDIT',
                     'R RESETS THE STATE; IT DOES NOT RELOAD CODE']
            for i, line in enumerate(lines):
                p.text(57, 102 + i * 22, line, 10 if i in (0, 4) else 7)
        if paused:
            p.rect(68, 144, 376, 75, 1)
            p.rectb(68, 144, 376, 75, 10)
            message = 'PAUSED STATE KEPT / SPACE START, THEN P RESUME' if g.title else 'PAUSED / RELEASE, PRESS P, RELEASE TO RESUME'
            p.text(88, 165, message, 10)
            p.text(88, 190, 'STATE AND HISTORY STAY UNCHANGED', 7)

def tap(app, key):
    app.feed({key})
    app.feed(set())

def snapshot(app):
    g = app.game
    result = {'stage': STAGE, 'level': g.level, 'state': asdict(g.state),
              'title': g.title, 'event': g.event, 'gate': g.gate,
              'scope': 'actual Pyxel Linux headless rendering with synthetic input'}
    for field in ('probe', 'editing', 'proposed', 'paused'):
        if hasattr(g, field):
            result[field] = getattr(g, field)
    if hasattr(g, 'history'):
        result['history'] = [asdict(state) for state in g.history]
    return result

def demo(app):
    tap(app, 'SPACE')
    if STAGE == 1:
        tap(app, 'RIGHT')
    elif STAGE == 2:
        tap(app, 'RIGHT')
        tap(app, 'RIGHT')
    elif STAGE == 3:
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'SPACE')
    elif STAGE == 4:
        tap(app, 'SPACE')
    else:
        tap(app, 'SPACE')
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'Z')

EVENTS = {'ready': 'READY', 'probe': 'INSPECTION ONLY', 'assignment': 'LAB ASSIGNMENT CHANGED',
          'move': 'MOVED ONE TILE', 'water': 'WATER OR OUTSIDE: STATE UNCHANGED',
          'sunk': 'SUNK STONE: STATE UNCHANGED', 'bank': 'SWAP REJECTED: STAND ON DRY LAND',
          'swap': 'BOTH RULES COMMITTED TOGETHER', 'success': 'DELIVERY COMPLETE',
          'invalid': 'INVALID ACTION OR RULE PAIR', 'terminal': 'ALREADY DELIVERED',
          'cancel': 'PREVIEW CANCELLED: STATE UNCHANGED', 'same': 'SAME ASSIGNMENT: STATE UNCHANGED',
          'undo': 'ONE ACCEPTED ACTION UNDONE'}

def main(headless=False, screenshot=None, state_json=None, checkpoint=False, case=None):
    import pyxel as p
    app = App()
    if case is not None:
        app.game.level = case
        app.game.reset(False)
    if checkpoint:
        demo(app)
    p.init(512, 480, title='022 Word Bridge / Stage ' + str(STAGE), fps=30,
           display_scale=1, headless=headless)
    keymap = {key: getattr(p, 'KEY_' + key) for key in KEYS}
    def update():
        if headless and p.frame_count >= 4:
            app.draw(p)
            if screenshot:
                p.screen.save(screenshot, 1)
            if state_json:
                with Path(state_json).open('x', encoding='utf-8') as stream:
                    json.dump(snapshot(app), stream, ensure_ascii=False, indent=2)
                    stream.write('\n')
            p.quit()
            return
        app.feed(set() if headless else {key for key, code in keymap.items() if p.btn(code)})
    p.run(update, lambda: app.draw(p))

if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser(description='Standalone Word Bridge teaching stage')
    parser.add_argument('--headless-smoke', action='store_true')
    parser.add_argument('--demo-checkpoint', action='store_true')
    parser.add_argument('--screenshot')
    parser.add_argument('--state-json')
    parser.add_argument('--case', choices=('A', 'B', 'C'))
    args = parser.parse_args()
    if (args.demo_checkpoint or args.screenshot is not None or args.state_json is not None or args.case) and not args.headless_smoke:
        parser.error('diagnostic options require --headless-smoke')
    if args.case and STAGE != 5:
        parser.error('--case is available only in stage 05')
    for field, suffix in (('screenshot', '.png'), ('state_json', '.json')):
        value = getattr(args, field)
        if value is not None:
            if not value.strip():
                parser.error('output path must not be empty')
            target = Path(value).absolute()
            if target.suffix.lower() != suffix or not target.parent.is_dir() or target.exists() or target.is_symlink():
                parser.error('output must be a new ' + suffix + ' in an existing directory')
            setattr(args, field, str(target))
    main(args.headless_smoke, args.screenshot, args.state_json, args.demo_checkpoint,
         'ABC'.index(args.case) if args.case else None)

# -*- coding: utf-8 -*-

# LICENSE.txt (unchanged text):
# 022 Word Bridge / ことばの橋
# Original code and pixel shapes: provided for the user's game project.
# Bundled Japanese bitmap glyphs were rendered from Noto Sans CJK Regular.
# Noto font data is licensed under SIL Open Font License 1.1.
# See assets/NOTO-LICENSE.txt for copyright and the complete license.
# Glyph generation: tools/build_font.py. Pillow is a development-only dependency.
# Runtime engine: Pyxel 2.9.9 (MIT license, installed separately by pip).
# No downloaded sprites, music, sound recordings, network services or LLM models.

# DISTRIBUTION_PERMISSION.txt (unchanged text):
# 022 ことばの橋：公開・教材配布の補足
# 記録日：2026年10月6日
# 
# この作品のコードと自作図形、および本講座用の段階教材は、プロジェクト所有者の承認に基づき、
# 「Pyxel入門 Pythonゲームの作り方」で学習・改造用のソース付き教材として配布しています。
# 教材をダウンロードし、内容を読んで学び、ご自身の制作のために変更して試すことができます。
# 
# 原納品物の LICENSE.txt は変更せずに同梱しています。
# この補足は今回の公開・教材配布と学習利用の許諾を記録するものであり、原LICENSEをMIT本文へ
# 置き換えたり、元からMITの記載があったものとして扱ったりするものではありません。
# 本作品と原作の権利表示を、ほかの作品の権利表示で上書きしないでください。
# 
# コード・図形と外部ライブラリー・字形データの条件は区別します。
# ・ゲームの図形は、Pyxelの矩形・線・円・三角形などで描いたものです。
# ・元の完成版の日本語字形はNoto Sans CJK Regular由来です。
#   SIL Open Font License 1.1の原文を assets/NOTO-LICENSE.txt に保持しています。
# ・Pyxelは別途インストールする外部ライブラリーです。Pyxel自身のライセンスが適用されます。
# ・段階教材の画面は標準ASCII描画を使い、Noto字形データの追加導入を必要としません。
# 
# 元コード・図形の提供に関する記載、外部由来の字形の著作権とライセンスは、原本のまま残しています。

"""022 Word Bridge: a standalone, incrementally runnable teaching stage.
Original notice: LICENSE.txt. Teaching distribution: DISTRIBUTION_PERMISSION.txt.
No image/font file is needed. Pyxel is imported only when the window starts.
"""
from dataclasses import dataclass, replace, asdict
from pathlib import Path
import json

STAGE = 4
STAGE_TITLE = 'PREVIEW / CONFIRM / CANCEL'
CONTROLS = ['ARROWS MOVE / SPACE PREVIEW, RELEASE, SPACE CONFIRM', 'Z CANCEL PREVIEW / R RESET / Q TITLE / ESC QUIT', 'RELEASE ALL KEYS AT EVERY MODE CHANGE']
KEYS = {'UP', 'DOWN', 'LEFT', 'RIGHT', 'SPACE', 'R', 'Q', 'Z'}

DIRECTIONS = {'UP': (0, -1), 'DOWN': (0, 1), 'LEFT': (-1, 0), 'RIGHT': (1, 0)}
MOVEMENT_PRIORITY = ('UP', 'DOWN', 'LEFT', 'RIGHT')
LIGHT_X = range(1, 6)

@dataclass(frozen=True)
class Level:
    width: int = 7
    height: int = 5
    dry: frozenset = frozenset(((0, 2), (6, 2)))
    light: frozenset = frozenset((x, 2) for x in LIGHT_X)
    heavy: frozenset = frozenset((x, 1) for x in (1, 2, 3))
    start: tuple = (0, 2)
    goal: tuple = (6, 2)

LEVELS = (Level(),)

def opposite(floating):
    return 'H' if floating == 'L' else 'L'

def rules(state):
    # The two complete assignments always contain one FLOAT and one SINK.
    return {'L': 'FLOAT' if state.floating == 'L' else 'SINK',
            'H': 'FLOAT' if state.floating == 'H' else 'SINK'}

def terrain(level, position):
    if position in level.dry:
        return 'DRY'
    if position in level.light:
        return 'LIGHT'
    if position in level.heavy:
        return 'HEAVY'
    return 'WATER'

def walkable(level, position, floating):
    return position in level.dry or position in (level.light if floating == 'L' else level.heavy)

INITIAL_FLOATING = 'H'

@dataclass(frozen=True)
class State:
    position: tuple
    floating: str
    moves: int = 0
    changes: int = 0
    status: str = 'playing'

@dataclass(frozen=True)
class Result:
    state: State
    event: str
    changed: bool = False

def initial(level):
    return State(level.start, INITIAL_FLOATING)

def transition(level, state, action):
    if state.status == 'success':
        return Result(state, 'terminal')
    if action == 'SWAP':
        if state.position not in level.dry:
            return Result(state, 'bank')
        return Result(replace(state, floating=opposite(state.floating),
                              changes=state.changes + 1), 'swap', True)
    if action not in DIRECTIONS:
        return Result(state, 'invalid')
    dx, dy = DIRECTIONS[action]
    destination = (state.position[0] + dx, state.position[1] + dy)
    if not walkable(level, destination, state.floating):
        event = 'sunk' if destination in level.light | level.heavy else 'water'
        return Result(state, event)
    end = destination == level.goal
    return Result(replace(state, position=destination, moves=state.moves + 1,
                          status='success' if end else 'playing'),
                  'success' if end else 'move', True)

def apply_rules(level, state, light, heavy):
    if (light, heavy) not in (('FLOAT', 'SINK'), ('SINK', 'FLOAT')):
        return Result(state, 'invalid')
    target = 'L' if light == 'FLOAT' else 'H'
    if target == state.floating:
        return Result(state, 'same')
    return transition(level, state, 'SWAP')

class Game:
    def __init__(self):
        self.level = 0
        self.title = True
        self.reset(False)

    @property
    def layout(self):
        return LEVELS[self.level]

    def reset(self, gate=True):
        self.state = initial(self.layout)
        self.gate = gate
        self.event = 'ready'
        self.editing = False
        self.proposed = self.state.floating

    def act(self, action):
        result = transition(self.layout, self.state, action)
        self.event = result.event
        self.state = result.state
        if self.state.status == 'success':
            self.gate = True
        return result

    def update(self, held, edges):
        # Mode changes require an entirely neutral frame, including new edges.
        if self.gate:
            if not (held | edges) & KEYS:
                self.gate = False
            return
        if self.title:
            if 'SPACE' in edges:
                self.title = False
                self.gate = True
            return
        if 'Q' in edges:
            self.title = True
            self.gate = True
            self.editing = False
            return
        if 'R' in edges:
            self.reset()
            return
        if self.state.status == 'success':
            return
        if self.editing:
            if 'Z' in edges:
                self.editing = False
                self.proposed = self.state.floating
                self.event = 'cancel'
                self.gate = True
            elif 'SPACE' in edges:
                cards = rules(State(self.state.position, self.proposed))
                result = apply_rules(self.layout, self.state, cards['L'], cards['H'])
                self.state = result.state
                self.event = result.event
                self.editing = False
                self.gate = True
            return
        if 'SPACE' in edges:
            self.editing = True
            self.proposed = opposite(self.state.floating)
            self.gate = True
            return
        for key in MOVEMENT_PRIORITY:
            if key in edges:
                self.act(key)
                break

class App:
    """Turn sampled keys into new edges; drawing cannot change the model."""
    def __init__(self):
        self.game = Game()
        self.previous = set()

    def feed(self, held):
        held = set(held)
        edges = held - self.previous
        self.previous = held
        self.game.update(held, edges)

    def draw(self, p):
        g = self.game
        level, state = g.layout, g.state
        editing = getattr(g, 'editing', False)
        paused = getattr(g, 'paused', False)
        p.cls(1)
        p.text(16, 12, '022 WORD BRIDGE / STAGE ' + str(STAGE), 10)
        p.text(16, 27, 'LAYOUT ' + 'ABC'[g.level] + ' / ' + STAGE_TITLE, 7)
        p.text(16, 45, 'L = LIGHT / H = HEAVY / S = START / G = GOAL', 6)
        cell, ox, oy = 36, (512 - level.width * 36) // 2, 70
        for y in range(level.height):
            for x in range(level.width):
                pos = (x, y)
                xx, yy = ox + x * cell, oy + y * cell
                p.rectb(xx, yy, cell, cell, 5)
                p.line(xx + 7, yy + 27, xx + 15, yy + 27, 5)
                if pos in level.dry:
                    p.rect(xx + 2, yy + 2, cell - 4, cell - 4, 4)
                    p.rectb(xx + 2, yy + 2, cell - 4, cell - 4, 9)
                    p.text(xx + 4, yy + 5, 'S' if pos == level.start else 'G' if pos == level.goal else 'ISLE', 10)
                elif pos in level.light | level.heavy:
                    category = 'L' if pos in level.light else 'H'
                    active = category == state.floating
                    color = 11 if category == 'L' else 15
                    if active:
                        p.rect(xx + 5, yy + 5, cell - 10, cell - 10, color)
                        p.text(xx + 15, yy + 14, category, 1)
                    else:
                        p.rectb(xx + 6, yy + 11, cell - 12, cell - 15, 5)
                        p.text(xx + 15, yy + 16, category, 6)
                    if editing:
                        if category == g.proposed:
                            for a in range(1, cell - 1, 4):
                                p.pset(xx + a, yy + 1, 10)
                                p.pset(xx + a, yy + cell - 2, 10)
                                p.pset(xx + 1, yy + a, 10)
                                p.pset(xx + cell - 2, yy + a, 10)
                        else:
                            p.text(xx + 26, yy + 3, 'v', 8)
        if STAGE == 1:
            x, y = g.probe
            xx, yy = ox + x * cell, oy + y * cell
            p.rectb(xx, yy, cell, cell, 7)
            p.rectb(xx + 1, yy + 1, cell - 2, cell - 2, 7)
            label = terrain(level, g.probe)
            allowed = walkable(level, g.probe, state.floating)
            p.text(16, 300, 'PROBE ' + str(g.probe) + ' / ' + label + ' / ' + ('WALKABLE' if allowed else 'BLOCKED'), 10)
        else:
            x, y = state.position
            xx, yy = ox + x * cell, oy + y * cell
            p.circ(xx + 18, yy + 17, 7, 8)
            p.pset(xx + 20, yy + 15, 7)
            p.rect(xx + 24, yy + 19, 6, 7, 10)
            p.text(16, 300, 'POS ' + str(state.position) + ' / MOVES ' + str(state.moves) + ' / CHANGES ' + str(state.changes), 7)
            if STAGE == 5:
                p.text(332, 300, 'HISTORY ' + str(len(g.history)), 6)
        current = rules(state)
        p.rectb(12, 319, 488, 62, 5)
        p.text(22, 329, 'CURRENT / L ' + current['L'] + ' / H ' + current['H'], 7)
        if editing:
            proposed = {'L': 'FLOAT' if g.proposed == 'L' else 'SINK',
                        'H': 'FLOAT' if g.proposed == 'H' else 'SINK'}
            p.text(22, 345, 'PROPOSED / L ' + proposed['L'] + ' / H ' + proposed['H'], 10)
            allowed = state.position in level.dry
            p.text(22, 363, 'DRY: CONFIRM ALLOWED' if allowed else 'ON STONE: CONFIRM WILL BE REJECTED', 11 if allowed else 8)
        else:
            p.text(22, 350, 'ONE FLOAT + ONE SINK / BOTH ROWS CHANGE TOGETHER', 6)
            p.text(22, 365, 'NO TIMER / NO LIVES / NO LANGUAGE MODEL', 6)
        status = 'PREVIEW ONLY: DOTS = WILL FLOAT / v = WILL SINK' if editing else EVENTS.get(g.event, g.event.upper())
        p.text(16, 395, status, 8 if g.event in ('bank', 'water', 'sunk') and not editing else 10)
        for i, line in enumerate(CONTROLS):
            p.text(16, 417 + i * 15, line, 7 if i == 0 else 6)
        if getattr(state, 'status', '') == 'success':
            p.rect(90, 130, 332, 74, 1)
            p.rectb(90, 130, 332, 74, 10)
            p.text(160, 148, 'DELIVERY COMPLETE', 10)
            p.text(108, 174, 'N NEXT / Z UNDO / R RETRY' if STAGE == 5 else 'R RETRY / Q TITLE / ESC QUIT', 7)
        if g.title:
            p.rect(40, 82, 432, 200, 1)
            p.rectb(40, 82, 432, 200, 10)
            lines = ['WORD BRIDGE / STAGE ' + str(STAGE), STAGE_TITLE,
                     'ARROWS INSPECT TILES; CURSOR IS NOT A PLAYER' if STAGE == 1 else 'WALK ONLY ON DRY LAND OR FLOATING STONES',
                     'TWO COMPLEMENTARY RULES: ONE FLOAT, ONE SINK',
                     'SPACE START / RELEASE BEFORE THE NEXT ACTION',
                     'LEFT RIGHT: CHOOSE A / B / C' if STAGE == 5 else 'THIS STAGE USES ONLY LAYOUT A',
                     'SAVE CODE, QUIT AND RERUN AFTER AN EDIT',
                     'R RESETS THE STATE; IT DOES NOT RELOAD CODE']
            for i, line in enumerate(lines):
                p.text(57, 102 + i * 22, line, 10 if i in (0, 4) else 7)
        if paused:
            p.rect(68, 144, 376, 75, 1)
            p.rectb(68, 144, 376, 75, 10)
            message = 'PAUSED STATE KEPT / SPACE START, THEN P RESUME' if g.title else 'PAUSED / RELEASE, PRESS P, RELEASE TO RESUME'
            p.text(88, 165, message, 10)
            p.text(88, 190, 'STATE AND HISTORY STAY UNCHANGED', 7)

def tap(app, key):
    app.feed({key})
    app.feed(set())

def snapshot(app):
    g = app.game
    result = {'stage': STAGE, 'level': g.level, 'state': asdict(g.state),
              'title': g.title, 'event': g.event, 'gate': g.gate,
              'scope': 'actual Pyxel Linux headless rendering with synthetic input'}
    for field in ('probe', 'editing', 'proposed', 'paused'):
        if hasattr(g, field):
            result[field] = getattr(g, field)
    if hasattr(g, 'history'):
        result['history'] = [asdict(state) for state in g.history]
    return result

def demo(app):
    tap(app, 'SPACE')
    if STAGE == 1:
        tap(app, 'RIGHT')
    elif STAGE == 2:
        tap(app, 'RIGHT')
        tap(app, 'RIGHT')
    elif STAGE == 3:
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'SPACE')
    elif STAGE == 4:
        tap(app, 'SPACE')
    else:
        tap(app, 'SPACE')
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'Z')

EVENTS = {'ready': 'READY', 'probe': 'INSPECTION ONLY', 'assignment': 'LAB ASSIGNMENT CHANGED',
          'move': 'MOVED ONE TILE', 'water': 'WATER OR OUTSIDE: STATE UNCHANGED',
          'sunk': 'SUNK STONE: STATE UNCHANGED', 'bank': 'SWAP REJECTED: STAND ON DRY LAND',
          'swap': 'BOTH RULES COMMITTED TOGETHER', 'success': 'DELIVERY COMPLETE',
          'invalid': 'INVALID ACTION OR RULE PAIR', 'terminal': 'ALREADY DELIVERED',
          'cancel': 'PREVIEW CANCELLED: STATE UNCHANGED', 'same': 'SAME ASSIGNMENT: STATE UNCHANGED',
          'undo': 'ONE ACCEPTED ACTION UNDONE'}

def main(headless=False, screenshot=None, state_json=None, checkpoint=False, case=None):
    import pyxel as p
    app = App()
    if case is not None:
        app.game.level = case
        app.game.reset(False)
    if checkpoint:
        demo(app)
    p.init(512, 480, title='022 Word Bridge / Stage ' + str(STAGE), fps=30,
           display_scale=1, headless=headless)
    keymap = {key: getattr(p, 'KEY_' + key) for key in KEYS}
    def update():
        if headless and p.frame_count >= 4:
            app.draw(p)
            if screenshot:
                p.screen.save(screenshot, 1)
            if state_json:
                with Path(state_json).open('x', encoding='utf-8') as stream:
                    json.dump(snapshot(app), stream, ensure_ascii=False, indent=2)
                    stream.write('\n')
            p.quit()
            return
        app.feed(set() if headless else {key for key, code in keymap.items() if p.btn(code)})
    p.run(update, lambda: app.draw(p))

if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser(description='Standalone Word Bridge teaching stage')
    parser.add_argument('--headless-smoke', action='store_true')
    parser.add_argument('--demo-checkpoint', action='store_true')
    parser.add_argument('--screenshot')
    parser.add_argument('--state-json')
    parser.add_argument('--case', choices=('A', 'B', 'C'))
    args = parser.parse_args()
    if (args.demo_checkpoint or args.screenshot is not None or args.state_json is not None or args.case) and not args.headless_smoke:
        parser.error('diagnostic options require --headless-smoke')
    if args.case and STAGE != 5:
        parser.error('--case is available only in stage 05')
    for field, suffix in (('screenshot', '.png'), ('state_json', '.json')):
        value = getattr(args, field)
        if value is not None:
            if not value.strip():
                parser.error('output path must not be empty')
            target = Path(value).absolute()
            if target.suffix.lower() != suffix or not target.parent.is_dir() or target.exists() or target.is_symlink():
                parser.error('output must be a new ' + suffix + ' in an existing directory')
            setattr(args, field, str(target))
    main(args.headless_smoke, args.screenshot, args.state_json, args.demo_checkpoint,
         'ABC'.index(args.case) if args.case else None)

# -*- coding: utf-8 -*-

# LICENSE.txt (unchanged text):
# 022 Word Bridge / ことばの橋
# Original code and pixel shapes: provided for the user's game project.
# Bundled Japanese bitmap glyphs were rendered from Noto Sans CJK Regular.
# Noto font data is licensed under SIL Open Font License 1.1.
# See assets/NOTO-LICENSE.txt for copyright and the complete license.
# Glyph generation: tools/build_font.py. Pillow is a development-only dependency.
# Runtime engine: Pyxel 2.9.9 (MIT license, installed separately by pip).
# No downloaded sprites, music, sound recordings, network services or LLM models.

# DISTRIBUTION_PERMISSION.txt (unchanged text):
# 022 ことばの橋：公開・教材配布の補足
# 記録日：2026年10月6日
# 
# この作品のコードと自作図形、および本講座用の段階教材は、プロジェクト所有者の承認に基づき、
# 「Pyxel入門 Pythonゲームの作り方」で学習・改造用のソース付き教材として配布しています。
# 教材をダウンロードし、内容を読んで学び、ご自身の制作のために変更して試すことができます。
# 
# 原納品物の LICENSE.txt は変更せずに同梱しています。
# この補足は今回の公開・教材配布と学習利用の許諾を記録するものであり、原LICENSEをMIT本文へ
# 置き換えたり、元からMITの記載があったものとして扱ったりするものではありません。
# 本作品と原作の権利表示を、ほかの作品の権利表示で上書きしないでください。
# 
# コード・図形と外部ライブラリー・字形データの条件は区別します。
# ・ゲームの図形は、Pyxelの矩形・線・円・三角形などで描いたものです。
# ・元の完成版の日本語字形はNoto Sans CJK Regular由来です。
#   SIL Open Font License 1.1の原文を assets/NOTO-LICENSE.txt に保持しています。
# ・Pyxelは別途インストールする外部ライブラリーです。Pyxel自身のライセンスが適用されます。
# ・段階教材の画面は標準ASCII描画を使い、Noto字形データの追加導入を必要としません。
# 
# 元コード・図形の提供に関する記載、外部由来の字形の著作権とライセンスは、原本のまま残しています。

"""022 Word Bridge: a standalone, incrementally runnable teaching stage.
Original notice: LICENSE.txt. Teaching distribution: DISTRIBUTION_PERMISSION.txt.
No image/font file is needed. Pyxel is imported only when the window starts.
"""
from dataclasses import dataclass, replace, asdict
from pathlib import Path
import json

STAGE = 5
STAGE_TITLE = 'UNDO AND THREE ORIGINAL LAYOUTS'
CONTROLS = ['ARROWS MOVE / SPACE PREVIEW, RELEASE, SPACE CONFIRM', 'Z CANCEL OR UNDO / R RESET / P PAUSE / Q TITLE', 'AFTER SUCCESS N NEXT / ESC QUIT / RELEASE ALL KEYS']

# Original pure model, retained verbatim below.
"""Finite, immutable river model. No renderer, clock, randomness, or network."""
from dataclasses import dataclass, replace, asdict
import hashlib, json

DIRECTIONS={'UP':(0,-1),'DOWN':(0,1),'LEFT':(-1,0),'RIGHT':(1,0)}
ACTIONS=tuple(DIRECTIONS)+('SWAP',)
REASONS={'ready':'荷物を旗まで届けよう','move':'浮いている石だけ歩ける',
 'water':'水には進めません','sunk':'その石は沈んでいます','bank':'陸で文を替えよう',
 'swap':'同じ印の石が、全部入れ替わった','success':'配達できた！','invalid':'その文は作れません',
 'terminal':'配達済みです','cancel':'文を替えずに戻りました','same':'文はそのまま','undo':'一手戻しました'}
@dataclass(frozen=True)
class Level:
    title:str
    width:int
    height:int
    dry:frozenset
    light:frozenset
    heavy:frozenset
    start:tuple
    goal:tuple
    floating:str
    def __post_init__(self):
        if self.floating not in ('L','H'):raise ValueError('unknown category')
        if self.dry&self.light or self.dry&self.heavy or self.light&self.heavy:raise ValueError('overlapping terrain')
        if self.start not in self.dry or self.goal not in self.dry:raise ValueError('endpoints must be dry')
        if self.start==self.goal:raise ValueError('endpoints must differ')
        if any(not(0<=x<self.width and 0<=y<self.height) for x,y in self.dry|self.light|self.heavy):raise ValueError('out of bounds')
@dataclass(frozen=True)
class State:
    position:tuple
    floating:str
    moves:int=0
    changes:int=0
    status:str='playing'
@dataclass(frozen=True)
class Result:
    state:State
    event:str
    changed:bool=False

LEVELS=(
 Level('短い文',7,5,frozenset(((0,2),(6,2))),frozenset((x,2) for x in range(1,6)),frozenset((x,1) for x in (1,2,3)),(0,2),(6,2),'H'),
 Level('中ほどの句点',7,5,frozenset(((0,2),(3,2),(6,2))),frozenset(((1,2),(2,2))),frozenset(((4,2),(5,2))),(0,2),(6,2),'L'),
 Level('近く見える継ぎ目',8,6,frozenset(((0,2),(2,4),(7,2))),frozenset(((1,2),(2,2),(3,2),(2,3))),frozenset(((4,2),(5,2),(6,2),(3,4),(4,4),(5,4),(6,4),(6,3))),(0,2),(7,2),'L'))

def initial(level):return State(level.start,level.floating)
def rules(state):return {'L':'FLOAT' if state.floating=='L' else 'SINK','H':'FLOAT' if state.floating=='H' else 'SINK'}
def walkable(level,position,floating):return position in level.dry or position in (level.light if floating=='L' else level.heavy)
def invariant(level,state):
    return state.floating in ('L','H') and walkable(level,state.position,state.floating) and state.status==('success' if state.position==level.goal else 'playing')
def transition(level,state,action):
    if state.status=='success':return Result(state,'terminal')
    if action=='SWAP':
        if state.position not in level.dry:return Result(state,'bank')
        return Result(replace(state,floating='H' if state.floating=='L' else 'L',changes=state.changes+1),'swap',True)
    if action not in DIRECTIONS:return Result(state,'invalid')
    dx,dy=DIRECTIONS[action];p=(state.position[0]+dx,state.position[1]+dy)
    if not walkable(level,p,state.floating):return Result(state,'sunk' if p in level.light|level.heavy else 'water')
    end=p==level.goal
    return Result(replace(state,position=p,moves=state.moves+1,status='success' if end else 'playing'),'success' if end else 'move',True)
def apply_rules(level,state,light,heavy):
    """Only two complete complementary assignments exist; reject malformed cards atomically."""
    if (light,heavy) not in (('FLOAT','SINK'),('SINK','FLOAT')):return Result(state,'invalid')
    target='L' if light=='FLOAT' else 'H'
    if target==state.floating:return Result(state,'same')
    return transition(level,state,'SWAP')
def state_hash(state):return hashlib.sha256(json.dumps(asdict(state),sort_keys=True,separators=(',',':')).encode('utf-8')).hexdigest()
def semantic(state):return state.position,state.floating,state.status

# Original controller, with only its module import removed.
"""Edge-only input controller. All mode changes gate actions until a neutral frame."""
KEYS={'UP','DOWN','LEFT','RIGHT','SPACE','Z','R','P','N','Q'}
class Game:
    def __init__(self):
        self.level=0;self.title=True;self.reset(False)
    @property
    def layout(self):return LEVELS[self.level]
    def reset(self,gate=True):
        self.state=initial(self.layout);self.history=[];self.editing=False;self.paused=False
        self.row=0;self.proposed=self.state.floating;self.gate=gate;self.event='ready'
    def act(self,action):
        r=transition(self.layout,self.state,action);self.event=r.event
        if r.changed:self.history.append(self.state);self.state=r.state
        if self.state.status=='success':self.gate=True
        return r
    def undo(self):
        if self.history:self.state=self.history.pop();self.event='undo'
        self.editing=False;self.proposed=self.state.floating;self.gate=True
    def update(self,held,edges):
        # Include both held and new edges: this catches adjacent-frame combinations.
        if self.gate:
            if not (held|edges)&KEYS:self.gate=False
            return
        if self.title:
            if 'LEFT' in edges:self.level=(self.level-1)%3;self.reset(False)
            elif 'RIGHT' in edges:self.level=(self.level+1)%3;self.reset(False)
            elif 'SPACE' in edges:self.title=False;self.gate=True
            return
        if 'Q' in edges:self.title=True;self.editing=False;self.gate=True;return
        if 'R' in edges:self.reset();return
        if 'P' in edges:self.paused=not self.paused;self.gate=True;return
        if self.paused:return
        if 'Z' in edges:
            if self.editing:self.editing=False;self.proposed=self.state.floating;self.gate=True;self.event='cancel'
            else:self.undo()
            return
        if self.state.status=='success':
            if 'N' in edges:self.level=(self.level+1)%3;self.reset()
            return
        if self.editing:
            if 'SPACE' in edges:
                if self.proposed!=self.state.floating:self.act('SWAP')
                else:self.event='same'
                self.editing=False;self.gate=True
            return
        if 'SPACE' in edges:
            self.editing=True;self.proposed='H' if self.state.floating=='L' else 'L';self.gate=True;return
        # At most one move per press. Simultaneous arrows have explicit priority.
        for key in ('UP','DOWN','LEFT','RIGHT'):
            if key in edges:self.act(key);break

class App:
    """Turn sampled keys into new edges; drawing cannot change the model."""
    def __init__(self):
        self.game = Game()
        self.previous = set()

    def feed(self, held):
        held = set(held)
        edges = held - self.previous
        self.previous = held
        self.game.update(held, edges)

    def draw(self, p):
        g = self.game
        level, state = g.layout, g.state
        editing = getattr(g, 'editing', False)
        paused = getattr(g, 'paused', False)
        p.cls(1)
        p.text(16, 12, '022 WORD BRIDGE / STAGE ' + str(STAGE), 10)
        p.text(16, 27, 'LAYOUT ' + 'ABC'[g.level] + ' / ' + STAGE_TITLE, 7)
        p.text(16, 45, 'L = LIGHT / H = HEAVY / S = START / G = GOAL', 6)
        cell, ox, oy = 36, (512 - level.width * 36) // 2, 70
        for y in range(level.height):
            for x in range(level.width):
                pos = (x, y)
                xx, yy = ox + x * cell, oy + y * cell
                p.rectb(xx, yy, cell, cell, 5)
                p.line(xx + 7, yy + 27, xx + 15, yy + 27, 5)
                if pos in level.dry:
                    p.rect(xx + 2, yy + 2, cell - 4, cell - 4, 4)
                    p.rectb(xx + 2, yy + 2, cell - 4, cell - 4, 9)
                    p.text(xx + 4, yy + 5, 'S' if pos == level.start else 'G' if pos == level.goal else 'ISLE', 10)
                elif pos in level.light | level.heavy:
                    category = 'L' if pos in level.light else 'H'
                    active = category == state.floating
                    color = 11 if category == 'L' else 15
                    if active:
                        p.rect(xx + 5, yy + 5, cell - 10, cell - 10, color)
                        p.text(xx + 15, yy + 14, category, 1)
                    else:
                        p.rectb(xx + 6, yy + 11, cell - 12, cell - 15, 5)
                        p.text(xx + 15, yy + 16, category, 6)
                    if editing:
                        if category == g.proposed:
                            for a in range(1, cell - 1, 4):
                                p.pset(xx + a, yy + 1, 10)
                                p.pset(xx + a, yy + cell - 2, 10)
                                p.pset(xx + 1, yy + a, 10)
                                p.pset(xx + cell - 2, yy + a, 10)
                        else:
                            p.text(xx + 26, yy + 3, 'v', 8)
        if STAGE == 1:
            x, y = g.probe
            xx, yy = ox + x * cell, oy + y * cell
            p.rectb(xx, yy, cell, cell, 7)
            p.rectb(xx + 1, yy + 1, cell - 2, cell - 2, 7)
            label = terrain(level, g.probe)
            allowed = walkable(level, g.probe, state.floating)
            p.text(16, 300, 'PROBE ' + str(g.probe) + ' / ' + label + ' / ' + ('WALKABLE' if allowed else 'BLOCKED'), 10)
        else:
            x, y = state.position
            xx, yy = ox + x * cell, oy + y * cell
            p.circ(xx + 18, yy + 17, 7, 8)
            p.pset(xx + 20, yy + 15, 7)
            p.rect(xx + 24, yy + 19, 6, 7, 10)
            p.text(16, 300, 'POS ' + str(state.position) + ' / MOVES ' + str(state.moves) + ' / CHANGES ' + str(state.changes), 7)
            if STAGE == 5:
                p.text(332, 300, 'HISTORY ' + str(len(g.history)), 6)
        current = rules(state)
        p.rectb(12, 319, 488, 62, 5)
        p.text(22, 329, 'CURRENT / L ' + current['L'] + ' / H ' + current['H'], 7)
        if editing:
            proposed = {'L': 'FLOAT' if g.proposed == 'L' else 'SINK',
                        'H': 'FLOAT' if g.proposed == 'H' else 'SINK'}
            p.text(22, 345, 'PROPOSED / L ' + proposed['L'] + ' / H ' + proposed['H'], 10)
            allowed = state.position in level.dry
            p.text(22, 363, 'DRY: CONFIRM ALLOWED' if allowed else 'ON STONE: CONFIRM WILL BE REJECTED', 11 if allowed else 8)
        else:
            p.text(22, 350, 'ONE FLOAT + ONE SINK / BOTH ROWS CHANGE TOGETHER', 6)
            p.text(22, 365, 'NO TIMER / NO LIVES / NO LANGUAGE MODEL', 6)
        status = 'PREVIEW ONLY: DOTS = WILL FLOAT / v = WILL SINK' if editing else EVENTS.get(g.event, g.event.upper())
        p.text(16, 395, status, 8 if g.event in ('bank', 'water', 'sunk') and not editing else 10)
        for i, line in enumerate(CONTROLS):
            p.text(16, 417 + i * 15, line, 7 if i == 0 else 6)
        if getattr(state, 'status', '') == 'success':
            p.rect(90, 130, 332, 74, 1)
            p.rectb(90, 130, 332, 74, 10)
            p.text(160, 148, 'DELIVERY COMPLETE', 10)
            p.text(108, 174, 'N NEXT / Z UNDO / R RETRY' if STAGE == 5 else 'R RETRY / Q TITLE / ESC QUIT', 7)
        if g.title:
            p.rect(40, 82, 432, 200, 1)
            p.rectb(40, 82, 432, 200, 10)
            lines = ['WORD BRIDGE / STAGE ' + str(STAGE), STAGE_TITLE,
                     'ARROWS INSPECT TILES; CURSOR IS NOT A PLAYER' if STAGE == 1 else 'WALK ONLY ON DRY LAND OR FLOATING STONES',
                     'TWO COMPLEMENTARY RULES: ONE FLOAT, ONE SINK',
                     'SPACE START / RELEASE BEFORE THE NEXT ACTION',
                     'LEFT RIGHT: CHOOSE A / B / C' if STAGE == 5 else 'THIS STAGE USES ONLY LAYOUT A',
                     'SAVE CODE, QUIT AND RERUN AFTER AN EDIT',
                     'R RESETS THE STATE; IT DOES NOT RELOAD CODE']
            for i, line in enumerate(lines):
                p.text(57, 102 + i * 22, line, 10 if i in (0, 4) else 7)
        if paused:
            p.rect(68, 144, 376, 75, 1)
            p.rectb(68, 144, 376, 75, 10)
            message = 'PAUSED STATE KEPT / SPACE START, THEN P RESUME' if g.title else 'PAUSED / RELEASE, PRESS P, RELEASE TO RESUME'
            p.text(88, 165, message, 10)
            p.text(88, 190, 'STATE AND HISTORY STAY UNCHANGED', 7)

def tap(app, key):
    app.feed({key})
    app.feed(set())

def snapshot(app):
    g = app.game
    result = {'stage': STAGE, 'level': g.level, 'state': asdict(g.state),
              'title': g.title, 'event': g.event, 'gate': g.gate,
              'scope': 'actual Pyxel Linux headless rendering with synthetic input'}
    for field in ('probe', 'editing', 'proposed', 'paused'):
        if hasattr(g, field):
            result[field] = getattr(g, field)
    if hasattr(g, 'history'):
        result['history'] = [asdict(state) for state in g.history]
    return result

def demo(app):
    tap(app, 'SPACE')
    if STAGE == 1:
        tap(app, 'RIGHT')
    elif STAGE == 2:
        tap(app, 'RIGHT')
        tap(app, 'RIGHT')
    elif STAGE == 3:
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'SPACE')
    elif STAGE == 4:
        tap(app, 'SPACE')
    else:
        tap(app, 'SPACE')
        tap(app, 'SPACE')
        tap(app, 'RIGHT')
        tap(app, 'Z')

EVENTS = {'ready': 'READY', 'probe': 'INSPECTION ONLY', 'assignment': 'LAB ASSIGNMENT CHANGED',
          'move': 'MOVED ONE TILE', 'water': 'WATER OR OUTSIDE: STATE UNCHANGED',
          'sunk': 'SUNK STONE: STATE UNCHANGED', 'bank': 'SWAP REJECTED: STAND ON DRY LAND',
          'swap': 'BOTH RULES COMMITTED TOGETHER', 'success': 'DELIVERY COMPLETE',
          'invalid': 'INVALID ACTION OR RULE PAIR', 'terminal': 'ALREADY DELIVERED',
          'cancel': 'PREVIEW CANCELLED: STATE UNCHANGED', 'same': 'SAME ASSIGNMENT: STATE UNCHANGED',
          'undo': 'ONE ACCEPTED ACTION UNDONE'}

def main(headless=False, screenshot=None, state_json=None, checkpoint=False, case=None):
    import pyxel as p
    app = App()
    if case is not None:
        app.game.level = case
        app.game.reset(False)
    if checkpoint:
        demo(app)
    p.init(512, 480, title='022 Word Bridge / Stage ' + str(STAGE), fps=30,
           display_scale=1, headless=headless)
    keymap = {key: getattr(p, 'KEY_' + key) for key in KEYS}
    def update():
        if headless and p.frame_count >= 4:
            app.draw(p)
            if screenshot:
                p.screen.save(screenshot, 1)
            if state_json:
                with Path(state_json).open('x', encoding='utf-8') as stream:
                    json.dump(snapshot(app), stream, ensure_ascii=False, indent=2)
                    stream.write('\n')
            p.quit()
            return
        app.feed(set() if headless else {key for key, code in keymap.items() if p.btn(code)})
    p.run(update, lambda: app.draw(p))

if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser(description='Standalone Word Bridge teaching stage')
    parser.add_argument('--headless-smoke', action='store_true')
    parser.add_argument('--demo-checkpoint', action='store_true')
    parser.add_argument('--screenshot')
    parser.add_argument('--state-json')
    parser.add_argument('--case', choices=('A', 'B', 'C'))
    args = parser.parse_args()
    if (args.demo_checkpoint or args.screenshot is not None or args.state_json is not None or args.case) and not args.headless_smoke:
        parser.error('diagnostic options require --headless-smoke')
    if args.case and STAGE != 5:
        parser.error('--case is available only in stage 05')
    for field, suffix in (('screenshot', '.png'), ('state_json', '.json')):
        value = getattr(args, field)
        if value is not None:
            if not value.strip():
                parser.error('output path must not be empty')
            target = Path(value).absolute()
            if target.suffix.lower() != suffix or not target.parent.is_dir() or target.exists() or target.is_symlink():
                parser.error('output must be a new ' + suffix + ' in an existing directory')
            setattr(args, field, str(target))
    main(args.headless_smoke, args.screenshot, args.state_json, args.demo_checkpoint,
         'ABC'.index(args.case) if args.case else None)