import { spawn, spawnSync } from 'node:child_process';
import { fileURLToPath } from 'node:url';
import { chromium } from 'playwright';
import {
  desktopBrowserContextOptions,
  desktopBrowserViewport
} from './desktop-browser-viewport.mjs';

const battleId = 'second-battle-yellow-turban-pursuit';
const renderer = process.env.VERIFY_BATTLE_KEYBOARD_RENDERER;
if (!renderer) {
  for (const requestedRenderer of ['canvas', 'webgl']) {
    const result = spawnSync(
      process.execPath,
      [fileURLToPath(import.meta.url)],
      {
        cwd: process.cwd(),
        env: {
          ...process.env,
          VERIFY_BATTLE_KEYBOARD_RENDERER: requestedRenderer
        },
        stdio: 'inherit'
      }
    );
    if (result.status !== 0) {
      process.exit(result.status ?? 1);
    }
  }
  process.exit(0);
}
assert(
  renderer === 'canvas' || renderer === 'webgl',
  `Unsupported renderer: ${renderer}`
);
const baseUrl =
  process.env.VERIFY_BATTLE_KEYBOARD_URL ??
  'http://127.0.0.1:41796/heros_web/';
const targetUrl = withDebugOptions(baseUrl, renderer);

let serverProcess;
let browser;

try {
  serverProcess = await ensureLocalServer(targetUrl);
  browser = await chromium.launch({
    headless: process.env.VERIFY_BATTLE_KEYBOARD_HEADLESS !== '0'
  });
  const context = await browser.newContext(desktopBrowserContextOptions);
  const page = await context.newPage();
  page.setDefaultTimeout(30000);

  const pageErrors = [];
  const consoleErrors = [];
  page.on('pageerror', (error) => pageErrors.push(error.stack ?? error.message));
  page.on('console', (message) => {
    if (message.type() === 'error') {
      consoleErrors.push(message.text());
    }
  });

  await page.goto(targetUrl, {
    waitUntil: 'domcontentloaded',
    timeout: 90000
  });
  await page.evaluate(() => window.localStorage.clear());
  await page.reload({
    waitUntil: 'domcontentloaded',
    timeout: 90000
  });
  await waitForDebugApi(page);
  await assertDesktopViewport(page);
  await assertRendererAndBasePath(page, renderer);

  await page.evaluate((requestedBattleId) => {
    window.__HEROS_DEBUG__?.goToBattle(requestedBattleId);
  }, battleId);
  await page.waitForFunction(
    (requestedBattleId) => {
      const battle = window.__HEROS_DEBUG__?.battle();
      return (
        battle?.battleId === requestedBattleId &&
        ['deployment', 'idle'].includes(battle.phase) &&
        battle.mapBackgroundReady === true &&
        (battle.phase === 'idle' ||
          ['ready', 'degraded'].includes(battle.combatAssets?.status))
      );
    },
    battleId,
    { timeout: 90000 }
  );

  await page.evaluate(() => {
    const scene = window.__HEROS_GAME__?.scene.getScene('BattleScene');
    if (scene?.phase === 'deployment') {
      scene.confirmPreBattleDeployment();
    }
  });
  await page.waitForFunction(
    (requestedBattleId) => {
      const battle = window.__HEROS_DEBUG__?.battle();
      return battle?.battleId === requestedBattleId && battle.phase === 'idle';
    },
    battleId,
    { timeout: 30000 }
  );

  const fixture = await page.evaluate(async () => {
    const scene = window.__HEROS_GAME__?.scene.getScene('BattleScene');
    const units = scene?.debugBattleUnits?.() ?? [];
    const unit = units.find(
      (candidate) =>
        candidate.id === 'liu-bei' &&
        candidate.faction === 'ally' &&
        candidate.hp > 0
    );
    if (!scene || !unit) {
      return null;
    }

    scene.hideBattleEventBanner();
    scene.hideTurnEndPrompt();
    scene.hideSaveSlotPanel();
    scene.hideMapMenu();
    scene.hideCommandMenu();
    scene.clearMarkers();
    scene.activeFaction = 'ally';
    scene.phase = 'idle';
    scene.selectedUnit = undefined;
    scene.pendingMove = undefined;
    scene.targetingAction = undefined;
    scene.selectedUsable = undefined;
    scene.actedUnitIds.clear();
    units
      .filter((candidate) => candidate.faction === 'ally' && candidate.hp > 0)
      .forEach((candidate) => {
        candidate.hp = candidate.maxHp;
      });
    scene.centerCameraOnTile(unit.x, unit.y);
    scene.selectUnit(unit);
    await scene.moveSelectedUnit(unit.x, unit.y);

    const recordPointerInput = () => {
      window.__HEROS_KEYBOARD_COMMAND_QA__.pointerInputCount += 1;
    };
    window.__HEROS_KEYBOARD_COMMAND_QA__ = {
      pointerInputCount: 0,
      recordPointerInput
    };
    window.addEventListener('mousedown', recordPointerInput, true);
    window.addEventListener('pointerdown', recordPointerInput, true);

    const state = window.__HEROS_DEBUG__?.battle();
    return {
      unitId: unit.id,
      unitTile: { x: unit.x, y: unit.y },
      pendingMove: state?.pendingMove ?? null,
      commandMenu: state?.commandMenuKeyboard ?? null
    };
  });

  assert(fixture, 'Expected the keyboard command fixture to select Liu Bei.');
  assert(
    fixture.pendingMove?.unitId === fixture.unitId,
    `Expected a preserved pending stay-in-place move: ${JSON.stringify(fixture)}`
  );
  assertCommandMenuFocus(fixture.commandMenu, 'command');
  assert(
    fixture.commandMenu.items.some(
      ({ id, available }) => id === 'attack' && available === false
    ),
    `Expected the distant attack command to be unavailable for skip QA: ${JSON.stringify(fixture.commandMenu)}`
  );
  assert(
    fixture.commandMenu.items.some(
      ({ id, available }) => id === 'strategy' && available
    ),
    `Expected Liu Bei to have an available strategy: ${JSON.stringify(fixture.commandMenu)}`
  );
  assert(
    fixture.commandMenu.focusedItem.id === 'strategy',
    `Default focus must skip unavailable attack and land on strategy: ${JSON.stringify(fixture.commandMenu)}`
  );

  await page.screenshot({
    path: `dist/verification-battle-keyboard-command-focus-${renderer}.png`,
    fullPage: true
  });

  const initialCommandFocus = fixture.commandMenu.focusedItem.id;
  const availableCommandIds = fixture.commandMenu.items
    .filter(({ available }) => available)
    .map(({ id }) => id);
  const previousCommandId =
    availableCommandIds[
      (availableCommandIds.indexOf(initialCommandFocus) -
        1 +
        availableCommandIds.length) %
        availableCommandIds.length
    ];

  await page.keyboard.press('Shift+Tab');
  let state = await readBattleState(page);
  assertCommandMenuFocus(state.commandMenuKeyboard, 'command');
  assert(
    state.commandMenuKeyboard.focusedItem.id === previousCommandId,
    `Shift+Tab must wrap to the previous available command: ${JSON.stringify(state.commandMenuKeyboard)}`
  );

  await page.keyboard.press('Tab');
  state = await readBattleState(page);
  assert(
    state.commandMenuKeyboard.focusedItem.id === initialCommandFocus,
    `Tab must wrap back to the initial command without visiting a disabled row: ${JSON.stringify(state.commandMenuKeyboard)}`
  );

  const visitedCommands = [];
  for (let index = 0; index < availableCommandIds.length; index += 1) {
    await page.keyboard.press('Tab');
    state = await readBattleState(page);
    assertCommandMenuFocus(state.commandMenuKeyboard, 'command');
    visitedCommands.push(state.commandMenuKeyboard.focusedItem.id);
  }
  assert(
    visitedCommands.at(-1) === initialCommandFocus &&
      visitedCommands.every((id) => availableCommandIds.includes(id)),
    `Command focus must wrap and skip every unavailable row: ${JSON.stringify({
      availableCommandIds,
      visitedCommands
    })}`
  );

  await focusMenuItem(page, 'strategy');
  const beforeUsable = await readBattleState(page);
  await page.keyboard.press('Enter');
  await page.waitForFunction(() => {
    const keyboard = window.__HEROS_DEBUG__?.battle()?.commandMenuKeyboard;
    return keyboard?.visible === true && keyboard.mode === 'usable';
  });

  state = await readBattleState(page);
  assertCommandMenuFocus(state.commandMenuKeyboard, 'usable');
  assert(
    state.selectedUnitId === fixture.unitId &&
      state.pendingMove?.unitId === fixture.unitId &&
      state.commandMenuKeyboard.parentCommand === 'strategy',
    `Entering the usable menu must preserve unit and pending move: ${JSON.stringify(state)}`
  );
  assert(
    state.commandMenuKeyboard.items.some(({ available }) => !available) &&
      state.commandMenuKeyboard.focusedItem.available === true,
    `Usable default focus must skip an unavailable full-HP heal: ${JSON.stringify(state.commandMenuKeyboard)}`
  );
  assert(
    !state.commandMenuKeyboard.items.find(
      ({ id }) => id === state.commandMenuKeyboard.focusedItem.id
    )?.available === false,
    `Usable focus landed on an unavailable item: ${JSON.stringify(state.commandMenuKeyboard)}`
  );

  await page.keyboard.press('Shift+Tab');
  state = await readBattleState(page);
  assertCommandMenuFocus(state.commandMenuKeyboard, 'usable');
  assert(
    state.commandMenuKeyboard.focusedItem.available === true,
    `Usable Shift+Tab must skip unavailable rows: ${JSON.stringify(state.commandMenuKeyboard)}`
  );

  await page.screenshot({
    path: `dist/verification-battle-keyboard-usable-focus-${renderer}.png`,
    fullPage: true
  });

  await page.keyboard.press('Escape');
  await page.waitForFunction(() => {
    const keyboard = window.__HEROS_DEBUG__?.battle()?.commandMenuKeyboard;
    return (
      keyboard?.visible === true &&
      keyboard.mode === 'command' &&
      keyboard.focusedItem?.id === 'strategy'
    );
  });
  state = await readBattleState(page);
  assertCommandMenuFocus(state.commandMenuKeyboard, 'command');
  assert(
    state.selectedUnitId === fixture.unitId &&
      state.pendingMove?.unitId === fixture.unitId &&
      state.pendingMove.toX === beforeUsable.pendingMove.toX &&
      state.pendingMove.toY === beforeUsable.pendingMove.toY,
    `Esc must return one level without clearing selection or pending move: ${JSON.stringify(state)}`
  );

  await focusMenuItem(page, 'wait');
  await page.keyboard.press('Enter');
  await page.waitForFunction(
    (unitId) => {
      const battle = window.__HEROS_DEBUG__?.battle();
      return (
        battle?.commandMenuKeyboard?.visible === false &&
        battle?.actedUnitIds?.includes(unitId)
      );
    },
    fixture.unitId
  );

  const completed = await page.evaluate((unitId) => {
    const state = window.__HEROS_DEBUG__?.battle();
    const qa = window.__HEROS_KEYBOARD_COMMAND_QA__;
    if (qa?.recordPointerInput) {
      window.removeEventListener('mousedown', qa.recordPointerInput, true);
      window.removeEventListener('pointerdown', qa.recordPointerInput, true);
    }
    return {
      selectedUnitId: state?.selectedUnitId ?? null,
      pendingMove: state?.pendingMove ?? null,
      acted: state?.actedUnitIds?.includes(unitId) ?? false,
      commandMenu: state?.commandMenuKeyboard ?? null,
      pointerInputCount: qa?.pointerInputCount ?? -1
    };
  }, fixture.unitId);
  assert(
    completed.acted &&
      completed.pendingMove === null &&
      completed.commandMenu?.visible === false,
    `Keyboard Enter on wait must complete exactly one unit action: ${JSON.stringify(completed)}`
  );
  assert(
    completed.pointerInputCount === 0,
    `The command action cycle emitted mouse/pointer input after setup: ${JSON.stringify(completed)}`
  );
  assert(
    pageErrors.length === 0,
    `Unexpected browser errors: ${JSON.stringify(pageErrors.slice(-5))}`
  );
  assert(
    consoleErrors.length === 0,
    `Unexpected console errors: ${JSON.stringify(consoleErrors.slice(-5))}`
  );

  console.log(
    `Verified ${renderer} keyboard-only battle command flow at ${desktopBrowserViewport.width}x${desktopBrowserViewport.height} DPR1 under /heros_web/: ` +
      'default focus skips disabled commands, Tab and Shift+Tab wrap available rows, Enter opens strategy, ' +
      'usable focus skips unavailable choices, Esc preserves the selected unit and pending move, and Enter completes wait with zero mouse input.'
  );
} finally {
  await browser?.close();
  await stopServerProcess(serverProcess);
}

function withDebugOptions(url, requestedRenderer) {
  const parsed = new URL(url);
  parsed.searchParams.set('debug', '1');
  parsed.searchParams.set('renderer', requestedRenderer);
  parsed.searchParams.set('debugCombatAssetWatchdogMs', '250');
  return parsed.toString();
}

async function focusMenuItem(page, expectedId) {
  for (let attempt = 0; attempt < 8; attempt += 1) {
    const keyboard = await page.evaluate(
      () => window.__HEROS_DEBUG__?.battle()?.commandMenuKeyboard
    );
    assertCommandMenuFocus(keyboard, keyboard?.mode);
    if (keyboard.focusedItem.id === expectedId) {
      return;
    }
    const target = keyboard.items.find(({ id }) => id === expectedId);
    assert(
      target?.available,
      `Expected ${expectedId} to be keyboard-selectable: ${JSON.stringify(keyboard)}`
    );
    await page.keyboard.press('Tab');
  }
  throw new Error(`Could not focus command menu item ${expectedId}.`);
}

function assertCommandMenuFocus(keyboard, expectedMode) {
  assert(
    keyboard?.visible === true &&
      keyboard.mode === expectedMode &&
      keyboard.focusedItem?.available === true &&
      keyboard.focusedItem.bounds &&
      keyboard.focusedItem.lineWidth >= 3 &&
      keyboard.focusMarker?.visible === true &&
      keyboard.focusMarker.text === '▶' &&
      keyboard.focusMarker.bounds &&
      boundsInside(keyboard.focusMarker.bounds, keyboard.focusedItem.bounds) &&
      keyboard.guidance?.text.includes('↑↓/Tab') &&
      keyboard.guidance.text.includes('Enter') &&
      keyboard.guidance.text.includes('Esc') &&
      boundsInsideViewport(keyboard.guidance.bounds),
    `Expected one visible non-color keyboard focus and on-screen controls guidance: ${JSON.stringify(keyboard)}`
  );
  assert(
    keyboard.items.filter(({ focused }) => focused).length === 1,
    `Expected exactly one focused menu item: ${JSON.stringify(keyboard)}`
  );
}

async function readBattleState(page) {
  return page.evaluate(() => window.__HEROS_DEBUG__?.battle());
}

function boundsInside(inner, outer) {
  return (
    inner.x >= outer.x - 1 &&
    inner.y >= outer.y - 1 &&
    inner.x + inner.width <= outer.x + outer.width + 1 &&
    inner.y + inner.height <= outer.y + outer.height + 1
  );
}

function boundsInsideViewport(bounds) {
  return (
    bounds &&
    bounds.x >= 0 &&
    bounds.y >= 0 &&
    bounds.x + bounds.width <= desktopBrowserViewport.width &&
    bounds.y + bounds.height <= desktopBrowserViewport.height
  );
}

async function waitForDebugApi(page) {
  await page.waitForFunction(
    () =>
      Boolean(
        window.__HEROS_DEBUG__?.activeScenes &&
          window.__HEROS_DEBUG__?.goToBattle
      ),
    undefined,
    { timeout: 90000 }
  );
}

async function assertDesktopViewport(page) {
  const viewport = await page.evaluate(() => {
    const canvas = document.querySelector('canvas');
    return {
      width: window.innerWidth,
      height: window.innerHeight,
      dpr: window.devicePixelRatio,
      zoom: window.visualViewport?.scale ?? 1,
      canvas: canvas
        ? { width: canvas.width, height: canvas.height }
        : null
    };
  });
  assert(
    viewport.width === desktopBrowserViewport.width &&
      viewport.height === desktopBrowserViewport.height &&
      viewport.dpr === 1 &&
      viewport.zoom === 1 &&
      viewport.canvas?.width === desktopBrowserViewport.width &&
      viewport.canvas?.height === desktopBrowserViewport.height,
    `Expected explicit 1920x1080 CSS viewport, 100% zoom, and DPR1: ${JSON.stringify(viewport)}`
  );
}

async function assertRendererAndBasePath(page, requestedRenderer) {
  const runtime = await page.evaluate(() => ({
    pathname: window.location.pathname,
    rendererType: window.__HEROS_GAME__?.renderer?.type ?? null,
    rendererName:
      window.__HEROS_GAME__?.renderer?.constructor?.name ?? null
  }));
  const expectedRendererType = requestedRenderer === 'canvas' ? 1 : 2;
  assert(
    runtime.pathname === '/heros_web/' &&
      runtime.rendererType === expectedRendererType,
    `Expected ${requestedRenderer} under /heros_web/: ${JSON.stringify(runtime)}`
  );
}

async function ensureLocalServer(url) {
  if (await canReach(url)) {
    return undefined;
  }

  const parsed = new URL(url);
  if (!['localhost', '127.0.0.1', '0.0.0.0'].includes(parsed.hostname)) {
    throw new Error(`No server responded at ${url}`);
  }

  const stderr = [];
  const child = spawn(
    process.execPath,
    [
      'node_modules/vite/bin/vite.js',
      '--host',
      '127.0.0.1',
      '--port',
      parsed.port || '41796',
      '--strictPort'
    ],
    {
      cwd: process.cwd(),
      env: process.env,
      stdio: ['ignore', 'pipe', 'pipe']
    }
  );
  child.stderr.on('data', (chunk) => stderr.push(chunk.toString()));
  child.stdout.on('data', () => {});

  for (let attempt = 0; attempt < 120; attempt += 1) {
    if (await canReach(url)) {
      return child;
    }
    await delay(250);
  }

  await stopServerProcess(child);
  throw new Error(
    `Vite server did not start at ${url}\n${stderr.join('')}`
  );
}

async function canReach(url) {
  try {
    const response = await fetch(url, {
      signal: AbortSignal.timeout(1000)
    });
    return response.ok;
  } catch {
    return false;
  }
}

function delay(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

async function stopServerProcess(child) {
  if (!child || child.exitCode !== null) {
    return;
  }

  const exited = new Promise((resolve) => {
    child.once('exit', resolve);
  });
  child.kill();
  await Promise.race([exited, delay(5000)]);
  if (child.exitCode === null) {
    child.kill('SIGKILL');
    await Promise.race([exited, delay(2000)]);
  }
}

function assert(condition, message) {
  if (!condition) {
    throw new Error(message);
  }
}