/* ============================================================
 * Diablo2D — main.js : bootstrap & game loop
 * ============================================================ */
'use strict';
window.D2 = window.D2 || {};
(function (D2) {

  let lastT = 0;
  let hudRefreshT = 0;
  const G = D2.game;

  /* ---------------- pause ---------------- */

  function togglePause() {
    const overlay = document.getElementById('pause-overlay');
    if (G.state === 'playing') {
      G.state = 'paused';
      overlay.classList.remove('hidden');
      D2.audio.stopMusic(0.3);
    } else if (G.state === 'paused') {
      G.state = 'playing';
      overlay.classList.add('hidden');
      if (G.world) D2.audio.playMusic(G.world.isTown ? 'town' : (G.world.isBossLair ? 'boss' : G.world.theme.music));
    }
  }

  function exitToTitle() {
    G.saveGame();
    G.state = 'title';
    document.getElementById('pause-overlay').classList.add('hidden');
    D2.ui.closeAllPanels();
    D2.ui.hideHud();
    D2.ui.showTitle();
  }

  function openHelpInGame() {
    G.state = 'paused';
    document.getElementById('pause-overlay').classList.add('hidden');
    D2.ui.showHelp(() => {
      if (G.player && !G.player.dead) {
        G.state = 'playing';
        D2.ui.hideScreens();
      } else {
        D2.ui.showTitle();
      }
    });
  }

  /* ---------------- boot ---------------- */

  function boot() {
    /* load persisted settings before anything uses them */
    const savedSettings = D2.save.get(D2.save.KEY.SETTINGS);
    if (savedSettings) Object.assign(G.settings, savedSettings);
    D2.i18n.setLang(G.settings.lang);

    const canvas = document.getElementById('game-canvas');
    D2.render.init(canvas);
    D2.input.init(canvas);
    D2.audio.playMusic('title');   // becomes pending until first gesture

    /* staged loading for the progress bar feel */
    D2.ui.showLoading();
    const steps = [
      ['Carving tiles…', () => { D2.sprites.init(); }],
      ['Binding sigils…', () => { D2.ui.init(); D2.ui.initPanels(); }],
      ['Raising the dead…', () => { D2.game.updateQuests(); }],
      ['Opening the gates…', () => {}],
    ];
    let i = 0;
    const stepFn = () => {
      if (i < steps.length) {
        const [label, fn] = steps[i];
        try { fn(); } catch (e) { console.error('boot step failed:', label, e); }
        i++;
        D2.ui.setLoadingProgress(i / steps.length);
        setTimeout(stepFn, 120);
      } else {
        finishBoot();
      }
    };
    setTimeout(stepFn, 200);
  }

  function finishBoot() {
    wirePauseMenu();
    window.D2.main = api;   // expose after full init
    G.applySettings();

    /* click anywhere unlocks audio */
    const unlock = () => { D2.audio.unlock(); };
    window.addEventListener('mousedown', unlock, { once: true });
    window.addEventListener('keydown', unlock, { once: true });

    /* autosave on tab close while playing */
    window.addEventListener('beforeunload', () => {
      if ((G.state === 'playing' || G.state === 'paused') && G.player) G.saveGame();
    });
    document.addEventListener('visibilitychange', () => {
      if (document.hidden && G.state === 'playing') togglePause();
    });

    G.state = 'title';
    D2.ui.showTitle();
    requestAnimationFrame(loop);
  }

  function wirePauseMenu() {
    document.getElementById('btn-resume').addEventListener('click', togglePause);
    document.getElementById('btn-pause-settings').addEventListener('click', () => {
      D2.ui.showSettings(() => {
        document.getElementById('screen-settings').classList.add('hidden');
        if (G.state === 'paused') document.getElementById('pause-overlay').classList.remove('hidden');
      });
      document.getElementById('pause-overlay').classList.add('hidden');
    });
    document.getElementById('btn-pause-help').addEventListener('click', () => {
      document.getElementById('pause-overlay').classList.add('hidden');
      D2.ui.showHelp(() => {
        document.getElementById('screen-help').classList.add('hidden');
        document.getElementById('pause-overlay').classList.remove('hidden');
      });
    });
    document.getElementById('btn-save-exit').addEventListener('click', exitToTitle);
  }

  /* ---------------- main loop ---------------- */

  function loop(t) {
    requestAnimationFrame(loop);
    const dt = Math.min(0.05, (t - lastT) / 1000 || 0.016);
    lastT = t;

    /* consume this frame's inputs first, act on them, clear edges LAST */
    D2.ui.tickGlobalKeys();

    if (G.state === 'playing') {
      G.update(dt);
      D2.render.frame(G, dt);
      D2.ui.tick(dt);
      hudRefreshT -= dt;
      if (hudRefreshT <= 0) { hudRefreshT = 0.12; D2.ui.refreshHud(); }
    } else if (G.state === 'paused' || G.state === 'dead' || G.state === 'victory') {
      /* keep rendering the frozen world behind overlays */
      if (G.world) D2.render.frame(G, 0);
    }
    D2.input.endFrame();
  }

  /* ---------------- public api ---------------- */

  const api = {
    togglePause,
    exitToTitle,
    openHelp: openHelpInGame,
    openClassSelect() {
      D2.ui.showClassSelect();
    },
    startNewGame(classId) {
      D2.ui.hideScreens();
      D2.ui.hideHud ? null : 0;
      D2.ui.showHud();
      G.startNewGame(classId);
      D2.ui.refreshHud();
      D2.ui.renderQuestTracker();
      D2.ui.toast(D2.i18n.t('class.' + classId + '.name'), 'gold');
      setTimeout(() => {
        D2.ui.toast(D2.i18n.getLang() === 'vi'
          ? '🗣 Hãy nói chuyện với Kashya & Cain trong trại (phím F)'
          : '🗣 Speak with Kashya & Cain in camp (press F)', 'gold');
      }, 1200);
    },
    startContinue() {
      D2.ui.hideScreens();
      D2.ui.showHud();
      if (G.continueGame()) {
        D2.ui.refreshHud();
        D2.ui.renderQuestTracker();
      }
    },
  };

  window.addEventListener('DOMContentLoaded', boot);
})(window.D2);