// App shell: screens, character select, local/host/client match drivers.
import { SNAP_EVERY } from './consts.js';
import { randomSeed } from './rng.js';
import { CHARS } from './characters.js';
import { createGame, step, snapshot, applySnapshot } from './sim.js';
import { initInput, getBits, getMergedBits } from './input.js';
import { initRender, resetRender, render, fxEvents } from './render.js';
import { initAudio, playEvents, sfx, toggleMute } from './audio.js';
import { randomKey, hostRoom, joinRoom, peerAvailable } from './net.js';

const $ = (id) => document.getElementById(id);

// ---- state ----
let mode = null;            // 'local' | 'host' | 'client'
let net = null;
let game = null;
let picks = [null, null];   // local char select
let myPick = null, remotePick = null, peerJoined = false;
let remoteBits = 0;
let pendingEvs = [];
let clientOverT = 0;
let resultShown = false;
let paused = false;
let rafId = null, acc = 0, last = 0;
const TICK_MS = 1000 / 60;

// ---- screens ----
const SCREENS = ['s-menu', 's-host', 's-join', 's-chars', 's-game', 's-result'];
function show(id) {
  for (const s of SCREENS) $(s).classList.toggle('hidden', s !== id);
  $('cv').classList.toggle('dim', id !== 's-game');
}

function setStatus(el, msg, isErr = false) {
  el.textContent = msg;
  el.classList.toggle('err', isErr);
}

// ---- boot ----
window.addEventListener('DOMContentLoaded', () => {
  initInput();
  initRender($('cv'));
  buildCharCards();
  wireMenus();
  show('s-menu');
  // background demo map behind menus
  game = createGame(randomSeed(), [{ charId: 0 }, { charId: 1 }]);
  resetRender(game);
  startLoop();
});

window.addEventListener('pointerdown', () => initAudio()); // any gesture unlocks audio
window.addEventListener('keydown', (e) => {
  initAudio(); // browsers require a gesture before audio
  if (e.target && e.target.tagName === 'INPUT') return; // don't eat typing in the room-key field
  if (e.code === 'KeyM') {
    const m = toggleMute();
    $('mute').textContent = m ? '🔇' : '🔊';
  }
  if (e.code === 'Escape') onEscape();
  if (e.code === 'Enter' && !$('s-result').classList.contains('hidden')) doRematch();
});

function onEscape() {
  if (!$('s-game').classList.contains('hidden')) {
    if (mode === 'local') {
      paused = !paused;
      $('pause-tag').classList.toggle('hidden', !paused);
    } else {
      leaveToMenu('Left the match.');
    }
  } else if ($('s-menu').classList.contains('hidden')) {
    leaveToMenu();
  }
}

function leaveToMenu(msg) {
  if (net) { try { net.send({ t: 'bye' }); net.destroy(); } catch (_) {} net = null; }
  mode = null; paused = false; resultShown = false;
  myPick = null; remotePick = null; peerJoined = false; picks = [null, null];
  $('pause-tag').classList.add('hidden');
  if (msg) setStatus($('menu-status'), msg);
  game = createGame(randomSeed(), [{ charId: 0 }, { charId: 1 }]);
  resetRender(game);
  show('s-menu');
  refreshCharUI();
}

// ---- menus ----
function wireMenus() {
  $('btn-local').onclick = () => { sfx('ui'); mode = 'local'; picks = [null, null]; show('s-chars'); refreshCharUI(); };
  $('btn-host').onclick = () => { sfx('ui'); startHost(); };
  $('btn-join').onclick = () => { sfx('ui'); show('s-join'); setStatus($('join-status'), ''); $('join-key').focus(); };
  $('btn-join-go').onclick = () => doJoin();
  $('join-key').addEventListener('keydown', (e) => { if (e.key === 'Enter') doJoin(); });
  $('btn-host-cancel').onclick = () => leaveToMenu();
  $('btn-join-cancel').onclick = () => leaveToMenu();
  $('btn-chars-back').onclick = () => leaveToMenu();
  $('btn-start').onclick = () => tryStart();
  $('btn-rematch').onclick = () => doRematch();
  $('btn-newdogs').onclick = () => doChangeDogs();
  $('btn-result-menu').onclick = () => leaveToMenu();
}

// ---- char select ----
function buildCharCards() {
  const grid = $('char-grid');
  grid.innerHTML = '';
  for (const c of CHARS) {
    const card = document.createElement('div');
    card.className = 'card';
    card.id = `card-${c.id}`;
    card.style.borderColor = c.color;
    card.innerHTML = `
      <div class="card-head" style="color:${c.color}">${c.name}</div>
      <div class="card-breed">${c.breed}</div>
      <canvas class="card-cv" width="90" height="56"></canvas>
      <div class="card-desc">${c.desc}</div>
      <ul class="card-moves">${c.moves.map(m => `<li>${m}</li>`).join('')}</ul>
      <div class="card-tags"></div>`;
    card.onclick = () => pickChar(c.id);
    grid.appendChild(card);
    drawCardDog(card.querySelector('.card-cv'), c);
  }
}

function drawCardDog(cv2, c) {
  const x = cv2.getContext('2d');
  x.translate(45, 32);
  x.fillStyle = c.color;
  x.beginPath(); x.ellipse(0, 0, 22 * c.body, 13 * c.body, 0, 0, 7); x.fill();
  x.beginPath(); x.arc(17, -12, 11 * c.body, 0, 7); x.fill();
  x.beginPath(); x.ellipse(17 + 9, -10, 9 * c.snout, 5, 0, 0, 7); x.fill();
  x.fillStyle = c.accent;
  x.beginPath(); x.moveTo(13, -20); x.lineTo(16, -30); x.lineTo(20, -19); x.fill();
  x.fillStyle = '#1a1a1a';
  x.beginPath(); x.arc(19, -14, 2.5, 0, 7); x.fill();
  x.strokeStyle = c.accent; x.lineWidth = 4; x.lineCap = 'round';
  for (let i = 0; i < 4; i++) {
    x.beginPath(); x.moveTo(-14 + i * 9, 10); x.lineTo(-14 + i * 9, 20); x.stroke();
  }
  x.lineWidth = 3;
  x.beginPath(); x.moveTo(-21, -4); x.quadraticCurveTo(-32, -14, -34, -8); x.stroke();
}

function pickChar(id) {
  sfx('ui');
  if (mode === 'local') {
    if (picks[0] === null) picks[0] = id;
    else if (picks[1] === null) picks[1] = id;
    else { picks = [id, null]; } // third click restarts picking
  } else {
    myPick = id;
    if (net) net.send({ t: 'char', c: id });
  }
  refreshCharUI();
}

function refreshCharUI() {
  for (const c of CHARS) {
    const tags = $(`card-${c.id}`)?.querySelector('.card-tags');
    if (!tags) continue;
    const t = [];
    if (mode === 'local') {
      if (picks[0] === c.id) t.push('<span class="tag p1">P1</span>');
      if (picks[1] === c.id) t.push('<span class="tag p2">P2</span>');
    } else {
      if (myPick === c.id) t.push('<span class="tag p1">YOU</span>');
      if (remotePick === c.id) t.push('<span class="tag p2">THEM</span>');
    }
    tags.innerHTML = t.join('');
  }
  const status = $('chars-status');
  const startBtn = $('btn-start');
  if (mode === 'local') {
    startBtn.classList.remove('hidden');
    startBtn.disabled = picks[0] === null || picks[1] === null;
    setStatus(status, picks[0] === null ? 'Player 1: pick your dog'
      : picks[1] === null ? 'Player 2: pick your dog' : 'Ready! Hit Start.');
  } else if (mode === 'host') {
    startBtn.classList.remove('hidden');
    startBtn.disabled = myPick === null || remotePick === null;
    const key = $('room-key-tag');
    key.classList.remove('hidden');
    setStatus(status, !peerJoined ? 'Waiting for player 2 to join…'
      : myPick === null ? 'Pick your dog'
      : remotePick === null ? 'Waiting for them to pick…' : 'Both ready — Start!');
  } else if (mode === 'client') {
    startBtn.classList.add('hidden');
    setStatus(status, myPick === null ? 'Pick your dog' : 'Waiting for host to start…');
  }
  $('room-key-tag').classList.toggle('hidden', mode !== 'host');
}

function tryStart() {
  if (mode === 'local') {
    if (picks[0] === null || picks[1] === null) return;
    startMatch(randomSeed(), [{ charId: picks[0] }, { charId: picks[1] }]);
  } else if (mode === 'host') {
    if (myPick === null || remotePick === null) return;
    const seed = randomSeed();
    net.send({ t: 'start', seed, chars: [myPick, remotePick] });
    startMatch(seed, [{ charId: myPick }, { charId: remotePick }]);
  }
}

// ---- networking ----
function startHost() {
  if (net) return; // a connection attempt is already in flight
  if (!peerAvailable()) { setStatus($('menu-status'), 'PeerJS not loaded — online play needs internet.', true); return; }
  mode = 'host';
  myPick = null; remotePick = null; peerJoined = false;
  const key = randomKey();
  show('s-host');
  setStatus($('host-status'), 'Opening room…');
  $('host-key').textContent = key;
  $('room-key').textContent = key;
  net = hostRoom(key, {
    open: () => setStatus($('host-status'), 'Room open! Share the key — waiting for player 2…'),
    conn: () => {
      peerJoined = true;
      net.send({ t: 'welcome' });
      show('s-chars');
      refreshCharUI();
    },
    data: onNetData,
    close: (msg) => netClosed(msg),
  });
}

function doJoin() {
  if (net) return; // a connection attempt is already in flight
  if (!peerAvailable()) { setStatus($('join-status'), 'PeerJS not loaded — online play needs internet.', true); return; }
  const key = $('join-key').value.toUpperCase().trim();
  if (key.length < 4) { setStatus($('join-status'), 'Enter the 5-letter room key.', true); return; }
  mode = 'client';
  myPick = null; remotePick = null;
  setStatus($('join-status'), 'Connecting…');
  net = joinRoom(key, {
    conn: () => { show('s-chars'); refreshCharUI(); },
    data: onNetData,
    close: (msg) => netClosed(msg),
  });
}

function netClosed(msg) {
  if (mode === 'host' || mode === 'client') leaveToMenu(msg || 'Connection closed.');
}

function onNetData(msg) {
  if (!msg || typeof msg !== 'object') return;
  switch (msg.t) {
    case 'char':
      remotePick = msg.c;
      refreshCharUI();
      break;
    case 'start': // client: host started the match
      if (mode === 'client') startMatch(msg.seed, [{ charId: msg.chars[0] }, { charId: msg.chars[1] }]);
      break;
    case 'i': // host: remote inputs
      remoteBits = msg.b | 0;
      break;
    case 's': // client: snapshot
      if (mode === 'client' && game) {
        const evs = applySnapshot(game, msg.s);
        fxEvents(evs, game);
        playEvents(evs);
      }
      break;
    case 'rematch':
      if (mode === 'client') startMatch(msg.seed, [{ charId: msg.chars[0] }, { charId: msg.chars[1] }]);
      break;
    case 'tochars':
      if (mode === 'client') { myPick = null; remotePick = null; resultShown = false; show('s-chars'); refreshCharUI(); }
      break;
    case 'bye':
      netClosed('Other player left.');
      break;
  }
}

// ---- match lifecycle ----
function startMatch(seed, defs) {
  game = createGame(seed, defs);
  resetRender(game);
  pendingEvs = [];
  remoteBits = 0;
  clientOverT = 0;
  resultShown = false;
  paused = false;
  acc = 0;
  show('s-game');
  sfx('count');
}

function doRematch() {
  sfx('ui');
  if (mode === 'local') {
    startMatch(randomSeed(), [{ charId: picks[0] }, { charId: picks[1] }]);
  } else if (mode === 'host') {
    const seed = randomSeed();
    net.send({ t: 'rematch', seed, chars: [myPick, remotePick] });
    startMatch(seed, [{ charId: myPick }, { charId: remotePick }]);
  }
}

function doChangeDogs() {
  sfx('ui');
  resultShown = false; // lets the host tick() guard idle the finished match
  if (mode === 'local') {
    picks = [null, null];
    show('s-chars'); refreshCharUI();
  } else if (mode === 'host') {
    net.send({ t: 'tochars' });
    myPick = null; remotePick = null;
    show('s-chars'); refreshCharUI();
  }
}

function showResult() {
  resultShown = true;
  const w = game.over.winner;
  $('result-title').textContent = w >= 0 ? `${game.players[w].name} wins!` : 'Double KO!';
  $('result-title').style.color = w >= 0 ? CHARS[game.players[w].charId].color : '#fff';
  const isClient = mode === 'client';
  $('btn-rematch').classList.toggle('hidden', isClient);
  $('btn-newdogs').classList.toggle('hidden', isClient);
  $('result-wait').classList.toggle('hidden', !isClient);
  show('s-result');
}

// ---- main loop ----
function startLoop() {
  if (rafId) cancelAnimationFrame(rafId);
  last = performance.now();
  const frame = (t) => {
    rafId = requestAnimationFrame(frame);
    acc += t - last;
    last = t;
    if (acc > 200) acc = 200; // tab was backgrounded; don't spiral
    while (acc >= TICK_MS) {
      acc -= TICK_MS;
      tick();
    }
    if (game) render(game, { smooth: mode === 'client' });
  };
  rafId = requestAnimationFrame(frame);
}

function tick() {
  if (!game || paused) return;
  const inGame = !$('s-game').classList.contains('hidden');

  if (mode === 'local' || mode === null) {
    // local match, or attract-mode demo behind menus (no inputs)
    const i0 = inGame ? getBits(0) : 0;
    const i1 = inGame ? getBits(1) : 0;
    const evs = step(game, [i0, i1]);
    if (inGame) { fxEvents(evs, game); playEvents(evs); }
    if (inGame && game.over && game.overT > 140 && !resultShown) showResult();

  } else if (mode === 'host') {
    if (!inGame && !resultShown) return; // still in lobby/charselect
    const evs = step(game, [getMergedBits(), remoteBits]);
    pendingEvs.push(...evs);
    fxEvents(evs, game);
    playEvents(evs);
    if (game.tick % SNAP_EVERY === 0 && net) {
      net.send({ t: 's', s: snapshot(game, pendingEvs) });
      pendingEvs = [];
    }
    if (game.over && game.overT > 140 && !resultShown) showResult();

  } else if (mode === 'client') {
    if (!inGame && !resultShown) return;
    if (net) net.send({ t: 'i', b: getMergedBits() });
    // sim runs on host; we just count toward the result screen
    if (game.over && ++clientOverT > 140 && !resultShown) showResult();
  }
}