const canvas = document.getElementById('game');
const ctx = canvas.getContext('2d');
const scoreEl = document.getElementById('score');
const heartsEl = document.getElementById('hearts');
const deathScreenEl = document.getElementById('deathScreen');
const finalScoreEl = document.getElementById('finalScore');
const leaderboardEl = document.getElementById('leaderboard');
const saveScoreFormEl = document.getElementById('saveScoreForm');
const playerNameEl = document.getElementById('playerName');
const restartBtnEl = document.getElementById('restartBtn');

const keys = new Set();
const gravity = 1900;
const groundY = 420;
const worldWidth = 6000;

let audioCtx = null;

function ensureAudioCtx() {
  if (!audioCtx) audioCtx = new (window.AudioContext || window.webkitAudioContext)();
  if (audioCtx.state === 'suspended') audioCtx.resume();
}

function playSfx(type) {
  try {
    ensureAudioCtx();
    const now = audioCtx.currentTime;
    const osc = audioCtx.createOscillator();
    const gain = audioCtx.createGain();
    osc.connect(gain);
    gain.connect(audioCtx.destination);

    const presets = {
      jump: { f0: 420, f1: 680, dur: 0.1, wave: 'triangle', vol: 0.06 },
      squish: { f0: 180, f1: 120, dur: 0.12, wave: 'square', vol: 0.07 },
      duck: { f0: 240, f1: 180, dur: 0.06, wave: 'sine', vol: 0.05 },
      ptero_spawn: { f0: 520, f1: 460, dur: 0.1, wave: 'sawtooth', vol: 0.05 },
      meteor_spawn: { f0: 300, f1: 200, dur: 0.14, wave: 'sawtooth', vol: 0.06 },
      meteor_land: { f0: 140, f1: 70, dur: 0.18, wave: 'square', vol: 0.08 },
      hit: { f0: 260, f1: 140, dur: 0.1, wave: 'square', vol: 0.06 }
    };

    const p = presets[type];
    if (!p) return;
    osc.type = p.wave;
    osc.frequency.setValueAtTime(p.f0, now);
    osc.frequency.exponentialRampToValueAtTime(Math.max(40, p.f1), now + p.dur);
    gain.gain.setValueAtTime(p.vol, now);
    gain.gain.exponentialRampToValueAtTime(0.0001, now + p.dur);
    osc.start(now);
    osc.stop(now + p.dur);
  } catch (_) {
    // ignore audio errors in unsupported environments
  }
}

const waterGaps = [
  { x: 700, width: 130 },
  { x: 1300, width: 150 },
  { x: 2100, width: 170 },
  { x: 3000, width: 140 },
  { x: 3900, width: 200 }
];

function createInitialState() {
  return {
    running: true,
    dead: false,
    deadReason: '',
    lastTs: performance.now(),
    score: 0,
    stepCarry: 0,
    cameraX: 0,
    hearts: 3,
    hitCooldown: 0,
    ants: [
      { x: 1000, y: groundY - 20, width: 22, height: 20, vx: -65, alive: true },
      { x: 1750, y: groundY - 20, width: 22, height: 20, vx: -70, alive: true },
      { x: 2600, y: groundY - 20, width: 22, height: 20, vx: -80, alive: true },
      { x: 3400, y: groundY - 20, width: 22, height: 20, vx: -75, alive: true }
    ],
    pterodactyls: [],
    pteroSpawnTimer: 0,
    meteors: [],
    meteorSpawnTimer: 0,
    floatingTexts: [],
    player: {
      x: 160,
      y: groundY - 76,
      width: 64,
      height: 76,
      standingHeight: 76,
      duckHeight: 48,
      vx: 0,
      vy: 0,
      speed: 300,
      jumpPower: 760,
      onGround: true,
      ducking: false
    }
  };
}

let state = createInitialState();
let saveEligible = false;
let scoreSavedThisRun = false;
let saveInFlight = false;

const saveScoreBtnEl = saveScoreFormEl.querySelector('button[type="submit"]');

function setSaveFormBusy(isBusy) {
  saveInFlight = isBusy;
  playerNameEl.disabled = isBusy;
  if (saveScoreBtnEl) saveScoreBtnEl.disabled = isBusy;
}

window.addEventListener('keydown', (e) => {
  if (["ArrowUp", "ArrowDown", "ArrowLeft", "ArrowRight"].includes(e.key)) e.preventDefault();
  keys.add(e.key);
  if (e.key === 'ArrowUp' && state.player.onGround && state.running) {
    state.player.vy = -state.player.jumpPower;
    state.player.onGround = false;
    playSfx('jump');
  }
});
window.addEventListener('keyup', (e) => keys.delete(e.key));

restartBtnEl.addEventListener('click', () => {
  state = createInitialState();
  keys.clear();
  deathScreenEl.classList.add('hidden');
  saveScoreFormEl.classList.add('hidden');
  saveEligible = false;
  scoreSavedThisRun = false;
  setSaveFormBusy(false);
});

saveScoreFormEl.addEventListener('submit', async (e) => {
  e.preventDefault();
  if (!saveEligible || saveInFlight || scoreSavedThisRun) return;
  const name = playerNameEl.value.trim() || 'Anonymous';

  setSaveFormBusy(true);
  try {
    const res = await fetch('api/scores.php', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ name, score: state.score })
    });

    if (!res.ok) throw new Error('Score save failed');

    saveEligible = false;
    scoreSavedThisRun = true;
    saveScoreFormEl.classList.add('hidden');
    await populateLeaderboard();
  } catch (err) {
    console.error(err);
  } finally {
    setSaveFormBusy(false);
  }
});

function drawBackground() {
  ctx.fillStyle = '#8ddcff';
  ctx.fillRect(0, 0, canvas.width, canvas.height);
  ctx.fillStyle = '#88d34f';
  ctx.fillRect(0, groundY, canvas.width, canvas.height - groundY);

  for (const gap of waterGaps) {
    const sx = gap.x - state.cameraX;
    if (sx + gap.width < 0 || sx > canvas.width) continue;
    ctx.fillStyle = '#2e8bcf';
    ctx.fillRect(sx, groundY, gap.width, canvas.height - groundY);
  }
}

function drawTRex(p) {
  const sx = p.x - state.cameraX;
  ctx.fillStyle = '#35535f';
  ctx.fillRect(sx, p.y, p.width, p.height);
  ctx.fillStyle = '#27404a';
  ctx.fillRect(sx + p.width - 12, p.y + 14, 7, 7);
  ctx.fillRect(sx + 10, p.y + p.height - 8, 14, 8);
  ctx.fillRect(sx + p.width - 24, p.y + p.height - 8, 14, 8);
}

function drawAnts() {
  ctx.fillStyle = '#5a1e0d';
  for (const ant of state.ants) {
    if (!ant.alive) continue;
    const sx = ant.x - state.cameraX;
    if (sx + ant.width < 0 || sx > canvas.width) continue;
    ctx.fillRect(sx, ant.y, ant.width, ant.height);
    ctx.fillRect(sx - 4, ant.y + 6, 4, 4);
    ctx.fillRect(sx + ant.width, ant.y + 6, 4, 4);
  }
}

function drawPterodactyls() {
  ctx.fillStyle = '#6e5a8a';
  for (const p of state.pterodactyls) {
    const sx = p.x - state.cameraX;
    if (sx + p.width < 0 || sx > canvas.width) continue;
    ctx.fillRect(sx, p.y, p.width, p.height);
    ctx.fillRect(sx - 8, p.y + 6, 8, 4);
    ctx.fillRect(sx + p.width, p.y + 6, 8, 4);
  }
}

function drawMeteors() {
  ctx.fillStyle = '#6b4d2e';
  for (const m of state.meteors) {
    const sx = m.x - state.cameraX;
    if (sx + m.width < 0 || sx > canvas.width) continue;
    ctx.fillRect(sx, m.y, m.width, m.height);
  }
}

function addFloatingText(x, y, text, color = '#ffe066') {
  state.floatingTexts.push({ x, y, text, color, ttl: 0.8, vy: -36 });
}

function updateFloatingTexts(dt) {
  for (const t of state.floatingTexts) {
    t.ttl -= dt;
    t.y += t.vy * dt;
  }
  state.floatingTexts = state.floatingTexts.filter((t) => t.ttl > 0);
}

function drawFloatingTexts() {
  ctx.save();
  ctx.font = 'bold 22px Arial';
  ctx.textAlign = 'center';
  for (const t of state.floatingTexts) {
    const alpha = Math.max(0, Math.min(1, t.ttl / 0.8));
    ctx.globalAlpha = alpha;
    ctx.fillStyle = t.color;
    ctx.fillText(t.text, t.x - state.cameraX, t.y);
  }
  ctx.restore();
}

const intersects = (a, b) => a.x < b.x + b.width && a.x + a.width > b.x && a.y < b.y + b.height && a.y + a.height > b.y;

function updateHeartsUI() {
  const active = '<span class="heart heart-active">❤</span>'.repeat(state.hearts);
  const lost = '<span class="heart heart-lost">❤</span>'.repeat(Math.max(0, 3 - state.hearts));
  heartsEl.innerHTML = active + lost;
}

async function loadTopScores() {
  const res = await fetch('api/scores.php');
  return res.ok ? res.json() : [];
}

async function populateLeaderboard() {
  const scores = await loadTopScores();
  leaderboardEl.innerHTML = '';
  scores.forEach((s) => {
    const li = document.createElement('li');
    li.textContent = `${s.name} — ${s.score}`;
    leaderboardEl.appendChild(li);
  });

  const qualifies = scores.length < 10 || state.score > (scores[scores.length - 1]?.score ?? -1);
  saveEligible = qualifies && !scoreSavedThisRun && !saveInFlight;
  saveScoreFormEl.classList.toggle('hidden', !saveEligible);
}

async function kill(reason) {
  if (state.dead) return;
  state.running = false;
  state.dead = true;
  state.deadReason = reason;

  finalScoreEl.textContent = `Final Score: ${state.score}`;
  await populateLeaderboard();
  deathScreenEl.classList.remove('hidden');
}

function applyHit(reason) {
  if (state.hitCooldown > 0 || state.dead) return;
  state.hearts -= 1;
  state.hitCooldown = 1;
  playSfx('hit');
  if (state.hearts <= 0) kill(reason);
}

function isOverWater(player) {
  const centerX = player.x + player.width / 2;
  return waterGaps.some((g) => centerX >= g.x && centerX <= g.x + g.width);
}

function updateAnts(dt) {
  const p = state.player;
  const prevBottom = p.y + p.height - p.vy * dt;

  for (const ant of state.ants) {
    if (!ant.alive) continue;
    ant.x += ant.vx * dt;
    if (ant.x < 200) ant.vx = Math.abs(ant.vx);
    if (ant.x > worldWidth - 200) ant.vx = -Math.abs(ant.vx);

    if (intersects(p, ant)) {
      const playerBottom = p.y + p.height;
      const stomped = p.vy > 0 && prevBottom <= ant.y + 4 && playerBottom >= ant.y;
      if (stomped) {
        ant.alive = false;
        p.vy = -380;
        state.score += 50;
        addFloatingText(ant.x + ant.width / 2, ant.y - 10, '+50', '#ffe066');
        playSfx('squish');
      } else {
        applyHit('A swarm of ants got you.');
      }
    }
  }
}

const PTERODACTYL_LANES = [
  // low lane: standing dino collides, ducking dino should pass underneath
  { y: groundY - 80, height: 28 }
];

function getPterodactylHitbox(flyer) {
  return {
    x: flyer.x + 8,
    y: flyer.y + 6,
    width: flyer.width - 16,
    height: flyer.height - 12
  };
}

function getPlayerHitboxForAirHazards(player) {
  const widthInset = player.ducking ? 8 : 6;
  const topInset = player.ducking ? 8 : 4;
  const bottomInset = 2;

  return {
    x: player.x + widthInset,
    y: player.y + topInset,
    width: player.width - widthInset * 2,
    height: player.height - topInset - bottomInset
  };
}

function updatePterodactyls(dt) {
  if (state.score <= 100) return;
  state.pteroSpawnTimer -= dt;

  if (state.pteroSpawnTimer <= 0) {
    const lane = PTERODACTYL_LANES[Math.floor(Math.random() * PTERODACTYL_LANES.length)];
    state.pterodactyls.push({
      x: state.cameraX + canvas.width + 80,
      y: lane.y,
      width: 54,
      height: lane.height,
      vx: -280
    });
    playSfx('ptero_spawn');
    state.pteroSpawnTimer = 2.2;
  }

  const p = state.player;
  const playerHitbox = getPlayerHitboxForAirHazards(p);
  for (const flyer of state.pterodactyls) {
    flyer.x += flyer.vx * dt;
    if (intersects(playerHitbox, getPterodactylHitbox(flyer))) applyHit('Pterodactyl collision. Duck next time!');
  }
  state.pterodactyls = state.pterodactyls.filter((f) => f.x + f.width > state.cameraX - 150);
}

function updateMeteors(dt) {
  if (state.score <= 250) return;
  state.meteorSpawnTimer -= dt;

  if (state.meteorSpawnTimer <= 0) {
    const spawnX = state.cameraX + 80 + Math.random() * (canvas.width - 160);
    state.meteors.push({ x: spawnX, y: -30, width: 24, height: 30, vy: 420, landed: false });
    playSfx('meteor_spawn');
    state.meteorSpawnTimer = 1.5;
  }

  const p = state.player;
  for (const m of state.meteors) {
    m.y += m.vy * dt;

    if (!m.landed && m.y + m.height >= groundY) {
      m.landed = true;
      playSfx('meteor_land');
    }

    if (intersects(p, m)) {
      applyHit('Meteor strike!');
      m.y = canvas.height + 100;
    }
  }
  state.meteors = state.meteors.filter((m) => m.y < canvas.height + 80);
}

function updatePlayer(dt) {
  const p = state.player;
  let move = 0;
  if (keys.has('ArrowLeft')) move -= 1;
  if (keys.has('ArrowRight')) move += 1;

  const wasDucking = p.ducking;
  p.ducking = keys.has('ArrowDown') && p.onGround;
  if (!wasDucking && p.ducking) playSfx('duck');
  const targetHeight = p.ducking ? p.duckHeight : p.standingHeight;
  if (targetHeight !== p.height) {
    p.y += p.height - targetHeight;
    p.height = targetHeight;
  }

  p.vx = move * p.speed;
  const oldX = p.x;
  p.x += p.vx * dt;
  p.x = Math.max(0, Math.min(worldWidth - p.width, p.x));

  if (p.x > oldX) {
    state.stepCarry += p.x - oldX;
    while (state.stepCarry >= 8) {
      state.score += 1;
      state.stepCarry -= 8;
    }
  }

  p.vy += gravity * dt;
  p.y += p.vy * dt;

  if (p.y + p.height >= groundY) {
    p.y = groundY - p.height;
    p.vy = 0;
    p.onGround = true;
    if (isOverWater(p)) kill('SPLASH! Water is instant death.');
  } else {
    p.onGround = false;
  }

  state.cameraX = Math.max(0, Math.min(worldWidth - canvas.width, p.x - 240));
}

function tick(ts) {
  const dt = Math.min((ts - state.lastTs) / 1000, 0.05);
  state.lastTs = ts;

  if (state.running) {
    state.hitCooldown = Math.max(0, state.hitCooldown - dt);
    updatePlayer(dt);
    updateAnts(dt);
    updatePterodactyls(dt);
    updateMeteors(dt);
    updateFloatingTexts(dt);
  }

  ctx.clearRect(0, 0, canvas.width, canvas.height);
  drawBackground();
  drawAnts();
  drawPterodactyls();
  drawMeteors();
  drawFloatingTexts();
  drawTRex(state.player);

  scoreEl.textContent = `Score: ${state.score}`;
  updateHeartsUI();

  requestAnimationFrame(tick);
}

requestAnimationFrame((ts) => {
  state.lastTs = ts;
  updateHeartsUI();
  requestAnimationFrame(tick);
});