/* ============================================================
   TAB SHOOTER — Shared Game Engine
   Wird von popup.js (Overlay) und game.js (Vollbild) genutzt.
   ============================================================ */

// ---------- UTILITIES ----------
export function clamp(v, min, max) {
  return Math.max(min, Math.min(max, v));
}

export function rand(min, max) {
  return Math.random() * (max - min) + min;
}

export function pick(arr) {
  return arr[Math.floor(Math.random() * arr.length)];
}

export function roundRect(ctx, x, y, w, h, r) {
  ctx.beginPath();
  ctx.moveTo(x + r, y);
  ctx.arcTo(x + w, y, x + w, y + h, r);
  ctx.arcTo(x + w, y + h, x, y + h, r);
  ctx.arcTo(x, y + h, x, y, r);
  ctx.arcTo(x, y, x + w, y, r);
  ctx.closePath();
}

export function drawLetterAvatar(ctx, title, x, y, size) {
  const colors = ["#ff6b6b", "#4ecdc4", "#ffe66d", "#a8e6cf", "#c7b3ff", "#ffb3d9"];
  const letter = (title || "?").trim().charAt(0).toUpperCase() || "?";
  const color = colors[(title || "").length % colors.length];
  ctx.fillStyle = color;
  ctx.fillRect(x, y, size, size);
  ctx.fillStyle = "#ffffff";
  ctx.font = "bold 10px Segoe UI, Arial";
  ctx.textAlign = "center";
  ctx.textBaseline = "middle";
  ctx.fillText(letter, x + size / 2, y + size / 2 + 1);
}

// Load a favicon via Chrome's _favicon API (requires "favicon" permission).
// Returns a Promise<Image | null>.
export function loadFavicon(pageUrl, size = 32) {
  return new Promise((resolve) => {
    if (!pageUrl) return resolve(null);
    const favUrl = `/_favicon/?pageUrl=${encodeURIComponent(pageUrl)}&size=${size}`;
    const img = new Image();
    img.onload = () => resolve(img);
    img.onerror = () => resolve(null);
    img.src = favUrl;
  });
}

/**
 * Load all real Chrome tabs that are valid targets.
 * ROBUST SELF-PROTECTION:
 *   - never the game tab itself (its id passed via `excludeTabId`)
 *   - never any tab belonging to this extension (chrome.runtime.id)
 *   - never chrome://, devtools://, etc.
 */
export async function loadTabs(scope, excludeTabId = null) {
  let tabs = [];
  if (scope === "all") {
    tabs = await chrome.tabs.query({});
  } else {
    const win = await chrome.windows.getLastFocused();
    tabs = await chrome.tabs.query({ windowId: win.id });
  }
  const ownId = chrome.runtime.id;
  const playable = tabs.filter((t) => {
    if (!t.id) return false;
    // 1) never the current game tab itself
    if (excludeTabId !== null && t.id === excludeTabId) return false;
    // 2) never any tab of THIS extension (popup, game.html, options, …)
    if (ownId && t.url && t.url.startsWith(`chrome-extension://${ownId}`)) return false;
    // 3) generic chrome-extension:// filter (covers edge cases)
    if (t.url && t.url.startsWith("chrome-extension://")) return false;
    // 4) internal browser pages
    if (t.url && t.url.startsWith("chrome://")) return false;
    if (t.url && t.url.startsWith("devtools://")) return false;
    if (t.url && t.url.startsWith("edge://")) return false;
    if (t.url && t.url.startsWith("about:")) return false;
    return true;
  });
  return playable;
}

// ============================================================
// GAME CLASS
// ============================================================
export class TabShooterGame {
  /**
   * @param canvas    <canvas> element
   * @param hud       object of DOM elements for HUD updates
   * @param callbacks { onGameOver, onScoreChange, onLivesChange, onTabsChange }
   */
  constructor(canvas, hud, callbacks = {}) {
    this.canvas = canvas;
    this.ctx = canvas.getContext("2d");
    this.hud = hud;
    this.callbacks = callbacks;

    this.W = canvas.width;
    this.H = canvas.height;

    this.enemies = [];
    this.bullets = [];
    this.enemyBullets = [];
    this.particles = [];
    this.powerups = [];
    this.floatingTexts = [];

    this.player = {
      x: this.W / 2,
      y: this.H - 70,
      w: 44,
      h: 40,
      speed: 6,
      cooldown: 0,
      lives: 3,
      invincible: 0,
    };

    this.score = 0;
    this.tabsDestroyed = 0;
    this.totalTabs = 0;
    this.keys = {};
    this.mouseX = null;
    this.firing = false;

    this.tripleShot = 0;
    this.rapidFire = 0;
    this.shield = 0;

    this.running = false;
    this.lastTime = 0;
    this.spawnTimer = 0;
    this.spawnIndex = 0;
    this.spawnQueue = [];

    // Input handlers (bound so we can remove them later)
    this._onKeyDown = this.onKeyDown.bind(this);
    this._onKeyUp = this.onKeyUp.bind(this);
    this._onMouseMove = this.onMouseMove.bind(this);
    this._onMouseDown = this.onMouseDown.bind(this);
    this._onMouseUp = this.onMouseUp.bind(this);
    this._onMouseLeave = this.onMouseLeave.bind(this);
    this._loop = this.loop.bind(this);
  }

  async init(tabs) {
    this.totalTabs = tabs.length;
    // Preload favicons, build spawn queue
    this.spawnQueue = await Promise.all(
      tabs.map(async (t) => ({
        tabId: t.id,
        title: (t.title || "Tab").slice(0, 22),
        url: t.url,
        favicon: await loadFavicon(t.url || "", 32),
      }))
    );
    // Shuffle for variety
    this.spawnQueue.sort(() => Math.random() - 0.5);
  }

  start() {
    this.running = true;
    this.attachInput();
    this.lastTime = performance.now();
    requestAnimationFrame(this._loop);
  }

  stop() {
    this.running = false;
    this.detachInput();
  }

  // ---------- INPUT ----------
  attachInput() {
    window.addEventListener("keydown", this._onKeyDown);
    window.addEventListener("keyup", this._onKeyUp);
    this.canvas.addEventListener("mousemove", this._onMouseMove);
    this.canvas.addEventListener("mousedown", this._onMouseDown);
    this.canvas.addEventListener("mouseup", this._onMouseUp);
    this.canvas.addEventListener("mouseleave", this._onMouseLeave);
  }
  detachInput() {
    window.removeEventListener("keydown", this._onKeyDown);
    window.removeEventListener("keyup", this._onKeyUp);
    this.canvas.removeEventListener("mousemove", this._onMouseMove);
    this.canvas.removeEventListener("mousedown", this._onMouseDown);
    this.canvas.removeEventListener("mouseup", this._onMouseUp);
    this.canvas.removeEventListener("mouseleave", this._onMouseLeave);
  }
  onKeyDown(e) {
    this.keys[e.key.toLowerCase()] = true;
    if ([" ", "ArrowLeft", "ArrowRight", "ArrowUp", "ArrowDown"].includes(e.key)) {
      e.preventDefault();
    }
  }
  onKeyUp(e) {
    this.keys[e.key.toLowerCase()] = false;
  }
  onMouseMove(e) {
    const rect = this.canvas.getBoundingClientRect();
    // Scale from CSS pixels to canvas pixels if needed
    const scaleX = this.canvas.width / rect.width;
    this.mouseX = (e.clientX - rect.left) * scaleX;
  }
  onMouseDown() {
    this.firing = true;
  }
  onMouseUp() {
    this.firing = false;
  }
  onMouseLeave() {
    this.mouseX = null;
    this.firing = false;
  }

  // ---------- SPAWNING ----------
  spawnEnemy() {
    if (this.spawnIndex >= this.spawnQueue.length) return;
    const data = this.spawnQueue[this.spawnIndex];
    this.spawnIndex++;

    const w = 64;
    const h = 54;
    const x = rand(30, this.W - 30 - w);
    const isShooter = Math.random() < 0.25;

    this.enemies.push({
      x,
      y: -h - 10,
      w,
      h,
      vx: rand(-1.2, 1.2),
      vy: rand(0.5, 1.1),
      hp: 1,
      tabId: data.tabId,
      title: data.title,
      favicon: data.favicon,
      shooter: isShooter,
      shootCooldown: rand(60, 180),
      swayPhase: rand(0, Math.PI * 2),
      hit: 0,
      closing: false,
    });
  }

  // ---------- SHOOTING ----------
  fireBullet() {
    if (this.player.cooldown > 0) return;
    const baseCd = this.rapidFire > 0 ? 6 : 14;
    this.player.cooldown = baseCd;

    const px = this.player.x;
    const py = this.player.y - this.player.h / 2;

    if (this.tripleShot > 0) {
      this.bullets.push({ x: px, y: py, vx: 0, vy: -9 });
      this.bullets.push({ x: px - 6, y: py + 4, vx: -2.5, vy: -8.5 });
      this.bullets.push({ x: px + 6, y: py + 4, vx: 2.5, vy: -8.5 });
    } else {
      this.bullets.push({ x: px, y: py, vx: 0, vy: -9 });
    }
  }

  // ---------- POWER-UPS ----------
  maybeDropPowerup(x, y) {
    if (Math.random() < 0.18) {
      this.powerups.push({
        x,
        y,
        vy: 1.6,
        type: pick(["triple", "rapid", "shield"]),
        rot: 0,
      });
    }
  }

  applyPowerup(type) {
    if (type === "triple") {
      this.tripleShot = 360;
      this.pushFloatingText("TRIPLE SHOT!", "#00f0ff");
    } else if (type === "rapid") {
      this.rapidFire = 360;
      this.pushFloatingText("RAPID FIRE!", "#ffaa00");
    } else if (type === "shield") {
      this.shield = 1;
      this.pushFloatingText("SHIELD UP!", "#00ff88");
    }
    this.callbacks.onPowerups?.(this);
  }

  pushFloatingText(text, color) {
    this.floatingTexts.push({
      text,
      color,
      x: this.player.x,
      y: this.player.y - 30,
      life: 60,
    });
  }

  // ---------- DAMAGE ----------
  damagePlayer() {
    if (this.player.invincible > 0) return;
    if (this.shield > 0) {
      this.shield = 0;
      this.pushFloatingText("SHIELD GONE", "#ff4444");
      this.callbacks.onPowerups?.(this);
      this.player.invincible = 40;
      return;
    }
    this.player.lives--;
    this.player.invincible = 90;
    this.callbacks.onLives?.(this.player.lives);
    this.spawnExplosion(this.player.x, this.player.y, "#ff4444", 20);
    if (this.player.lives <= 0) this.gameOver();
  }

  spawnExplosion(x, y, color, count = 15) {
    for (let i = 0; i < count; i++) {
      const angle = rand(0, Math.PI * 2);
      const speed = rand(1, 5);
      this.particles.push({
        x,
        y,
        vx: Math.cos(angle) * speed,
        vy: Math.sin(angle) * speed,
        life: rand(20, 45),
        maxLife: 45,
        size: rand(2, 4),
        color,
      });
    }
  }

  // ---------- TAB CLOSING ----------
  closeTab(tabId) {
    if (chrome.tabs && typeof chrome.tabs.remove === "function") {
      chrome.tabs.remove(tabId).catch(() => { /* already gone */ });
    }
  }

  // ---------- MAIN LOOP ----------
  loop(now) {
    if (!this.running) return;
    const dt = Math.min(40, now - this.lastTime);
    this.lastTime = now;
    this.update(dt);
    this.render();
    requestAnimationFrame(this._loop);
  }

  update(dt) {
    const p = this.player;

    // Movement: keyboard
    let dx = 0;
    if (this.keys["arrowleft"] || this.keys["a"]) dx -= 1;
    if (this.keys["arrowright"] || this.keys["d"]) dx += 1;
    p.x += dx * p.speed;
    // Movement: mouse (gently follows)
    if (this.mouseX !== null) {
      p.x += (this.mouseX - p.x) * 0.25;
    }
    p.x = clamp(p.x, p.w / 2, this.W - p.w / 2);

    // Firing
    if (this.keys[" "] || this.firing) this.fireBullet();
    if (p.cooldown > 0) p.cooldown--;
    if (p.invincible > 0) p.invincible--;
    let powerupChanged = false;
    if (this.tripleShot > 0) { this.tripleShot--; if (this.tripleShot === 0) powerupChanged = true; }
    if (this.rapidFire > 0)  { this.rapidFire--;  if (this.rapidFire === 0)  powerupChanged = true; }
    if (powerupChanged) this.callbacks.onPowerups?.(this);

    // Spawn enemies
    this.spawnTimer--;
    if (this.spawnTimer <= 0 && this.spawnIndex < this.spawnQueue.length) {
      this.spawnEnemy();
      this.spawnTimer = rand(35, 80);
    }

    // Player bullets
    for (let i = this.bullets.length - 1; i >= 0; i--) {
      const b = this.bullets[i];
      b.x += b.vx; b.y += b.vy;
      if (b.y < -10 || b.x < -10 || b.x > this.W + 10) this.bullets.splice(i, 1);
    }

    // Enemy bullets
    for (let i = this.enemyBullets.length - 1; i >= 0; i--) {
      const b = this.enemyBullets[i];
      b.y += b.vy; b.x += b.vx;
      if (Math.abs(b.x - p.x) < p.w / 2 && Math.abs(b.y - p.y) < p.h / 2) {
        this.enemyBullets.splice(i, 1);
        this.damagePlayer();
        continue;
      }
      if (b.y > this.H + 10) this.enemyBullets.splice(i, 1);
    }

    // Enemies
    for (let i = this.enemies.length - 1; i >= 0; i--) {
      const e = this.enemies[i];
      e.swayPhase += 0.04;
      e.x += e.vx + Math.sin(e.swayPhase) * 0.4;
      e.y += e.vy;
      if (e.hit > 0) e.hit--;

      if (e.x < 5 || e.x + e.w > this.W - 5) {
        e.vx *= -1;
        e.x = clamp(e.x, 5, this.W - 5 - e.w);
      }

      if (e.shooter && !e.closing) {
        e.shootCooldown--;
        if (e.shootCooldown <= 0) {
          this.enemyBullets.push({ x: e.x + e.w / 2, y: e.y + e.h, vx: 0, vy: 3.2 });
          e.shootCooldown = rand(90, 220);
        }
      }

      if (e.y > this.H) { this.enemies.splice(i, 1); continue; }

      // Bullet hits
      for (let j = this.bullets.length - 1; j >= 0; j--) {
        const b = this.bullets[j];
        if (b.x > e.x && b.x < e.x + e.w && b.y > e.y && b.y < e.y + e.h) {
          this.bullets.splice(j, 1);
          e.hp--;
          e.hit = 6;
          if (e.hp <= 0) {
            this.closeTab(e.tabId);
            e.closing = true;
            this.spawnExplosion(e.x + e.w / 2, e.y + e.h / 2, "#ff8844", 18);
            this.maybeDropPowerup(e.x + e.w / 2, e.y + e.h / 2);
            this.score += 100;
            this.tabsDestroyed++;
            this.callbacks.onScore?.(this.score);
            this.callbacks.onTabs?.(Math.max(0, this.totalTabs - this.tabsDestroyed));
            this.enemies.splice(i, 1);
          }
          break;
        }
      }
    }

    // Enemy collides with player
    for (let i = this.enemies.length - 1; i >= 0; i--) {
      const e = this.enemies[i];
      if (
        Math.abs(e.x + e.w / 2 - p.x) < p.w / 2 + e.w / 2 - 8 &&
        Math.abs(e.y + e.h / 2 - p.y) < p.h / 2 + e.h / 2 - 8
      ) {
        if (!e.closing) { this.closeTab(e.tabId); e.closing = true; }
        this.spawnExplosion(e.x + e.w / 2, e.y + e.h / 2, "#ff4444", 14);
        this.enemies.splice(i, 1);
        this.damagePlayer();
      }
    }

    // Power-ups
    for (let i = this.powerups.length - 1; i >= 0; i--) {
      const pu = this.powerups[i];
      pu.y += pu.vy;
      pu.rot += 0.08;
      if (Math.abs(pu.x - p.x) < p.w / 2 + 12 && Math.abs(pu.y - p.y) < p.h / 2 + 12) {
        this.applyPowerup(pu.type);
        this.powerups.splice(i, 1);
        continue;
      }
      if (pu.y > this.H + 20) this.powerups.splice(i, 1);
    }

    // Particles
    for (let i = this.particles.length - 1; i >= 0; i--) {
      const pt = this.particles[i];
      pt.x += pt.vx; pt.y += pt.vy;
      pt.vx *= 0.96; pt.vy *= 0.96;
      pt.life--;
      if (pt.life <= 0) this.particles.splice(i, 1);
    }

    // Floating texts
    for (let i = this.floatingTexts.length - 1; i >= 0; i--) {
      const ft = this.floatingTexts[i];
      ft.y -= 0.6;
      ft.life--;
      if (ft.life <= 0) this.floatingTexts.splice(i, 1);
    }

    // Win condition
    if (this.spawnIndex >= this.spawnQueue.length && this.enemies.length === 0) {
      this.gameOver(true);
    }
  }

  // ---------- RENDER ----------
  render() {
    const ctx = this.ctx;
    ctx.clearRect(0, 0, this.W, this.H);
    this.renderBackground();

    // Player bullets
    for (const b of this.bullets) {
      ctx.fillStyle = "#00f0ff";
      ctx.shadowColor = "#00f0ff";
      ctx.shadowBlur = 10;
      ctx.fillRect(b.x - 2, b.y - 8, 4, 12);
    }
    ctx.shadowBlur = 0;

    // Enemy bullets
    for (const b of this.enemyBullets) {
      ctx.fillStyle = "#ff3366";
      ctx.shadowColor = "#ff3366";
      ctx.shadowBlur = 8;
      ctx.beginPath();
      ctx.arc(b.x, b.y, 4, 0, Math.PI * 2);
      ctx.fill();
    }
    ctx.shadowBlur = 0;

    for (const e of this.enemies) this.renderEnemy(e);
    for (const pu of this.powerups) this.renderPowerup(pu);
    this.renderPlayer();

    // Particles
    for (const pt of this.particles) {
      ctx.globalAlpha = pt.life / pt.maxLife;
      ctx.fillStyle = pt.color;
      ctx.fillRect(pt.x - pt.size / 2, pt.y - pt.size / 2, pt.size, pt.size);
    }
    ctx.globalAlpha = 1;

    // Floating texts
    for (const ft of this.floatingTexts) {
      ctx.globalAlpha = clamp(ft.life / 60, 0, 1);
      ctx.fillStyle = ft.color;
      ctx.font = "bold 13px Segoe UI, Arial";
      ctx.textAlign = "center";
      ctx.fillText(ft.text, ft.x, ft.y);
    }
    ctx.globalAlpha = 1;
  }

  renderBackground() {
    const ctx = this.ctx;
    if (!this._stars) {
      this._stars = [];
      for (let i = 0; i < 60; i++) {
        this._stars.push({
          x: Math.random() * this.W,
          y: Math.random() * this.H,
          s: Math.random() * 1.5 + 0.3,
          v: Math.random() * 0.8 + 0.2,
        });
      }
    }
    ctx.fillStyle = "#ffffff";
    for (const st of this._stars) {
      st.y += st.v;
      if (st.y > this.H) st.y = 0;
      ctx.globalAlpha = 0.3 + st.s * 0.3;
      ctx.fillRect(st.x, st.y, st.s, st.s);
    }
    ctx.globalAlpha = 1;
  }

  renderEnemy(e) {
    const ctx = this.ctx;
    ctx.save();
    ctx.translate(e.x, e.y);

    if (e.hit > 0) { ctx.shadowColor = "#ffffff"; ctx.shadowBlur = 15; }

    ctx.fillStyle = e.shooter ? "#3a1530" : "#1a1a3a";
    ctx.strokeStyle = e.shooter ? "#ff3366" : "#444466";
    ctx.lineWidth = 1.5;
    roundRect(ctx, 0, 0, e.w, e.h, 8);
    ctx.fill();
    ctx.stroke();
    ctx.shadowBlur = 0;

    if (e.favicon) {
      try { ctx.drawImage(e.favicon, 6, 4, 16, 16); }
      catch (_) { drawLetterAvatar(ctx, e.title, 6, 4, 16); }
    } else {
      drawLetterAvatar(ctx, e.title, 6, 4, 16);
    }

    ctx.fillStyle = "#ccccdd";
    ctx.font = "9px Segoe UI, Arial";
    ctx.textAlign = "left";
    ctx.textBaseline = "top";
    const title = e.title.length > 14 ? e.title.slice(0, 13) + "…" : e.title;
    ctx.fillText(title, 26, 6, e.w - 30);

    if (e.shooter) {
      ctx.fillStyle = "#ff3366";
      ctx.font = "8px Segoe UI, Arial";
      ctx.fillText("● feindlich", 6, 26);
    }
    ctx.restore();
  }

  renderPlayer() {
    const ctx = this.ctx;
    const p = this.player;
    ctx.save();
    ctx.translate(p.x, p.y);

    if (this.shield > 0) {
      ctx.strokeStyle = "rgba(0,255,136,0.6)";
      ctx.lineWidth = 2;
      ctx.beginPath();
      ctx.arc(0, 0, p.w / 2 + 8, 0, Math.PI * 2);
      ctx.stroke();
    }
    if (p.invincible > 0 && Math.floor(p.invincible / 4) % 2 === 0) ctx.globalAlpha = 0.4;

    ctx.fillStyle = "#00f0ff";
    ctx.strokeStyle = "#ffffff";
    ctx.lineWidth = 1.5;
    ctx.beginPath();
    ctx.moveTo(0, -p.h / 2);
    ctx.lineTo(-p.w / 2, p.h / 2);
    ctx.lineTo(-p.w / 4, p.h / 3);
    ctx.lineTo(p.w / 4, p.h / 3);
    ctx.lineTo(p.w / 2, p.h / 2);
    ctx.closePath();
    ctx.fill();
    ctx.stroke();

    ctx.fillStyle = "#ff00e5";
    ctx.beginPath();
    ctx.arc(0, -2, 5, 0, Math.PI * 2);
    ctx.fill();

    ctx.fillStyle = "#ffaa00";
    ctx.globalAlpha = 0.7 * ctx.globalAlpha;
    ctx.fillRect(-4, p.h / 3, 8, 6);

    ctx.restore();
    ctx.globalAlpha = 1;
  }

  renderPowerup(pu) {
    const ctx = this.ctx;
    ctx.save();
    ctx.translate(pu.x, pu.y);
    ctx.rotate(pu.rot);
    const colors = { triple: "#00f0ff", rapid: "#ffaa00", shield: "#00ff88" };
    const icons = { triple: "T", rapid: "R", shield: "S" };
    const c = colors[pu.type];
    ctx.fillStyle = c;
    ctx.shadowColor = c;
    ctx.shadowBlur = 12;
    ctx.beginPath();
    ctx.arc(0, 0, 10, 0, Math.PI * 2);
    ctx.fill();
    ctx.shadowBlur = 0;
    ctx.fillStyle = "#05060f";
    ctx.font = "bold 12px Segoe UI, Arial";
    ctx.textAlign = "center";
    ctx.textBaseline = "middle";
    ctx.rotate(-pu.rot);
    ctx.fillText(icons[pu.type], 0, 1);
    ctx.restore();
  }

  gameOver(victory = false) {
    this.stop();
    this.callbacks.onGameOver?.({
      score: this.score,
      tabsDestroyed: this.tabsDestroyed,
      totalTabs: this.totalTabs,
      victory,
    });
  }
}