/**
 * SkinScene.js
 * Tank skin gallery scene where players can preview, purchase, and equip skins.
 */

const {
  SCREEN_WIDTH,
  SCREEN_HEIGHT,
  COLORS,
  SCENE,
} = require('../base/GameGlobal');
const { t } = require('../i18n/I18n');

// Layout constants
const COLS = 2;
const CARD_GAP = 10;
const CARD_W = Math.min((SCREEN_WIDTH * 0.85 - CARD_GAP) / COLS, 150);
const CARD_H = 100;
const GRID_W = COLS * CARD_W + (COLS - 1) * CARD_GAP;
const GRID_LEFT = (SCREEN_WIDTH - GRID_W) / 2;
const CARDS_START_Y = SCREEN_HEIGHT * 0.18;

const SkinScene = {
  _buttons: {},
  _skinCards: [],
  _message: '',
  _messageTimer: 0,
  _scrollY: 0,

  enter() {
    this._message = '';
    this._messageTimer = 0;
    this._scrollY = 0;
    this._calculateLayout();
  },

  exit() {},

  _calculateLayout() {
    const sm = GameGlobal.skinManager;
    if (!sm) return;

    const skins = sm.getAllSkins();
    this._skinCards = [];

    for (let i = 0; i < skins.length; i++) {
      const col = i % COLS;
      const row = Math.floor(i / COLS);
      const x = GRID_LEFT + col * (CARD_W + CARD_GAP);
      const y = CARDS_START_Y + row * (CARD_H + CARD_GAP);

      this._skinCards.push({
        ...skins[i],
        rect: { x, y, w: CARD_W, h: CARD_H },
      });
    }

    // Back button
    const backW = 100;
    const backH = 36;
    const lastRow = Math.ceil(skins.length / COLS);
    const backY = CARDS_START_Y + lastRow * (CARD_H + CARD_GAP) + 10;
    this._buttons = {
      back: { x: (SCREEN_WIDTH - backW) / 2, y: backY, w: backW, h: backH },
    };
  },

  update(dt) {
    if (this._messageTimer > 0) {
      this._messageTimer -= dt;
      if (this._messageTimer <= 0) {
        this._message = '';
      }
    }
  },

  render(ctx) {
    // Background
    ctx.fillStyle = COLORS.MENU_BG;
    ctx.fillRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);

    // Title
    ctx.fillStyle = COLORS.MENU_TITLE;
    ctx.font = 'bold 22px Arial';
    ctx.textAlign = 'center';
    ctx.textBaseline = 'middle';
    ctx.fillText(t('skin.title') || 'Tank Skins', SCREEN_WIDTH / 2, SCREEN_HEIGHT * 0.06);

    // Gold balance
    const gold = GameGlobal.currencyManager ? GameGlobal.currencyManager.getGold() : 0;
    ctx.fillStyle = '#FFD700';
    ctx.font = 'bold 14px Arial';
    ctx.fillText(`🪙 ${gold}`, SCREEN_WIDTH / 2, SCREEN_HEIGHT * 0.12);

    const sm = GameGlobal.skinManager;
    if (!sm) return;

    const equippedId = sm.getEquippedSkinId();

    // Render skin cards
    for (const card of this._skinCards) {
      this._renderSkinCard(ctx, card, sm.isUnlocked(card.id), equippedId === card.id);
    }

    // Back button
    this._renderButton(ctx, this._buttons.back, t('common.back') || '← Back', '#666666');

    // Message toast
    if (this._message) {
      ctx.fillStyle = 'rgba(0,0,0,0.7)';
      const msgW = 200;
      const msgH = 30;
      const msgX = (SCREEN_WIDTH - msgW) / 2;
      const msgY = SCREEN_HEIGHT * 0.92;
      ctx.fillRect(msgX, msgY, msgW, msgH);
      ctx.fillStyle = '#FFFFFF';
      ctx.font = '13px Arial';
      ctx.textAlign = 'center';
      ctx.textBaseline = 'middle';
      ctx.fillText(this._message, SCREEN_WIDTH / 2, msgY + msgH / 2);
    }
  },

  _renderSkinCard(ctx, card, isUnlocked, isEquipped) {
    const { rect } = card;

    // Card background
    if (isEquipped) {
      ctx.fillStyle = 'rgba(76, 175, 80, 0.3)';
      ctx.strokeStyle = '#4CAF50';
    } else if (isUnlocked) {
      ctx.fillStyle = 'rgba(255,255,255,0.08)';
      ctx.strokeStyle = '#666666';
    } else {
      ctx.fillStyle = 'rgba(255,255,255,0.03)';
      ctx.strokeStyle = '#444444';
    }
    ctx.lineWidth = isEquipped ? 2.5 : 1.5;

    // Rounded rect
    const r = 8;
    ctx.beginPath();
    ctx.moveTo(rect.x + r, rect.y);
    ctx.lineTo(rect.x + rect.w - r, rect.y);
    ctx.arcTo(rect.x + rect.w, rect.y, rect.x + rect.w, rect.y + r, r);
    ctx.lineTo(rect.x + rect.w, rect.y + rect.h - r);
    ctx.arcTo(rect.x + rect.w, rect.y + rect.h, rect.x + rect.w - r, rect.y + rect.h, r);
    ctx.lineTo(rect.x + r, rect.y + rect.h);
    ctx.arcTo(rect.x, rect.y + rect.h, rect.x, rect.y + rect.h - r, r);
    ctx.lineTo(rect.x, rect.y + r);
    ctx.arcTo(rect.x, rect.y, rect.x + r, rect.y, r);
    ctx.closePath();
    ctx.fill();
    ctx.stroke();

    const cx = rect.x + rect.w / 2;

    // Tank preview (mini tank icon)
    this._drawMiniTank(ctx, cx, rect.y + 28, card);

    // Skin name
    ctx.fillStyle = '#FFFFFF';
    ctx.font = 'bold 12px Arial';
    ctx.textAlign = 'center';
    ctx.textBaseline = 'middle';
    ctx.fillText(t(card.nameKey) || card.id, cx, rect.y + 58);

    // Status / price
    if (isEquipped) {
      ctx.fillStyle = '#4CAF50';
      ctx.font = 'bold 11px Arial';
      ctx.fillText(t('skin.equipped') || '✓ Equipped', cx, rect.y + rect.h - 16);
    } else if (isUnlocked) {
      ctx.fillStyle = '#AAAAAA';
      ctx.font = '11px Arial';
      ctx.fillText(t('skin.owned') || 'Owned', cx, rect.y + rect.h - 16);
    } else {
      const canAfford = GameGlobal.currencyManager && GameGlobal.currencyManager.hasGold(card.cost);
      ctx.fillStyle = canAfford ? '#FFD700' : '#FF4444';
      ctx.font = 'bold 11px Arial';
      ctx.fillText(`🪙 ${card.cost}`, cx, rect.y + rect.h - 16);
    }
  },

  /**
   * Draw a mini tank preview with skin colors.
   */
  _drawMiniTank(ctx, cx, cy, card) {
    const size = 14;
    const bodyColor = card.colors ? card.colors.body : '#FFD700';
    const turretColor = card.colors ? card.colors.turret : '#B8860B';
    const trackColor = card.colors ? card.colors.track : '#8B6914';

    ctx.save();
    ctx.translate(cx, cy);

    // Body
    ctx.fillStyle = bodyColor;
    ctx.fillRect(-size, -size / 2, size * 2, size);

    // Turret (barrel)
    ctx.fillStyle = turretColor;
    ctx.fillRect(-2, -size / 2 - 10, 4, 10);

    // Center detail
    ctx.fillStyle = turretColor;
    ctx.fillRect(-size * 0.3, -size * 0.3, size * 0.6, size * 0.6);

    // Tracks
    ctx.fillStyle = trackColor;
    ctx.fillRect(-size - 3, -size / 2, 3, size);
    ctx.fillRect(size, -size / 2, 3, size);

    ctx.restore();
  },

  _renderButton(ctx, rect, label, color) {
    if (!rect) return;

    ctx.fillStyle = color;
    ctx.strokeStyle = '#333333';
    ctx.lineWidth = 1;

    const r = 6;
    ctx.beginPath();
    ctx.moveTo(rect.x + r, rect.y);
    ctx.lineTo(rect.x + rect.w - r, rect.y);
    ctx.arcTo(rect.x + rect.w, rect.y, rect.x + rect.w, rect.y + r, r);
    ctx.lineTo(rect.x + rect.w, rect.y + rect.h - r);
    ctx.arcTo(rect.x + rect.w, rect.y + rect.h, rect.x + rect.w - r, rect.y + rect.h, r);
    ctx.lineTo(rect.x + r, rect.y + rect.h);
    ctx.arcTo(rect.x, rect.y + rect.h, rect.x, rect.y + rect.h - r, r);
    ctx.lineTo(rect.x, rect.y + r);
    ctx.arcTo(rect.x, rect.y, rect.x + r, rect.y, r);
    ctx.closePath();
    ctx.fill();
    ctx.stroke();

    ctx.fillStyle = '#FFFFFF';
    ctx.font = 'bold 14px Arial';
    ctx.textAlign = 'center';
    ctx.textBaseline = 'middle';
    ctx.fillText(label, rect.x + rect.w / 2, rect.y + rect.h / 2);
  },

  _hitTest(tx, ty, rect) {
    if (!rect) return false;
    return tx >= rect.x && tx <= rect.x + rect.w && ty >= rect.y && ty <= rect.y + rect.h;
  },

  _showMessage(msg) {
    this._message = msg;
    this._messageTimer = 2;
  },

  handleTouch(eventType, e) {
    if (eventType !== 'touchstart') return;

    const touch = e.touches[0];
    const tx = touch.clientX;
    const ty = touch.clientY;
    const sm = GameGlobal.skinManager;
    if (!sm) return;

    // Check skin cards
    for (const card of this._skinCards) {
      if (this._hitTest(tx, ty, card.rect)) {
        if (sm.isUnlocked(card.id)) {
          // Equip
          if (sm.getEquippedSkinId() !== card.id) {
            const result = sm.equipSkin(card.id);
            if (result.success) {
              this._showMessage(t('skin.equipSuccess') || '✓ Skin equipped!');
            }
          }
        } else {
          // Purchase
          const result = sm.purchaseSkin(card.id);
          if (result.success) {
            this._showMessage(t('skin.purchaseSuccess') || '✓ Skin unlocked!');
            // Auto-equip after purchase
            sm.equipSkin(card.id);
          } else if (result.error === 'Insufficient gold') {
            this._showMessage(t('currency.insufficient') || 'Insufficient Gold');
          }
        }
        return;
      }
    }

    // Back button
    if (this._hitTest(tx, ty, this._buttons.back)) {
      GameGlobal.sceneManager.switchTo(SCENE.MENU);
      return;
    }
  },
};

module.exports = SkinScene;