/**
 * Cart Store
 * Manages shopping cart state with localStorage persistence
 * Dispatches 'cart-updated' events when cart changes
 */

const CART_STORAGE_KEY = "milinda-cart";

class CartStore {
  constructor() {
    this.items = this.loadFromStorage();
  }

  /**
   * Load cart from localStorage
   */
  loadFromStorage() {
    try {
      const stored = localStorage.getItem(CART_STORAGE_KEY);
      return stored ? JSON.parse(stored) : [];
    } catch (e) {
      console.error("Failed to load cart from storage:", e);
      return [];
    }
  }

  /**
   * Save cart to localStorage
   */
  saveToStorage() {
    try {
      localStorage.setItem(CART_STORAGE_KEY, JSON.stringify(this.items));
    } catch (e) {
      console.error("Failed to save cart to storage:", e);
    }
  }

  /**
   * Dispatch cart-updated event
   */
  notifyUpdate() {
    window.dispatchEvent(
      new CustomEvent("cart-updated", {
        detail: {
          items: this.items,
          count: this.getItemCount(),
          total: this.getTotal(),
        },
      })
    );
  }

  /**
   * Add item to cart
   * @param {Object} item - Item to add { title, author, price, type, image }
   */
  addItem(item) {
    // Check if item already exists (by title and type)
    const existingIndex = this.items.findIndex(
      (i) => i.title === item.title && i.type === item.type
    );

    if (existingIndex >= 0) {
      // Increment quantity
      this.items[existingIndex].quantity += 1;
    } else {
      // Add new item
      this.items.push({
        ...item,
        quantity: 1,
        addedAt: Date.now(),
      });
    }

    this.saveToStorage();
    this.notifyUpdate();

    return this.items;
  }

  /**
   * Remove item from cart
   * @param {number} index - Index of item to remove
   */
  removeItem(index) {
    if (index >= 0 && index < this.items.length) {
      this.items.splice(index, 1);
      this.saveToStorage();
      this.notifyUpdate();
    }
    return this.items;
  }

  /**
   * Update item quantity
   * @param {number} index - Index of item
   * @param {number} quantity - New quantity
   */
  updateQuantity(index, quantity) {
    if (index >= 0 && index < this.items.length) {
      if (quantity <= 0) {
        this.removeItem(index);
      } else {
        this.items[index].quantity = quantity;
        this.saveToStorage();
        this.notifyUpdate();
      }
    }
    return this.items;
  }

  /**
   * Clear all items from cart
   */
  clear() {
    this.items = [];
    this.saveToStorage();
    this.notifyUpdate();
    return this.items;
  }

  /**
   * Get all items
   */
  getItems() {
    return this.items;
  }

  /**
   * Get total item count (sum of quantities)
   */
  getItemCount() {
    return this.items.reduce((sum, item) => sum + item.quantity, 0);
  }

  /**
   * Get cart total price
   */
  getTotal() {
    return this.items.reduce((sum, item) => {
      // Parse price like "€ 24,95" to number
      const priceStr = item.price || "0";
      const price = parseFloat(
        priceStr.replace(/[€$£\s]/g, "").replace(",", ".")
      );
      return sum + price * item.quantity;
    }, 0);
  }
}

// Create singleton instance
const cart = new CartStore();

// Export for module use
export default cart;

// Also attach to window for global access
window.cartStore = cart;