import { createSlice, PayloadAction } from '@reduxjs/toolkit';
import { CartItem, CatalogItem } from '../interfaces';

interface CartState {
  items: CartItem[];
  couponCode: string | null;
  discount: number;
  providerId: string | null;
  providerName: string | null;
}

const initialState: CartState = {
  items: [],
  couponCode: null,
  discount: 0,
  providerId: null,
  providerName: null,
};

const cartSlice = createSlice({
  name: 'cart',
  initialState,
  reducers: {
    addItem(state, action: PayloadAction<{ providerId: string; providerName: string; item: CatalogItem }>) {
      const { providerId, providerName, item } = action.payload;
      if (state.providerId && state.providerId !== providerId) {
        state.items = [];
      }
      state.providerId = providerId;
      state.providerName = providerName;
      const existing = state.items.find((i) => i.item.id === item.id);
      if (existing) {
        existing.quantity += 1;
      } else {
        state.items.push({
          id: `${providerId}-${item.id}`,
          providerId,
          providerName,
          item,
          quantity: 1,
        });
      }
    },
    removeItem(state, action: PayloadAction<string>) {
      const existing = state.items.find((i) => i.item.id === action.payload);
      if (existing) {
        if (existing.quantity > 1) {
          existing.quantity -= 1;
        } else {
          state.items = state.items.filter((i) => i.item.id !== action.payload);
        }
      }
      if (state.items.length === 0) {
        state.providerId = null;
        state.providerName = null;
      }
    },
    clearCart(state) {
      state.items = [];
      state.couponCode = null;
      state.discount = 0;
      state.providerId = null;
      state.providerName = null;
    },
    applyCoupon(state, action: PayloadAction<string>) {
      state.couponCode = action.payload;
      state.discount = 50;
    },
    removeCoupon(state) {
      state.couponCode = null;
      state.discount = 0;
    },
  },
});

export const { addItem, removeItem, clearCart, applyCoupon, removeCoupon } = cartSlice.actions;

export const selectCartTotal = (state: { cart: CartState }) => {
  const subtotal = state.cart.items.reduce(
    (sum, item) => sum + item.item.price * item.quantity,
    0,
  );
  const deliveryFee = 40;
  const platformFee = 10;
  const discount = state.cart.discount;
  return {
    subtotal,
    deliveryFee,
    platformFee,
    discount,
    total: Math.max(0, subtotal + deliveryFee + platformFee - discount),
    itemCount: state.cart.items.reduce((sum, item) => sum + item.quantity, 0),
  };
};

export default cartSlice.reducer;