import { useReducer } from "react";

export interface Order {
    name: string;
    quantity: number;
    HOT: boolean;
    price: number;
};

interface OrderState {
    orders: Order[];
};

const initialState = {
    orders: [],
} as OrderState;

export type OrderAction =
    | { type: "ADD_ORDER"; order: Order }
    | { type: "REMOVE_ORDER"; order: Order }
    | { type: "UPDATE_ORDER"; order: Order };

function compareOrder(a: Order, b: Order) {
    if (a.name < b.name) {
        return -1;
    }
    if (a.name > b.name) {
        return 1;
    }
    if (a.HOT && !b.HOT) {
        return -1;
    }
    if (!a.HOT && b.HOT) {
        return 1;
    }
    return 0;
}

function reducer(state: OrderState, action: OrderAction): OrderState {
    switch (action.type) {
        case "ADD_ORDER":
            if (state.orders.find(order => compareOrder(order, action.order) === 0)) {
                return {
                    orders: state.orders.map(order => compareOrder(order, action.order) === 0 ? {
                        ...order,
                        quantity: Math.max(order.quantity + action.order.quantity, 0)
                    } : order),
                };
            }
            return {
                orders: [...state.orders, action.order],
            };
        case "REMOVE_ORDER":
            return {
                orders: state.orders.filter(order => compareOrder(order, action.order) !== 0),
            };
        case "UPDATE_ORDER":
            return {
                orders: state.orders.map(order => compareOrder(order, action.order) === 0 ? action.order : order),
            };
        default:
            return state;
    }
}

export function useOrder() {
    const [state, dispatch] = useReducer(reducer, initialState);
    return { state, dispatch };
}