eiru_pos/src/store/modules/cart.js

const state = {
    cartItems: [],
    cartTotal: 0,
    itemToDiscount: null
}

const getters = {
    cartItems (state) {
        return state.cartItems
    },
    cartTotal (state, getters) {
        return state.cartTotal
    },
    itemToDiscount (state) {
        return state.itemToDiscount
    }
}

const mutations = {
    setCart (state, payload) {
        state.cartItems = payload
    },
    pushToCart (state, payload) {
        let productFound = state.cartItems.find(item => item.id === payload.id)

        if (productFound) {
            if (payload.quantity > 1) {
                if (productFound.quantity === payload.quantity) {
                    productFound.quantity = productFound.quantity + 1    
                } else {
                    productFound.quantity = payload.quantity
                }
            } else {
                productFound.quantity = productFound.quantity + payload.quantity
            }
            return
        }

        state.cartItems = [payload, ...state.cartItems]
    },
    pullFromCart (state, payload) {
        let productFoundIndex = state.cartItems.findIndex(item => item.id === payload.item.id)

        if (state.cartItems[productFoundIndex].quantity === 1) {
            payload.mode = 'full'
        }

        if (payload.mode === 'partial') {
            if (payload.item.quantity !== -1) {
                state.cartItems[productFoundIndex].quantity = payload.item.quantity
            } else {
                state.cartItems[productFoundIndex].quantity = state.cartItems[productFoundIndex].quantity - 1
            }
        } else {
            state.cartItems.splice(productFoundIndex, 1)
        }
    },
    setCartTotal (state, payload) {
        state.cartTotal = payload
    },
    setItemToDiscount (state, payload) {
        state.itemToDiscount = payload
    },
    setItemPrice (state, payload) {
        let foundProduct = state.cartItems.find(item => item.id === state.itemToDiscount.id)

        foundProduct.price = payload
    },
    resetPrice (state, payload) {
        let foundProduct = state.cartItems.find(item => item.id === payload.id)
        foundProduct.price = foundProduct.listPrice
    }
}

const actions = {
    addToCart ({ commit }, payload) {
        commit('pushToCart', payload)
    },
    decreaseFromCart ({ commit }, payload) {
        commit('pullFromCart', {
            item: payload,
            mode: 'partial'
        })
    },
    undoPrice ({ commit }, payload) {
        commit('resetPrice', payload)
    },
    changePrice ({ commit }, payload) {
        commit('setItemToDiscount', payload)
    },
    applyPrice ({ commit }, payload) {
        if (payload) {
            commit('setItemPrice', payload)
        }

        commit('setItemToDiscount', null)
    },
    removeFromCart ({ commit }, payload) {
        commit('pullFromCart', {
            item: payload,
            mode: 'full'
        })
    },
    changeCartTotal ({ commit, dispatch }, payload) {
        commit('setCartTotal', payload)
        dispatch('changeAmountToPay', payload)
    },
    updateFromSaleOrder({ commit, dispatch }, saleOrder) {
        dispatch('resetCart', [])

        if (!saleOrder) {
            return
        }

        let total = 0
        for (let line of saleOrder.lines) {
            total = total + (line.price * line.quantity)

            commit('pushToCart', line)
        }

        dispatch('changeCartTotal', total)
    },
    resetCart ({ commit }) {
        commit('setCart', [])
        commit('setCartTotal', 0)
    }
}

export default {
    state,
    getters,
    mutations,
    actions
}