local Krypton = require("Krypton")
local ScanInventory = require("core.inventory.ScanInventory")
local Pricing = require("core.Pricing")
local sound = require("util.sound")
local eventHook = require("util.eventHook")

local blinkFrequency = 3
local shopSyncFrequency = 30
local shopSyncChannel = 9773

---@class ShopState
---@field running boolean
local ShopState = {}
local ShopState_mt = { __index = ShopState }

function ShopState.new(config, products, peripherals, version, logs, eventHooks)
    local self = setmetatable({}, ShopState_mt)

    self.running = false
    self.config = config
    self.peripherals = peripherals
    self.products = products
    self.version = version
    if config.currencies and config.currencies[1] then
        self.selectedCurrency = config.currencies[1]
    else
        self.selectedCurrency = nil
    end
    self.selectedCategory = 1
    self.numCategories = 1
    self.productsChanged = false
    self.logs = logs
    self.eventHooks = eventHooks
    self.lastTouched = os.epoch("utc")

    return self
end

local function waitForAnimation(uid)
    coroutine.yield("animationFinished", uid)
end

local function parseMeta(transactionMeta)
    local meta = {}
    local i = 1
    if transactionMeta and #transactionMeta > 0 then
        for metaEntry in transactionMeta:gmatch("([^;]+)") do
            if metaEntry:find("=") then
                local key, value = metaEntry:match("([^=]+)=([^=]+)")
                meta[key] = value
            else
                meta[metaEntry] = true
                meta[i] = metaEntry
                i = i + 1
            end
        end
    end
    return meta
end

local function validateReturnAddress(address)
    -- Primitive validation, will accept all valid addresses at the expense of some false positives
    if address:find("@") then
        local metaname, name = address:match("([^@]+)@([^@]+).%w+")
        if not metaname or not name then
            return false
        end
        if #name > 64 or #metaname > 32 then
            return false
        end
    else
        if #address > 64 then
            return false
        end
    end
    return true
end

local function isRelative(name)
    return name == "top" or name == "bottom" or name == "left" or name == "right" or name == "front" or name == "back"
end

local function refund(currency, address, meta, value, message, error)
    message = message or "Here is your refund!"
    local returnTo = address
    if meta and meta["return"] then
        if validateReturnAddress(meta["return"]) then
            returnTo = meta["return"]
        end
    end
    if not error then
        currency.krypton.ws:makeTransaction(returnTo, value, "message=" .. message)
    else
        currency.krypton.ws:makeTransaction(returnTo, value, "error=" .. message)
    end
end

local function handlePurchase(transaction, meta, sentMetaname, transactionCurrency, transactionCurrency, state)
    local purchasedProduct = nil
    if state.eventHooks and state.eventHooks.preProduct then
        purchasedProduct = eventHook.execute(state.eventHooks.preProduct, transaction, transactionCurrency, meta, sentMetaname, state.products)
    end
    if purchasedProduct == nil then
        for _, product in ipairs(state.products) do
            if product.address:lower() == sentMetaname:lower() or product.name:gsub(" ", ""):lower() == sentMetaname:lower() then
                purchasedProduct = product
                break
            end
        end
    end
    if purchasedProduct then
        local productPrice = Pricing.getProductPrice(purchasedProduct, transactionCurrency)
        local amountPurchased = math.floor(transaction.value / productPrice)
        if purchasedProduct.maxQuantity then
            amountPurchased = math.min(amountPurchased, purchasedProduct.maxQuantity)
        end
        if amountPurchased > 0 then
            local productsPurchased = {}
            if purchasedProduct.modid then
                table.insert(productsPurchased, { product = purchasedProduct, quantity = 1 })
            end
            if purchasedProduct.bundle and #purchasedProduct.bundle > 0 then
                for _, bundleProduct in ipairs(purchasedProduct.bundle) do
                    for _, product in ipairs(state.products) do
                        if product.address:lower() == bundleProduct.product:lower() or product.name:lower() == bundleProduct.product:lower() or (product.productId and product.productId:lower() == bundleProduct.product:lower()) then
                            local productFound = false
                            for _, productPurchased in ipairs(productsPurchased) do
                                if productPurchased.product == product then
                                    productPurchased.quantity = productPurchased.quantity + bundleProduct.quantity
                                    productFound = true
                                    break
                                end
                            end
                            if not productFound then
                                table.insert(productsPurchased, { product = product, quantity = bundleProduct.quantity })
                            end
                            break
                        end
                    end
                end
            end
            local available = amountPurchased
            for _, productPurchased in ipairs(productsPurchased) do
                local productSources, productAvailable = ScanInventory.findProductItems(state.products, productPurchased.product, productPurchased.quantity * amountPurchased)
                available = math.min(available, math.floor(productAvailable / productPurchased.quantity))
                productPurchased.sources = productSources
                if available == 0 then
                    break
                end
            end
            if available > 0 then
                local refundAmount = math.floor(transaction.value - (available * productPrice))
                if available > 0 then
                    local allowPurchase = true
                    local err
                    local errMessage
                    if state.eventHooks and state.eventHooks.prePurchase then
                        allowPurchase, err, errMessage = eventHook.execute(state.eventHooks.prePurchase, purchasedProduct, available, refundAmount, transaction, transactionCurrency)
                    end
                    if allowPurchase ~= false then
                        print("Purchased " .. available .. " of " .. purchasedProduct.name .. " for " .. transaction.from .. " for " .. transaction.value .. " " .. transactionCurrency.id .. " (refund " .. refundAmount .. ")")
                        for _, productPurchased in ipairs(productsPurchased) do
                            for _, productSource in ipairs(productPurchased.sources) do
                                if state.config.peripherals.outputChest == "self" then
                                    if not turtle then
                                        error("Self output but not a turtle!")
                                    end
                                    if not state.peripherals.modem.getNameLocal() then
                                        error("Modem is not connected! Try right clicking it")
                                    end
                                    if turtle.getSelectedSlot() ~= 1 then
                                        turtle.select(1)
                                    end
                                    peripheral.call(productSource.inventory, "pushItems", state.peripherals.modem.getNameLocal(), productSource.slot, productSource.amount, 1)
                                    if state.config.settings.dropDirection == "forward" then
                                        turtle.drop(productSource.amount)
                                    elseif state.config.settings.dropDirection == "up" then
                                        turtle.dropUp(productSource.amount)
                                    elseif state.config.settings.dropDirection == "down" then
                                        turtle.dropDown(productSource.amount)
                                    else
                                        error("Invalid drop direction: " .. state.config.settings.dropDirection)
                                    end
                                else
                                    peripheral.call(productSource.inventory, "pushItems", state.config.peripherals.outputChest, productSource.slot, productSource.amount, 1)
                                    --peripheral.call(state.config.peripherals.outputChest, "drop", 1, productSource.amount, state.config.settings.dropDirection)
                                end
                            end
                            productPurchased.product.quantity = productPurchased.product.quantity - (productPurchased.quantity * available)
                        end
                        if not purchasedProduct.modid then
                            purchasedProduct.quantity = math.max(0, purchasedProduct.quantity - available)
                        end
                        if refundAmount > 0 then
                            refund(transactionCurrency, transaction.from, meta, refundAmount, state.config.lang.refundRemaining)
                        end
                        if state.config.settings.playSounds then
                            sound.playSound(state.peripherals.speaker, state.config.sounds.purchase)
                        end
                        if state.eventHooks and state.eventHooks.purchase then
                            eventHook.execute(state.eventHooks.purchase, purchasedProduct, available, refundAmount, transaction, transactionCurrency)
                        end
                    else
                        refund(transactionCurrency, transaction.from, meta, transaction.value, errMessage or state.config.lang.refundDenied, err)
                        if state.eventHooks and state.eventHooks.failedPurchase then
                            eventHook.execute(state.eventHooks.failedPurchase, transaction, transactionCurrency, purchasedProduct, errMessage or state.config.lang.refundDenied, err)
                        end
                    end
                else
                    refund(transactionCurrency, transaction.from, meta, transaction.value, state.config.lang.refundOutOfStock)
                    if state.eventHooks and state.eventHooks.failedPurchase then
                        eventHook.execute(state.eventHooks.failedPurchase, transaction, transactionCurrency, purchasedProduct, state.config.lang.refundOutOfStock)
                    end
                end
            else
                refund(transactionCurrency, transaction.from, meta, transaction.value, state.config.lang.refundOutOfStock)
                if state.eventHooks and state.eventHooks.failedPurchase then
                    eventHook.execute(state.eventHooks.failedPurchase, transaction, transactionCurrency, purchasedProduct, state.config.lang.refundOutOfStock)
                end
            end
        else
            refund(transactionCurrency, transaction.from, meta, transaction.value, state.config.lang.refundAtLeastOne, true)
            if state.eventHooks and state.eventHooks.failedPurchase then
                eventHook.execute(state.eventHooks.failedPurchase, transaction, transactionCurrency, purchasedProduct, state.config.lang.refundAtLeastOne)
            end
        end
    else
        if state.config.settings.refundInvalidMetaname then
            refund(transactionCurrency, transaction.from, meta, transaction.value, state.config.lang.refundInvalidProduct, true)
        end
        if state.eventHooks and state.eventHooks.failedPurchase then
            eventHook.execute(state.eventHooks.failedPurchase, transaction, transactionCurrency, nil, state.config.lang.refundInvalidProduct)
        end
    end
end

local function setupKrypton(state)
    state.selectedCurrency = state.config.currencies[1]
    state.currencies = {}
    state.kryptonListeners = {}
    for _, currency in ipairs(state.config.currencies) do
        if currency.name == "" then
            currency.name = nil
        end
        local node = currency.node
        if not node and currency.id == "krist" then
            node = "https://krist.dev/"
        elseif not node and currency.id == "tenebra" then
            node = "https://tenebra.lil.gay/"
        end
        currency.krypton = Krypton.new({
            privateKey = currency.pkey,
            node = node,
            id = currency.id,
        })
        local pkey = currency.pkey
        if currency.pkeyFormat == "kristwallet" then
            pkey = currency.krypton:toKristWalletFormat(currency.pkey)
        end
        currency.host = currency.krypton:makev2address(pkey)
        currency.krypton.privateKey = pkey
        table.insert(state.currencies, currency)
        local kryptonWs = currency.krypton:connect()
        kryptonWs:subscribe("ownTransactions")
        kryptonWs:getSelf()
        if currency.name then
            local name = currency.name
            if name:find("%.") then
                name = name:sub(1, name:find("%.") - 1)
            end
            local nameInfo = currency.krypton:getName(name)
            if not nameInfo then
                error("Name " .. currency.name .. " does not exist!")
            end
            if nameInfo.name.owner:lower() ~= currency.host:lower() then
                error("Name " .. currency.name .. " is not owned by " .. currency.host .. "!")
            end
        end
        table.insert(state.kryptonListeners, function() kryptonWs:listen() end)
        state.kryptonReady = true
    end
end

-- Anytime the shop state is resumed, animation should be finished instantly. (call animation finish hooks)
---@param state ShopState
local function runShop(state)
    -- Shop is starting
    -- Wait for config ready
    while not state.config.ready do sleep(0.5) end
    state.running = true
    state.currencies = {}
    state.kryptonListeners = {}
    setupKrypton(state)
    parallel.waitForAny(function()
        while true do
            local event, transactionEvent = os.pullEvent("transaction")
            if event == "transaction" then
                local transactionCurrency = nil
                for _, currency in ipairs(state.currencies) do
                    if currency.krypton.id == transactionEvent.source then
                        transactionCurrency = currency
                        break
                    end
                end
                if transactionCurrency then
                    local transaction = transactionEvent.transaction
                    local sentName = transaction.sent_name
                    local sentMetaname = transaction.sent_metaname
                    local nameSuffix = transactionCurrency.krypton.currency.name_suffix
                    if sentName and transactionCurrency.name and transactionCurrency.name:find(".") then
                        sentName = sentName .. "." .. nameSuffix
                    end
                    if transaction.from ~= transactionCurrency.host and (not transactionCurrency.name and not sentName) or (transactionCurrency.name and sentName and sentName:lower() == transactionCurrency.name:lower()) then
                        local meta = parseMeta(transaction.metadata)
                        if transaction.to == transactionCurrency.host and not transactionCurrency.name and not sentMetaname then
                            sentMetaname = meta[1]
                        end
                        if sentMetaname then
                            local success, err = pcall(handlePurchase, transaction, meta, sentMetaname, transactionCurrency, transactionCurrency, state)
                            if success then
                                -- Success :D
                            else
                                refund(transactionCurrency, transaction.from, meta, transaction.value, state.config.lang.refundError, true)
                                if state.eventHooks and state.eventHooks.failedPurchase then
                                    eventHook.execute(state.eventHooks.failedPurchase, transaction, transactionCurrency, nil, state.config.lang.refundError)
                                end
                                error(err)
                            end
                        else
                            if state.config.settings.refundInvalidMetaname then
                                refund(transactionCurrency, transaction.from, meta, transaction.value, state.config.lang.refundNoProduct, true)
                            end
                            if state.eventHooks and state.eventHooks.failedPurchase then
                                eventHook.execute(state.eventHooks.failedPurchase, transaction, transactionCurrency, nil, state.config.lang.refundNoProduct)
                            end
                        end
                    end
                end
            end
        end
    end, function()
        while state.running do
            local onInventoryRefresh = nil
            if state.eventHooks and state.eventHooks.onInventoryRefresh then
                onInventoryRefresh = state.eventHooks.onInventoryRefresh
            end
            ScanInventory.updateProductInventory(state.products, onInventoryRefresh)
            if state.config.settings.hideUnavailableProducts then
                state.productsChanged = true
            end
            sleep(state.config.settings.pollFrequency)
        end
    end, function()
        while state.running do
            if state.config.settings.categoryCycleFrequency > 0 and os.epoch("utc") > state.lastTouched + (state.config.settings.activityTimeout * 1000) then
                state.selectedCategory = state.selectedCategory + 1
                if state.selectedCategory > state.numCategories then
                    state.selectedCategory = 1
                end
                state.productsChanged = true
            end
            sleep(math.min(1, state.config.settings.categoryCycleFrequency))
        end
    end, function()
        local blinkState = false
        while state.running do
            blinkState = not blinkState
            if state.config.peripherals.blinker then
                redstone.setOutput(state.config.peripherals.blinker, blinkState) 
            end
            if state.eventHooks and state.eventHooks.blink then
                eventHook.execute(state.eventHooks.blink, blinkState)
            end
            sleep(blinkFrequency)
        end
    end, function()
        while state.running do
            sleep(shopSyncFrequency)
            if state.config.shopSync and state.config.shopSync.enabled and state.peripherals.shopSyncModem then
                local items = {}
                for i = 1, #state.products do
                    local product = state.products[i]
                    local prices = {}
                    local nbt = nil
                    local predicates = nil
                    if product.predicates then
                        nbt = ""
                        predicates = product.predicates
                    end
                    for j = 1, #state.config.currencies do
                        local currency = state.config.currencies[j]
                        local currencyName = "KST"
                        if currency.krypton and currency.krypton.currency and currency.krypton.currency.currency_symbol then
                            currencyName = currency.krypton.currency.currency_symbol
                        end
                        local address = currency.host
                        local requiredMeta = nil
                        if currency.name then
                            address = product.address .. "@" .. currency.name
                        else
                            requiredMeta = product.address
                        end
                        table.insert(prices, {
                            value = product.price / currency.value,
                            currency = currencyName,
                            address = address,
                            --requiredMeta = requiredMeta
                        })
                    end
                    table.insert(items, {
                        price = prices,
                        item = {
                            name = product.modid,
                            displayName = product.name,
                            nbt = nbt,
                            --predicates = predicates
                        }
                    })
                end
                state.peripherals.shopSyncModem.transmit(shopSyncChannel, os.getComputerID(), {
                    type = "ShopSync",
                    info = {
                        name = state.config.shopSync.name,
                        description = state.config.shopSync.description,
                        owner = state.config.shopSync.owner,
                        software = {
                            name = "Radon",
                            version = state.version
                        },
                        location = state.config.shopSync.location,
                    },
                    items = {

                    }
                })
            end
        end
    end, function()
        while state.running do
            if state.changedCurrencies and state.oldConfig then
                state.changedCurrencies = false
                state.kryptonReady = false
                for i = 1, #state.oldConfig.currencies do
                    local currency = state.oldConfig.currencies[i]
                    if (currency.krypton and currency.krypton.ws) then
                        currency.krypton.ws:disconnect()
                        currency.krypton = nil
                    end
                end
                for i = 1, #state.currencies do
                    local currency = state.currencies[i]
                    if (currency.krypton and currency.krypton.ws) then
                        currency.krypton.ws:disconnect()
                        currency.krypton = nil
                    end
                end
                setupKrypton(state)
                state.kryptonReady = true
                state.oldConfig = nil
            end
            sleep(0.5)
        end
    end, function()
        while state.running do
            if state.kryptonReady then
                parallel.waitForAny(function()
                    while state.kryptonReady do
                        sleep(0.5)
                    end
                end, unpack(state.kryptonListeners))
            end
            sleep(0.5)
        end
    end)
end

return {
    ShopState = ShopState,
    runShop = runShop,
}