local __requestQueue={}
local _requestCount=0
local _Request={
    command="",
    currentTime=0,
    timeOut=2,
    id='0',
}
local __defaultErrorFunction=nil
local isDebugActive=false

local JS={}

function JS.callJS(funcToCall)
    print("callJavascriptFunction "..funcToCall)
end

--You can pass a set of commands here and, it is a syntactic sugar for executing many commands inside callJS, as it only calls a function
--If you pass arguments to the func beyond the string, it will perform automatically string.format
--Return statement is possible inside this structure
--This will return a string containing a function to be called by JS.callJS
function JS.stringFunc(str,...)
    str="(function(){"..str.."})()"
    if (#arg>0) then
        str=str:format(unpack(arg))
    end
    str=str:gsub("[\n\t]","")
    return str
end

--The call will store in the webDB the return value from the function passed it timeouts
local function retrieveJS(funcToCall,filename)
    --Used for retrieveData function
    JS.callJS(("FS.writeFile('%s/%s',%s);"):format(love.filesystem.getSaveDirectory(),filename,funcToCall))
end

--Call JS.newRequest instead
function _Request:new(isPromise,command,onDataLoaded,onError,timeout,id)
    local obj={}
    setmetatable(obj,self)
    obj.command=command
    obj.onError=onError or __defaultErrorFunction
    if not isPromise then
        retrieveJS(command,self.filename)
    else
        JS.callJS(command)
    end
    obj.onDataLoaded=onDataLoaded
    obj.timeOut=(timeout==nil) and obj.timeOut or timeout
    obj.id=id
    obj.filename="__temp"..id


    function obj:getData()
        --Try to read from webdb
        if love.filesystem.getInfo(self.filename) then
            return love.filesystem.read(self.filename)
        end
    end

    function obj:purgeData()
        --Data must be purged for not allowing old data to be retrieved
        love.filesystem.remove(self.filename)
    end

    function obj:update(dt)
        self.timeOut=self.timeOut-dt
        local retData=self:getData()

        if ((retData~=nil and retData~="nil") or self.timeOut<=0) then
            if (retData~=nil and retData:match("ERROR")==nil) then
                if isDebugActive then
                    print("Data has been retrieved "..retData)
                end
                self.onDataLoaded(retData)
            else
                self.onError(self.id,retData)
            end
            self:purgeData()
            return false
        else
            return true
        end
    end
    return obj
end

--Place this function on love.update and set it to return if it returns false (This API is synchronous)
function JS.retrieveData(dt)
    local isRetrieving=#__requestQueue~=0
    local deadRequests={}
    for i=1,#__requestQueue do
        local isUpdating=__requestQueue[i]:update(dt)
        if not isUpdating then
            table.insert(deadRequests,i)
        end
    end
    for i=1,#deadRequests do
        if (isDebugActive) then
            print("Request died: "..deadRequests[i])
        end
        table.remove(__requestQueue,deadRequests[i])
    end
    return isRetrieving
end

--May only be used for functions that don't return a promise
function JS.newRequest(funcToCall,onDataLoaded,onError,timeout,optionalId)
    table.insert(__requestQueue,_Request:new(false,funcToCall,onDataLoaded,onError,timeout or 5,optionalId or _requestCount))
end

--This function can be handled manually (in JS code)
--How to: add the function call when your events resolve: FS.writeFile("Put love.filesystem.getSaveDirectory here", "Pass a string here (NUMBER DONT WORK"))
--Or it can be handled by Lua, it auto sets your data if you write the following command:
-- _$_(yourStringOrFunctionHere)
function JS.newPromiseRequest(funcToCall,onDataLoaded,onError,timeout,optionalId)
    optionalId=optionalId or _requestCount
    funcToCall=funcToCall:gsub("_$_%(","FS.writeFile('"..love.filesystem.getSaveDirectory().."/__temp"..optionalId.."', ")
    table.insert(__requestQueue,_Request:new(true,funcToCall,onDataLoaded,onError,timeout or 5,optionalId))
end


--It receives the ID from ther request
--Don't try printing the request.command, as it will execute the javascript command
function JS.setDefaultErrorFunction(func)
    __defaultErrorFunction=func
end

JS.setDefaultErrorFunction(function(id,error)
    if (isDebugActive) then
        local msg="Data could not be loaded for id:'"..id.."'"
        if (error) then
            msg=msg.."\nError: "..error
        end
        print(msg)
    end
end)


JS.callJS(JS.stringFunc("__getWebDB('%s');","__LuaJSDB"))

return JS