-- Tweaks
local plainRenderer = Renderer
Renderer = function(...)
    local r = plainRenderer(...)
    local mt = getmetatable(r)
    local oldFunc = mt.__index.loadTexture
    local textureWatcher = setmetatable({}, {__mode="k"})
    local lastCallTime = os.time()
    mt.__index.loadTexture = function(...)
        print("loadTexture invoked.")
        local text = oldFunc(...)
        textureWatcher[text] = true
        if os.time() - lastCallTime > 3 then
            local cnt = 0
            for t, b in pairs(textureWatcher) do
                cnt = cnt + 1
            end
            print("Total weak texture: ", cnt)
            if cnt > 100 then
                collectgarbage()
            end
            lastCallTime = os.time()
        end
        return text
    end
    Renderer = plainRenderer
    return r
end

-- Promise, Async/Await Helpers
function Promise(callback)
    local p = {
        __waiting = {},
        __status = 0
    }

    p.resolve = function(...)
        p.__ret = table.pack(...)
        p.__status = 1
        while #p.__waiting > 0 do
            local co = p.__waiting[1]
            table.remove(p.__waiting, 1)
            coroutine.resume(co)
        end
    end

    p.reject = function(err)
        p.__ret = err
        p.__status = 2
        while #p.__waiting > 0 do
            local co = p.__waiting[1]
            table.remove(p.__waiting, 1)
            coroutine.resume(co)
        end
    end

    callback(p.resolve, p.reject)

    return p
end

function await(p)
    if p.__status ~= 0 then
        if p.__status == 1 then
            return table.unpack(p.__ret)
        else
            error(p.__ret)
        end
    else
        local current = coroutine.running()
        table.insert(p.__waiting, current)
        coroutine.yield(p)
    end
end

function async(fn)
    return function()
        local co = coroutine.create(fn)
        local ret = table.pack(coroutine.resume(fn))
        if coroutine.status(co) == "dead" then
            local success = table.remove(ret, 1)
            ret.n = ret.n - 1
            local p = {}
            if success then
                p.__status = 1  -- resolved
                p.__ret = ret
            else
                p.__status = 2  -- rejected
                p.__ret = ret[1]
            end
            return p
        else
            return ret[2]
        end
    end
end

-- Load & run game
local gameMain = loadfile("code/game.lua")
xpcall(gameMain, function(err)
    print("LuaMain Exception: ", err)
    print(debug.traceback())
end)