--!optimize 2
--!strict
--@EternityDev
local Client = {}

local RunService = game:GetService("RunService")
local Thread = require("./Util/Thread")
local Buffer = require("./Util/Buffer")
local Replication = require("./Replication")
local Event: RemoteEvent = script.Parent:WaitForChild("Event")
local UnreliableEvent: UnreliableRemoteEvent = script.Parent:WaitForChild("UnreliableEvent")
local deltaT: number, cycle: number = 0, 1 / 61
local writer: Buffer.Writer = Buffer.createWriter()

type Connection = {
	Connected: boolean,
	Disconnect: (self: Connection) -> (),
}
type Event = {
	i: number,
	c: (Player, ...any?) -> ...any?,
}

local queueEvent: { { any } } = {}
local queueUnreliableEvent: { { any } } = {}
local eventListeners: { Event } = {}
local eventSchemas: { [number]: Buffer.SchemaType } = {}

local pendingInvokes: { [string]: thread } = {}
local invokeId = 0

--@optional
-- Yields the current thread until the client has successfully initialized and synchronized with the server's replication data (identifier). Its optionally, but highly recommended to call this before firing or connecting to any events to ensure the network is fully ready.
Client.awaitReady = Replication.wait_for_ready

--@remoteName string
--@schema Buffer.SchemaType
-- Define a schema for strict data packing on a specific event.
Client.useSchema = function(remoteName: string, schema: Buffer.SchemaType)
	local id = Replication.get_id[remoteName]
	if not id then
		warn(`[Warp]: ".useSchema"::"{remoteName}" does not exist, likely its not registered on the server yet.`)
		return
	end
	eventSchemas[id] = schema
end

--@remoteName string
--@fn function
-- Connect to an event to receive incoming data from the server.
Client.Connect = function(remoteName: string, fn: (Player, ...any?) -> ...any?): Connection
	local id = Replication.get_id[remoteName]
	if not id then
		warn(`[Warp]: ".Connect"::"{remoteName}" does not exist, likely its not registered on the server yet.`)
		return { Connected = false, Disconnect = function() return end } :: Connection
	end
	local detail = {
		i = id,
		c = fn,
	}
	table.insert(eventListeners, detail)
	return {
		Connected = true,
		Disconnect = function(self: Connection)
			if not self.Connected then
				return
			end
			self.Connected = false
			local idx = table.find(eventListeners, detail)
			if idx then
				table.remove(eventListeners, idx)
			end
		end,
	} :: Connection
end

--@remoteName string
--@fn function
-- Similar to :Connect but automatically disconnects after the first firing.
Client.Once = function(remoteName: string, fn: (...any?) -> ()): Connection
	local connection
	connection = Client.Connect(remoteName, function(...: any?)
		if connection then
			connection:Disconnect()
		end
		fn(...)
	end)
	return connection
end

--@remoteName string
-- Wait for an event to be triggered. Yields the current thread.
Client.Wait = function(remoteName: string): (number, ...any?)
	local thread, t = coroutine.running(), os.clock()
	Client.Once(remoteName, function(...: any?)
		task.spawn(thread, os.clock() - t, ...)
	end)
	return coroutine.yield()
end

--@remoteName string
-- Disconnect all connections for a specific event.
Client.DisconnectAll = function(remoteName: string)
	local id = Replication.get_id[remoteName]
	if not id then
		return
	end
	for idx = #eventListeners, 1, -1 do
		if eventListeners[idx].i == id then
			table.remove(eventListeners, idx)
		end
	end
end

--@remoteName string
-- Disconnect all connections and remove the event.
Client.Destroy = Client.DisconnectAll

--@remoteName string
--@reliable boolean
-- Fire an event to the server.
Client.Fire = function(remoteName: string, reliable: boolean, ...: any?)
	local id = Replication.get_id[remoteName]
	if id then
		table.insert(reliable and queueEvent or queueUnreliableEvent, {
			Replication.get_id[remoteName],
			{ ... } :: any,
		})
	end
end

--@remoteName string
--@timeout number?
-- Invoke the server with timeout support. Yields the current thread. Returns nil if timeout occurs.
Client.Invoke = function(remoteName: string, timeout: number?, ...: any?): ...any?
	local id = Replication.get_id[remoteName]
	if not id then
		return nil
	end
	invokeId += 1
	local reqid, thread = `{invokeId}`, coroutine.running()

	pendingInvokes[reqid] = thread
	task.delay(timeout or 2, function()
		local pending = pendingInvokes[reqid]
		if not pending then
			return
		end
		task.spawn(pending, nil)
		pendingInvokes[reqid] = nil
	end)
	table.insert(queueEvent, {
		0,
		{ id, reqid :: any, { ... } :: any } :: any,
	})
	return coroutine.yield()
end

if RunService:IsClient() then
	local function processIncoming(b: buffer, ref: { Instance }?, handleInvokes: boolean)
		if type(b) ~= "buffer" then
			return
		end
		local contents = Buffer.readEvents(b, ref, eventSchemas)
		for _, content in contents do
			local remote = content[1]
			local content = content[2]
			if handleInvokes then
				if remote == 0 then
					local id = content[1]
					local results = content[2]
					local pending = pendingInvokes[id]
					if pending then
						task.spawn(pending :: any, table.unpack(results))
						pendingInvokes[id] = nil
					end
					continue
				end
				if remote == 1 then
					if #eventListeners == 0 then
						continue
					end
					local remoteName = content[1]
					local id = content[2]
					local args = content[3]
					for _, connection in eventListeners do
						if connection.i == remoteName then
							Thread(function()
								local results = { connection.c(table.unpack(args)) }
								table.insert(queueEvent, {
									1,
									{ id, results } :: any,
								})
							end)
							break
						end
					end
					continue
				end
			end
			if #eventListeners == 0 then
				continue
			end
			for _, connection in eventListeners do
				if connection.i ~= remote then
					continue
				end
				Thread(connection.c, table.unpack(content))
			end
		end
	end

	Event.OnClientEvent:Connect(function(b: buffer, ref: { Instance }?)
		processIncoming(b, ref, true)
	end)

	UnreliableEvent.OnClientEvent:Connect(function(b: buffer, ref: { Instance }?)
		processIncoming(b, ref, false)
	end)

	RunService.PostSimulation:Connect(function(d: number)
		deltaT += d
		if deltaT < cycle then
			return
		end
		deltaT = 0

		-- reliable
		if #queueEvent > 0 then
			Buffer.writeEvents(writer, queueEvent, eventSchemas)
			do
				local buf, ref = Buffer.buildWithRefs(writer)
				Buffer.reset(writer)
				if not ref or #ref == 0 then
					Event:FireServer(buf)
				else
					Event:FireServer(buf, ref)
				end
			end
			table.clear(queueEvent)
		end
		-- unreliable
		if #queueUnreliableEvent > 0 then
			Buffer.writeEvents(writer, queueUnreliableEvent, eventSchemas)
			do
				local buf, ref = Buffer.buildWithRefs(writer)
				Buffer.reset(writer)
				if not ref or #ref == 0 then
					UnreliableEvent:FireServer(buf)
				else
					UnreliableEvent:FireServer(buf, ref)
				end
			end
			table.clear(queueUnreliableEvent)
		end
	end)
end

--[[
    @class Client
    @schema
    define a schema for your data and use a strict packing
]]
Client.Schema = Buffer.Schema

return Client :: typeof(Client)