-- linksocket.lua
-- 功能：管理多个 TCP Socket 连接，支持手动连接/断开，自动重连，数据收发

local log = require "log"
local sys = require "sys"
local socket = require "socket"

-- 服务器配置
local SERVER_IP = "121.43.69.62"
local SERVER_PORT = 8767
local MAX_CLIENTS = 6

-- 客户端状态表
local clients = {}
local keepConnecting = {}
local recvCallback = nil

-- 初始化所有socket槽位
for i = 1, MAX_CLIENTS do
    clients[i] = {
        id = i,
        socket = nil,
        connected = false
    }
    keepConnecting[i] = false
end

-- 发送连接状态响应
local function sendConnStatus(subCmd, socketId, status)
    local uart = require "uart"
    local frame = string.char(0x55, 0xAA, 0x83, subCmd, socketId, status, 0xAA, 0x55)
    uart.write(1, frame)
    log.debug("Socket", socketId, "status response, subCmd=", subCmd, "status=", status)
end

-- 设置是否保持连接
local function setKeepConnecting(id, keep)
    if id < 1 or id > MAX_CLIENTS then
        return false
    end
    keepConnecting[id] = keep
    if not keep and clients[id].connected and clients[id].socket then
        clients[id].socket:close()
        clients[id].socket = nil
        clients[id].connected = false
        sendConnStatus(0x02, id, 0)
    end
    return true
end

-- 发送数据到指定socket
local function sendToSocket(id, data)
    if id < 1 or id > MAX_CLIENTS then
        log.error("sendToSocket: invalid id", id)
        return false
    end
    if clients[id].connected and clients[id].socket then
        clients[id].socket:asyncSend(data)
        log.info("Send to socket", id, "len=", #data)
        return true
    else
        log.warn("Socket", id, "not connected, cannot send")
        return false
    end
end

-- 注册数据接收回调
local function setRecvCallback(cb)
    recvCallback = cb
end

-- 为每个socket创建常驻任务
for id = 1, MAX_CLIENTS do
    sys.taskInit(function()
        local socketId = id
        log.debug("Socket", socketId, "control task started")

        while true do
            while not keepConnecting[socketId] do
                sys.wait(1000)
            end

            while keepConnecting[socketId] do
                while not socket.isReady() do
                    if not keepConnecting[socketId] then break end
                    sys.wait(1000)
                end
                if not keepConnecting[socketId] then break end

                local sock = socket.tcp()
                log.debug("Socket", socketId, "connecting to", SERVER_IP, SERVER_PORT)
                local connected = false
                while not connected and keepConnecting[socketId] do
                    connected = sock:connect(SERVER_IP, SERVER_PORT)
                    if not connected then
                        log.warn("Socket", socketId, "connect failed, retry in 3s")
                        sys.wait(3000)
                    end
                end

                if not keepConnecting[socketId] then
                    if sock then sock:close() end
                    break
                end

                clients[socketId].socket = sock
                clients[socketId].connected = true
                log.info("Socket", socketId, "connected")
                sendConnStatus(0x01, socketId, 0)

                while keepConnecting[socketId] and clients[socketId].connected do
                    local ok = sock:asyncSelect(60, "recv")
                    if not ok then
                        log.warn("Socket", socketId, "connection lost")
                        break
                    end
                    sys.wait(100)
                end

                if clients[socketId].socket then
                    clients[socketId].socket:close()
                    clients[socketId].socket = nil
                end
                clients[socketId].connected = false

                if not keepConnecting[socketId] then
                    sendConnStatus(0x02, socketId, 0)
                    break
                else
                    log.info("Socket", socketId, "will reconnect after 3s")
                    sys.wait(3000)
                end
            end
        end
    end)
end

-- 订阅底层Socket接收事件
sys.subscribe("SOCKET_RECV", function(socketId)
    for i, client in ipairs(clients) do
        if client.socket and client.socket.id == socketId and client.connected then
            local data = client.socket:asyncRecv()
            if data and #data > 0 then
                log.info("Socket", client.id, "received data len=", #data)
                if recvCallback then
                    recvCallback(client.id, data)
                end
            end
            break
        end
    end
end)

-- 模块接口
local M = {
    setKeepConnecting = setKeepConnecting,
    sendToSocket = sendToSocket,
    setRecvCallback = setRecvCallback,
}
return M