-- cmd.lua
-- 功能：解析串口帧，调用 linksocket 接口，执行系统命令

local log = require "log"
local sys = require "sys"
local uart = require "uart"
local ril = require "ril"
local linksocket = require "linksocket"

local uartID = 1

-- 辅助函数：字节转十六进制（调试用）
local function toHexcode(str)
    if not str then return "" end
    local hex = ""
    for i = 1, #str do
        hex = hex .. string.format("%02X", str:byte(i))
    end
    return hex
end

-- 发送通用响应帧：55 AA mainCmd subCmd [payload] AA 55
local function sendCmdResponse(mainCmd, subCmd, payload)
    local frame = string.char(0x55, 0xAA, mainCmd, subCmd)
    if payload and #payload > 0 then
        frame = frame .. payload
    end
    frame = frame .. string.char(0xAA, 0x55)
    uart.write(uartID, frame)
    log.debug("sendCmdResponse: mainCmd=", string.format("0x%02X", mainCmd),
              "subCmd=", string.format("0x%02X", subCmd))
end

-- 发送通用响应帧：55 AA 83 subCmd socketId status AA 55
local function sendResponse(subCmd, socketId, status)
    sendCmdResponse(0x83, subCmd, string.char(socketId, status or 0))
    log.debug("Response: subCmd=", subCmd, "socketId=", socketId, "status=", status)
end

-- 命令处理函数 ---------------------------------------------------------------

-- 0x01: 数据发送到指定Socket
local function handleCmd01(subCmd, payload)
    local socketId = subCmd
    if socketId < 1 or socketId > 6 then
        log.error("Invalid socket id in cmd 0x01:", socketId)
        sendResponse(0x03, socketId, 1)
        return
    end
    local success = linksocket.sendToSocket(socketId, payload)
    if not success then
        log.warn("Send failed, socket", socketId, "not connected")
        sendResponse(0x03, socketId, 1)
    else
        log.info("Data sent to socket", socketId, "len=", #payload)
    end
end

-- 0x02: 系统重启
local function handleCmd02()
    log.info("System restart command received")
    sys.restart()
end

-- 0x03: Socket连接/断开控制
-- subCmd: 0x01=连接 0x02=断开
-- payload: socket_id (1字节)
local function handleCmd03(subCmd, payload)
    if #payload < 1 then return end
    local socketId = payload:byte(1)
    if socketId < 1 or socketId > 6 then
        log.error("Cmd 0x03 invalid socket:", socketId)
        return
    end

    if subCmd == 0x01 then
        log.info("STM32 request connect socket", socketId)
        linksocket.connectSocket(socketId)
    elseif subCmd == 0x02 then
        log.info("STM32 request disconnect socket", socketId)
        linksocket.disconnectSocket(socketId)
    else
        log.error("Unknown subCmd for 0x03:", subCmd)
    end
end

-- 0x04: 设置服务器地址
-- payload: ip_len(1) + ip_str(ip_len) + port_hi(1) + port_lo(1)
local function handleCmd04(subCmd, payload)
    if #payload < 3 then
        log.error("Cmd 0x04 payload too short")
        sendCmdResponse(0x87, 0x00, string.char(1))
        return
    end
    local ip_len = payload:byte(1)
    if ip_len > 100 or #payload < (2 + ip_len + 1) then
        log.error("Cmd 0x04 invalid ip_len")
        sendCmdResponse(0x87, 0x00, string.char(1))
        return
    end
    local ip_str = payload:sub(2, 1 + ip_len)
    local port_hi = payload:byte(2 + ip_len)
    local port_lo = payload:byte(3 + ip_len)
    local port = port_hi * 256 + port_lo

    log.info("Set server address:", ip_str, port)

    local ok = linksocket.setServerAddress(ip_str, port)
    if ok then
        sendCmdResponse(0x87, 0x00, string.char(0))
    else
        sendCmdResponse(0x87, 0x00, string.char(1))
    end
end

-- 0x05: 查询SIM卡信息
-- subCmd: 0x01=ICCID 0x02=IMSI 0x03=IMEI
local function handleCmd05(subCmd)
    local at_cmds = {
        [0x01] = "AT+ICCID",
        [0x02] = "AT+CIMI",
        [0x03] = "AT+CGSN",
    }
    local at_cmd = at_cmds[subCmd]
    if not at_cmd then
        log.error("Unknown SIM query type:", string.format("0x%02X", subCmd))
        return
    end

    ril.request(at_cmd, nil, function(cmd, result, respdata, interdata)
        -- interdata才是实际的AT命令响应数据，result只是布尔值表示成功/失败
        local response = interdata or ""
        -- 去除可能的空白字符
        response = response:gsub("^[\r\n]+", ""):gsub("[\r\n]+$", "")

        local value = ""
        if subCmd == 0x01 then
            value = string.match(response, "%+ICCID:%s*(%S+)") or string.match(response, "ICCID:%s*(%S+)") or response:match("^(%S+)") or ""
        elseif subCmd == 0x02 then
            value = string.match(response, "%+CIMI:%s*(%S+)") or string.match(response, "CIMI:%s*(%S+)") or response:match("^(%S+)") or ""
        elseif subCmd == 0x03 then
            value = string.match(response, "%+CGSN:%s*(%S+)") or string.match(response, "CGSN:%s*(%S+)") or response:match("^(%S+)") or ""
        end

        value = value or ""
        log.info("SIM query result type=", string.format("0x%02X", subCmd), "value=", value)

        local data = string.char(#value) .. value
        sendCmdResponse(0x84, subCmd, data)
    end)
end

-- 0x06: 查询信号强度（CSQ）
local function handleCmd06()
    ril.request("AT+CSQ", nil, function(cmd, result)
        local csq = 0
        local ber = 99
        -- result可能是布尔值，需要确保是字符串才能进行模式匹配
        if result and type(result) == "string" then
            local c, b = string.match(result, "CSQ:%s*(%d+),%s*(%d+)")
            if c then csq = tonumber(c) or 0 end
            if b then ber = tonumber(b) or 99 end
        end
        log.info("Signal query: CSQ=", csq, "BER=", ber)
        sendCmdResponse(0x85, 0x01, string.char(csq, ber))
    end)
end

-- 0x07: 查询链路状态
local function handleCmd07()
    local status = linksocket.getLinkStatus()
    if status then
        local payload = ""
        for i = 1, 6 do
            payload = payload .. string.char(status[i] and 1 or 0)
        end
        sendCmdResponse(0x86, 0x01, payload)
        log.info("Link status sent, 6 sockets")
    end
end

local frameBuffer = ""

-- 对外接口：处理串口接收到的原始数据
local function process(rawData)
    if not rawData or #rawData < 1 then
        return
    end

    frameBuffer = frameBuffer .. rawData

    while true do
        if #frameBuffer < 7 then break end

        if frameBuffer:byte(1) == 0x55 and frameBuffer:byte(2) == 0xAA then
            local tail = frameBuffer:find(string.char(0xAA, 0x55), 5, true)
            if not tail then break end
            tail = tail + 1

            local frame = frameBuffer:sub(1, tail)
            frameBuffer = frameBuffer:sub(tail + 1)

            log.info("CMD raw data:", toHexcode(frame))

            local mainCmd = frame:byte(3)
            local subCmd = frame:byte(4)
            local payload = frame:sub(5, -3)

            if mainCmd == 0x01 then
                 handleCmd01(subCmd, payload)
            elseif mainCmd == 0x02 then
                handleCmd02()
            elseif mainCmd == 0x03 then
                handleCmd03(subCmd, payload)
            elseif mainCmd == 0x04 then
                handleCmd04(subCmd, payload)
            elseif mainCmd == 0x05 then
                handleCmd05(subCmd)
            elseif mainCmd == 0x06 then
                handleCmd06()
            elseif mainCmd == 0x07 then
                handleCmd07()
            else
                log.warn("Unknown main command:", string.format("0x%02X", mainCmd))
            end
        else
            local skip = frameBuffer:find(string.char(0x55, 0xAA), 2, true)
            if skip then
                log.warn("Skipped", skip - 1, "bytes before frame header")
                frameBuffer = frameBuffer:sub(skip)
            else
                frameBuffer = ""
                break
            end
        end
    end
end

-- 模块接口
local M = {
    process = process,
}
return M