module(..., package.seeall)
require"radio"
require "sx126x_driver"

-- --------------------- 常量定义 ---------------------
local MASTER_ADDR = 0x00
local MIN_SLAVE_ADDR = 0x01
local MAX_SLAVE_ADDR = 0x05
local QUERY_TIMEOUT_MS = 6

local FRAME_HEADER1 = 0x5A
local FRAME_HEADER2 = 0xA5
local FRAME_TYPE_QUERY = 0x03
local FRAME_TYPE_DATA  = 0x02


-- --------------------- 工具函数 ---------------------
-- CRC16 (Modbus)
local function Modbus_CRC16(data, len)
    local crc = 0xFFFF
    for i = 1, len do
        crc = bit.bxor(crc, data[i])
        for _ = 1, 8 do
            if bit.band(crc, 0x0001) ~= 0 then
                crc = bit.rshift(crc,1)
                crc = bit.bxor(crc,0xA001)
            else
                crc = bit.rshift(crc,1)
            end
        end
    end
    return bit.rshift(crc,8) + bit.lshift(bit.band(crc,0xFF),8)

end


-- 工具函数：将“十进制字节表”转为“十六进制字符串”（如 {0x5A, 0xA5} → "5AA5"）
local function byte_table_to_hex_str(byte_table)
    local hex_str = ""
    for _, byte_val in ipairs(byte_table) do
        -- 确保每个字节转为两位十六进制（不足两位补0，如0x5 → "05"）
        hex_str = hex_str .. string.format("%02X", byte_val)
    end
    return hex_str
end
-- 将 {0x5A,0xA5} 转成 "\x5A\xA5" 这种二进制字符串
local function byte_table_to_bin_str(byte_table)
    local chars = {}
    for i = 1, #byte_table do
        chars[i] = string.char(byte_table[i])
    end
    return table.concat(chars)
end

-- --------------------- 发送查询帧 ---------------------
local function send_query_frame(slave_addr)
    log.info("Frame","发送查询帧",slave_addr)
    local buf = {
        FRAME_HEADER1, FRAME_HEADER2,
        MASTER_ADDR, slave_addr,
        FRAME_TYPE_QUERY,
        0x00, 0x00 -- reserved
    }
    local crc = Modbus_CRC16(buf, #buf)
    table.insert(buf, bit.band(crc,0xFF))    -- CRC低字节
    table.insert(buf, bit.rshift(crc,8))     -- CRC高字节

    log.info("查询帧构建完毕，长度="..#buf.."字节")

    -- ✅ 转换成二进制字符串
    local hex_buf = byte_table_to_hex_str(buf)
    local lenHex  = string.format("%02X", #buf)
    sx126x_driver.RadioSend(hex_buf, lenHex, "00")

    -- sys.wait(200) 
    log.info("查询帧发送完毕，配置的PayloadLength="..#buf)
end



-- -- --------------------- 解析传感器数据 ---------------------
local function bytes_to_float(b1,b2,b3,b4)
    local sign = bit.rshift(b4,7)
    local expo = bit.band(bit.rshift(b4,0),0x7F) * 2 + bit.rshift(b3,7)
    local mant = bit.lshift(bit.band(b3,0x7F),16) + bit.lshift(b2,8) + b1
    if expo == 0 then
        return 0.0
    elseif expo == 255 then
        return (mant == 0) and (sign==0 and math.huge or -math.huge) or 0/0
    end
    return (sign==1 and -1 or 1) * (1 + mant/0x800000) * 2^(expo-127)
end

-- 解码传感器数据，返回 (value, unit, type)
local function decode_sensor(sensor)
    if sensor.data_type == 0x01 then
        local t = bit.lshift(sensor.data[1],8) + sensor.data[2]
        return t / 100.0, "°C", "temperature"
    elseif sensor.data_type == 0x02 then
        local h = bit.lshift(sensor.data[1],8) + sensor.data[2]
        return h / 100.0, "%", "humidity"
    elseif sensor.data_type == 0x03 then
        return sensor.data[1], "lux", "light"
    elseif sensor.data_type == 0x04 then
        return sensor.data[1], "ppm", "smoke"
    elseif sensor.data_type == 0x10 then
        if #sensor.data == 4 then
            local val = bytes_to_float(sensor.data[1],sensor.data[2],sensor.data[3],sensor.data[4])
            return val, "L", "liquid"
        end
    end
    return sensor.data, "raw", "unknown"
end


-- 解析接收到的帧，返回符合 JSON 格式的表
local function parse_received_frame(hex_str)
    local buf = {}
    for i = 1, #hex_str, 2 do
        local hex_byte = hex_str:sub(i, i+1)
        table.insert(buf, tonumber(hex_byte, 16))
    end
    if #buf < 9 then return nil end
    if buf[1] ~= FRAME_HEADER1 or buf[2] ~= FRAME_HEADER2 then return nil end

    local src_addr   = buf[3]
    local dst_addr   = buf[4]
    local frame_type = buf[5]
    if dst_addr ~= MASTER_ADDR or frame_type ~= FRAME_TYPE_DATA then return nil end

    local sensor_count   = buf[6]
    local data_total_len = buf[7]

    -- CRC 校验
    local crc_low, crc_high = buf[#buf-1], buf[#buf]
    local crc_recv = crc_low + bit.lshift(crc_high,8)
    local crc_calc = Modbus_CRC16(buf, #buf-2)
    if crc_recv ~= crc_calc then return nil end

    -- ✅ 返回简洁 JSON
    local result = {
        ts      = os.time(),
        addr    = src_addr,
        sensors = {}
    }

    local offset = 8
    local data_end = 8 + data_total_len - 1
    for i = 1, sensor_count do
        if offset + 2 > data_end then break end
        local sensor = {
            id        = buf[offset],
            data_type = buf[offset+1],
            data_len  = buf[offset+2],
            data      = {}
        }
        for j = 1, sensor.data_len do
            table.insert(sensor.data, buf[offset+2+j])
        end

        local value, unit, type = decode_sensor(sensor)
        table.insert(result.sensors, {
            id    = sensor.id,
            type  = type,
            value = value,
            unit  = unit
        })

        offset = offset + 3 + sensor.data_len
    end

    return result
end





-- --------------------- 主机轮询 ---------------------
function master_query_loop()
    
        for addr=MIN_SLAVE_ADDR, MAX_SLAVE_ADDR do
            sx126x_driver.ReceiveData = "" 
            log.info("Host","查询从机地址",string.format("0x%02X",addr))
            send_query_frame(addr)

            local start = os.time()
            local response = false
            while (os.time()-start) < QUERY_TIMEOUT_MS do
                if sx126x_driver.dataReady() then
                    local rx_buf = sx126x_driver.RadioGetBuffer()
                    log.info("Host","收到从机数据", "十六进制字符串="..rx_buf)
                    if rx_buf == "" then
                        log.info("返回空")
                        break
                    end

                    local slave_addr_hex = string.format("%02X", addr)  -- 把当前查询的从机地址转成两位十六进制字符串
                    log.info("slave_addr_hex",slave_addr_hex)
                    -- log.info("rx_buf:sub(7,8)",rx_buf:sub(7,8))
                    -- log.info("rx_buf:sub(5,6)",rx_buf:sub(5,6))
                    if rx_buf:sub(1,2) ~= "5A" then
                        log.info("帧头错误")
                        break
                    end
                    if rx_buf:sub(5,6) ~= slave_addr_hex then  
                        log.info("从机地址不匹配")
                        break
                    end
                    if rx_buf:sub(7,8) ~= "00" then
                        log.info("主机地址不匹配")
                        break
                    end
                        local result = parse_received_frame(rx_buf)
                        if result then
                            -- 发布事件，外部来处理
                            sys.publish("SENSOR_UPDATE",result)
                            break
                        end
                end
                sys.wait(50)
            end
            if not response then
                -- log.warn("Host",string.format("从机0x%02X无响应",addr))
            end
            sys.wait(5000)
        end
end


sys.taskInit(function()


    sys.wait(10000)

    radio.RadioInit()
    radio.RadioStandby()

    sx126x_driver.RadioSetTxConfig(sx126x_reg.RadioModems_t.MODEM_LORA,"16",0,1,7,"01","0c","00","01","00","00","00",3000)
    sx126x_driver.RadioSetChannel(433000000) 
    sys.wait(2000)
    sx126x_driver.RadioRx(0)
    local payload = "Hehehe123456"
    local num = 1
    while true do
        master_query_loop()

        --  send_query_frame(0x01)


        -- RadioStandby()
        -- sx126x_driver.sentString("hello,My_name_is_XuXinyi\n")
        sys.wait(1500)
        log.info("Radio", "测试接收数据中。。。")
     
        -- sx126x_driver.sentString("5AA50005030000093C")
    --     sx126x_driver.sentString(payload)
    --  sx126x_driver.RadioRx(0)
        -- -- -- sx126x_driver.RadioRx(0)
        -- sx126x_driver.SX126xWakeup()
  
        -- payload = payload .. num
        -- num = num + 1

    end
end)