import struct
from crc import Calculator, Crc16
from utl import display_hex, trans_list_to_str

modbus_map = {
    # 1 - Hex
    # 2 - Int16
    # 3 - lnt32
    # 4 - str
    # 5 - addr
    # 6 - float
    0x01: ["Hex示例",   1],
    0x02: ["Int示例",   2],
    0x03: ["Int32示例", 3],
    0x04: ["str示例",   4, 16],
    0x10: ["addr示例",  5,  6],
    0x20: ["Float示例", 6],
}


def make_frame_modbus(block:dict):
    """ modbus 生成函数"""
    frame = []
    calculator = Calculator(Crc16.MODBUS)

    frame.append(block['addr_dev'])
    if block['type'] == 'update':
        """ 升级系列报文 """
        frame.append(0x07)
        if len(block['file']) <= block["header_offset"]:
            raise Exception("Modbus Update error, file too small.")
        
        if block['step'] == 'start':
            frame.append(0x01)
            frame.append(0x00)
            frame.append(0x00)
            frame.append(0x00)
            frame.append(block['header_offset'] // 256)
            frame.append(block['header_offset'] % 256)
            frame += list(block['file'][:block['header_offset']])
        elif block['step'] == 'trans':
            file_offset = block["header_offset"] + block['index'] * block['file_block_size']
            file_block = block['file'][file_offset: file_offset + block['file_block_size']]
            frame.append(0x02)
            frame.append(0x00)
            frame.append(block['index'] // 256)
            frame.append(block['index'] % 256)
            frame.append(len(file_block) // 256)
            frame.append(len(file_block) % 256)
            frame += list(file_block)
        elif block['step'] == 'end':
            frame.append(0x03)
            frame.append(0x00)
            frame.append(block['index'] // 256)
            frame.append(block['index'] % 256)
            frame.append(0x00)
            frame.append(0x00)
        else:
            raise Exception("Modbus Update Frame Step Error.")
    else:
        """ 数据读取系列报文 """
        data_addr = block['data_addr']
        if block['type'] == "read":
            frame.append(0x03)
            data_len  = block['data_len']
            frame.append(data_addr // 256 % 256)
            frame.append(data_addr % 256)
            frame.append(data_len // 256 % 256)
            frame.append(data_len % 256)
        elif block['type'] == "write_one":
            frame.append(0x06)
            data_val  = block['data_val']
            if data_val < 0:
                data_val += 0x1_0000
            frame.append(data_addr // 256 % 256)
            frame.append(data_addr % 256)
            frame.append(data_val // 256 % 256)
            frame.append(data_val % 256)
        elif block['type'] == "write_dual":
            frame.append(0x10)
            data_val  = block['data_val']
            if data_val < 0:
                data_val += 0x1_0000_0000
            frame.append(data_addr // 256 % 256)
            frame.append(data_addr % 256)
            frame.append(0x00)
            frame.append(0x02)
            frame.append(0x04)
            frame.append(data_val // 256 % 256)
            frame.append(data_val % 256)
            data_val //= 0x1_0000
            frame.append(data_val // 256 % 256)
            frame.append(data_val % 256)
        elif block['type'] == "write_str":
            frame.append(0x10)
            data_len = len(block['data_val'])
            item_len = 2 * block['data_define'][data_addr][2]
            data_val  = block['data_val']
            if data_len > item_len:
                raise Exception("Modbus data len oversize.")
            elif data_len < item_len:
                data_val += '\000' * (item_len - data_len)
                data_len  = len(data_val)
            frame.append(data_addr // 256 % 256)
            frame.append(data_addr % 256)
            frame.append(0x00)
            frame.append(data_len // 2)
            frame.append(data_len)

            if type(data_val[0]) == str:
                data_val = list(map(lambda x: x.encode()[0], data_val))
            for i in range(data_len//2):
                frame.append(data_val[2*i + 1])
                frame.append(data_val[2*i])
        else:
            raise Exception("Modbus Frame Type Error.")


    crc = calculator.checksum(bytearray(frame))
    frame.append(crc % 256)
    frame.append(crc // 256)

    return frame

def make_frame_dlt645(block:dict):
    """ dlt645 生成函数"""
    frame = []

    if block['type'] == 'modbus':
        """ Modbus 透传帧 """
        ctrl_code = 0x1F    # Modbus 透传帧功能码
        data_frame = make_frame_modbus(block["data"])
        len_data = len(data_frame)
    else:
        raise Exception("Unknown dlt645 frame type.")

    frame.append(0x68)
    frame += block['addr'][:6]
    frame.append(0x68)
    frame.append(ctrl_code)
    frame.append(len_data)
    frame += data_frame
    frame.append(sum(frame) % 256)
    frame.append(0x16)

    return frame

def display_data(modbus_map: dict, address: int, data: list):
    """ 格式化表示数据 """
    def display_str(data, len_data):
        item = bytearray(data[:2 * len_data])
        for i in range(len_data):
            t = item[2*i]
            item[2*i] = item[2*i+1]
            item[2*i+1] = t
        return item

    output = "Parse Result: \n"
    idx = address
    len_max = 0
    while data:
        data_len = 1
        data_label = "未知数据"
        if idx not in modbus_map.keys():
            item = data[0] * 0x0100 + data[1]
            item = display_hex(item, 4)
        else:
            current_map = modbus_map[idx]
            data_label = current_map[0]
            if current_map[1] == 1:
                """ Hex字符表示 """
                item = data[0] * 0x0100 + data[1]
                item = display_hex(item, 4)
            elif current_map[1] == 2:
                """ 16位数值表示 """
                item = data[0] * 0x0100 + data[1]
                if item > 0x8000:
                    item -= 0x1_0000
            elif current_map[1] == 3:
                """ 32位数值表示 """
                item = data[2] * 0x0100 + data[3]
                item *= 0x10000
                item += data[0] * 0x0100 + data[1]
                if data[2] > 0x80:
                    item -= 0x1_0000_0000
                data_len = 2
            elif current_map[1] == 4:
                """ 字符串表示 """
                data_len = current_map[2]
                item = display_str(data, data_len)
                item = item.replace(b'\xff', b' 0xFF')
                item = item.decode()
            elif current_map[1] == 5:
                """ 载波地址表示 """
                data_len = current_map[2]
                item = display_str(data, data_len)
                item = trans_list_to_str(item)
            elif current_map[1] == 6:
                """ 浮点数值表示 """
                temp = [data[2], data[3], data[0], data[1]]
                item = struct.unpack('>f', bytes(temp))[0]
                data_len = 2

        if len_max < len(data_label):
            len_max = len(data_label)
        len_remain = len_max - len(data_label)
        output_line = "\t".join([display_hex(idx, 4), data_label + " " * len_remain, str(item)])
        
        idx += data_len
        del data[0:data_len * 2]
        output += output_line + "\n"
    return output

def check_frame_modbus(frame, block=None):
    """ 校验modbus帧回复 """
    calculator = Calculator(Crc16.MODBUS)
    if calculator.checksum(frame[:-2]) != (frame[-1] * 0x100 + frame[-2]):
        raise Exception("Frame Crc check failed.")
    elif frame[0] != 0x01:
        raise Exception("Frame device address error.")
    
    code_func = frame[1]
    code_subfunc = frame[2]
    if code_func == 0x07:
        """ 升级回复帧 """
        if frame[3] == 0x00:
            check_result = True
        else:
            check_result = False
        update_index = frame[4] * 256 + frame[5]
        check_hope = 0
        if code_subfunc == 0x01:
            """ 处理帧头 """
            check_hope = frame[6] * 256 + frame[7]
        elif code_subfunc == 0x02:
            """ 解析帧序号及返回值, 不做序列号校验 """
        elif code_subfunc == 0x03:
            """ 升级结束 """
        else:
            raise Exception("Func code or Return code error.")
        return check_result, update_index, check_hope
    elif code_func == 0x03 or code_func == 0x04:
        """ 数据读取帧 """
        if frame[2] == len(frame[3:-2]):
            if type(block) is dict:
                data_addr = block['data_addr']
                return display_data(block['data_define'], data_addr, list(frame[3:-2]))
            else:
                return list(frame[3:-2])
        else:
            raise Exception("Frame read error.")
    elif code_func == 0x06:
        """ 单个数据写入帧 """
        return frame[2:-2]
    elif code_func == 0x10:
        """ 多个数据写入帧 """
        return frame[2:-2]
    else:
        raise Exception(f"Frame Date error. func={code_func}, func_sub={code_subfunc}, len={len(frame)}")

def check_frame_dlt645(frame, block=None):
    """ 校验dlt645帧回复 """
    if sum(frame[:-2]) % 0x100 != frame[-2]:
        raise Exception("DLT645 Frame Verify error.")
    elif len(frame[10:-2]) != frame[9]:
        raise Exception("DLT645 Frame len error.")
    
    code_func = frame[8]
    if code_func == 0x9F:
        block = block['data']
        return check_frame_modbus(frame[10:-2], block)
    else:
        raise Exception("DLT645 Frame type error.")