#!/usr/bin/python
"""
A minimal utility to send structured commands to the BPS board
"""

import sys
import os
sys.path.insert(0, '../codegen')


import commands
from utils import mls
from analogvariables import *
from entities.descriptors import PayloadFieldEnum, PayloadFieldU8, PayloadFieldU16, PayloadFieldU32
from commutils import *
import serial


ASK_CONFIRM = False
SHOW_SENT_DATA = False
SHOW_RECEIVED_DATA = False
UART_DEV = '/dev/ttyUSB0'


def ask_confirm():
    answer = ""
    while answer not in ["y", "n"]:
        answer = raw_input("Confirm [Y/N]? ").lower()
    return answer == "y"


if __name__ == '__main__':
    # command line options
    # example
    # python sendcommand.py COMMAND_NAME payload0 payload1 ...
    # COMMAND_NAME is the human readable name of the command (e.g.: )

    # redirect stdout to null in order to avoid the warnings during object creation
    stdout = sys.stdout
    f = open(os.devnull, 'w')
    sys.stdout = f

    switch_list = commands.SwitchList()

    # analog_variable_list = commands.AnalogVariableList()
    # digital_variable_list = commands.DigitalVariableList()

    analog_variable_list = commands.AnalogVariableList(
        _var_enum_index_start=1,
        _alarm_enum_index_start=1)

    digital_variable_list = commands.DigitalVariableList(
        _var_enum_index_start=max(analog_variable_list.get_var_enum_indexes())+1,
        _alarm_enum_index_start=max(analog_variable_list.get_alarm_enum_indexes())+1)

    user_pin_list = commands.UserPinList()
    commands = commands.CommandList(switch_list, analog_variable_list, digital_variable_list, user_pin_list)

    # restore normal stdout
    sys.stdout = stdout

    # open the serial port
    ser = serial.Serial(UART_DEV, baudrate=19200, bytesize=serial.EIGHTBITS, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE, timeout=0.5)

    if len(sys.argv) <= 1:
        print "Command code missing"
        sys.exit(0)

    command_name = sys.argv[1].upper()

    filtered_commands = [command for command in commands.entries() if command.name.startswith(command_name)]

    if len(filtered_commands) == 0:
        print 'No command found with name starting with: "{}"'.format(command_name)
    elif len(filtered_commands) != 1:
        print 'More than one command found with name starting with: "{}":'.format(command_name)
        for command in filtered_commands:
            print '    {}'.format(command.name)
        sys.exit(0)

    # get the wanted command
    command = filtered_commands[0]

    # expected number of request fields:
    req_field_count = len(command.request_payload)

    if len(sys.argv) != req_field_count + 2:
        print 'Number of request payload fields not correct. The {} command expects {} fields; {} where given.'.format(command.name, len(command.request_payload), len(sys.argv) - 2)
        sys.exit(0)

    # prepare the payload
    payload_data = list()
    payload_field_values = list()
    idx = 2
    for field in command.request_payload:
        val = int(sys.argv[idx])
        payload_field_values.append(val)
        if isinstance(field, PayloadFieldU8):
            assert val < 2**8, 'Too big value for uint8'
            payload_data.append(val)
        elif isinstance(field, PayloadFieldU16):
            assert val < 2 ** 16, 'Too big value for uint16'
            payload_data.append((val >> 8) & 0xff)
            payload_data.append(val & 0xff)
        elif isinstance(field, PayloadFieldU32):
            assert val < 2 ** 32, 'Too big value for uint32'
            payload_data.append((val >> 24) & 0xff)
            payload_data.append((val >> 16) & 0xff)
            payload_data.append((val >> 8) & 0xff)
            payload_data.append(val & 0xff)
        elif isinstance(field, PayloadFieldEnum):
            assert val < 2 ** 8, 'Too big value for enum'
            payload_data.append(val)
        else:
            assert False, 'Unmanaged type {}'.format(field.__class__.__name__)
        idx += 1

    print "Sending packet:"
    print '    Command code: {} (raw data: {})'.format(command.name, command.request_code)
    # print '    Payload data: {} (raw data: {})'.format(payload_field_values, payload_data)
    print '    Request payload:'
    idx = 0
    for field in command.request_payload:
        print '        {} = {}'.format(field.name, payload_field_values[idx])
        idx += 1

    if ASK_CONFIRM:
        if not ask_confirm():
            print "Operation aborted by user"
            sys.exit()

    rawdata = packet_create_rawdata(command.request_code, payload_data)

    # send the message over the serial link    
    print "Packet sent."
    if SHOW_SENT_DATA:
        print "Sent data are:"
        for val in rawdata:
            print '\t{}\t(ascii: {})'.format(val, chr(val))
    ser.write(rawdata)

    # wait for a response (reads up to 1000 bytes, does not parse the packet)
    print 'Waiting for response...'
    ans = ser.read(1000)
    bytes = [ord(c) for c in ans]
    print '{} bytes received.'.format(len(ans))
    if SHOW_RECEIVED_DATA:
        if len(ans):
            print 'Received data:'
            for k in range(len(ans)):
                print '[byte #{}]\t0x{}\t(dec: {}, ascii: {})'.format(str(k), ans[k].encode('hex'), str(ord(ans[k])), ans[k])
    if not len(ans):
        sys.exit(0)

    # parses the response
    command_code, payload_bytes = packet_extract_data(bytes)
    print "Received raw payolad:", payload_bytes

    print "Received packet:"
    print '    Command code: {}'.format(command_code)
    # print '    Payload data: {} (raw data: {})'.format(payload_field_values, payload_data)
    print '    Response payload:'
    byte_idx = 0
    for field in command.response_payload:
        value = -1
        if isinstance(field, PayloadFieldU8):
            value = payload_bytes[byte_idx]
            byte_idx += 1
        elif isinstance(field, PayloadFieldU16):
            value = payload_bytes[byte_idx] << 8
            value += payload_bytes[byte_idx+1]
            byte_idx += 2
        elif isinstance(field, PayloadFieldU32):
            value = payload_bytes[byte_idx] << 24
            value += payload_bytes[byte_idx+1] << 16
            value += payload_bytes[byte_idx+2] << 8
            value += payload_bytes[byte_idx+3]
            byte_idx += 4
        elif isinstance(field, PayloadFieldEnum):
            value = field.get_value_by_index(payload_bytes[byte_idx])
            byte_idx += 1
        else:
            assert False, 'Unmanaged type {}'.format(field.__class__.__name__)

        print '        {} = {}'.format(field.name, value)