import sys
import glob
import time
import serial
import re

def get_serial_ports():
    if sys.platform.startswith('win'):
        ports = ['COM%s' % (i + 1) for i in range(256)]
    elif sys.platform.startswith('linux') or sys.platform.startswith('cygwin'):
        # this excludes your current terminal "/dev/tty"
        ports = glob.glob('/dev/tty[A-Za-z]*')
    elif sys.platform.startswith('darwin'):
        ports = glob.glob('/dev/tty.*')
    else:
        raise EnvironmentError('Unsupported platform')

    result = []
    for port in ports:
        try:
            s = serial.Serial(port)
            s.close()
            result.append(port)
        except (OSError, serial.SerialException):
            pass
    return result

printed_skipped_just_once=False
def get_rgb_2_hdmi_ports():
    global printed_skipped_just_once
    invalid_portnames = [ 'bluetooth']
    ports=get_serial_ports()
    
    for port in ports:
        skip=False
        for invalid_port in invalid_portnames:
            if re.search(invalid_port, port, re.IGNORECASE):
                if not printed_skipped_just_once:
                    print('Skip port', port)
                    printed_skipped_just_once=True
                skip=True
                break
        if skip:
            continue
        ser = serial.Serial(
            port=port,
            baudrate=115200,
            parity=serial.PARITY_NONE,
            stopbits=serial.STOPBITS_ONE,
            bytesize=serial.EIGHTBITS,
            timeout=1
        )
        if not ser.isOpen():
            continue
        print("Testing port", port)

        res = sendCommand(ser, "version")
        if res[0]:
            print("Found device on ", port, "(", res[1], ")")
            return (ser, port, res[1])
    return None

serialBusy=False
def sendCommand(ser, val):
    global serialBusy
    try:
        if serialBusy:
            return (False, '')
        serialBusy = True
        ser.write((val +'\n').encode('ascii'))
        ackLine=ser.readline()
        args=val.split(' ', 1)
        cmd = args[0]
        val = ""
        if len(args)>1:
            val=args[1]
        expected=('Request '+ cmd + '<' + cmd[0] + '>(' + val + ')\r\n').encode('ascii').lower()
        if (ackLine.lower() != expected):
            ser.flushInput()
            return (False, '')
        
        partial = ''
        result = ''
        while ( (partial := ser.readline()) != b''):
            result = result + partial.decode('ascii')
        serialBusy = False
        return (True, result.rstrip())
    except:
        ser.close()
        serialBusy = False
        return (False, '')

def isConnected(ser):
    global serialBusy
    if not ser.isOpen():
        return False
    if serialBusy:
        return True
    connected = True
    try:
        ser.write(b' ')
    except  Exception as e:
        ser.close()
        connected = False
    return connected