#!/usr/bin/env python3

import argparse
import base64
import errno
import markdown2
import os
import posix
import random
import stat
import string
import sys
import time

assert sys.version_info >= (3, 5)

FRAG_LEN = 1024

def send_line(line):
    for i in range(0, 10):
        fifo = -1
        try:
            fifo = posix.open(fifo_path, posix.O_WRONLY | posix.O_NONBLOCK)
            posix.write(fifo, line)
            return
        except OSError as e:
            if e.errno == errno.ENXIO or e.errno == errno.EAGAIN:
                time.sleep(1.0)
        finally:
            if fifo != -1:
                posix.close(fifo)
    raise Exception("Error sending line!")

parser = argparse.ArgumentParser(description='Post message using Matrix Bot.')
parser.add_argument('channel', type=str, help='channel to be used for posting')
parser.add_argument('--html', action='store_true', dest='is_html',
                    default=False, help='post html message')
parser.add_argument('--markdown', action='store_true', dest='is_markdown',
                    default=False, help='post markdown message')

args = parser.parse_args()

fifo_dir = os.getenv('MTXBOT_FIFO_DIR', '/run/mtxbot')
fifo_path = "%s/%s" % (fifo_dir, args.channel)

if not os.path.isdir(fifo_dir):
    print("Fifo directory %s does not exist!" % fifo_dir, file=sys.stderr)
    sys.exit(2)

if not ( os.path.exists(fifo_path) and
         stat.S_ISFIFO(os.stat(fifo_path).st_mode) ):
    print("Channel %s does not exist!" % args.channel, file=sys.stderr)
    sys.exit(3)

in_raw = sys.stdin.read()

if args.is_markdown:
    in_raw = markdown2.markdown(in_raw)

in_bytes = in_raw.encode("UTF-8")
in_b64 = base64.b64encode(in_bytes).decode("UTF-8")

msg_id = ''.join(random.choices(string.ascii_uppercase + string.digits, k=5))
msg_fmt = 'HTML' if (args.is_html or args.is_markdown) else 'PLAIN'
msg_len = len(in_b64) // FRAG_LEN + (0 if len(in_b64) % FRAG_LEN == 0 else 1)

send_line( ("%s %s %d\n" % (msg_id, msg_fmt, msg_len)).encode("UTF-8") )
for i in range(0, len(in_b64), FRAG_LEN):
    send_line( ("%s %d %s\n" % (msg_id, i//FRAG_LEN, in_b64[i:i+FRAG_LEN])).encode("UTF-8") )