#!/usr/bin/env python3

# How to read a line.

def deirc(nick, line):
    action = False
    if len(line) <= 3:
        return action, nick, line
    if line[0] == '\u200b':
        if line[1] == '<':
            try:
                close = line.index('>')
                assert(line[close+1] == ' ')
                assert(not any(map(lambda x: x.isspace(), line[2:close])))
                nick = line[2:close]
                line = line[close+2:]
            except:
                pass
        elif line[1:3] == '* ':
            try:
                close = line[3:].index(' ') + 3
                assert(not any(map(lambda x: x.isspace(), line[3:close])))
                nick = line[3:close]
                line = line[close+1:]
                action = True
            except:
                pass
    elif line[:8] == '\x01ACTION ' and line[-1] == '\x01':
        action = True
        line = line[8:-1]

    # Redact the nologs.
    if line.startswith('[nolog]') or line.startswith('nolog:'):
        line = '[REDACTED]'

    return action, nick, line

# Set flags and funcs.

from sys import argv
if len(argv) != 3:
    print('Usage: in out')
    exit(1)
_, fin, fout = argv

# Read the outfile.

class ReadOut:
    def __init__(self, fout=fout):
        self.file = open(fout, 'rb')
        self.first = True
    def cat(self):
        self.first = False
        for line in self.file:
            yield str(line[:-1], 'utf-8', 'ignore')
    def tac(self):
        if self.first:
            self.first = False
            self.file.seek(0, 2)
        buffer = b''
        if self.file.tell():
            self.file.seek(self.file.tell() - 1)
            if self.file.read(1) == b'\n':
                self.file.seek(self.file.tell() - 1)
        while self.file.tell():
            self.file.seek(self.file.tell() - 1)
            char = self.file.read(1)
            if char == b'\n':
                yield str(buffer[::-1], 'utf-8', 'ignore')
                buffer = b''
            else:
                buffer += char
            self.file.seek(self.file.tell() - 1)
        if buffer:
            yield str(buffer[::-1], 'utf-8', 'ignore')
    def close(self):
        self.file.close()

from re import compile as regex

xed_match = regex(r'x/((?:\\.|[^/])*)/((?:\\.|[^/])*)/([^\s~]*)(?:~(\d+))?')
xed_verbose_match = regex(r'xv/((?:\\.|[^/])*)/(?:((?:\\.|[^/])*)/)?')
sed_match = regex(r's/((?:\\.|[^/])*)/((?:\\.|[^/])*)/([^\s~]*)(?:~(\d+))?')
find_match = regex(r'p([\+-]\d+)?/((?:\\.|[^/])*)/([^\s~]*)(?:~(\d+))?')
tr_match = regex(r'y/((?:\\.|[^/])*)/((?:\\.|[^/])*)/([^\s~]*)(?:~(\d+))?')

matchers = [xed_match, sed_match, find_match, tr_match, xed_verbose_match]

def xed_test(nick, line):
    # Is it a command?
    match = xed_match.match(line)
    if not match:
        return None
    search, replace, who, back = match.groups()
    return search, replace, nick, who, back

import x as xed

def xed_method(search, replace, nick, who, back):
    # Some things to fix.
    if not back:
        back = 0
    else:
        back = int(back)

    fuzzy = True
    if not who:
        fuzzy = False
        who = nick
    elif who == 'g':
        who = ''
    who = who.lower()

    # Turn it into a possibility space.
    try:
        search = xed.parser.parse(search)
        replace = xed.parser.parse(replace)
    except e:
        print('| Parsing error:', e)
        return None
    search = xed.Expand().transform(search)
    lookup = xed.lookup(search)

    output = None

    # Now it is time to try to xed.
    log = ReadOut()
    for nline, line in enumerate(log.tac()):
        if nline > 500:
            log.close()
            break

        _, _, nick, line = line.split(' ', 3)
        nick = nick[1:-1]

        skip = False
        for test in matchers:
            if test.match(line):
                skip = True
                break
        if skip:
            continue

        action, nick, line = deirc(nick, line)

        match_nick = nick.lower().replace('*', '')
        if fuzzy and not match_nick.startswith(who):
            continue
        elif not fuzzy and match_nick != who:
            continue

        if action:
            action = False
            line = '\x01ACTION ' + line + '\x01'

        output = xed.findall(lookup, line)
        if not output:
            continue

        if back != 0:
            back -= 1
            continue

        log.close()
        break
    else:
        log.close()
        return None

    if not output:
        return None

    result = line
    replace = xed.Expand(amp=search).transform(replace)
    for n, i, j in reversed(output):
        rep = replace[n % len(replace)]
        result = result[:i] + rep + result[j:]

    if result[:8] == '\x01ACTION ' and result[-1] == '\x01':
        action = True
        result = result[8:-1]

    log.close()
    return action, nick + '*', result

# Execute a command.

from subprocess import Popen, PIPE

def cmd(args):
    proc = Popen(args, stdout=PIPE)
    while True:
        line = proc.stdout.readline()
        if line:
            try:
                yield str(line[:-1], 'utf-8', 'ignore')
            except:
                pass
        else:
            break

# Do the thing!
from time import sleep

def begin():
    for line in cmd(['tail', '-n', '0', '-f', fout]):
        _, _, nick, line = line.split(' ', 3)
        nick = nick[1:-1]

        # Ignore actions.
        if line[:8] == '\x01ACTION ' and line[-1] == '\x01':
            continue

        # Ignore bots and nologs.
        if line[0] == '\u200b':
            continue
        if line.startswith('[nolog]') or line.startswith('nolog:'):
            continue

        try:
            # Try it out.
            print('Testing xed.')
            result = xed_test(nick, line)
            if not result:
                print('| Test complete, yet invalid.')
                m = xed_verbose_match.match(line)
                if m:
                    n = m.group(2)
                    try:
                        m = xed.parser.parse(m.group(1))
                        if n:
                            n = xed.parser.parse(n)
                    except:
                        with open(fin, 'w') as fh:
                            fh.write('\u200b' + nick + ': Parsing error.\n')
                    m = xed.Expand().transform(m)
                    if n:
                        n = xed.Expand(amp=m).transform(n)
                    with open(fin, 'w') as fh:
                        if n:
                            fh.write('\u200b' + nick + ': ' + repr(m) + ' -> ' + repr(n) + '\n')
                        else:
                            fh.write('\u200b' + nick + ': ' + repr(m) + '\n')
                continue
            print('| Test complete and valid.\nProceeding with xed.')
            result = xed_method(*result)
            print('| Method complete.')
            if not result:
                continue
            action, nick, line = result
            if action:
                reply = '* ' + nick + ' ' + line
            else:
                reply = '<' + nick + '> ' + line
            print('| It is valid! Sending:', reply)
            with open(fin, 'w') as fh:
                fh.write('\u200b' + reply + '\n')
        except:
            with open(fin, 'w') as fh:
                fh.write('\u200b' + nick + ': This would have crashed me.\n')

begin()