#!/usr/bin/env python3

from datetime import datetime
from glob import glob
from zoneinfo import ZoneInfo
import contextlib
import os
import os.path
import subprocess
import sys
import time

@contextlib.contextmanager
def working_directory(dir):
    old_pwd = os.getcwd()
    try:
        os.chdir(dir)
        yield
    finally:
        os.chdir(old_pwd)

WIKIROOT = '/home/hugo/wiki'

WIKI_LIST = []
for file in os.listdir(WIKIROOT):
    path = os.path.join(WIKIROOT, file)
    if 'html' in file:
        continue
    if not os.path.isdir(path):
        continue
    WIKI_LIST.append(file)


def git(*args):
    base = 'git -c color.status=always -c color.ui=always'.split(' ')
    # print('git', args)
    cmdline = base + list(args)
    # TODO subprocess can't forward stdout to our file-like object
    #      and it doesn't tell us WHAT the problem is.
    #      This probably requires us to set up a proper pipe,
    #      and something which listen on that pipe.
    #      But multithreading in Python is *HaRd*.
    cmd = subprocess.run(cmdline, stdout=sys.stdout)


def commit(wiki, *msg):
    if not msg:
        now = datetime.now(Zoneinfo(time.tzname[0]))
        msg = f'{now:%Y-%m-%d %H:%M:%S %Z}'
    else:
        msg = ' '.join(msg)
    git('add', '-A')
    git('commit', '-m', msg)

def ammend(wiki, *msg):
    if not msg:
        git('commit', '--amend')
    else:
        msg = ' '.join(msg)
        git('commit', '--amend', '-m', msg)


def grep(wiki, *args):
    git('grep', '-E', '-i', ' '.join(args))


def go(*args):
    commit(wiki, *args)
    git('push')


def echo(wiki, *rest):
    print(f'-- {wiki} --')


commands = {
        'commit': commit,
        'ammend': ammend,
        'grep': grep,
        'g': go,
        'go': go,
        'echo': echo,
}


def wiki_do(wiki, command, *args):
    cmd = commands.get(command)
    with working_directory(os.path.join(WIKIROOT, wiki)):
        if cmd:
            cmd(wiki, *args)
        else:
            git(command, *args)

class Prepender:
    def __init__(self, prefix, to):
        self.buf = []
        self.prefix = prefix
        self.to = to

    def write(self, data):
        for c in data:
            if c == '\n':
                print(self.prefix + ':' + ''.join(self.buf), file=self.to)
                self.buf = []
            else:
                self.buf.append(c)


    def flush(self):
        if self.buf:
            print(self.prefix + ':' + ''.join(self.buf), file=self.to)
            self.buf = []


    def fileno(self):
        return -1

    # def read(size=-1):
    #     pass


def main():

    args = sys.argv[1:]
    wiki_list = []
    while args:
        if args[0] == '-w' or args[0] == '--wiki':
            wiki_list.append(args[1])
            args = args[2:]
            continue
        if args[0] == '-l' or args[0] == '--list':
            print("Available Wikis:")
            print("================")
            for wiki in WIKI_LIST:
                print(f' - {wiki}')
            sys.exit()
        if args[0] == '-h' or args[0] == '--help' or args[0] == '-?':
            help = '''
                Wiki helper. Usage:
                --help | -h :: Display this help
                --list | -l :: Show available wikis
                --wiki | -w <wiki> :: specify a specific wiki for operation

                Default acts on all wikis.

                wi commit [msg] :: Create a git commit on specified wikis
                wi ammend [msg] :: Change last commit
                wi g [msg] :: wi commit [msg]; wi push
                wi [git-command] :: run git commands on wikis
                '''
            for line in help.strip().split('\n'):
                print(line.strip())
            sys.exit()
        break

    if len(args) == 0:
        index = glob(os.path.join(WIKIROOT, 
                                  (wiki_list or WIKI_LIST)[0], 
                                  'index.*'))
        subprocess.run(['vim', index[0]])
    else:
        stdout = sys.stdout
        for wiki in wiki_list or WIKI_LIST:
            # TODO threads
            sys.stdout = Prepender(wiki, stdout)
            wiki_do(wiki, *args)


if __name__ == '__main__':
    main()