import sys
import os
from pathlib import Path
from configparser import ConfigParser

GITEA_REPOS = ['boxtools', 'frappy']
GITEA_URL = 'https://gitea.psi.ch/linse/%s.git'

GET_GITEA_TOKEN = """#!/bin/bash
if [ -z "$GITEA_TOKEN" ]; then
  re='^([0-9a-f]{8,}) ([^ ]*) (.*)$'
  if [[ "$LC_IDENTIFICATION" =~ $re ]]; then
    export GITEA_TOKEN=${BASH_REMATCH[1]}
    export GIT_AUTHOR_NAME=${BASH_REMATCH[3]}
  else
    echo "" 1>&2
    echo "you try to push without setting GITEA_TOKEN" 1>&2
    echo "please use 'setuser <user name>' to identify yourself" 1>&2
    echo "" 1>&2
    echo quit=1
    exit
  fi
fi
if [ "$1" == "get" ]; then
  echo "connecting with gitea token for $GIT_AUTHOR_NAME" 1>&2
fi
echo "username=_"
echo "password=$GITEA_TOKEN"
"""

PRE_COMMIT_HOOK = """#!/bin/bash
re='^([0-9a-f]{8,}) ([^ ]*) (.*)?$'
if [[ "$LC_IDENTIFICATION" =~ $re ]]; then
   export GIT_AUTHOR_EMAIL=${BASH_REMATCH[2]}
   export GIT_AUTHOR_NAME=${BASH_REMATCH[3]}
fi
if [ "$GIT_AUTHOR_NAME" == "PREVENT_DEFAULT" ]; then
   echo ''
   echo 'You try to commit without specified author'
   echo "please execute 'setuser <user name>' to identify yourself"
   echo 'or add the author with:  git commit --author=<your name>'
   echo ''
   exit 1
else
   echo "Author: $GIT_AUTHOR_NAME<$GIT_AUTHOR_EMAIL>"
fi
"""


def write_when_new(doit, filename, content, executable=False):
    newmode = 0o755 if executable else 0o644
    if content is None:
        lines = []
    else:
        if not content.endswith('\n'):
            content += '\n'
        lines = content.split('\n')
    try:
        with open(filename) as fil:
            old = fil.read()
        filemode = os.stat(filename).st_mode
    except FileNotFoundError:
        old = None
        filemode = 0
    if old == content and (filemode | newmode == filemode):
        return False
    if doit:
        if lines:
            with open(filename, 'w') as fil:
                fil.write(content)
            os.chmod(filename, newmode)
        else:
            os.remove(filename)
        return True
    elif old:
        print(filename, 'needs an update')
    else:
        print(filename, 'is missing')
    return True


def change_to_gitea(doit, *repos):
    if not repos:
        repos = GITEA_REPOS
    dirty = False
    cwd = os.getcwd()
    try:
        for repo in repos:
            repodir = Path('~').expanduser() / repo
            if not repodir.is_dir():
                print(repodir, 'does not exist')
                continue
            os.chdir(repodir)
            try:
                parser = ConfigParser()
                parser.read('.git/config')
            except FileNotFoundError:
                continue
            if write_when_new(doit, '.git/hooks/get_gitea_token', GET_GITEA_TOKEN, True):
                dirty = True
            if write_when_new(doit, '.git/hooks/pre-commit', PRE_COMMIT_HOOK, True):
                dirty = True
            helper_script = parser.get('credential', 'helper', fallback=None)
            new_helper = f'{os.getcwd()}/.git/hooks/get_gitea_token'
            if helper_script != new_helper:
                dirty = True
                if doit:
                    os.system(f'git config credential.helper "{new_helper}"')
                elif helper_script:
                    print('need to change gitea credential helper')
                else:
                    print('missing gitea credential helper')
            url = parser.get('remote "origin"', 'url', fallback=None)
            if url != GITEA_URL % repo:
                dirty = True
                if doit:
                    os.system(f'git remote set-url origin {GITEA_URL % repo}')
                else:
                    print('need to change remote url')
    finally:
        os.chdir(cwd)
    return dirty


if __name__ == '__main__':
    if sys.argv[-1] == 'y':
        change_to_gitea(True)
    elif len(sys.argv) > 1:
        change_to_gitea(True, *sys.argv[1:])
    else:
        change_to_gitea(False)
        print(f'\nUsage: python gitea.py y   # to update repos {" ".join(GITEA_REPOS)}\n')