# This file is part of the pycalver project
# https://github.com/mbarkhau/pycalver
#
# Copyright (c) 2018 Manuel Barkhau (@mbarkhau) - MIT License
# SPDX-License-Identifier: MIT
#
# pycalver/vcs.py (this file) is based on code from the
# bumpversion project: https://github.com/peritus/bumpversion
# Copyright (c) 2013-2014 Filip Noetzel - MIT License

import os
import logging
import tempfile
import typing as typ
import subprocess as sp


log = logging.getLogger("pycalver.vcs")

VCS_SUBCOMMANDS_BY_NAME = {
    'git': {
        'is_usable': "git rev-parse --git-dir",
        'fetch'    : "git fetch",
        'push_tag' : "git push {tag}",
        'commit'   : "git commit --file {path}",
        'status'   : "git status --porcelain",
        'tag'      : "git tag --annotate {version} --message '{version}'",
        'add_path' : "git add --update {path}",
        'ls_tags'  : "git tag --list v*",
    },
    'hg': {
        'is_usable': "hg root",
        'fetch'    : "hg pull",
        'push_tag' : "hg push {tag}",
        'commit'   : "hg commit --logfile",
        'status'   : "hg status -mard",
        'tag'      : "hg tag {version} --message '{version}'",
        'add_path' : "hg add {path}",
        'ls_tags'  : "hg tags",
    },
}


class VCS:
    """Version Control System absraction for git and mercurial"""

    def __init__(self, name: str, subcommands: typ.Dict[str, str] = None):
        self.name = name
        if subcommands is None:
            self.subcommands = VCS_SUBCOMMANDS_BY_NAME[name]
        else:
            self.subcommands = subcommands

    def __call__(self, cmd_name: str, env=None, **kwargs: str) -> bytes:
        cmd_str   = self.subcommands[cmd_name]
        cmd_parts = cmd_str.format(**kwargs).split()
        return sp.check_output(cmd_parts, env=env)

    @property
    def is_usable(self) -> bool:
        cmd = self.subcommands['is_usable'].split()

        try:
            retcode = sp.call(cmd, stderr=sp.PIPE, stdout=sp.PIPE)
            return retcode == 0
        except OSError as e:
            if e.errno == 2:
                # git/mercurial is not installed.
                return False
            raise

    def fetch(self) -> None:
        self('fetch')

    def status(self) -> typ.List[str]:
        status_output = self('status')
        return [
            line.decode("utf-8")[2:].strip()
            for line in status_output.splitlines()
            if not line.strip().startswith(b"??")
        ]

    def ls_tags(self) -> typ.List[str]:
        ls_tag_lines = self('ls_tags').splitlines()
        log.debug(f"ls_tags output {ls_tag_lines}")
        return [
            line.decode("utf-8").strip() for line in ls_tag_lines if line.strip().startswith(b"v")
        ]

    def add(self, path) -> None:
        log.info(f"{self.name} add {path}")
        self('add', path=path)

    def commit(self, message: str) -> None:
        log.info(f"{self.name} commit -m '{message}'")
        message_data = message.encode("utf-8")

        tmp_file = tempfile.NamedTemporaryFile("wb", delete=False)
        assert " " not in tmp_file

        with tmp_file as fh:
            fh.write(message_data)

        env = os.environ.copy()
        # TODO (mb 2018-09-04): check that this works on py27,
        #   might need to be bytes there, idk.
        env['HGENCODING'] = "utf-8"
        self('commit', env=env, path=tmp_file.name)
        os.unlink(tmp_file.name)

    def tag(self, name) -> None:
        self('tag', name=name)

    def push(self) -> None:
        self('push')

    def __repr__(self) -> str:
        return f"VCS(name='{self.name}')"


def get_vcs() -> VCS:
    for vcs_name in VCS_SUBCOMMANDS_BY_NAME.keys():
        vcs = VCS(name=vcs_name)
        if vcs.is_usable:
            return vcs

    raise OSError("No such directory .git/ or .hg/ ")