import os
import subprocess

from clams import arg, Command

from . import current_project


version = Command(
    name='version',
    title='Utilities for versioning and releases.',
    description='Utilities for versioning and releases.',
)


def _get_version():
    """Read and return the project version number."""
    from unb_cli import version
    v = version.read(current_project().version_file_path)
    return v or ''


def _list_tags():
    """List tags."""
    subprocess.call(['git', 'tag', '-l', '-n'])


def _tag(name, message, prefix='', suffix=''):
    """Create a git tag.

    Parameters
    ----------
    name : str
        The name of the tag to create
    message : str
        A short message about the tag
    prefix : str
        A prefix to add to the name
    suffix : str
        A suffix to add to the name

    Returns
    -------
    None

    """
    name = prefix + name + suffix
    subprocess.call(['git', 'tag', '-a', name, '-m', message])


def _push_tags():
    """Run `git push --follow-tags`."""
    subprocess.call(['git', 'push', '--follow-tags'])


@version.register('bump')
@arg('part', nargs='?', default='patch')
def bump(part):
    """Bump the version number."""
    from unb_cli import version
    version.bump_file(current_project().version_file_path, part, '0.0.0')


@version.register('tag')
@arg('message', nargs='?', default='',
     help='Annotate the tag with a message.')
@arg('--name', nargs='?', default='',
     help='Specify a tag name explicitly.')
@arg('--prefix', nargs='?', default='',
     help="""A prefix to add to the name.

     This is most useful when the name parameter is omitted.  For example, if
     the current version number were 1.2.3, ``unb version tag --prefix=v``
     would produce a tag named ``v1.2.3``.""")
@arg('--suffix', nargs='?', default='',
     help="""A suffix to add to the name.

     This is most useful when the name parameter is omitted.  For example, if
     the current version number were 1.2.3, ``unb version tag --suffix=-dev``
     would produce a tag named ``1.2.3-dev``.""")
def tag(message, name, prefix, suffix):
    """Create a git tag.

    If the tag name is not given explicitly, its name will equal the contents of
    the file project_root/VERSION.

    """
    if not name:
        name = _get_version()
    _tag(name, message, prefix, suffix)


@version.register('push-tags')
def push_tags():
    """Push and follow tags.  (`git push --follow-tags`)"""
    _push_tags()


@version.register('list-tags')
def list_tags():
    """List git tags."""
    _list_tags()


@version.register('version')
def get_version():
    """Get the version number of the current project."""
    print _get_version()