"""Utilities for interacting with git using planemo abstractions."""
from __future__ import absolute_import

import os
import subprocess

from galaxy.util import unicodify

from planemo import io


def git_env_for(path):
    """Setup env dictionary to target specified git repo with git commands."""
    env = {
        "GIT_WORK_DIR": path,
        "GIT_DIR": os.path.join(path, ".git")
    }
    return env


def add(ctx, repo_path, file_path):
    env = git_env_for(repo_path)
    io.communicate("cd '%s' && git add '%s'" % (repo_path, os.path.abspath(file_path)), env=env)


def commit(ctx, repo_path, message=""):
    env = git_env_for(repo_path)
    io.communicate(["git", "commit", "-m", message], env=env)


def push(ctx, repo_path, to, branch, force=False):
    env = git_env_for(repo_path)
    cmd = ["git", "push"]
    if force:
        cmd += ["--force"]
    cmd += [to, branch]
    io.communicate(cmd, env=env)


def branch(ctx, repo_path, branch, from_branch=None):
    env = git_env_for(repo_path)
    cmd = ["git", "checkout", "-b", branch]
    if from_branch is not None:
        cmd.append(from_branch)
    io.communicate(cmd, env=env)


def checkout(ctx, remote_repo, local_path, branch=None, remote="origin", from_branch="master"):
    """Checkout a new branch from a remote repository."""
    env = git_env_for(local_path)
    if not os.path.exists(local_path):
        io.communicate(command_clone(ctx, remote_repo, local_path))
    else:
        io.communicate(["git", "fetch", remote], env=env)

    if branch:
        io.communicate(["git", "checkout", "%s/%s" % (remote, from_branch), "-b", branch], env=env)
    else:
        io.communicate(["git", "merge", "--ff-only", "%s/%s" % (remote, from_branch)], env=env)


def command_clone(ctx, src, dest, mirror=False, branch=None):
    """Produce a command-line string to clone a repository.

    Take in ``ctx`` to allow more configurability down the road.
    """
    cmd = ['git', 'clone']
    if mirror:
        cmd.append("--mirror")
    if branch is not None:
        cmd.extend(["--branch", branch])
    cmd.extend([src, dest])
    return cmd


def diff(ctx, directory, range):
    """Produce a list of diff-ed files for commit range."""
    cmd_template = "cd '%s' && git diff --name-only '%s' --"
    cmd = cmd_template % (directory, range)
    stdout, _ = io.communicate(
        cmd,
        stdout=subprocess.PIPE, stderr=subprocess.PIPE,
        universal_newlines=True
    )
    return [l.strip() for l in unicodify(stdout).splitlines() if l]


def clone(*args, **kwds):
    """Clone a git repository.

    See :func:`command_clone` for description of arguments.
    """
    command = command_clone(*args, **kwds)
    return io.communicate(command)


def rev(ctx, directory):
    """Raw revision for git directory specified.

    Throws ``RuntimeError`` if not a git directory.
    """
    cmd_template = "cd '%s' && git rev-parse HEAD"
    cmd = cmd_template % directory
    stdout, _ = io.communicate(
        cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE
    )
    return unicodify(stdout).strip()


def is_rev_dirty(ctx, directory):
    """Check if specified git repository has uncommitted changes."""
    return io.shell(['git', 'diff', '--quiet'], cwd=directory) != 0


def rev_if_git(ctx, directory):
    """Determine git revision (or ``None``)."""
    try:
        the_rev = rev(ctx, directory)
        is_dirty = is_rev_dirty(ctx, directory)
        if is_dirty:
            the_rev += "-dirty"
        return the_rev
    except RuntimeError:
        return None