#-*- coding: utf-8 -*-

"""
 (c) 2015 - Copyright Red Hat Inc

 Authors:
   Pierre-Yves Chibon <pingou@pingoured.fr>

"""


import datetime
import json
import os
import random
import shutil
import string
import tempfile
import uuid

import pygit2

import progit.exceptions
import progit.notify
from progit.lib import model


def commit_to_patch(repo_obj, commits):
    ''' For a given commit (PyGit2 commit object) of a specified git repo,
    returns a string representation of the changes the commit did in a
    format that allows it to be used as patch.
    '''
    if not isinstance(commits, list):
        commits = [commits]

    patch = ""
    for cnt, commit in enumerate(commits):
        if commit.parents:
            diff = commit.tree.diff_to_tree()

            parent = repo_obj.revparse_single('%s^' % commit.oid.hex)
            diff = repo_obj.diff(parent, commit)
        else:
            # First commit in the repo
            diff = commit.tree.diff_to_tree(swap=True)

        subject = message = ''
        if '\n' in commit.message:
            subject, message = commit.message.split('\n', 1)
        else:
            subject = commit.message

        if len(commits) > 1:
            subject = '[PATCH %s/%s] %s' % (cnt + 1, len(commits), subject)

        patch += """From %(commit)s Mon Sep 17 00:00:00 2001
From: %(author_name)s <%(author_email)s>
Date: %(date)s
Subject: %(subject)s

%(msg)s
---

%(patch)s
""" % (
            {
                'commit': commit.oid.hex,
                'author_name': commit.author.name,
                'author_email': commit.author.email,
                'date': datetime.datetime.utcfromtimestamp(
                    commit.commit_time).strftime('%b %d %Y %H:%M:%S +0000'),
                'subject': subject,
                'msg': message,
                'patch': diff.patch,
            }
        )
    return patch