# Author: Nic Wolfe <nic@wolfeden.ca>
# URL: http://code.google.com/p/sickbeard/
#
# This file is part of SickRage.
#
# SickRage is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# SickRage is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with SickRage.  If not, see <http://www.gnu.org/licenses/>.
import os
from subprocess import check_output, PIPE, Popen
from os.path import join, split

try:
    import json
except ImportError:
    from lib import simplejson as json

import helpers


class GitHub(object):
    """
    Simple api wrapper for the Github API v3. Currently only supports the small thing that SB
    needs it for - list of commits.
    """

    def __init__(self, github_repo_user, github_repo, branch):

        self.github_repo_user = github_repo_user
        self.github_repo = github_repo
        self.branch = branch

    def _access_API(self, path, params=None):
        """
        Access the API at the path given and with the optional params given.

        path: A list of the path elements to use (eg. ['repos', 'midgetspy', 'Sick-Beard', 'commits'])
        params: Optional dict of name/value pairs for extra params to send. (eg. {'per_page': 10})

        Returns a deserialized json object of the result. Doesn't do any error checking (hope it works).
        """

        url = 'https://api.github.com/' + '/'.join(path)

        if params and type(params) is dict:
            url += '?' + '&'.join([str(x) + '=' + str(params[x]) for x in params.keys()])

        parsedJSON = helpers.getURL(url, json=True)
        if not parsedJSON:
            return []

        return parsedJSON

    def commits(self):
        """
        Uses the API to get a list of the 100 most recent commits from the specified user/repo/branch, starting from HEAD.

        user: The github username of the person whose repo you're querying
        repo: The repo name to query
        branch: Optional, the branch name to show commits from

        Returns a deserialized json object containing the commit info. See http://developer.github.com/v3/repos/commits/
        """
        access_API = self._access_API(['repos', self.github_repo_user, self.github_repo, 'commits'],
                                      params={'per_page': 100, 'sha': self.branch})
        return access_API

    def compare(self, base, head, per_page=1):
        """
        Uses the API to get a list of compares between base and head.

        user: The github username of the person whose repo you're querying
        repo: The repo name to query
        base: Start compare from branch
        head: Current commit sha or branch name to compare
        per_page: number of items per page

        Returns a deserialized json object containing the compare info. See http://developer.github.com/v3/repos/commits/
        """
        access_API = self._access_API(
            ['repos', self.github_repo_user, self.github_repo, 'compare', base + '...' + head],
            params={'per_page': per_page})
        return access_API

    def branches(self):
        access_API = self._access_API(
            ['repos', self.github_repo_user, self.github_repo, 'branches'],
            params={'per_page': 100})
        return access_API

    def installed_branch(self):
        installed_path = os.path.dirname(os.path.normpath(os.path.abspath(__file__)))
        return self.hash_dir(installed_path)

    def _lstree(self, files, dirs):
        """Make git ls-tree like output."""
        for f, sha1 in files:
            yield "100644 blob {}\t{}\0".format(sha1, f)

        for d, sha1 in dirs:
            yield "040000 tree {}\t{}\0".format(sha1, d)


    def _mktree(self, files, dirs):
        mkt = Popen(["git", "mktree", "-z"], stdin=PIPE, stdout=PIPE)
        return mkt.communicate("".join(self._lstree(files, dirs)))[0].strip()

    def hash_file(self, path):
        """Write file at path to Git index, return its SHA1 as a string."""
        return check_output(["git", "hash-object", "-w", "--", path]).strip()

    def hash_dir(self, path):
        """Write directory at path to Git index, return its SHA1 as a string."""
        dir_hash = {}

        for root, dirs, files in os.walk(path, topdown=False):
            f_hash = ((f, self.hash_file(join(root, f))) for f in files)
            d_hash = ((d, dir_hash[join(root, d)]) for d in dirs)
            # split+join normalizes paths on Windows (note the imports)
            dir_hash[join(*split(root))] = self._mktree(f_hash, d_hash)

        return dir_hash[path]