#!/usr/bin/python
# encoding: utf-8

import sys
import os
import argparse
from collections import namedtuple
from subprocess import Popen, PIPE

from urllib2 import urlopen
import json
from urlparse import urlparse

WHITELIST=[]
BLACKLIST=[]

ACCESS_TOKEN_PARAM = '?access_token=%s'
LISTING_FIX_PARAM = '&per_page=150'
GITHUB_API_HOST = 'https://api.github.com'

GIT_CLONE_CMD = 'git clone %s %s %s'
GIT_CLONE_API_URL = 'https://%s@github.com/%s'
GIT_SHA_CMD = 'git rev-parse --short %s'
GIT_FETCH_CMD = 'git fetch'
GIT_CHECK_REMOTE_CMD = 'git ls-remote'

USER_DETAILS_PATH = '/users/%s'

DEFAULT_TOKEN_FILE = os.path.expanduser('~/.config/ghtoken')

class Color:
    GREEN = "\033[1;32m"
    BLUE = "\033[1;34m"
    YELLOW = "\033[1;33m"
    RED = "\033[1;31m"
    END = "\033[0m"

def get_color_str(text, color):
    return color + str(text) + Color.END

def system_exec(command, directory=None, show_output=True, ignore_error=False):
    if not directory:
        directory = os.getcwd()

    try:
        process = Popen(command, stdout=PIPE, stderr=PIPE, shell=True, cwd=directory)
        (output, error) = process.communicate()
        output = output.strip()
        error = error.strip()

        if show_output and len(output) > 0:
            print output
            sys.stdout.flush()

        if process.returncode != 0 and not ignore_error:
            raise Exception(error)

        ReturnInfo = namedtuple('ReturnInfo', 'return_code output error')
        return ReturnInfo(process.returncode, output, error)

    except Exception as err:
        print >>sys.stderr, Color.RED + "Could not execute", command
        print >>sys.stderr, err, Color.END
        print >>sys.stderr, "Terminating early"
        exit(1)

class AttributeDict(dict):
    def __getattr__(self, attr):
        return self[attr]
    def __setattr__(self, attr, value):
        self[attr] = value

def read_api_uri(uri, config):
    uri += ACCESS_TOKEN_PARAM % config.token + LISTING_FIX_PARAM

    if config.debug:
        print "Trying:", uri

    return urlopen(uri).read()

def get_json(uri, config, obj_type=AttributeDict):
    return json.loads(read_api_uri(uri, config), object_hook=obj_type)

class GitHubRepo(AttributeDict):
    """Top-level class managing all content of a GitHub repository"""
    def __init__(self, *args, **kwargs):
        AttributeDict.__init__(self, *args, **kwargs)
        self.content = []

    def configure(self, config):
        self.config = config

        # Initialize the content repos
        self.content.append(CodeRepo(self, config))
        if self.config.full_backup:
            self.content.append(WikiRepo(self, config))
            if self.has_issues:
                self.content.append(IssuesRepo(self, config))
                self.content.append(MilestonesRepo(self, config))
            self.content.append(PullsRepo(self, config))
            # Teams are only available from user's repos
            if self.owner.login == self.config.username:
                self.content.append(TeamsRepo(self, config))
            self.content.append(CommentsRepo(self, config))
            self.content.append(ForksRepo(self, config))

    def update(self):
        [repo.update() for repo in self.content]

class CodeRepo(object):
    """GitHub code git repository"""
    def __init__(self, gh_repo, config):
        self.config = config

        # Copy the details we need from the JSON
        self.name = gh_repo.name
        self.full_name = gh_repo.full_name
        self.ssh_url = gh_repo.ssh_url
        self.default_branch = gh_repo.default_branch
        self.description = gh_repo.description

        self.target_directory = os.path.join(self.config.cwd, self.name)
        if self.config.mirror:
            self.target_directory += '.git'

    def try_clone(self, ignore_error=False):
        print "Using", self.target_directory
        if os.path.isdir(self.target_directory):
            return False

        print "Need to clone", self.name
        if self.config.mirror:
            clone_opts = '--mirror'
        else:
            clone_opts = '--recurse-submodules'
        if self.config.ssh:
            clone_url = self.ssh_url
        else:
            clone_url = GIT_CLONE_API_URL % (self.config.token,
                                             self.full_name)
        clone_cmd = GIT_CLONE_CMD % (clone_opts, clone_url, \
                                     self.target_directory)

        # Create leading directories if necessary
        clone_dir = os.path.dirname(self.target_directory)
        if not os.path.isdir(clone_dir):
            os.makedirs(clone_dir)

        # Let the caller decide if errors should be ignored.
        return_code = system_exec(clone_cmd, ignore_error=ignore_error).return_code
        if ignore_error and return_code != 0:
            print "Repo for %s not initialized, skipping" % self.name
            return True

        print "Finished cloning"
        return True

    def get_sha_str(self, branch, directory):
        if self.config.mirror:
            sha_cmd = GIT_SHA_CMD % branch
        else:
            sha_cmd = GIT_SHA_CMD % 'origin/' + branch
        sha = system_exec(sha_cmd, directory, False, True).output
        return get_color_str(sha, Color.GREEN)

    def print_start_sha(self, branch, directory):
        print("- " + get_color_str(branch, Color.GREEN) + " @ " \
                + self.get_sha_str(branch, directory) + ' ..'),

    def update(self, fatal_remote_errors = True):
        if self.try_clone(False):
            return

        # Check if the remote is still there before fetching
        return_code = system_exec(GIT_CHECK_REMOTE_CMD, self.target_directory, show_output=False, ignore_error=True).return_code
        if return_code != 0:
            # Is it fatal?
            if fatal_remote_errors:
                error_message = get_color_str("ERROR: Repo for %s seems to have been deleted. Skipping update." % self.full_name, Color.RED)
                print error_message
                raise Exception(error_message)
            else:
                print get_color_str("WARNING: Repo for %s seems to have been deleted. Skipping update." % self.full_name, Color.GREEN)
                return

        self.print_start_sha(self.default_branch, self.target_directory)
        system_exec(GIT_FETCH_CMD, self.target_directory, False)
        print self.get_sha_str(self.default_branch, self.target_directory)

class WikiRepo(CodeRepo):
    """GitHub wiki git repository"""
    def __init__(self, gh_repo, config):
        CodeRepo.__init__(self, gh_repo, config)

        # Put the wiki under the project.extras/wiki directory
        self.target_directory = os.path.join(self.config.cwd,
                                             self.name + '.extras',
                                             'wiki')
        if self.config.mirror:
            self.target_directory += '.git'

        # Adjust the name and hardcode master as the default branch
        self.name += '.wiki'
        self.full_name += '.wiki'
        self.ssh_url = self.ssh_url.rpartition('.git')[0] \
                       + '.wiki.git'
        self.default_branch = 'master'
        self.description += ' - Wiki'

    def try_clone(self, ignore_error=True):
        # This is sad. Github will tell us a repo has a wiki, but if the
        # wiki hasn't actually been initialized, it won't exist. Reuse the
        # GitRepo clone code, but allow it to fail.
        return CodeRepo.try_clone(self, True)

    def update(self):
        super(WikiRepo, self).update(fatal_remote_errors = False)

class JsonRepo(object):
    def __init__(self, gh_repo, api_url, config, content=None):
        self.config = config

        # Copy the details we need from the JSON
        self.name = gh_repo.name
        self.full_name = gh_repo.full_name
        self.repo_url = gh_repo.url
        self.description = gh_repo.description

        # Sanitize the content url to strip the {/number} type markers
        self.content_url = api_url.split('{')[0]

        # Put downloaded content in project.extras directory
        self.content_directory = os.path.join(self.config.cwd,
                                              self.name + '.extras')

        # If the content type was supplied, adjust the names further
        if content is not None:
            self.name += '.%s' % content
            self.full_name += '.%s' % content
            self.description += ' - %s' % content.title()
            self.content_directory = os.path.join(self.content_directory,
                                                  content)

    def download_file(self, url, suffix='.json'):
        if url == self.content_url:
            # Just use the content directory
            target = self.content_directory
        else:
            # Strip off base content URL path to get target
            base = os.path.relpath(urlparse(url).path,
                                   urlparse(self.content_url).path)
            target = os.path.join(self.content_directory, base)

        # Add suffix if specified
        if suffix:
            target += suffix

        target_directory = os.path.dirname(target)
        if not os.path.isdir(target_directory):
            os.makedirs(target_directory)

        if self.config.debug:
            print "Downloading %s" % target
        data = read_api_uri(url, self.config)
        with open(target, 'wb') as dl_file:
            dl_file.write(data)

class IssuesRepo(JsonRepo):
    def __init__(self, gh_repo, config):
        JsonRepo.__init__(self, gh_repo, gh_repo.issues_url, config, 'issues')

    def update(self):
        print "Using", self.content_directory
        for issue in get_json(self.content_url, self.config):
            self.download_file(issue.url)
            self.download_file(issue.comments_url)
            self.download_file(issue.events_url)

class PullsRepo(JsonRepo):
    def __init__(self, gh_repo, config):
        JsonRepo.__init__(self, gh_repo, gh_repo.pulls_url, config, 'pulls')

    def update(self):
        print "Using", self.content_directory
        for pull in get_json(self.content_url, self.config):
            self.download_file(pull.url)
            self.download_file(pull.commits_url)
            self.download_file(pull.comments_url)

class MilestonesRepo(JsonRepo):
    def __init__(self, gh_repo, config):
        JsonRepo.__init__(self, gh_repo, gh_repo.milestones_url, config,
                          'milestones')

    def update(self):
        print "Using", self.content_directory
        for milestone in get_json(self.content_url, self.config):
            self.download_file(milestone.url)

class TeamsRepo(JsonRepo):
    def __init__(self, gh_repo, config):
        JsonRepo.__init__(self, gh_repo, gh_repo.teams_url, config, 'teams')

    def update(self):
        print "Using", self.content_directory + '.json'
        self.download_file(self.content_url)

class CommentsRepo(JsonRepo):
    def __init__(self, gh_repo, config):
        JsonRepo.__init__(self, gh_repo, gh_repo.comments_url, config,
                          'comments')

    def update(self):
        print "Using", self.content_directory + '.json'
        self.download_file(self.content_url)

class ForksRepo(JsonRepo):
    def __init__(self, gh_repo, config):
        JsonRepo.__init__(self, gh_repo, gh_repo.forks_url, config, 'forks')

    def update(self):
        print "Using", self.content_directory + '.json'
        self.download_file(self.content_url)

class RepoUpdater(object):
    def __init__(self, args):
        # Keep a copy of the arguments dictionary
        self.args = args

        # Use current directory if unspecified
        self.args.cwd = args.directory if args.directory else os.getcwd()

        # Read a token file if necessary
        if self.args.token is None:
            try:
                with open(self.args.token_file, 'r') as tfile:
                    self.args.token = tfile.read().strip()
            except IOError as err:
                print >>sys.stderr, Color.RED + \
                    "Could not open token file %s: %s" \
                    % (self.args.token_file, err), \
                    Color.END
                print >>sys.stderr, "Terminating early"
                exit(1)

        if self.args.debug:
            print "Current configuration: "
            for arg in self.args:
                # We don't want this printed
                if arg != 'token':
                    print arg, ":", get_color_str(args[arg], Color.GREEN)

    def update(self):
        if not os.path.isdir(self.args.cwd):
            os.makedirs(self.args.cwd)

        print "User:", get_color_str(self.args.username, Color.GREEN)
        user_data = self.get_user_data()

        repos, excluded_repos = self.get_repos(user_data.repos_url, user_data.organizations_url)
        repos = self.filter_repo_names(repos, excluded_repos)
        for repo in repos:
            print get_color_str('{:-^60}'.format(repo.name), Color.YELLOW)
            repo.update()

    def get_user_data(self):
        return get_json(GITHUB_API_HOST + USER_DETAILS_PATH
                        % self.args.username, self.args)

    def get_own_repos(self, repos_url):
        repos = get_json(repos_url, self.args, GitHubRepo)
        [repo.configure(self.args) for repo in repos]
        repo_count = len(repos)

        if self.args.exclude_forks:
            repos = [repo for repo in repos if not repo.fork]

        return repos, repo_count

    def get_org_repos(self, orgs_url):
        all_orgs_repos = []
        repo_count = 0

        orgs = get_json(orgs_url, self.args)
        for org in orgs:
            org_repos = get_json(org.repos_url, self.args, GitHubRepo)
            [repo.configure(self.args) for repo in org_repos]
            repo_count += len(org_repos)

            if not self.args.include_public_org_repos:
                org_repos = [repo for repo in org_repos if repo.private]
            if not self.args.include_org_forks:
                org_repos = [repo for repo in org_repos if not repo.fork]

            all_orgs_repos += org_repos

        return all_orgs_repos, repo_count

    def get_repos(self, repos_url, orgs_url):
        repos = []
        if self.args.debug:
            print "Getting repo data from", get_color_str(repos_url, Color.GREEN)

        own_repos, repo_count = self.get_own_repos(repos_url)
        if not self.args.exclude_own:
            repos += own_repos

        org_repos, org_repo_count = self.get_org_repos(orgs_url)
        if not self.args.exclude_orgs:
            repos += org_repos

        if self.args.debug:
            print "Available repos:", get_color_str(str(len(repos)), Color.GREEN)
            for repo in repos:
                owner = repo.owner.login
                print " -", get_color_str(repo.name, Color.YELLOW)
                print " " * 5, repo.description

        excluded_repos = repo_count + org_repo_count - len(repos)
        return repos, excluded_repos

    def filter_repo_names(self, repos, excluded_repos):
        original_repos = len(repos)

        if BLACKLIST:
            repos = [repo for repo in repos if not repo.name in BLACKLIST]

        if WHITELIST:
            repos = [repo for repo in repos if repo.name in WHITELIST]

        filtered_repos = original_repos - len(repos)

        ignored_repos_str = " (" + str(filtered_repos) + " filtered, " + str(excluded_repos) + " excluded)"
        repo_count_str = str(original_repos - filtered_repos) + " / " + str(original_repos)
        print "Fetching repos:", get_color_str(repo_count_str + ignored_repos_str, Color.GREEN)

        for repo in repos:
            owner = repo.owner.login
            print " -", Color.YELLOW + repo.name, Color.END
            print " " * 5, repo.description

        return repos

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Retrieve and/or update local copies of GitHub-hosted repos')

    parser.add_argument('username', \
            help='GitHub username that will be used for cloning and fetching')
    parser.add_argument('token', \
            nargs='?', \
            help='GitHub auth token for that username. \
            You can create one at https://github.com/settings/applications')
    parser.add_argument('--version', \
            action='version', \
            version='%(prog)s v0.7')

    parser.add_argument('-d', '--directory', \
            help='Target directory for cloning and fetching')

    parser.add_argument('-t', '--token-file', \
            default=DEFAULT_TOKEN_FILE, \
            help='File containing the github token')
    parser.add_argument('-s', '--ssh', \
            help='Fetch repositories using ssh', \
            action='store_true')
    parser.add_argument('-m', '--mirror', \
            help='Mirror bare repositories instead of making full checkouts', \
            action='store_true')
    parser.add_argument('-x', '--exclude-own', \
            help='Exclude own repositories in the updates', \
            action='store_true')
    parser.add_argument('--exclude-forks', \
            help='Exclude forked repositories from the updates', \
            action='store_true')
    parser.add_argument('--exclude-orgs', \
            help='Exclude repos that are in user\'s orgs (this does not filter the ones you have)', \
            action='store_true')
    parser.add_argument('--include-org-forks', \
            help='Include forked repos that are in user\'s orgs', \
            action='store_true')
    parser.add_argument('--include-public-org-repos', \
            help='Include public repos that are in user\'s orgs', \
            action='store_true')
    parser.add_argument('--full-backup', \
            help='Include all repository content', \
            action='store_true')

    parser.add_argument('--debug', \
            help='Enable debugging output', \
            action='store_true')

    args = AttributeDict(vars(parser.parse_args()))

    RepoUpdater(args).update()