#! /usr/bin/python
# -*- coding: utf-8 -*-

"""
gitup: the git repository updater
"""

import argparse
import ConfigParser as configparser
import os
import re
import shlex
import subprocess

__author__ = "Ben Kurtovic"
__copyright__ = "Copyright (c) 2011-2012 Ben Kurtovic"
__license__ = "MIT License"
__version__ = "0.1"
__email__ = "ben.kurtovic@gmail.com"

config_filename = os.path.join(os.path.expanduser("~"), ".gitup")

# Text formatting functions
bold = lambda t: style_text(t, "bold")
red = lambda t: style_text(t, "red")
green = lambda t: style_text(t, "green")
yellow = lambda t: style_text(t, "yellow")
blue = lambda t: style_text(t, "blue")

def style_text(text, effect):
    """Give a text string a certain effect, such as boldness, or a color."""
    ansi = { # ANSI escape codes to make terminal output fancy
        "reset": "\x1b[0m",
        "bold": "\x1b[1m",
        "red": "\x1b[1m\x1b[31m",
        "green": "\x1b[1m\x1b[32m",
        "yellow": "\x1b[1m\x1b[33m",
        "blue": "\x1b[1m\x1b[34m",
    }

    try: # pad text with effect, unless effect does not exist
        return "{}{}{}".format(ansi[effect], text, ansi['reset'])
    except KeyError:
        return text

def out(indent, msg):
    """Print a message at a given indentation level."""
    width = 4 # amount to indent at each level
    if indent == 0:
        spacing = "\n"
    else:
        spacing = " " * width * indent
    msg = re.sub("\s+", " ", msg) # collapse multiple spaces into one
    print spacing + msg

def exec_shell(command):
    """Execute a shell command and get the output."""
    command = shlex.split(command)
    result = subprocess.check_output(command, stderr=subprocess.STDOUT)
    if result:
        result = result[:-1] # strip newline if command returned anything
    return result

def directory_is_git_repo(directory_path):
    """Check if a directory is a git repository."""
    if os.path.isdir(directory_path):
        git_subfolder = os.path.join(directory_path, ".git")
        if os.path.isdir(git_subfolder): # check for path/to/repository/.git
            return True
    return False

def update_repository(repo_path, repo_name):
    """Update a single git repository by pulling from the remote."""
    out(1, bold(repo_name) + ":")

    os.chdir(repo_path) # cd into our folder so git commands target the correct
                        # repo

    try:
        dry_fetch = exec_shell("git fetch --dry-run") # check if there is
                                                      # anything to pull, but
                                                      # don't do it yet
    except subprocess.CalledProcessError:
        out(2, red("Error: ") + "cannot fetch; do you have a remote " +
                 "repository configured correctly?")
        return

    try:
        last_commit = exec_shell("git log -n 1 --pretty=\"%ar\"")
    except subprocess.CalledProcessError:
        last_commit = "never" # couldn't get a log, so no commits

    if not dry_fetch: # no new changes to pull
        out(2, blue("No new changes.") + " Last commit was {}.".format(
                last_commit))

    else: # stuff has happened!
        out(2, "There are new changes upstream...")
        status = exec_shell("git status")

        if status.endswith("nothing to commit (working directory clean)"):
            out(2, green("Pulling new changes..."))
            result = exec_shell("git pull")
            out(2, "The following changes have been made since {}:".format(
                    last_commit))
            print result

        else:
            out(2, red("Warning: ") + "you have uncommitted changes in this " +
                    "repository!")
            out(2, "Ignoring.")

def update_directory(dir_path, dir_name, is_bookmark=False):
    """First, make sure the specified object is actually a directory, then
    determine whether the directory is a git repo on its own or a directory
    of git repositories. If the former, update the single repository; if the
    latter, update all repositories contained within."""
    if is_bookmark:
        dir_type = "bookmark" # where did we get this directory from?
    else:
        dir_type = "directory"

    dir_long_name = "{} '{}'".format(dir_type, bold(dir_path))

    try:
        os.listdir(dir_path) # test if we can access this directory
    except OSError:
        out(0, red("Error: ") + "cannot enter {}; does it exist?".format(
                dir_long_name))
        return

    if not os.path.isdir(dir_path):
        if os.path.exists(dir_path):
            out(0, red("Error: ") + dir_long_name + " is not a directory!")
        else:
            out(0, red("Error: ") + dir_long_name + " does not exist!")
        return

    if directory_is_git_repo(dir_path):
        out(0, dir_long_name.capitalize() + " is a git repository:")
        update_repository(dir_path, dir_name)

    else:
        repositories = []

        dir_contents = os.listdir(dir_path) # get potential repos in directory
        for item in dir_contents:
            repo_path = os.path.join(dir_path, item)
            repo_name = os.path.join(dir_name, item)
            if directory_is_git_repo(repo_path): # filter out non-repositories
                repositories.append((repo_path, repo_name))

        num_of_repos = len(repositories)
        if num_of_repos == 1:
            out(0, dir_long_name.capitalize() + " contains 1 git repository:")
        else:
            out(0, dir_long_name.capitalize() +
                    " contains {} git repositories:".format(num_of_repos))

        repositories.sort() # go alphabetically instead of randomly
        for repo_path, repo_name in repositories:
            update_repository(repo_path, repo_name)

def update_directories(paths):
    """Update a list of directories supplied by command arguments."""
    for path in paths:
        path = os.path.abspath(path) # convert relative to absolute path
        path_name = os.path.split(path)[1] # directory name; "x" in /path/to/x/
        update_directory(path, path_name, is_bookmark=False)

def update_bookmarks():
    """Loop through and update all bookmarks."""
    try:
        bookmarks = load_config_file().items("bookmarks")
    except configparser.NoSectionError:
        bookmarks = []

    if bookmarks:
        for bookmark_path, bookmark_name in bookmarks:
            update_directory(bookmark_path, bookmark_name, is_bookmark=True)
    else:
        out(0, "You don't have any bookmarks configured! Get help with " +
                "'gitup -h'.")

def load_config_file():
    """Read the file storing our config options from config_filename and return
    the resulting SafeConfigParser() object."""
    config = configparser.SafeConfigParser()
    config.optionxform = str # don't lowercase option names, because we are
                             # storing paths there
    config.read(config_filename)
    return config

def save_config_file(config):
    """Save our config changes to the config file specified by
    config_filename."""
    with open(config_filename, "wb") as config_file:
        config.write(config_file)

def add_bookmarks(paths):
    """Add a list of paths as bookmarks to the config file."""
    config = load_config_file()
    if not config.has_section("bookmarks"):
        config.add_section("bookmarks")

    out(0, yellow("Added bookmarks:"))

    for path in paths:
        path = os.path.abspath(path) # convert relative to absolute path
        if config.has_option("bookmarks", path):
            out(1, "'{}' is already bookmarked.".format(path))
        else:
            path_name = os.path.split(path)[1]
            config.set("bookmarks", path, path_name)
            out(1, bold(path))

    save_config_file(config)

def delete_bookmarks(paths):
    """Remove a list of paths from the bookmark config file."""
    config = load_config_file()

    if config.has_section("bookmarks"):
        out(0, yellow("Deleted bookmarks:"))
        for path in paths:
            path = os.path.abspath(path) # convert relative to absolute path
            config_was_changed = config.remove_option("bookmarks", path)
            if config_was_changed:
                out(1, bold(path))
            else:
                out(1, "'{}' is not bookmarked.".format(path))
        save_config_file(config)

    else:
        out(0, "There are no bookmarks to delete!")

def list_bookmarks():
    """Print all of our current bookmarks."""
    config = load_config_file()
    try:
        bookmarks = config.items("bookmarks")
    except configparser.NoSectionError:
        bookmarks = []

    if bookmarks:
        out(0, yellow("Current bookmarks:"))
        for bookmark_path, bookmark_name in bookmarks:
            out(1, bookmark_path)
    else:
        out(0, "You have no bookmarks to display.")

def main():
    """Parse arguments and then call the appropriate function(s)."""
    parser = argparse.ArgumentParser(description="""Easily pull to multiple git
            repositories at once.""", epilog="""Both relative and absolute
            paths are accepted by all arguments. Questions? Comments? Email the
            author at {}.""".format(__email__), add_help=False)

    group_u = parser.add_argument_group("updating repositories")
    group_b = parser.add_argument_group("bookmarking")
    group_m = parser.add_argument_group("miscellaneous")

    group_u.add_argument('directories_to_update', nargs="*", metavar="path",
            help="""update all repositories in this directory (or the directory
            itself, if it is a repo)""")

    group_u.add_argument('-u', '--update', action="store_true", help="""update
            all bookmarks (default behavior when called without arguments)""")

    group_b.add_argument('-a', '--add', dest="bookmarks_to_add", nargs="+",
            metavar="path", help="add directory(s) as bookmarks")

    group_b.add_argument('-d', '--delete', dest="bookmarks_to_del", nargs="+",
            metavar="path",
            help="delete bookmark(s) (leaves actual directories alone)")

    group_b.add_argument('-l', '--list', dest="list_bookmarks",
            action="store_true", help="list current bookmarks")

    group_m.add_argument('-h', '--help', action="help",
            help="show this help message and exit")

    group_m.add_argument('-v', '--version', action="version",
            version="gitup version "+__version__)

    args = parser.parse_args()

    print bold("gitup") + ": the git-repo-updater"

    if args.bookmarks_to_add:
        add_bookmarks(args.bookmarks_to_add)

    if args.bookmarks_to_del:
        delete_bookmarks(args.bookmarks_to_del)

    if args.list_bookmarks:
        list_bookmarks()

    if args.directories_to_update:
        update_directories(args.directories_to_update)

    if args.update:
        update_bookmarks()

    if not any(vars(args).values()): # if they did not tell us to do anything,
        update_bookmarks()           # automatically update bookmarks

if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        out(0, "Stopped by user.")