# mass-build - Easily Build Software Involving a Large Amount of Source Repositories
# Copyright (C) 2012-2013 Ralf Jung <post@ralfj.de>
#
# This program 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 2 of the License, or
# (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

import os, subprocess, re

'''A VCS must have an "update" method with an optional "mode" parameter taking one of the three values below,
a "version" method returning a version name (or None),
and a "newVersions" method which checks for new versions and prints the result to standard output.'''
MODE_FETCH = 0
MODE_REBASE = 1
MODE_RESET = 2

def natural_sort_key(val):
    return [ (int(c) if c.isdigit() else c) for c in re.split('([0-9]+)', val) ]

def get_non_digit_prefix(val):
    return re.match('[^0-9]*', val).group(0)

class GitCommand:
    def __getattr__(self, name):
        def call(*args, get_stderr = False):
            cmd = ["git", name.replace('_', '-')] + list(args)
            output = subprocess.check_output(cmd, stderr=subprocess.STDOUT if get_stderr else None)
            return output.decode('utf-8').strip('\n')
        return call
git = GitCommand()

# Fetch updates from git
class Git:
    def __init__(self, folder, config):
        self.folder = os.path.abspath(folder)
        self.url = config['url']
        self.commit = config['version']

    def update(self, mode = MODE_REBASE):
        isBranch = (self.commit.startswith('origin/'))
        if isBranch:
            branchname = self.commit[len('origin/'):]
        else:
            branchname = "tag"
        # get us a git repository, and the "origin" remote
        if os.path.exists(self.folder):
            # load existing repo
            os.chdir(self.folder)
            git.remote("set-url", "origin", self.url) # make sure we use the current URL
        else:
            # create a new one
            os.makedirs(self.folder)
            os.chdir(self.folder)
            git.init()
            git.remote("add", "origin", self.url)
        git.fetch("origin")
        if mode == MODE_FETCH:
            return
        # create/find correct branch
        if not git.branch("--list", branchname): # the branch does not yet exit
            git.branch(branchname, self.commit)
            if isBranch: # make sure we track the correct remote branch
                git.branch("-u", self.commit, branchname)
        # update it to the latest remote commit
        git.checkout(branchname, get_stderr=True)
        if mode == MODE_RESET:
            git.reset("--hard", self.commit)
        else:
            git.rebase(self.commit)
        # update submodules
        git.submodule("update", "--init", "--recursive", "--rebase")
        # done
        print("...done", end=' ')
        if git.rev_parse("HEAD") != git.rev_parse(self.commit):
            print("(keeping local patches around)", end=' ')
        print()

    def version(self):
        os.chdir(self.folder)
        v = git.describe()
        return v[len(get_non_digit_prefix(v)):] # remove the non-digit prefix from v (so that it starts with a number)

    def checkVersions(self):
        self.update(mode = MODE_FETCH)
        currentVersion = git.describe()
        # get sorted list of tag names with the same non-digit prefix and higher version number
        tags = git.tag().split('\n')
        tags = [t for t in tags if get_non_digit_prefix(t) == get_non_digit_prefix(currentVersion) and natural_sort_key(t) > natural_sort_key(currentVersion)]
        if not tags: return
        tags.sort(key = natural_sort_key)
        print("Versions newer than "+currentVersion+" available:")
        print(tags)

# Fetch updates via SVN
class SVN:
    def __init__(self, folder, url):
        self.folder = os.path.abspath(folder)
        self.url = url

    def update(self, mode = MODE_REBASE):
        if mode == MODE_FETCH: raise Exception("Just fetching is not supported with SVN")
        if os.path.exists(self.folder):
            os.chdir(self.folder) # go into repository
            if mode == MODE_RESET: subprocess.check_call(['svn', 'revert', '-R', '.'])
            subprocess.check_call(['svn', 'switch', self.url]) # and update to the URL we got
        else:
            os.makedirs(self.folder) # if even the parent folder does not exist, svn fails
            subprocess.check_call(['svn', 'co', self.url, self.folder]) # just download it
    
    def version(self):
        return None
    
    def checkVersions(self):
        print("Version checking not supporting with SVN")