#!/usr/bin/python

import os
import sys
import subprocess
import shutil

def clonePackage(base, pkg):
    if not os.path.isdir('%s.git' % pkg):
        if os.path.isdir(pkg):
            shutil.rmtree(pkg)
        # Use --no-follow-parent because we're going to handle that with
        # grafts.
        subprocess.check_call(['git', 'svn', 'clone',
                               '--no-follow-parent',
                               '-Aauthors',
                               '-q',
                               '--no-metadata',
                               '%s/packages/%s' % (base, pkg)],
                              stdout=subprocess.PIPE)
        
        # Then make the repository bare, because git-svn can't do this
        shutil.move('%s/.git' % pkg, '%s.git' % pkg)
        shutil.rmtree(pkg)
        subprocess.check_call(['git', 'config', 'core.bare', 'true'],
                              cwd='%s.git' % pkg)
        
    # Some of these repos have a rev where everything was deleted
    # as a result of the move. We don't want that rev to exist.
    p = subprocess.Popen(['git', 'ls-tree', 'HEAD'],
                         cwd='%s.git' % pkg,
                         stdout=subprocess.PIPE)
    p.wait()
    if len(p.stdout.read()) == 0:
        subprocess.check_call(['git', 'reset', '--soft', 'HEAD^'],
                              cwd='%s.git' % pkg)

def cloneAllPackages(base):
    for pkg in open('package-list'):
        clonePackage(base, pkg.strip())

def mergeHistory(old_pkg, new_pkg, n):
    cwd = os.getcwd()
    subprocess.check_call(['git', 'push',
                           'file:///%s/%s.git' % (cwd, new_pkg),
                           'master:refs/heads/%s' % old_pkg],
                          cwd='%s.git' % old_pkg)

def mergeHistories():
    merges = []
    for line in open('merges'):
        line = line.strip()
        if line == '' or line[0] == '#':
            continue
        
        merges.append(line.split())
    
    for merge in merges:
        mergeHistory(*merge)

if __name__ == '__main__':
    try:
        base = sys.argv[1]
    except:
        base = 'svn://invirt.mit.edu/trunk'
    
    cloneAllPackages(base)
    mergeHistories()