# This script requires [pyyaml](http://pyyaml.org/wiki/PyYAMLDocumentation). It
# also requires all supported VCS to be in PATH so they can be invoked from a
# shell
#   Supported VCS are Subversion, Mercurial
#
# Installation procedure on Windows:
# - Install Python with the Windows installer
# - Install Microsoft Visual C++ 2010 Express Edition
# - clone PyYAML from Bitbucket repository https://bitbucket.org/xi/pyyaml/src
# - open a shell in the PyYAML directory
# - run {VC2010++Path}/Common7/Tools/vsvars32.bat in shell
# - run `python setup.py install` in *the same* shell

import re, yaml, os, sys, xml.dom, tempfile, shutil
from xml.dom.minidom import parseString, parse
from subprocess import Popen, PIPE

def stop(n):
	if n > 0 and not 'PROMPT' in os.environ:
		print("Hit ENTER to continue")
		input()
	sys.exit(n)

def cmd(command):
	p = Popen(command, 0, None, None, PIPE, PIPE)
	p.wait()
	return p


# ========= Fetchers =========
def fetch_svn(key, type, url, tag):
	rev = "HEAD"
	if not tag == False:
		# get repo url
		p = cmd(['svn','info','--xml', url])
		dom = parse(p.stdout)
		try:
			repourl = dom.getElementsByTagName("root")[0].firstChild.nodeValue
		except Exception as e:
			raise Exception("Could not retrieve repository information", url)

		if tag == "latest":
			# get latest tag revision
			p = cmd(['svn','log',"--limit=1","--xml","-q",repourl+"/tags"])
			try:
				dom = parse(p.stdout)
				rev = dom.getElementsByTagName("logentry")[0].attributes["revision"].nodeValue
			except Exception as e:
				wait = 1
				print("Warning: This repository seems to have no tags! Using HEAD revision instead.")
				print("- Given URL", url)
				print("- /tags URL", repourl+"/tags/latest")
		else:
			# get revision of supplied tag
			p = cmd(['svn','info',"--xml",repourl+"/tags/"+tag])
			try:
				if p.returncode != 0:
					raise Exception("Svn info error", p.returncode)
				dom = parse(p.stdout)
				rev = dom.getElementsByTagName("commit")[0].attributes["revision"].nodeValue
			except Exception as e:
				wait = 1
				print("Warning: Tag not found! Using HEAD revision instead.")
				print("- Given URL", url)
				print("- /tags URL", repourl+"/tags/"+tag)
	
	p = cmd(['svn','co',url,key,"-r",rev])
	return p.returncode == 0

def fetch_hg(key, type, url, tag):
	if tag == False:
		tag = "tip"
	elif tag == "latest":
		# find latest tag
		p = cmd(['hg','parents','-y','--template',"{latesttag}","-R",url])
		tag = p.stdout.readall().decode(sys.stdout.encoding)
		
		print(tag)
		if not tag or tag == "null":
			print("Warning: No Tags were found! Using 'tip' instead.")
			wait = 1
			tag = "tip"
	
	p = cmd(['hg','clone','-Uqy',url,key])
	if p.returncode != 0:
		raise Exception("Error cloning repository", key, url)
	
	p = cmd(['hg','update','-y','-r',tag,'-R',key])
	if p.returncode != 0:
		print("Warning: Could not update to selected tag '"+tag+"'! Using 'tip' instead.")
		wait = 1
	
		p = cmd(['hg','update','-y','-r','tip','-R',key])
		if p.returncode != 0:
			raise Exception("Error updating repository", key, url)
	
	return p.returncode == 0

Fetchers = {
	'subversion' : fetch_svn, 'svn' : fetch_svn,
	'mercurial'  : fetch_hg,  'hg'  : fetch_hg,
}

# ========= Testers =========
def test_svn(url):
	p = cmd(['svn','info','--non-interactive',url])
	return p.returncode == 0

def test_hg(url):
	# create temporary directory
	tmpdir = tempfile.mkdtemp('', 'fetchlibs-')
	p = cmd(['hg','clone','-Uy','-r0',url,tmpdir])
	shutil.rmtree(tmpdir)
	
	return p.returncode == 0

Testers = {
	'mercurial' : test_hg,
	'subversion': test_svn,
}

wait = 0
try:
	stream = open(".pkgmeta", 'r')
	doc = yaml.load(stream)
except Exception as e:
	print(e)
	stop(1)

if 'externals' in doc:
	externals = doc['externals'];
	for key in externals:
		external = externals[key]
		key = os.path.relpath(key)
		url = external['url']
		tag = False
		type = False
		if 'tag' in external:
			tag = external['tag']

		if os.path.exists(key):
			print("Directory already exists, remove it to fetch the library again")
			print("-", key)
			wait = 1
			continue
		
		if 'type' in external:
			type = external['type']

		# try to detect repository type by URL protocol
		if type == False:
			if re.match("^svn:", url):
				type = 'subversion'
			elif re.match("^git:", url):
				type = 'git'
		
		# detect repository type by probing
		if type == False:
			print("Probing url to detect repository type of", url)
			for test in Testers:
				print("- probing for", test)
				if Testers[test](url):
					print("- Detected", test)
					type = test
					break
		
		if type in Fetchers:
			try:
				Fetchers[type](key, type, url, tag)
			except Exception as e:
				wait = 1
				print("Error fetching",key,":\n-",e)
				raise e
		else:
			print("Unknown or unsupported VCS:", type, url)
			print("The script also does not yet support challenge-response authentication, sorry!")
			wait = 1
			continue

stop(wait)