#!/usr/bin/env python
# encoding: utf-8
"""
	Convert snipmate compatible snippets to UltiSnips compatible snippets
	by Phillip Berndt
"""
import sys
import re
import os

def convert_snippet_contents(content):
	" If the snippet contains snipmate style substitutions, convert them to ultisnips style "
	content = re.sub("`([^`]+`)", "`!v \g<1>", content)
	return content

def convert_snippet_file(source):
	" One file per filetype "
	retval = ""
	state = 0
	for line in open(source).readlines():
		# Ignore empty lines
		if line.strip() == "":
			continue
		# The rest of the handlig is stateful
		if state == 0:
			# Find snippet start
			if line[:8] == "snippet ":
				snippet_info = re.match("(\S+)\s*(.*)", line[8:])
				if not snippet_info:
					print >> sys.stderr, "Warning: Malformed snippet\n %s\n" % line
					continue
				retval += 'snippet %s "%s"' % (snippet_info.group(1), snippet_info.group(2) if snippet_info.group(2) else snippet_info.group(1)) + "\n"
				state = 1
				snippet = ""
		elif state == 1:
			# First line of snippet: Get indentation
			whitespace = re.search("^\s+", line)
			if not whitespace:
				print >> sys.stderr, "Warning: Malformed snippet, content not indented.\n"
				retval += "endsnippet\n\n"
				state = 0
			else:
				whitespace = whitespace.group(0)
				snippet += line[len(whitespace):]
				state = 2
		elif state == 2:
			# In snippet: Check if indentation level is the same. If not, snippet has ended
			if line[:len(whitespace)] != whitespace:
				retval += convert_snippet_contents(snippet) + "endsnippet\n\n"
				state = 0
			else:
				snippet += line[len(whitespace):]
	if state == 2:
		retval += convert_snippet_contents(snippet) + "endsnippet\n\n"
	return retval
	
def convert_snippet(source):
	" One file per snippet "
	name = os.path.basename(source)[:-8]
	return 'snippet %s "%s"' % (name, name) + "\n" + \
		convert_snippet_contents(open(source).read()) + \
		"\nendsnippet\n"
	
def convert_snippets(source):
	if os.path.isdir(source):
		return "\n".join((convert_snippet(os.path.join(source, x)) for x in os.listdir(source) if x[-8:] == ".snippet"))
	else:
		return convert_snippet_file(source)

if __name__ == '__main__':
	if len(sys.argv) not in (3, 2):
		print >> sys.stderr, "Syntax: get_snipmate_snippets.py <source directory or file> [target file]"
		print >> sys.stderr
		sys.exit(1)
	if len(sys.argv) == 2:
		source = sys.argv[1]
		target = sys.stdout
	else:
		source, target = sys.argv[1:]
		target = open(target, "w")

	snippets = convert_snippets(source)
	print >> target, snippets