# -*- coding: utf-8 -*-
from __future__ import unicode_literals

__license__ = 'MIT License <http://www.opensource.org/licenses/mit-license.php>'
__author__ = 'Lucas Theis <lucas@theis.io>'
__docformat__ = 'epytext'
__version__ = '1.2.0'

import re
import publications.six as six

# special character mapping
special_chars = (
	(r'\"{a}', 'ä'), (r'{\"a}', 'ä'), (r'\"a', 'ä'), (r'H{a}', 'ä'),
	(r'\"{A}', 'Ä'), (r'{\"A}', 'Ä'), (r'\"A', 'Ä'), (r'H{A}', 'Ä'),
	(r'\"{o}', 'ö'), (r'{\"o}', 'ö'), (r'\"o', 'ö'), (r'H{o}', 'ö'),
	(r'\"{O}', 'Ö'), (r'{\"O}', 'Ö'), (r'\"O', 'Ö'), (r'H{O}', 'Ö'),
	(r'\"{u}', 'ü'), (r'{\"u}', 'ü'), (r'\"u', 'ü'), (r'H{u}', 'ü'),
	(r'\"{U}', 'Ü'), (r'{\"U}', 'Ü'), (r'\"U', 'Ü'), (r'H{U}', 'Ü'),
	(r'{‘a}', 'à'), (r'\‘A', 'À'),
	(r'{‘e}', 'è'), (r'\‘E', 'È'),
	(r'{‘o}', 'ò'), (r'\‘O', 'Ò'),
	(r'{‘u}', 'ù'), (r'\‘U', 'Ù'),
	(r'{’a}', 'á'), (r'\’A', 'Á'),
	(r'{’e}', 'é'), (r'\’E', 'É'),
	(r'{’o}', 'ó'), (r'\’O', 'Ó'),
	(r'{’u}', 'ú'), (r'\’U', 'Ú'),
	(r'\`a', 'à'), (r'\`A', 'À'),
	(r'\`e', 'è'), (r'\`E', 'È'),
	(r'\`u', 'ù'), (r'\`U', 'Ù'),
	(r'\`o', 'ò'), (r'\`O', 'Ò'),
	(r'\^o', 'ô'), (r'\^O', 'Ô'),
	(r'\o', 'ø'), (r'\O', 'Ø'),
	(r'\ss', 'ß'),
	(r'\%', '%'),
	(r'\ae', 'æ'), (r'\AE', 'Æ'))

def parse(string):
	"""
	Takes a string in BibTex format and returns a list of BibTex entries, where
	each entry is a dictionary containing the entries' key-value pairs.

	@type  string: string
	@param string: bibliography in BibTex format

	@rtype: list
	@return: a list of dictionaries representing a bibliography
	"""

	# bibliography
	bib = []

	# make sure we are dealing with unicode strings
	if not isinstance(string, six.text_type):
		string = string.decode('utf-8')

	# replace special characters
	for key, value in special_chars:
		string = string.replace(key, value)
	string = re.sub(r'\\[cuHvs]{?([a-zA-Z])}?', r'\1', string)

	# split into BibTex entries
	entries = re.findall(r'(?u)@(\w+)[ \t]?{[ \t]*([^,\s]*)[ \t]*,?\s*((?:[^=,\s]+\s*\=\s*(?:"[^"]*"|{(?:[^{}]*|{[^{}]*})*}|[^,}]*),?\s*?)+)\s*}', string)

	for entry in entries:
		# parse entry
		pairs = re.findall(r'(?u)([^=,\s]+)\s*\=\s*("[^"]*"|{(?:[^{}]*|{[^{}]*})*}|[^,]*)', entry[2])

		# add to bibliography
		bib.append({'type': entry[0].lower(), 'key': entry[1]})

		for key, value in pairs:
			# post-process key and value
			key = key.lower()
			if value and value[0] == '"' and value[-1] == '"':
				value = value[1:-1]
			if value and value[0] == '{' and value[-1] == '}':
				value = value[1:-1]
			if key not in ['booktitle', 'title']:
				value = value.replace('}', '').replace('{', '')
			else:
				if value.startswith('{') and value.endswith('}'):
					value = value[1:]
					value = value[:-1]
			value = value.strip()
			value = re.sub(r'\s+', ' ', value)

			# store pair in bibliography
			bib[-1][key] = value

	return bib
