import os
import yaml


class QuestionException(Exception):
	""" Exception to be thrown when there is something wrong with
	    the question file. """
	pass

class Questions(object):
	""" Object holding all the questions """

	QUESTION_TYPES = ["Text", "Image", "Music", "Code", "Video"]
	QUESTION_KEYS = ["Name", "Question", "Answer", "Type", "Double-Jeopardy", "Audio"]

	def __init__(self, qfile, appendPath=False, verbose=False):
		self.qfile = qfile
		self._questions = []
		self._appendPath = appendPath
		self._verbose = verbose
		self._title = "Round n"

		self._read_questions(self.qfile)

	def get_title(self):
		return self._title

	def get_sections(self):
		return [s["Section"] for s in self._questions]

	def get_questions(self, section):
		sec = filter(lambda s: s["Section"] ==  section, self._questions)
		if len(sec) < 1:
			raise ValueError("Section %s does not exist" % (section,))
		return sec[0]["Questions"]

	def get_question(self, section, question):
		if type(question) != int or question < 1 or question > 5:
			raise ValueError("question parameter needs to be an integer between 1 and 5")
		return self.get_questions(section)[question-1]

	def get_number_from_section(self, section):
		for i,s in enumerate(self._questions, 1):
			if s["Section"] == section:
				return i
		raise ValueError("Section '%s' does not exist" % section)

	def _get_yaml(self, filename):
		f = None

		# open file
		try:
			f = open(filename)
		except OSError as e:
			raise QuestionException("Could not read question file '%s': %s" % (filename, e))

		# load yaml
		ysrc = None
		try:
			ysrc = yaml.safe_load(f.read())
		except Exception as e:
			raise QuestionException("Error parsing YAML in question file '%s': %s" % (filename, e))

		return ysrc

	def _gen_error(self, filename, error):
		raise QuestionException("Error parsing question file '%s': %s" % (filename, error))

	def _read_questions(self, filename):
		ysrc = self._get_yaml(filename)

		if type(ysrc) == list:
			# "old style" question file, list of sections
			# just read sections and return happily ever after
			self._read_sections(ysrc, filename)

			return True
		elif type(ysrc) == dict:
			# "new style" quetion file, dict of Name and Sections
			self._read_newstyle_questions(ysrc, filename)

			return True
		else:
			self._gen_error(filename, "Contents of YAML is neither a dict nor a list (format error), see seopardy guide for question file format documentation.")

	def _read_newstyle_questions(self, ysrc, filename):
		if type(ysrc) != dict:
			self._gen_error(filename, "Error parsing question file '%s': Is not a dict (and this sould(tm) have been safeguarded by an earlier if)")

		if "Name" not in ysrc.keys():
			self._gen_error(filename, "Missing 'Name' key.")

		if "Sections" not in ysrc.keys():
			self._gen_error(filename, "Missing 'Sections' key.")

		extra_keys = filter(lambda _x: _x not in ["Name", "Sections"], ysrc.keys())
		if extra_keys:
			self._gen_error(filename, "Unsupported keys found: %s (only 'Name' and 'Sections' are supported. Is your case correct?)" % (", ".join(extra_keys),))

		if type(ysrc["Sections"]) != list:
			self._gen_error(filename, "The 'Sections' part needs to be a list of filenames, not a '%s'" % (type(ysrc["Sections"]),))

		self._title = ysrc["Name"]

		# read sections
		basedir = os.path.dirname(filename)
		for n, sec_filename in enumerate(ysrc["Sections"], 1):
			if type(sec_filename) != str:
				self._gen_error(filename, "Section element %d is not a string (type %s found)" % (n, type(sec_filename)))

			fpath = os.path.join(basedir, sec_filename)
			sec_ysrc = self._get_yaml(fpath)
			self._read_sections(sec_ysrc, fpath)

	def _read_sections(self, ysrc, filename):
		basedir = os.path.dirname(filename)

		# now to check the integrity of the question file
		if type(ysrc) is not list:
			self._gen_error(filename, "The questionfile has to be a list of sections")
		
		for i, sec in enumerate(ysrc, 1):
			if not "Section" in sec.keys() or not "Questions" in sec.keys():
				self._gen_error(filename, "Section %d needs to have the keys 'Section' and 'Question' (case-sensitive)" % i)

			for j, q in enumerate(sec["Questions"], 1):
				# check for keys we need in each question
				if any([x not in q.keys() for x in ["Question", "Answer", "Type"]]):
					self._gen_error(filename, "Question %d from section %d (%s) is missing one of the keywords Question, Answer or Type" % (j, i, sec["Section"]))

				# check wether the question is a string (else we'll get display errors)
				if type(q["Question"]) != str:
					self._gen_error(filename, "Question %d from section %d (%s) needs to have a string as question (put the Question in \"\")" % (j, i, sec["Section"]))


				# check for keys we do not know
				for key in q.keys():
					if key not in self.QUESTION_KEYS:
						self._gen_error(filename, "Qestion %d from section %d (%s) has invalid keyword '%s'" % (j, i, sec["Section"], key))

				# check Double-Jeopardy is a bool and is set to false if non-existant
				if "Double-Jeopardy" not in q.keys():
					q["Double-Jeopardy"] = False
				elif type(q["Double-Jeopardy"]) != bool:
					self._gen_error(filename, "The Double-Jeopardy key from question %d from section %d (%s) must be either true or false" % (j, i, sec["Section"]))

				# check Audio is a bool and is set to false if non-existant
				if "Audio" not in q.keys():
					q["Audio"] = False
				elif type(q["Audio"]) != bool:
					self._gen_error(filename, "The Audio key from question %d from section %d (%s) must be either true or false" % (j, i, sec["Section"]))

				# check for broken question types
				if q["Type"] not in self.QUESTION_TYPES:
					self._gen_error(filename, "Question %d from Section %d (%s) has an invalid type '%s' (valid types are %s)" % (j, i, sec["Section"], q["Type"], ", ".join(self.QUESTION_TYPES)))

				# check if file for music/image questions exist
				if q["Type"] in ("Music", "Image", "Video"):
					if self._appendPath:
						q["Question"] = os.path.join(basedir, q["Question"])
					if not os.path.isfile(q["Question"]):
						fname_error = ""
						if self._verbose:
							fname_error = " (path: %s)" % (q["Question"],)
						self._gen_error(filename, "File for question %d, section %d (%s) not found%s" % (j, i, sec["Section"], fname_error))

			# check if this section has enough questions
			if j != 5:
				self._gen_error(filename, "Section %d (%s) needs to have exactly %d questions (has %d)" % (i, sec["Section"], 5, j))

		# done, save yaml src to _questions
		self._questions.extend(ysrc)

		# check for only having unique section names
		sections = [s["Section"] for s in self._questions]
		if len(sections) != len(set(sections)):
			map(lambda _x: sections.remove(_x), set(sections))
			self._gen_error(filename, "All section names must be unique (clashing: %s)" % (", ".join(sections),))

		return True

if __name__ == '__main__':
	q = Questions("questions/template.q")
	print(q.get_sections())
	print(q.get_questions("A"))
	print(q.get_question("A", 1))