from panflute import Doc, Div
import os
import warnings

# This class is used to keep state while transforming the document using
# transform.py. For the context to be available to the html and TeX generators,
# individual keys must be manually assigned to the individual elements. This is
# done in transform.py.
#
# The context is also aware of its parent contexts and relevant data (such as
# metadata and commands) can be read from the closest parent context. Writing
# only happens to the current one.
#
# This class is basically an extension to panflute's doc, this is why metadata
# is read directly from it.
class Context:
	def __init__(self, doc: Doc, path: str, parent: 'Context'=None, trusted: bool=True):
		self.parent = parent
		self._commands = {}
		self.doc = doc
		self.trusted = trusted
		self.path = path
		self.dir = os.path.dirname(path) if os.path.dirname(path) != "" else "."
		self.filename = os.path.basename(path)
		if self.get_metadata("flags", immediate=True) is None:
			self.set_metadata("flags", {})

	def get_command(self, command: str):
		if command in self._commands:
			return self._commands[command]
		elif self.parent:
			return self.parent.get_command(command)
		else:
			return None

	def set_command(self, command: str, val):
		self._commands[command] = val
	
	def unset_command(self, command: str):
		del self._commands[command]

	def is_flag_set(self, flag: str):
		if self.get_metadata("flags."+flag):
			if self.get_metadata("flags."+flag):
				return True
			else:
				return False
		elif self.parent:
			return self.parent.is_flag_set(flag)
		else:
			return False

	def set_flag(self, flag: str, val: bool):
		self.set_metadata("flags."+flag, val)

	def unset_flag(self, flag: str):
		self.unset_metadata("flags."+flag)

	def get_metadata(self, key: str, simple: bool=True, immediate: bool=False):
		value = self.doc.get_metadata(key, None, simple)
		if value is not None:
			return value
		elif self.parent and not immediate:
			return self.parent.get_metadata(key)
		else:
			return None

	def set_metadata(self, key: str, value):
		if key == "language":
			warnings.warn("Setting language this way doesn't propagate to TeX. Either use the Front Matter or specify it additionally using the \\languagexx macro.", UserWarning)
		meta = self.doc.metadata
		keys = key.split(".")
		for k in keys[:-1]:
			meta = meta[k]
		meta[keys[-1]] = value
	
	def unset_metadata(self, key: str):
		meta = self.doc.metadata
		keys = key.split(".")
		for k in keys[:-1]:
			meta = meta[k]
		del meta.content[key[-1]] # A hack because MetaMap doesn't have a __delitem__


# This is a custom element which creates \begingroup \endgroup groups in TeX
# and also causes KaTeX math blocks to be isolated in a similar way.
#
# Whenever a new context is created, its content should be eclosed in a group and vice-versa.
class Group(Div):
	def __init__(self, *args, metadata={}, **kwargs):
		self.metadata = metadata
		super().__init__(*args, **kwargs)