import io
import traceback

from hserver.mimeheaders import MIMEHeaders

class MIMEException(Exception):
	pass
	
class ContentSizeLimitException(MIMEException):
	pass

class MIME:

	def __init__(self,fp=None,source=None,limit=10485760,defaultlength=-1,parent=None):
		if (not fp is None):
			self.__fp = fp
		elif (not source is None):
			self.__fp = io.BytesIO(source)
		
		self.__parent = parent
		self.__limit = limit
		self.__defaultlength = defaultlength
	
		self.__body = None
		self.__headers = None
		self.__multipart = False
		self.__parts = []
	
		self.__parse()
		
	def __getitem__(self,name):
		if self.__multipart:
			for p in self.__parts:
				if not p.name() is None:
					return p.name()
		raise KeyError()

	def __contains__(self, name):
		return name in self.__headers
	
	def headers(self):
		return self.__headers
	
	def multipart(self):
		return self.__multipart
		
	def parts(self):
		return self.__parts
		
	def name(self):
		pp = self.__headers.parameters("CONTENT-DISPOSITION")
		if (not pp is None) and ("name" in pp.keys()):
			return pp["name"]
		return None
		
	def body(self):
		return self.__body
	
	def __parse(self):
		self.__headers = MIMEHeaders( fp=self.__fp )
		l = int(self.__headers.value("CONTENT-LENGTH",self.__defaultlength))
		if (l > self.__limit):
			raise ContentSizeLimitException(size=l,limit=self.__limit)
			
		self.__body = self.__fp.read(l)
		
		if (not "filename" in self.__headers.parameters("CONTENT-DISPOSITION")) and (self.__headers.value("CONTENT-TYPE").upper() == "TEXT/PLAIN"):
			if ("charset" in self.__headers.parameters("CONTENT-TYPE")):
				charset = self.__headers.parameters("CONTENT-TYPE")["charset"]
			else:
#				charset = "us-ascii"
				charset = "utf-8"
			self.__body = str(self.__body,charset)
		
		type = self.__headers.value("CONTENT-TYPE","/").split("/")[0].upper()
		if (type == "MULTIPART"):
			try:
				self.__parsemultipart()
			except Exception as ex:
				traceback.print_exception(type(ex),ex,ex.__traceback__)			
			
	def __parsemultipart(self):
		"""
		p = start of preceeding boundary
		c = end of preceeding boundary
		e = start of following boundary
		"""
		self.__multipart = True
		
		boundary = b'--' + bytes(self.__headers.get("CONTENT-TYPE").parameters()["boundary"],"iso-8859-1")
		
		p = self.__body.find(boundary)
		c = p + len(boundary) + 2
		
		boundary = b'\r\n' + boundary

		while (True):
			e = self.__body.find(boundary,c)
		
			if (e < 0):
				return
			else:
				self.__parts.append(MIME(source=self.__body[c : e],parent=self))
								
			p = e
			c = p + len(boundary) + 2
			
			if (self.__body[c - 2 : c] == b"--"):
				return