import gsm7
import ems

class EmsSplit:
	def __init__(self, contents):
		self.segments = []
		self.max_packet_len = 140
		self.base_len = 0 # or 6 UDHL + IE Concat
		self.segment_reset()
		try:
			self.split(contents)
		except:
			self.segments = []
			self.base_len = 6
			self.segment_reset()
			self.split(contents)

	def split(self, contents):
		for type, content in contents:
			if type == 'Text':
				self.add_text(content)
				continue
			if type == 'Bitmap':
				bitmap = content
				content = ems.Picture(bitmap.width, bitmap.height, bitmap.data)
			elif type == 'Melody':
				sound = content
				if sound.predefined:
					content = ems.PredefinedSound(sound.id, raw_data=True)
				else:
					content = ems.UserDefinedSound(sound.data, raw_data=True)
			if content.size + self.packet_len > self.max_packet_len:
				self.add_segment()
			self.add_ie(content)
		if self.ies or self.user_data:
			self.add_segment()
		self.make_payloads()

	def segment_reset(self):
		self.packet_len = self.base_len
		self.user_data = ''
		self.cursor_pos = 0
		self.ies = []

	def add_segment(self):
		if len(self.segments) >= 1 and self.base_len <= 1:
			raise ValueError, (self.segments, self.base_len)
		self.segments.append((self.ies, self.user_data))
		self.segment_reset()

	def get_max_text_len(self):
		return (160 * 7 - self.packet_len * 8) / 7 - len(self.user_data)

	def add_text(self, text):
		text = gsm7.gsm7bit_encode(text)
		while text:
			max_text_len = self.get_max_text_len()
			if len(text) <= max_text_len:
				self.cursor_pos += len(text)
				self.user_data += text
				return
			self.user_data += text[:max_text_len]
			self.add_segment()
			text = text[max_text_len:]
	def add_ie(self, ie):
		if not self.ies and self.base_len == 0:
			self.base_len = 1
		ie.pos = self.cursor_pos
		self.ies.append(ie)
		self.packet_len += ie.size + 3

	def make_payloads(self):
		import status
		self.payloads = []
		for i, (ies, user_data) in enumerate(self.segments):
			if len(self.segments) > 1:
				udh = '\x00\x03' + chr(status.message_reference) + chr(len(self.segments)) + chr(i+1)
			else:
				udh = ''
			for ie in ies:
				udh += ie.make_header()
			if udh:
				udh = chr(len(udh)) + udh
			pad = (len(udh) * 8) % 7
			if pad:
				pad = 7 - pad
			udl = (len(udh) * 8 + pad + len(user_data) * 7)/7
			payload = chr(udl) + udh + gsm7.gsm7_pack(user_data, pad)
			self.payloads.append((udh, payload))
		status.message_reference += 1
		if status.message_reference > 255:
			status.message_reference = 0

def split_test():
	contents = [('Text', 'i'*640)]
	ems = EmsSplit(contents)
	contents = [('Text', 'eoie'*10)]
	ems = EmsSplit(contents)

def split_bitmap():
	class o:
		pass
	b = o()
	b.width = 32
	b.height = 32
	b.data = '0' * (32 * 4)
	contents = [('Text', 'eoie'*6),('Bitmap',b),('Bitmap',b)]

if __name__ == '__main__':
	split_test()