from fontTools.misc import sstruct
from fontTools.misc.textTools import tobytes, tostr, safeEval
from . import DefaultTable

GMAPFormat = """
		>	# big endian
		tableVersionMajor:	H
		tableVersionMinor: 	H
		flags:	H
		recordsCount:		H
		recordsOffset:		H
		fontNameLength:		H
"""
# psFontName is a byte string which follows the record above. This is zero padded
# to the beginning of the records array. The recordsOffsst is 32 bit aligned.

GMAPRecordFormat1 = """
		>	# big endian
		UV:			L
		cid:		H
		gid:		H
		ggid:		H
		name:		32s
"""


class GMAPRecord(object):
	def __init__(self, uv=0, cid=0, gid=0, ggid=0, name=""):
		self.UV = uv
		self.cid = cid
		self.gid = gid
		self.ggid = ggid
		self.name = name

	def toXML(self, writer, ttFont):
		writer.begintag("GMAPRecord")
		writer.newline()
		writer.simpletag("UV", value=self.UV)
		writer.newline()
		writer.simpletag("cid", value=self.cid)
		writer.newline()
		writer.simpletag("gid", value=self.gid)
		writer.newline()
		writer.simpletag("glyphletGid", value=self.gid)
		writer.newline()
		writer.simpletag("GlyphletName", value=self.name)
		writer.newline()
		writer.endtag("GMAPRecord")
		writer.newline()

	def fromXML(self, name, attrs, content, ttFont):
		value = attrs["value"]
		if name == "GlyphletName":
			self.name = value
		else:
			setattr(self, name, safeEval(value))

	def compile(self, ttFont):
		if 	self.UV is None:
			self.UV = 0
		nameLen = len(self.name)
		if nameLen < 32:
			self.name = self.name + "\0"*(32 - nameLen)
		data = sstruct.pack(GMAPRecordFormat1, self)
		return data

	def __repr__(self):
		return "GMAPRecord[ UV: " + str(self.UV) + ", cid: " + str(self.cid) + ", gid: " + str(self.gid) + ", ggid: " + str(self.ggid) + ", Glyphlet Name: " + str(self.name) + " ]"


class table_G_M_A_P_(DefaultTable.DefaultTable):

	dependencies = []

	def decompile(self, data, ttFont):
		dummy, newData = sstruct.unpack2(GMAPFormat, data, self)
		self.psFontName = tostr(newData[:self.fontNameLength])
		assert (self.recordsOffset % 4) == 0, "GMAP error: recordsOffset is not 32 bit aligned."
		newData = data[self.recordsOffset:]
		self.gmapRecords = []
		for i in range (self.recordsCount):
			gmapRecord, newData = sstruct.unpack2(GMAPRecordFormat1, newData, GMAPRecord())
			gmapRecord.name = gmapRecord.name.strip('\0')
			self.gmapRecords.append(gmapRecord)

	def compile(self, ttFont):
		self.recordsCount = len(self.gmapRecords)
		self.fontNameLength = len(self.psFontName)
		self.recordsOffset = 4 * (((self.fontNameLength + 12) + 3) // 4)
		data = sstruct.pack(GMAPFormat, self)
		data = data + tobytes(self.psFontName)
		data = data + b"\0" * (self.recordsOffset - len(data))
		for record in self.gmapRecords:
			data = data + record.compile(ttFont)
		return data

	def toXML(self, writer, ttFont):
		writer.comment("Most of this table will be recalculated by the compiler")
		writer.newline()
		formatstring, names, fixes = sstruct.getformat(GMAPFormat)
		for name in names:
			value = getattr(self, name)
			writer.simpletag(name, value=value)
			writer.newline()
		writer.simpletag("PSFontName", value=self.psFontName)
		writer.newline()
		for gmapRecord in self.gmapRecords:
			gmapRecord.toXML(writer, ttFont)

	def fromXML(self, name, attrs, content, ttFont):
		if name == "GMAPRecord":
			if not hasattr(self, "gmapRecords"):
				self.gmapRecords = []
			gmapRecord = GMAPRecord()
			self.gmapRecords.append(gmapRecord)
			for element in content:
				if isinstance(element, str):
					continue
				name, attrs, content = element
				gmapRecord.fromXML(name, attrs, content, ttFont)
		else:
			value = attrs["value"]
			if name == "PSFontName":
				self.psFontName = value
			else:
				setattr(self, name, safeEval(value))
