import sys
import os
import struct

class DataScanner:
	def __init__(self, data):
		self.offset = 0
		self.data = data

	def advance(self, length):
		self.offset += length

	def read(self, length):
		output = self.peek(length)
		self.advance(length)
		return output

	def peek(self, length):
		return self.data[self.offset:(self.offset + length)]

	def readString(self):
		length = int.from_bytes(self.peek(4), byteorder="little")
		length += (4 - length) % 4
		return self.read(length + 4)

	def rest(self):
		return self.data[self.offset:]

def readString(str):
	length = int.from_bytes(str[0:4], byteorder="little")
	return str[4:(4+length)].decode("utf-8")

class FontFile:
	def __init__(self, data, filename):
		stringLength = int.from_bytes(data[(4 * 15):(4 * 16)], byteorder="little")
		if stringLength in range(4, 26): # Assumes filenames are between 4 and 25 chars
			print(f"Detected {filename} as coming from TextMesh Pro")
			self.type = "TMP"
			self._fromAssetCreator(data, filename)
		else:
			stringLength = int.from_bytes(data[(4*12):(4*13)], byteorder="little")
			if stringLength == 1:
				print(f"Detected {filename} as coming from a newer Higurashi game")
				self.type = "Hima"
			else:
				print(f"Detected {filename} as coming from an older Higurashi game")
				self.type = "Oni"
			self._fromGame(data, filename)
		self.filename = readString(self.Filename)

	def _readArray(self, data, itemLength):
		self.Array = data.read(4)
		length = int.from_bytes(self.Array, byteorder="little")
		atlasWidth = struct.unpack("<f", self.AtlasWidth)[0]
		atlasHeight = struct.unpack("<f", self.AtlasHeight)[0]
		for _ in range(length):
			info = bytearray(data.read(4 * 8))
			if itemLength > 8:
				data.advance((itemLength - 8) * 4)
			x, y = struct.unpack("<ff", info[4:12])
			if x > atlasWidth:
				info[4:8] = self.AtlasWidth
			if y > atlasHeight:
				info[8:12] = self.AtlasHeight
			self.Array += info

	def _fromGame(self, data, filename):
		data = DataScanner(data)
		self.Header = data.read(4 * 7)
		self.Filename = data.readString()
		if self.type == "Hima":
			self.BeforeFontName = data.read(4)
		else:
			self.BeforeFontName = bytes()
		self.FontName = data.readString()
		# Font face data
		self.PointSize = data.read(4)
		self.Padding = data.read(4)
		self.LineHeight = data.read(4)
		self.Baseline = data.read(4)
		self.Ascender = data.read(4)
		self.Descender = data.read(4)
		self.CenterLine = data.read(4)
		self.SuperscriptOffset = data.read(4)
		self.SubscriptOffest = data.read(4)
		self.SubSize = data.read(4)
		self.Underline = data.read(4)
		self.UnderlineThickness = data.read(4)
		self.TabWidth = data.read(4)
		self.CharacterCount = data.read(4)
		self.AtlasWidth = data.read(4)
		self.AtlasHeight = data.read(4)

		self.AfterFontFace = data.read(4 * 8)
		self._readArray(data, 8)
		self.Footer = data.rest()

	def _fromAssetCreator(self, data, filename):
		data = DataScanner(data)
		self.Header = data.read(4 * 15)
		self.Filename = data.readString()
		self.BeforeFontName = data.read(4 * 7)
		self.FontName = data.readString()
		# Font face data
		self.PointSize = data.read(4)
		self.Scale = data.read(4)
		self.CharacterCount = data.read(4)
		self.LineHeight = data.read(4)
		self.Baseline = data.read(4)
		self.Ascender = data.read(4)
		self.CapHeight = data.read(4)
		self.Descender = data.read(4)
		self.CenterLine = data.read(4)
		self.SuperscriptOffset = data.read(4)
		self.SubscriptOffest = data.read(4)
		self.SubSize = data.read(4)
		self.Underline = data.read(4)
		self.UnderlineThickness = data.read(4)
		self.strikethrough = data.read(4)
		self.strikethroughThickness = data.read(4)
		self.TabWidth = data.read(4)
		self.Padding = data.read(4)
		self.AtlasWidth = data.read(4)
		self.AtlasHeight = data.read(4)

		self.AfterFontFace = data.read(4 * 3)
		self._readArray(data, 9)
		self.Footer = data.rest()

def combineFonts(original: FontFile, new: FontFile):
	out = bytes()
	out += original.Header
	out += original.Filename
	out += original.BeforeFontName
	out += new.FontName

	out += new.PointSize
	out += new.Padding
	out += new.LineHeight
	out += new.Baseline
	out += new.Ascender
	out += new.Descender
	out += new.CenterLine
	out += new.SuperscriptOffset
	out += new.SubscriptOffest
	out += new.SubSize
	out += new.Underline
	out += new.UnderlineThickness
	out += new.TabWidth
	out += new.CharacterCount
	out += new.AtlasWidth
	out += new.AtlasHeight

	out += original.AfterFontFace
	out += new.Array
	out += original.Footer

	return out

if len(sys.argv) > 4:
	atlasFN = sys.argv[1]
	behaviourFN = sys.argv[2]
	originalFN = sys.argv[3]
	outFN = sys.argv[4]
else:
	if len(sys.argv) < 4:
		print("Usage: " + sys.argv[0] + " [newAtlas.dat] newMonoBehaviour.dat originalMonoBehaviour.dat outputFolder")
		exit()

	behaviourFN = sys.argv[1]
	originalFN = sys.argv[2]
	outFN = sys.argv[3]

if not os.path.isdir(outFN):
	print("Output folder " + outFN + " must be a directory!")
	exit()

with open(originalFN, "rb") as originalFile:
	original = FontFile(originalFile.read(), originalFN)
with open(behaviourFN, "rb") as behaviourFile:
	behaviour = FontFile(behaviourFile.read(), behaviourFN)
if len(sys.argv) > 4:
	with open(atlasFN, "rb") as atlasFile:
		atlas = DataScanner(atlasFile.read())
	atlasOut = b""
	if int.from_bytes(atlas.peek(4), byteorder="little") not in range(8, 32):
		atlas.advance(4 * 7)
		atlasName = atlas.readString()
		atlas.advance(4 * 4)
	else:
		atlasName = atlas.readString()
	atlasOut += atlasName
	atlasOut += atlas.rest()

atlasName = readString(atlasName)
with open(outFN + "/" + atlasName + "_Texture2D.dat", "wb") as outFile:
	outFile.write(atlasOut)
with open(outFN + "/" + original.filename + "_TextMeshProFont.dat", "wb") as outFile:
	outFile.write(combineFonts(original=original, new=behaviour))