#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
osLibFound = False
sysLibFound = False
shutilLibFound = False
structLibFound = False

try:
	import os
except ImportError:
	print ("[Error] os python library is required to be installed!")
else:
	osLibFound = True

try:
	import sys
except ImportError:
	print ("[Error] sys python library is required to be installed!")
else:
	sysLibFound = True

try:
	import struct
except ImportError:
	print ("[Error] struct python library is required to be installed!")
else:
	structLibFound = True

if 	(not osLibFound) \
	or (not sysLibFound) \
	or (not structLibFound):
	sys.stdout.write("[Error] Errors were found when trying to import required python libraries\n")
	sys.exit(1)

pathToParent = os.path.join(os.path.dirname(os.path.abspath(__file__)), os.pardir)
pathToCommon = os.path.join(pathToParent, "common")
sys.path.append(pathToCommon)

from struct import *
from pythonCompat import *

MY_MODULE_VERSION = "0.70"
MY_MODULE_NAME = "treFileLib"


class TreHeader(object):
	numOfTextResources = -1
	def __init__(self):
		return


class treFile(object):
	m_header = TreHeader()
	simpleTextResourceFileName = 'GENERIC.TRE'
	stringEntriesLst = []  # list of two-value tuples. First value is ID, second value is String content
	stringOffsets = []
	m_traceModeEnabled = False

	# traceModeEnabled is bool to enable more printed debug messages
	def __init__(self, traceModeEnabled = True):
		del self.stringEntriesLst[:]
		del self.stringOffsets[:]
		self.simpleTextResourceFileName = 'GENERIC.TRE'
		self.m_traceModeEnabled = traceModeEnabled
		return

	def loadTreFile(self, treBytesBuff, maxLength, treFileName):
		self.simpleTextResourceFileName = treFileName
		offsInTreFile = 0
		#
		# parse TRE file fields for header
		#
		try:
			tmpTuple = struct.unpack_from('I', treBytesBuff, offsInTreFile)  # unsigned integer 4 bytes
			self.header().numOfTextResources = tmpTuple[0]
			offsInTreFile += 4
			#
			# string IDs table (each entry is unsigned integer 4 bytes)
			#
			if self.m_traceModeEnabled:
				print ("[Info] Total texts in Text Resource file: %d" % (self.header().numOfTextResources))
			for idx in range(0, self.header().numOfTextResources):
				tmpTuple = struct.unpack_from('I', treBytesBuff, offsInTreFile)  # unsigned integer 4 bytes
				self.stringEntriesLst.append( (tmpTuple[0], '') )
				offsInTreFile += 4

			# string offsets table (each entry is unsigned integer 4 bytes)
			for idx in range(0, self.header().numOfTextResources):
				tmpTuple = struct.unpack_from('I', treBytesBuff, offsInTreFile)  # unsigned integer 4 bytes
				self.stringOffsets.append( tmpTuple[0] )
				offsInTreFile += 4
			#
			# strings (all entries are null terminated)
			#  TODO +++
			absStartOfIndexTable = 4
			#absStartOfOffsetTable = absStartOfIndexTable + (self.header().numOfTextResources * 4)
			#absStartOfStringTable = absStartOfOffsetTable + ((self.header().numOfTextResources+1) * 4)

			#print ("[Debug] buffer type: ", type(treBytesBuff)) # it is str

			for idx in range(0, self.header().numOfTextResources):
				currOffset = self.stringOffsets[idx] + absStartOfIndexTable
				# the buffer (treBytesBuff) where we read the TRE file into, is "str" type but contains multiple null terminated strings
				# the solution here (to not get out of index errors when reading the null terminator points) is
				# to split the substring starting at the indicated offset each time, at the null character, and get the first string token.
				# This works ok.
				#
				print (treBytesBuff[currOffset:])
				if sys.version_info[0] <= 2:
					allTextsFound = treBytesBuff[currOffset:].split('\x00')
				else:
					allTextsFound = treBytesBuff[currOffset:].split(b'\0')
				print (allTextsFound[0])
				### check "problematic" character cases:
				##if self.m_traceModeEnabled:
				##	if  currOffset == 5982 or currOffset == 6050 or currOffset == 2827  or currOffset == 2880:
				##		print ("[Debug] Offs: %d\tFound String: %s" % (currOffset, ''.join(allTextsFound[0]) ))
				(theId, stringOfIdx) = self.stringEntriesLst[idx]
				if sys.version_info[0] <= 2:
					self.stringEntriesLst[idx] = (theId, ''.join(allTextsFound[0]))
				else:
					self.stringEntriesLst[idx] = (theId, allTextsFound[0])

				if self.m_traceModeEnabled:
					if sys.version_info[0] <= 2:
						print ("[Trace] ID: %d\tFound String: %s" % (theId, ''.join(allTextsFound[0]) ))
					else:
						print ("[Trace] ID: %d\tFound String: %s" % (theId, allTextsFound[0] ))
			return True
		except Exception as e:
			print ("[Error] Loading Text Resource %s failed!" % (self.simpleTextResourceFileName) + " " + str(e))
			return False

	def header(self):
		return self.m_header
#
#
#
if __name__ == '__main__':
	#	 main()
	errorFound = False
	# By default assumes a file of name ACTORS.TRE in same directory
	# otherwise tries to use the first command line argument as input file
	inTREFile = None
	inTREFileName =  'ACTORS.TRE'

	if len(sys.argv[1:])  > 0 \
		and os.path.isfile(os.path.join(u'.', sys.argv[1])) \
		and len(sys.argv[1]) >= 5 \
		and sys.argv[1][-3:].upper() == 'TRE':
		inTREFileName = sys.argv[1]
		print ("[Info] Attempting to use %s as input TRE file..." % (inTREFileName))
	elif os.path.isfile(os.path.join(u'.', inTREFileName)):
		print ("[Info] Using default %s as input TRE file..." % (inTREFileName))
	else:
		print ("[Error] No valid input file argument was specified and default input file %s is missing." % (inTREFileName))
		errorFound = True

	if not errorFound:
		try:
			print ("[Info] Opening %s" % (inTREFileName))
			inTREFile = open(os.path.join(u'.', inTREFileName), 'rb')
		except:
			errorFound = True
			print ("[Error] Unexpected event: ", sys.exc_info()[0])
			raise
		if not errorFound:
			allOfTreFileInBuffer = inTREFile.read()
			treFileInstance = treFile(True)
			if treFileInstance.m_traceModeEnabled:
				print ("[Debug] Running %s (%s) as main module" % (MY_MODULE_NAME, MY_MODULE_VERSION))
			if treFileInstance.loadTreFile(allOfTreFileInBuffer, len(allOfTreFileInBuffer), inTREFileName):
				print ("[Info] Text Resource file loaded successfully!")
			else:
				print ("[Error] Error while loading Text Resource file!")
			inTREFile.close()
else:
	#debug
	#print ("[Debug] Running %s (%s) imported from another module" % (MY_MODULE_NAME, MY_MODULE_VERSION))
	pass