# Copyright 2013 Google, Inc. All Rights Reserved.
#
# Google Author(s): Behdad Esfahbod, Roozbeh Pournader

"""Font merger.
"""

from __future__ import print_function, division
from fontTools.misc.py23 import *
from fontTools import ttLib, cffLib
from fontTools.ttLib.tables import otTables, _h_e_a_d
from fontTools.ttLib.tables.DefaultTable import DefaultTable
from functools import reduce
import sys
import time
import operator


def _add_method(*clazzes, **kwargs):
	"""Returns a decorator function that adds a new method to one or
	more classes."""
	allowDefault = kwargs.get('allowDefaultTable', False)
	def wrapper(method):
		for clazz in clazzes:
			assert allowDefault or clazz != DefaultTable, 'Oops, table class not found.'
			assert method.__name__ not in clazz.__dict__, \
				"Oops, class '%s' has method '%s'." % (clazz.__name__,
								       method.__name__)
			setattr(clazz, method.__name__, method)
		return None
	return wrapper

# General utility functions for merging values from different fonts

def equal(lst):
	t = iter(lst)
	first = next(t)
	assert all(item == first for item in t)
	return first

def first(lst):
	return next(iter(lst))

def recalculate(lst):
	return NotImplemented

def current_time(lst):
	return int(time.time() - _h_e_a_d.mac_epoch_diff)

def bitwise_and(lst):
	return reduce(operator.and_, lst)

def bitwise_or(lst):
	return reduce(operator.or_, lst)

def avg_int(lst):
	lst = list(lst)
	return sum(lst) // len(lst)

def implementedFilter(func):
	"""Returns a filter func that when called with a list,
	only calls func on the non-NotImplemented items of the list,
	and only so if there's at least one item remaining.
	Otherwise returns NotImplemented."""

	def wrapper(lst):
		items = [item for item in lst if item is not NotImplemented]
		return func(items) if items else NotImplemented

	return wrapper

def sumLists(lst):
	l = []
	for item in lst:
		l.extend(item)
	return l

def sumDicts(lst):
	d = {}
	for item in lst:
		d.update(item)
	return d

def mergeObjects(lst):
	lst = [item for item in lst if item is not None and item is not NotImplemented]
	if not lst:
		return None # Not all can be NotImplemented

	clazz = lst[0].__class__
	assert all(type(item) == clazz for item in lst), lst
	logic = clazz.mergeMap
	returnTable = clazz()

	allKeys = set.union(set(), *(vars(table).keys() for table in lst))
	for key in allKeys:
		try:
			mergeLogic = logic[key]
		except KeyError:
			try:
				mergeLogic = logic['*']
			except KeyError:
				raise Exception("Don't know how to merge key %s of class %s" %
						(key, clazz.__name__))
		if mergeLogic is NotImplemented:
			continue
		value = mergeLogic(getattr(table, key, NotImplemented) for table in lst)
		if value is not NotImplemented:
			setattr(returnTable, key, value)

	return returnTable

def mergeBits(logic, lst):
	lst = list(lst)
	returnValue = 0
	for bitNumber in range(logic['size']):
		try:
			mergeLogic = logic[bitNumber]
		except KeyError:
			try:
				mergeLogic = logic['*']
			except KeyError:
				raise Exception("Don't know how to merge bit %s" % bitNumber)
		shiftedBit = 1 << bitNumber
		mergedValue = mergeLogic(bool(item & shiftedBit) for item in lst)
		returnValue |= mergedValue << bitNumber
	return returnValue


@_add_method(DefaultTable, allowDefaultTable=True)
def merge(self, m, tables):
	if not hasattr(self, 'mergeMap'):
		m.log("Don't know how to merge '%s'." % self.tableTag)
		return NotImplemented

	return m.mergeObjects(self, self.mergeMap, tables)

ttLib.getTableClass('maxp').mergeMap = {
	'*': max,
	'tableTag': equal,
	'tableVersion': equal,
	'numGlyphs': sum,
	'maxStorage': max, # FIXME: may need to be changed to sum
	'maxFunctionDefs': sum,
	'maxInstructionDefs': sum,
	# TODO When we correctly merge hinting data, update these values:
	# maxFunctionDefs, maxInstructionDefs, maxSizeOfInstructions
}

headFlagsMergeMap = {
	'size': 16,
	'*': bitwise_or,
	1: bitwise_and, # Baseline at y = 0
	2: bitwise_and, # lsb at x = 0
	3: bitwise_and, # Force ppem to integer values. FIXME?
	5: bitwise_and, # Font is vertical
	6: lambda bit: 0, # Always set to zero
	11: bitwise_and, # Font data is 'lossless'
	13: bitwise_and, # Optimized for ClearType
	14: bitwise_and, # Last resort font. FIXME? equal or first may be better
	15: lambda bit: 0, # Always set to zero
}

ttLib.getTableClass('head').mergeMap = {
	'tableTag': equal,
	'tableVersion': max,
	'fontRevision': max,
	'checkSumAdjustment': lambda lst: 0, # We need *something* here
	'magicNumber': equal,
	'flags': lambda lst: mergeBits(headFlagsMergeMap, lst),
	'unitsPerEm': equal,
	'created': current_time,
	'modified': current_time,
	'xMin': min,
	'yMin': min,
	'xMax': max,
	'yMax': max,
	'macStyle': first,
	'lowestRecPPEM': max,
	'fontDirectionHint': lambda lst: 2,
	'indexToLocFormat': recalculate,
	'glyphDataFormat': equal,
}

ttLib.getTableClass('hhea').mergeMap = {
	'*': equal,
	'tableTag': equal,
	'tableVersion': max,
	'ascent': max,
	'descent': min,
	'lineGap': max,
	'advanceWidthMax': max,
	'minLeftSideBearing': min,
	'minRightSideBearing': min,
	'xMaxExtent': max,
	'caretSlopeRise': first,
	'caretSlopeRun': first,
	'caretOffset': first,
	'numberOfHMetrics': recalculate,
}

os2FsTypeMergeMap = {
	'size': 16,
	'*': lambda bit: 0,
	1: bitwise_or, # no embedding permitted
	2: bitwise_and, # allow previewing and printing documents
	3: bitwise_and, # allow editing documents
	8: bitwise_or, # no subsetting permitted
	9: bitwise_or, # no embedding of outlines permitted
}

def mergeOs2FsType(lst):
	lst = list(lst)
	if all(item == 0 for item in lst):
		return 0

	# Compute least restrictive logic for each fsType value
	for i in range(len(lst)):
		# unset bit 1 (no embedding permitted) if either bit 2 or 3 is set
		if lst[i] & 0x000C:
			lst[i] &= ~0x0002
		# set bit 2 (allow previewing) if bit 3 is set (allow editing)
		elif lst[i] & 0x0008:
			lst[i] |= 0x0004
		# set bits 2 and 3 if everything is allowed
		elif lst[i] == 0:
			lst[i] = 0x000C

	fsType = mergeBits(os2FsTypeMergeMap, lst)
	# unset bits 2 and 3 if bit 1 is set (some font is "no embedding")
	if fsType & 0x0002:
		fsType &= ~0x000C
	return fsType


ttLib.getTableClass('OS/2').mergeMap = {
	'*': first,
	'tableTag': equal,
	'version': max,
	'xAvgCharWidth': avg_int, # Apparently fontTools doesn't recalc this
	'fsType': mergeOs2FsType, # Will be overwritten
	'panose': first, # FIXME: should really be the first Latin font
	'ulUnicodeRange1': bitwise_or,
	'ulUnicodeRange2': bitwise_or,
	'ulUnicodeRange3': bitwise_or,
	'ulUnicodeRange4': bitwise_or,
	'fsFirstCharIndex': min,
	'fsLastCharIndex': max,
	'sTypoAscender': max,
	'sTypoDescender': min,
	'sTypoLineGap': max,
	'usWinAscent': max,
	'usWinDescent': max,
	'ulCodePageRange1': bitwise_or,
	'ulCodePageRange2': bitwise_or,
	'usMaxContex': max,
	# TODO version 5
}

@_add_method(ttLib.getTableClass('OS/2'))
def merge(self, m, tables):
	DefaultTable.merge(self, m, tables)
	if self.version < 2:
		# bits 8 and 9 are reserved and should be set to zero
		self.fsType &= ~0x0300
	if self.version >= 3:
		# Only one of bits 1, 2, and 3 may be set. We already take
		# care of bit 1 implications in mergeOs2FsType. So unset
		# bit 2 if bit 3 is already set.
		if self.fsType & 0x0008:
			self.fsType &= ~0x0004
	return self

ttLib.getTableClass('post').mergeMap = {
	'*': first,
	'tableTag': equal,
	'formatType': max,
	'isFixedPitch': min,
	'minMemType42': max,
	'maxMemType42': lambda lst: 0,
	'minMemType1': max,
	'maxMemType1': lambda lst: 0,
	'mapping': implementedFilter(sumDicts),
	'extraNames': lambda lst: [],
}

ttLib.getTableClass('vmtx').mergeMap = ttLib.getTableClass('hmtx').mergeMap = {
	'tableTag': equal,
	'metrics': sumDicts,
}

ttLib.getTableClass('gasp').mergeMap = {
	'tableTag': equal,
	'version': max,
	'gaspRange': first, # FIXME? Appears irreconcilable
}

ttLib.getTableClass('name').mergeMap = {
	'tableTag': equal,
	'names': first, # FIXME? Does mixing name records make sense?
}

ttLib.getTableClass('loca').mergeMap = {
	'*': recalculate,
	'tableTag': equal,
}

ttLib.getTableClass('glyf').mergeMap = {
	'tableTag': equal,
	'glyphs': sumDicts,
	'glyphOrder': sumLists,
}

@_add_method(ttLib.getTableClass('glyf'))
def merge(self, m, tables):
	for table in tables:
		for g in table.glyphs.values():
			# Drop hints for now, since we don't remap
			# functions / CVT values.
			g.removeHinting()
			# Expand composite glyphs to load their
			# composite glyph names.
			if g.isComposite():
				g.expand(table)
	return DefaultTable.merge(self, m, tables)

ttLib.getTableClass('prep').mergeMap = NotImplemented
ttLib.getTableClass('fpgm').mergeMap = NotImplemented
ttLib.getTableClass('cvt ').mergeMap = NotImplemented

@_add_method(ttLib.getTableClass('cmap'))
def merge(self, m, tables):
	# TODO Handle format=14.
	cmapTables = [t for table in tables for t in table.tables
		      if t.platformID == 3 and t.platEncID in [1, 10]]
	# TODO Better handle format-4 and format-12 coexisting in same font.
	# TODO Insert both a format-4 and format-12 if needed.
	module = ttLib.getTableModule('cmap')
	assert all(t.format in [4, 12] for t in cmapTables)
	format = max(t.format for t in cmapTables)
	cmapTable = module.cmap_classes[format](format)
	cmapTable.cmap = {}
	cmapTable.platformID = 3
	cmapTable.platEncID = max(t.platEncID for t in cmapTables)
	cmapTable.language = 0
	for table in cmapTables:
		# TODO handle duplicates.
		cmapTable.cmap.update(table.cmap)
	self.tableVersion = 0
	self.tables = [cmapTable]
	self.numSubTables = len(self.tables)
	return self


otTables.ScriptList.mergeMap = {
	'ScriptCount': sum,
	'ScriptRecord': lambda lst: sorted(sumLists(lst), key=lambda s: s.ScriptTag),
}

otTables.FeatureList.mergeMap = {
	'FeatureCount': sum,
	'FeatureRecord': sumLists,
}

otTables.LookupList.mergeMap = {
	'LookupCount': sum,
	'Lookup': sumLists,
}

otTables.Coverage.mergeMap = {
	'glyphs': sumLists,
}

otTables.ClassDef.mergeMap = {
	'classDefs': sumDicts,
}

otTables.LigCaretList.mergeMap = {
	'Coverage': mergeObjects,
	'LigGlyphCount': sum,
	'LigGlyph': sumLists,
}

otTables.AttachList.mergeMap = {
	'Coverage': mergeObjects,
	'GlyphCount': sum,
	'AttachPoint': sumLists,
}

# XXX Renumber MarkFilterSets of lookups
otTables.MarkGlyphSetsDef.mergeMap = {
	'MarkSetTableFormat': equal,
	'MarkSetCount': sum,
	'Coverage': sumLists,
}

otTables.GDEF.mergeMap = {
	'*': mergeObjects,
	'Version': max,
}

otTables.GSUB.mergeMap = otTables.GPOS.mergeMap = {
	'*': mergeObjects,
	'Version': max,
}

ttLib.getTableClass('GDEF').mergeMap = \
ttLib.getTableClass('GSUB').mergeMap = \
ttLib.getTableClass('GPOS').mergeMap = \
ttLib.getTableClass('BASE').mergeMap = \
ttLib.getTableClass('JSTF').mergeMap = \
ttLib.getTableClass('MATH').mergeMap = \
{
	'tableTag': equal,
	'table': mergeObjects,
}


@_add_method(otTables.Feature)
def mapLookups(self, lookupMap):
	self.LookupListIndex = [lookupMap[i] for i in self.LookupListIndex]

@_add_method(otTables.FeatureList)
def mapLookups(self, lookupMap):
	for f in self.FeatureRecord:
		if not f or not f.Feature: continue
		f.Feature.mapLookups(lookupMap)

@_add_method(otTables.DefaultLangSys,
             otTables.LangSys)
def mapFeatures(self, featureMap):
	self.FeatureIndex = [featureMap[i] for i in self.FeatureIndex]
	if self.ReqFeatureIndex != 65535:
		self.ReqFeatureIndex = featureMap[self.ReqFeatureIndex]

@_add_method(otTables.Script)
def mapFeatures(self, featureMap):
	if self.DefaultLangSys:
		self.DefaultLangSys.mapFeatures(featureMap)
	for l in self.LangSysRecord:
		if not l or not l.LangSys: continue
		l.LangSys.mapFeatures(featureMap)

@_add_method(otTables.ScriptList)
def mapFeatures(self, featureMap):
	for s in self.ScriptRecord:
		if not s or not s.Script: continue
		s.Script.mapFeatures(featureMap)


class Options(object):

  class UnknownOptionError(Exception):
    pass

  def __init__(self, **kwargs):

    self.set(**kwargs)

  def set(self, **kwargs):
    for k,v in kwargs.items():
      if not hasattr(self, k):
        raise self.UnknownOptionError("Unknown option '%s'" % k)
      setattr(self, k, v)

  def parse_opts(self, argv, ignore_unknown=False):
    ret = []
    opts = {}
    for a in argv:
      orig_a = a
      if not a.startswith('--'):
        ret.append(a)
        continue
      a = a[2:]
      i = a.find('=')
      op = '='
      if i == -1:
        if a.startswith("no-"):
          k = a[3:]
          v = False
        else:
          k = a
          v = True
      else:
        k = a[:i]
        if k[-1] in "-+":
          op = k[-1]+'='  # Ops is '-=' or '+=' now.
          k = k[:-1]
        v = a[i+1:]
      k = k.replace('-', '_')
      if not hasattr(self, k):
        if ignore_unknown == True or k in ignore_unknown:
          ret.append(orig_a)
          continue
        else:
          raise self.UnknownOptionError("Unknown option '%s'" % a)

      ov = getattr(self, k)
      if isinstance(ov, bool):
        v = bool(v)
      elif isinstance(ov, int):
        v = int(v)
      elif isinstance(ov, list):
        vv = v.split(',')
        if vv == ['']:
          vv = []
        vv = [int(x, 0) if len(x) and x[0] in "0123456789" else x for x in vv]
        if op == '=':
          v = vv
        elif op == '+=':
          v = ov
          v.extend(vv)
        elif op == '-=':
          v = ov
          for x in vv:
            if x in v:
              v.remove(x)
        else:
          assert 0

      opts[k] = v
    self.set(**opts)

    return ret


class Merger(object):

	def __init__(self, options=None, log=None):

		if not log:
			log = Logger()
		if not options:
			options = Options()

		self.options = options
		self.log = log

	def merge(self, fontfiles):

		mega = ttLib.TTFont()

		#
		# Settle on a mega glyph order.
		#
		fonts = [ttLib.TTFont(fontfile) for fontfile in fontfiles]
		glyphOrders = [font.getGlyphOrder() for font in fonts]
		megaGlyphOrder = self._mergeGlyphOrders(glyphOrders)
		# Reload fonts and set new glyph names on them.
		# TODO Is it necessary to reload font?  I think it is.  At least
		# it's safer, in case tables were loaded to provide glyph names.
		fonts = [ttLib.TTFont(fontfile) for fontfile in fontfiles]
		for font,glyphOrder in zip(fonts, glyphOrders):
			font.setGlyphOrder(glyphOrder)
		mega.setGlyphOrder(megaGlyphOrder)

		for font in fonts:
			self._preMerge(font)

		allTags = reduce(set.union, (list(font.keys()) for font in fonts), set())
		allTags.remove('GlyphOrder')
		for tag in allTags:

			clazz = ttLib.getTableClass(tag)

			tables = [font.get(tag, NotImplemented) for font in fonts]
			table = clazz(tag).merge(self, tables)
			if table is not NotImplemented and table is not False:
				mega[tag] = table
				self.log("Merged '%s'." % tag)
			else:
				self.log("Dropped '%s'." % tag)
			self.log.lapse("merge '%s'" % tag)

		self._postMerge(mega)

		return mega

	def _mergeGlyphOrders(self, glyphOrders):
		"""Modifies passed-in glyphOrders to reflect new glyph names.
		Returns glyphOrder for the merged font."""
		# Simply append font index to the glyph name for now.
		# TODO Even this simplistic numbering can result in conflicts.
		# But then again, we have to improve this soon anyway.
		mega = []
		for n,glyphOrder in enumerate(glyphOrders):
			for i,glyphName in enumerate(glyphOrder):
				glyphName += "#" + repr(n)
				glyphOrder[i] = glyphName
				mega.append(glyphName)
		return mega

	def mergeObjects(self, returnTable, logic, tables):
		# Right now we don't use self at all.  Will use in the future
		# for options and logging.

		if logic is NotImplemented:
			return NotImplemented

		allKeys = set.union(set(), *(vars(table).keys() for table in tables if table is not NotImplemented))
		for key in allKeys:
			try:
				mergeLogic = logic[key]
			except KeyError:
				try:
					mergeLogic = logic['*']
				except KeyError:
					raise Exception("Don't know how to merge key %s of class %s" % 
							(key, returnTable.__class__.__name__))
			if mergeLogic is NotImplemented:
				continue
			value = mergeLogic(getattr(table, key, NotImplemented) for table in tables)
			if value is not NotImplemented:
				setattr(returnTable, key, value)

		return returnTable

	def _preMerge(self, font):

		GDEF = font.get('GDEF')
		GSUB = font.get('GSUB')
		GPOS = font.get('GPOS')

		for t in [GSUB, GPOS]:
			if not t: continue

			if t.table.LookupList and t.table.FeatureList:
				lookupMap = {i:id(v) for i,v in enumerate(t.table.LookupList.Lookup)}
				t.table.FeatureList.mapLookups(lookupMap)

			if t.table.FeatureList and t.table.ScriptList:
				featureMap = {i:id(v) for i,v in enumerate(t.table.FeatureList.FeatureRecord)}
				t.table.ScriptList.mapFeatures(featureMap)

		# TODO GDEF/Lookup MarkFilteringSets
		# TODO FeatureParams nameIDs

	def _postMerge(self, font):

		GDEF = font.get('GDEF')
		GSUB = font.get('GSUB')
		GPOS = font.get('GPOS')

		for t in [GSUB, GPOS]:
			if not t: continue

			if t.table.LookupList and t.table.FeatureList:
				lookupMap = {id(v):i for i,v in enumerate(t.table.LookupList.Lookup)}
				t.table.FeatureList.mapLookups(lookupMap)

			if t.table.FeatureList and t.table.ScriptList:
				featureMap = {id(v):i for i,v in enumerate(t.table.FeatureList.FeatureRecord)}
				t.table.ScriptList.mapFeatures(featureMap)

		# TODO GDEF/Lookup MarkFilteringSets
		# TODO FeatureParams nameIDs


class Logger(object):

  def __init__(self, verbose=False, xml=False, timing=False):
    self.verbose = verbose
    self.xml = xml
    self.timing = timing
    self.last_time = self.start_time = time.time()

  def parse_opts(self, argv):
    argv = argv[:]
    for v in ['verbose', 'xml', 'timing']:
      if "--"+v in argv:
        setattr(self, v, True)
        argv.remove("--"+v)
    return argv

  def __call__(self, *things):
    if not self.verbose:
      return
    print(' '.join(str(x) for x in things))

  def lapse(self, *things):
    if not self.timing:
      return
    new_time = time.time()
    print("Took %0.3fs to %s" %(new_time - self.last_time,
                                 ' '.join(str(x) for x in things)))
    self.last_time = new_time

  def font(self, font, file=sys.stdout):
    if not self.xml:
      return
    from fontTools.misc import xmlWriter
    writer = xmlWriter.XMLWriter(file)
    font.disassembleInstructions = False  # Work around ttLib bug
    for tag in font.keys():
      writer.begintag(tag)
      writer.newline()
      font[tag].toXML(writer, font)
      writer.endtag(tag)
      writer.newline()


__all__ = [
  'Options',
  'Merger',
  'Logger',
  'main'
]

def main(args):

	log = Logger()
	args = log.parse_opts(args)

	options = Options()
	args = options.parse_opts(args)

	if len(args) < 1:
		print("usage: pyftmerge font...", file=sys.stderr)
		sys.exit(1)

	merger = Merger(options=options, log=log)
	font = merger.merge(args)
	outfile = 'merged.ttf'
	font.save(outfile)
	log.lapse("compile and save font")

	log.last_time = log.start_time
	log.lapse("make one with everything(TOTAL TIME)")

if __name__ == "__main__":
	main(sys.argv[1:])