from fontTools.misc import psCharStrings
from fontTools import ttLib
from fontTools.pens.basePen import NullPen
from fontTools.pens.boundsPen import BoundsPen
from fontTools.misc.fixedTools import otRound
from fontTools.varLib.varStore import VarStoreInstancer

def _add_method(*clazzes):
	"""Returns a decorator function that adds a new method to one or
	more classes."""
	def wrapper(method):
		done = []
		for clazz in clazzes:
			if clazz in done: continue # Support multiple names of a clazz
			done.append(clazz)
			assert clazz.__name__ != 'DefaultTable', \
					'Oops, table class not found.'
			assert not hasattr(clazz, method.__name__), \
					"Oops, class '%s' has method '%s'." % (clazz.__name__,
									       method.__name__)
			setattr(clazz, method.__name__, method)
		return None
	return wrapper

def _uniq_sort(l):
	return sorted(set(l))

class _ClosureGlyphsT2Decompiler(psCharStrings.SimpleT2Decompiler):

	def __init__(self, components, localSubrs, globalSubrs):
		psCharStrings.SimpleT2Decompiler.__init__(self,
							  localSubrs,
							  globalSubrs)
		self.components = components

	def op_endchar(self, index):
		args = self.popall()
		if len(args) >= 4:
			from fontTools.encodings.StandardEncoding import StandardEncoding
			# endchar can do seac accent bulding; The T2 spec says it's deprecated,
			# but recent software that shall remain nameless does output it.
			adx, ady, bchar, achar = args[-4:]
			baseGlyph = StandardEncoding[bchar]
			accentGlyph = StandardEncoding[achar]
			self.components.add(baseGlyph)
			self.components.add(accentGlyph)

@_add_method(ttLib.getTableClass('CFF '))
def closure_glyphs(self, s):
	cff = self.cff
	assert len(cff) == 1
	font = cff[cff.keys()[0]]
	glyphSet = font.CharStrings

	decompose = s.glyphs
	while decompose:
		components = set()
		for g in decompose:
			if g not in glyphSet:
				continue
			gl = glyphSet[g]

			subrs = getattr(gl.private, "Subrs", [])
			decompiler = _ClosureGlyphsT2Decompiler(components, subrs, gl.globalSubrs)
			decompiler.execute(gl)
		components -= s.glyphs
		s.glyphs.update(components)
		decompose = components

@_add_method(ttLib.getTableClass('CFF '))
def prune_pre_subset(self, font, options):
	cff = self.cff
	# CFF table must have one font only
	cff.fontNames = cff.fontNames[:1]

	if options.notdef_glyph and not options.notdef_outline:
		for fontname in cff.keys():
			font = cff[fontname]
			c, fdSelectIndex = font.CharStrings.getItemAndSelector('.notdef')
			if hasattr(font, 'FDArray') and font.FDArray is not None:
				private = font.FDArray[fdSelectIndex].Private
			else:
				private = font.Private
			dfltWdX = private.defaultWidthX
			nmnlWdX = private.nominalWidthX
			pen = NullPen()
			c.draw(pen)  # this will set the charstring's width
			if c.width != dfltWdX:
				c.program = [c.width - nmnlWdX, 'endchar']
			else:
				c.program = ['endchar']

	# Clear useless Encoding
	for fontname in cff.keys():
		font = cff[fontname]
		# https://github.com/behdad/fonttools/issues/620
		font.Encoding = "StandardEncoding"

	return True # bool(cff.fontNames)

@_add_method(ttLib.getTableClass('CFF '))
def subset_glyphs(self, s):
	cff = self.cff
	for fontname in cff.keys():
		font = cff[fontname]
		cs = font.CharStrings

		# Load all glyphs
		for g in font.charset:
			if g not in s.glyphs: continue
			c, _ = cs.getItemAndSelector(g)

		if cs.charStringsAreIndexed:
			indices = [i for i,g in enumerate(font.charset) if g in s.glyphs]
			csi = cs.charStringsIndex
			csi.items = [csi.items[i] for i in indices]
			del csi.file, csi.offsets
			if hasattr(font, "FDSelect"):
				sel = font.FDSelect
				# XXX We want to set sel.format to None, such that the
				# most compact format is selected. However, OTS was
				# broken and couldn't parse a FDSelect format 0 that
				# happened before CharStrings. As such, always force
				# format 3 until we fix cffLib to always generate
				# FDSelect after CharStrings.
				# https://github.com/khaledhosny/ots/pull/31
				#sel.format = None
				sel.format = 3
				sel.gidArray = [sel.gidArray[i] for i in indices]
			cs.charStrings = {g:indices.index(v)
					  for g,v in cs.charStrings.items()
					  if g in s.glyphs}
		else:
			cs.charStrings = {g:v
					  for g,v in cs.charStrings.items()
					  if g in s.glyphs}
		font.charset = [g for g in font.charset if g in s.glyphs]
		font.numGlyphs = len(font.charset)

	return True # any(cff[fontname].numGlyphs for fontname in cff.keys())

@_add_method(psCharStrings.T2CharString)
def subset_subroutines(self, subrs, gsubrs):
	p = self.program
	assert len(p)
	for i in range(1, len(p)):
		if p[i] == 'callsubr':
			assert isinstance(p[i-1], int)
			p[i-1] = subrs._used.index(p[i-1] + subrs._old_bias) - subrs._new_bias
		elif p[i] == 'callgsubr':
			assert isinstance(p[i-1], int)
			p[i-1] = gsubrs._used.index(p[i-1] + gsubrs._old_bias) - gsubrs._new_bias

@_add_method(psCharStrings.T2CharString)
def drop_hints(self):
	hints = self._hints

	if hints.deletions:
		p = self.program
		for idx in reversed(hints.deletions):
			del p[idx-2:idx]

	if hints.has_hint:
		assert not hints.deletions or hints.last_hint <= hints.deletions[0]
		self.program = self.program[hints.last_hint:]
		if not self.program:
			# TODO CFF2 no need for endchar.
			self.program.append('endchar')
		if hasattr(self, 'width'):
			# Insert width back if needed
			if self.width != self.private.defaultWidthX:
				self.program.insert(0, self.width - self.private.nominalWidthX)

	if hints.has_hintmask:
		i = 0
		p = self.program
		while i < len(p):
			if p[i] in ['hintmask', 'cntrmask']:
				assert i + 1 <= len(p)
				del p[i:i+2]
				continue
			i += 1

	assert len(self.program)

	del self._hints

class _MarkingT2Decompiler(psCharStrings.SimpleT2Decompiler):

	def __init__(self, localSubrs, globalSubrs):
		psCharStrings.SimpleT2Decompiler.__init__(self,
							  localSubrs,
							  globalSubrs)
		for subrs in [localSubrs, globalSubrs]:
			if subrs and not hasattr(subrs, "_used"):
				subrs._used = set()

	def op_callsubr(self, index):
		self.localSubrs._used.add(self.operandStack[-1]+self.localBias)
		psCharStrings.SimpleT2Decompiler.op_callsubr(self, index)

	def op_callgsubr(self, index):
		self.globalSubrs._used.add(self.operandStack[-1]+self.globalBias)
		psCharStrings.SimpleT2Decompiler.op_callgsubr(self, index)

class _DehintingT2Decompiler(psCharStrings.T2WidthExtractor):

	class Hints(object):
		def __init__(self):
			# Whether calling this charstring produces any hint stems
			# Note that if a charstring starts with hintmask, it will
			# have has_hint set to True, because it *might* produce an
			# implicit vstem if called under certain conditions.
			self.has_hint = False
			# Index to start at to drop all hints
			self.last_hint = 0
			# Index up to which we know more hints are possible.
			# Only relevant if status is 0 or 1.
			self.last_checked = 0
			# The status means:
			# 0: after dropping hints, this charstring is empty
			# 1: after dropping hints, there may be more hints
			#	continuing after this, or there might be
			#	other things.  Not clear yet.
			# 2: no more hints possible after this charstring
			self.status = 0
			# Has hintmask instructions; not recursive
			self.has_hintmask = False
			# List of indices of calls to empty subroutines to remove.
			self.deletions = []
		pass

	def __init__(self, css, localSubrs, globalSubrs, nominalWidthX, defaultWidthX):
		self._css = css
		psCharStrings.T2WidthExtractor.__init__(
			self, localSubrs, globalSubrs, nominalWidthX, defaultWidthX)

	def execute(self, charString):
		old_hints = charString._hints if hasattr(charString, '_hints') else None
		charString._hints = self.Hints()

		psCharStrings.T2WidthExtractor.execute(self, charString)

		hints = charString._hints

		if hints.has_hint or hints.has_hintmask:
			self._css.add(charString)

		if hints.status != 2:
			# Check from last_check, make sure we didn't have any operators.
			for i in range(hints.last_checked, len(charString.program) - 1):
				if isinstance(charString.program[i], str):
					hints.status = 2
					break
				else:
					hints.status = 1 # There's *something* here
			hints.last_checked = len(charString.program)

		if old_hints:
			assert hints.__dict__ == old_hints.__dict__

	def op_callsubr(self, index):
		subr = self.localSubrs[self.operandStack[-1]+self.localBias]
		psCharStrings.T2WidthExtractor.op_callsubr(self, index)
		self.processSubr(index, subr)

	def op_callgsubr(self, index):
		subr = self.globalSubrs[self.operandStack[-1]+self.globalBias]
		psCharStrings.T2WidthExtractor.op_callgsubr(self, index)
		self.processSubr(index, subr)

	def op_hstem(self, index):
		psCharStrings.T2WidthExtractor.op_hstem(self, index)
		self.processHint(index)
	def op_vstem(self, index):
		psCharStrings.T2WidthExtractor.op_vstem(self, index)
		self.processHint(index)
	def op_hstemhm(self, index):
		psCharStrings.T2WidthExtractor.op_hstemhm(self, index)
		self.processHint(index)
	def op_vstemhm(self, index):
		psCharStrings.T2WidthExtractor.op_vstemhm(self, index)
		self.processHint(index)
	def op_hintmask(self, index):
		rv = psCharStrings.T2WidthExtractor.op_hintmask(self, index)
		self.processHintmask(index)
		return rv
	def op_cntrmask(self, index):
		rv = psCharStrings.T2WidthExtractor.op_cntrmask(self, index)
		self.processHintmask(index)
		return rv

	def processHintmask(self, index):
		cs = self.callingStack[-1]
		hints = cs._hints
		hints.has_hintmask = True
		if hints.status != 2:
			# Check from last_check, see if we may be an implicit vstem
			for i in range(hints.last_checked, index - 1):
				if isinstance(cs.program[i], str):
					hints.status = 2
					break
			else:
				# We are an implicit vstem
				hints.has_hint = True
				hints.last_hint = index + 1
				hints.status = 0
		hints.last_checked = index + 1

	def processHint(self, index):
		cs = self.callingStack[-1]
		hints = cs._hints
		hints.has_hint = True
		hints.last_hint = index
		hints.last_checked = index

	def processSubr(self, index, subr):
		cs = self.callingStack[-1]
		hints = cs._hints
		subr_hints = subr._hints

		# Check from last_check, make sure we didn't have
		# any operators.
		if hints.status != 2:
			for i in range(hints.last_checked, index - 1):
				if isinstance(cs.program[i], str):
					hints.status = 2
					break
			hints.last_checked = index

		if hints.status != 2:
			if subr_hints.has_hint:
				hints.has_hint = True

				# Decide where to chop off from
				if subr_hints.status == 0:
					hints.last_hint = index
				else:
					hints.last_hint = index - 2 # Leave the subr call in

		elif subr_hints.status == 0:
			hints.deletions.append(index)

		hints.status = max(hints.status, subr_hints.status)

class _DesubroutinizingT2Decompiler(psCharStrings.SimpleT2Decompiler):

	def __init__(self, localSubrs, globalSubrs, private=None):
		psCharStrings.SimpleT2Decompiler.__init__(self,
							  localSubrs,
							  globalSubrs, private)

	def execute(self, charString):
		if (hasattr(charString, '_desubroutinized') and
				charString._desubroutinized):
			return

		charString._patches = []
		psCharStrings.SimpleT2Decompiler.execute(self, charString)
		desubroutinized = charString.program[:]
		for idx,expansion in reversed (charString._patches):
			assert idx >= 2
			assert desubroutinized[idx - 1] in ['callsubr', 'callgsubr'], desubroutinized[idx - 1]
			assert type(desubroutinized[idx - 2]) == int
			if expansion[-1] == 'return':
				expansion = expansion[:-1]
			desubroutinized[idx-2:idx] = expansion
		if not charString.isCFF2:
			if 'endchar' in desubroutinized:
				# Cut off after first endchar
				desubroutinized = desubroutinized[:desubroutinized.index('endchar') + 1]
			else:
				if not len(desubroutinized) or desubroutinized[-1] != 'return':
					desubroutinized.append('return')

		charString._desubroutinized = desubroutinized
		del charString._patches

	def op_callsubr(self, index):
		subr = self.localSubrs[self.operandStack[-1]+self.localBias]
		psCharStrings.SimpleT2Decompiler.op_callsubr(self, index)
		self.processSubr(index, subr)

	def op_callgsubr(self, index):
		subr = self.globalSubrs[self.operandStack[-1]+self.globalBias]
		psCharStrings.SimpleT2Decompiler.op_callgsubr(self, index)
		self.processSubr(index, subr)

	def processSubr(self, index, subr):
		cs = self.callingStack[-1]
		cs._patches.append((index, subr._desubroutinized))


@_add_method(ttLib.getTableClass('CFF '))
def prune_post_subset(self, font, options):
	cff = self.cff
	for fontname in cff.keys():
		font = cff[fontname]
		cs = font.CharStrings

		# Drop unused FontDictionaries
		if hasattr(font, "FDSelect"):
			sel = font.FDSelect
			indices = _uniq_sort(sel.gidArray)
			sel.gidArray = [indices.index (ss) for ss in sel.gidArray]
			arr = font.FDArray
			arr.items = [arr[i] for i in indices]
			del arr.file, arr.offsets

		# Desubroutinize if asked for
		if options.desubroutinize:
			for g in font.charset:
				c, _ = cs.getItemAndSelector(g)
				c.decompile()
				subrs = getattr(c.private, "Subrs", [])
				decompiler = _DesubroutinizingT2Decompiler(subrs, c.globalSubrs)
				decompiler.execute(c)
				c.program = c._desubroutinized

		# Drop hints if not needed
		if not options.hinting:

			# This can be tricky, but doesn't have to. What we do is:
			#
			# - Run all used glyph charstrings and recurse into subroutines,
			# - For each charstring (including subroutines), if it has any
			#   of the hint stem operators, we mark it as such.
			#   Upon returning, for each charstring we note all the
			#   subroutine calls it makes that (recursively) contain a stem,
			# - Dropping hinting then consists of the following two ops:
			#   * Drop the piece of the program in each charstring before the
			#     last call to a stem op or a stem-calling subroutine,
			#   * Drop all hintmask operations.
			# - It's trickier... A hintmask right after hints and a few numbers
			#    will act as an implicit vstemhm. As such, we track whether
			#    we have seen any non-hint operators so far and do the right
			#    thing, recursively... Good luck understanding that :(
			css = set()
			for g in font.charset:
				c, _ = cs.getItemAndSelector(g)
				c.decompile()
				subrs = getattr(c.private, "Subrs", [])
				decompiler = _DehintingT2Decompiler(css, subrs, c.globalSubrs,
								    c.private.nominalWidthX,
								    c.private.defaultWidthX)
				decompiler.execute(c)
				c.width = decompiler.width
			for charstring in css:
				charstring.drop_hints()
			del css

			# Drop font-wide hinting values
			all_privs = []
			if hasattr(font, 'FDSelect'):
				all_privs.extend(fd.Private for fd in font.FDArray)
			else:
				all_privs.append(font.Private)
			for priv in all_privs:
				for k in ['BlueValues', 'OtherBlues',
					  'FamilyBlues', 'FamilyOtherBlues',
					  'BlueScale', 'BlueShift', 'BlueFuzz',
					  'StemSnapH', 'StemSnapV', 'StdHW', 'StdVW',
					  'ForceBold', 'LanguageGroup', 'ExpansionFactor']:
					if hasattr(priv, k):
						setattr(priv, k, None)

		# Renumber subroutines to remove unused ones

		# Mark all used subroutines
		for g in font.charset:
			c, _ = cs.getItemAndSelector(g)
			subrs = getattr(c.private, "Subrs", [])
			decompiler = _MarkingT2Decompiler(subrs, c.globalSubrs)
			decompiler.execute(c)

		all_subrs = [font.GlobalSubrs]
		if hasattr(font, 'FDSelect'):
			all_subrs.extend(fd.Private.Subrs for fd in font.FDArray if hasattr(fd.Private, 'Subrs') and fd.Private.Subrs)
		elif hasattr(font.Private, 'Subrs') and font.Private.Subrs:
			all_subrs.append(font.Private.Subrs)

		subrs = set(subrs) # Remove duplicates

		# Prepare
		for subrs in all_subrs:
			if not hasattr(subrs, '_used'):
				subrs._used = set()
			subrs._used = _uniq_sort(subrs._used)
			subrs._old_bias = psCharStrings.calcSubrBias(subrs)
			subrs._new_bias = psCharStrings.calcSubrBias(subrs._used)

		# Renumber glyph charstrings
		for g in font.charset:
			c, _ = cs.getItemAndSelector(g)
			subrs = getattr(c.private, "Subrs", [])
			c.subset_subroutines (subrs, font.GlobalSubrs)

		# Renumber subroutines themselves
		for subrs in all_subrs:
			if subrs == font.GlobalSubrs:
				if not hasattr(font, 'FDSelect') and hasattr(font.Private, 'Subrs'):
					local_subrs = font.Private.Subrs
				else:
					local_subrs = []
			else:
				local_subrs = subrs

			subrs.items = [subrs.items[i] for i in subrs._used]
			if hasattr(subrs, 'file'):
				del subrs.file
			if hasattr(subrs, 'offsets'):
				del subrs.offsets

			for subr in subrs.items:
				subr.subset_subroutines (local_subrs, font.GlobalSubrs)

		# Delete local SubrsIndex if empty
		if hasattr(font, 'FDSelect'):
			for fd in font.FDArray:
				_delete_empty_subrs(fd.Private)
		else:
			_delete_empty_subrs(font.Private)

		# Cleanup
		for subrs in all_subrs:
			del subrs._used, subrs._old_bias, subrs._new_bias

	return True


def _delete_empty_subrs(private_dict):
	if hasattr(private_dict, 'Subrs') and not private_dict.Subrs:
		if 'Subrs' in private_dict.rawDict:
			del private_dict.rawDict['Subrs']
		del private_dict.Subrs

@_add_method(ttLib.getTableClass('CFF2'))
def desubroutinize(self, font):
	cff = self.cff
	for fontname in cff.keys():
		font = cff[fontname]
		cs = font.CharStrings
		for g in font.charset:
			c, _ = cs.getItemAndSelector(g)
			c.decompile()
			subrs = getattr(c.private, "Subrs", [])
			decompiler = _DesubroutinizingT2Decompiler(subrs, c.globalSubrs, c.private)
			decompiler.execute(c)
			c.program = c._desubroutinized
		# Delete All the Subrs!!!
		if font.GlobalSubrs:
			del font.GlobalSubrs
		if hasattr(font, 'FDArray'):
			for fd in font.FDArray:
				pd = fd.Private
				if hasattr(pd, 'Subrs'):
					del pd.Subrs
				if 'Subrs' in pd.rawDict:
					del pd.rawDict['Subrs']


def interpolate_cff2_PrivateDict(topDict, interpolateFromDeltas):
	pd_blend_lists = ("BlueValues", "OtherBlues", "FamilyBlues",
						"FamilyOtherBlues", "StemSnapH",
						"StemSnapV")
	pd_blend_values = ("BlueScale", "BlueShift",
						"BlueFuzz", "StdHW", "StdVW")
	for fontDict in topDict.FDArray:
		pd = fontDict.Private
		vsindex = pd.vsindex if (hasattr(pd, 'vsindex')) else 0
		for key, value in pd.rawDict.items():
			if (key in pd_blend_values) and isinstance(value, list):
					delta = interpolateFromDeltas(vsindex, value[1:])
					pd.rawDict[key] = otRound(value[0] + delta)
			elif (key in pd_blend_lists) and isinstance(value[0], list):
				"""If any argument in a BlueValues list is a blend list,
				then they all are. The first value of each list is an
				absolute value. The delta tuples are calculated from
				relative master values, hence we need to append all the
				deltas to date to each successive absolute value."""
				delta = 0
				for i, val_list in enumerate(value):
					delta += otRound(interpolateFromDeltas(vsindex,
										val_list[1:]))
					value[i] = val_list[0] + delta


def interpolate_cff2_charstrings(topDict, interpolateFromDeltas, glyphOrder):
	charstrings = topDict.CharStrings
	for gname in glyphOrder:
		# Interpolate charstring
		charstring = charstrings[gname]
		pd = charstring.private
		vsindex = pd.vsindex if (hasattr(pd, 'vsindex')) else 0
		num_regions = pd.getNumRegions(vsindex)
		numMasters = num_regions + 1
		new_program = []
		last_i = 0
		for i, token in enumerate(charstring.program):
			if token == 'blend':
				num_args = charstring.program[i - 1]
				""" The stack is now:
				..args for following operations
				num_args values  from the default font
				num_args tuples, each with numMasters-1 delta values
				num_blend_args
				'blend'
				"""
				argi = i - (num_args*numMasters + 1)
				end_args = tuplei = argi + num_args
				while argi < end_args:
					next_ti = tuplei + num_regions
					deltas = charstring.program[tuplei:next_ti]
					delta = interpolateFromDeltas(vsindex, deltas)
					charstring.program[argi] += otRound(delta)
					tuplei = next_ti
					argi += 1
				new_program.extend(charstring.program[last_i:end_args])
				last_i = i + 1
		if last_i != 0:
			new_program.extend(charstring.program[last_i:])
			charstring.program = new_program


def interpolate_cff2_metrics(varfont, topDict, glyphOrder, loc):
	"""Unlike TrueType glyphs, neither advance width nor bounding box
	info is stored in a CFF2 charstring. The width data exists only in
	the hmtx and HVAR tables. Since LSB data cannot be interpolated
	reliably from the master LSB values in the hmtx table, we traverse
	the charstring to determine the actual bound box. """

	charstrings = topDict.CharStrings
	boundsPen = BoundsPen(glyphOrder)
	hmtx = varfont['hmtx']
	hvar_table = None
	if 'HVAR' in varfont:
		hvar_table = varfont['HVAR'].table
		fvar = varfont['fvar']
		varStoreInstancer = VarStoreInstancer(hvar_table.VarStore, fvar.axes, loc)

	for gid, gname in enumerate(glyphOrder):
		entry = list(hmtx[gname])
		# get width delta.
		if hvar_table:
			if hvar_table.AdvWidthMap:
				width_idx = hvar_table.AdvWidthMap.mapping[gname]
			else:
				width_idx = gid
			width_delta = otRound(varStoreInstancer[width_idx])
		else:
			width_delta = 0

		# get LSB.
		boundsPen.init()
		charstring = charstrings[gname]
		charstring.draw(boundsPen)
		if boundsPen.bounds is None:
			# Happens with non-marking glyphs
			lsb_delta = 0
		else:
			lsb = boundsPen.bounds[0]
		lsb_delta = entry[1] - lsb

		if lsb_delta or width_delta:
			if width_delta:
				entry[0] += width_delta
			if lsb_delta:
				entry[1] = lsb
			hmtx[gname] = tuple(entry)