# Edges in the same order as the edge bits in "case".
edges = (
	(1, 5), (5, 7), (3, 7), (1, 3),
	(0, 4), (1, 4), (2, 4), (3, 4),
	(4, 5), (4, 6), (4, 7), (4, 8),
	)

def computeCasePermutation(neighbourPermutation):
	return tuple(
		edges.index(tuple(sorted(
			(neighbourPermutation[n1], neighbourPermutation[n2])
			)))
		for n1, n2 in edges
		)

def permute(seq, permutation):
	seq = tuple(seq)
	assert len(seq) == len(permutation)
	return tuple(seq[index] for index in permutation)

def permuteCase(case, permutation):
	return sum(
		((case >> newBit) & 1) << oldBit
		for newBit, oldBit in enumerate(permutation)
		)

def gcd(a, b):
	'''Returns the greatest common divisor of a and b.
	'''
	while a != 0:
		a, b = b % a, a
	return b

def simplifyWeights(weights):
	'''Returns the lowest weight values of which the ratios are equal to the
	given weights.
	'''
	weights = tuple(weights)
	divider = reduce(gcd, weights, 0)
	return tuple(w / divider for w in weights)

def expandTopLeftWeights(weights):
	return weights[0 : 2] + (0, ) + weights[2 : 4] + (0, 0, 0, 0)

def expandQuadrant(topLeftQuadrant, zoom):
	quadrantWidth = (zoom + 1) / 2
	assert quadrantWidth ** 2 == len(topLeftQuadrant[0])
	mirrorMap = [None] * (zoom ** 2)
	permId = (0, 1, 2, 3, 4, 5, 6, 7, 8)
	permLR = (2, 1, 0, 5, 4, 3, 8, 7, 6)
	permTB = (6, 7, 8, 3, 4, 5, 0, 1, 2)
	for quadrantIndex in xrange(quadrantWidth ** 2):
		qy, qx = divmod(quadrantIndex, quadrantWidth)
		for ty, py in ((zoom - qy - 1, permTB), (qy, permId)):
			for tx, px in ((zoom - qx - 1, permLR), (qx, permId)):
				nperm = permute(px, py)
				cperm = computeCasePermutation(nperm)
				mirrorMap[ty * zoom + tx] = (quadrantIndex, cperm, nperm)
	return [
		[	permute(
				expandTopLeftWeights(
					topLeftQuadrant[permuteCase(case, cperm)][quadrantIndex]
					),
				nperm
				)
			for quadrantIndex, cperm, nperm in mirrorMap
			]
		for case in xrange(len(topLeftQuadrant))
		]

def computeZ2S0W0(case):
	if (case & 0xFF8) in (
		0x0A0, 0x1A0, 0x2A0, 0x3A0, 0x4A0, 0x5A0, 0x7A0,
		0x8A0, 0x9A0, 0xAA0, 0xBA0, 0xCA0, 0xDA0, 0xEA0,
		0x1A8, 0x4A8,
		0x0E0, 0x2E0, 0x4E0, 0x5E0,0x8E0, 0x9E0, 0xAE0, 0xCE0
		):
		return 0
	elif (case & 0x0B0) == 0:
		return 0
	elif (case & 0x010) == 0x010:
		return 0
	else:
		return 4

def computeZ2S0W1(case):
	if (case & 0xFF8) in (
		0x2A0, 0xAA0, 0x2B0, 0xAB0, 0xBB0, 0xCF0, 0x0E0, 0x8E0, 0x0F0, 0x8F0
		):
		return 6
	elif (case & 0x3FC) in (0x1D0, 0x1D8, 0x1F0, 0x1F4):
		return 4
	elif (case & 0x0B4) in (0x000, 0x010, 0x080, 0x004, 0x014, 0x084, 0x094):
		return 4
	elif (case & 0xFF1) in (0x130, 0x170, 0x330, 0x370, 0x770):
		return 4
	elif (case & 0xFF4) in (
		0x0D0, 0x2D0, 0x3D0, 0x8D0, 0xAD0, 0xBD0, 0xCD0, 0xED0, 0xFD0,
		0x090, 0x190, 0x290, 0x390, 0x590, 0x790,
		0x890, 0x990, 0xA90, 0xB90, 0xC90, 0xD90, 0xE90, 0xF90
		):
		return 4
	elif (case & 0xFF8) in (
		0x0A0, 0x1A0, 0x4A0, 0x8A0,
		0x0B0, 0x1B0, 0x3B0, 0x4B0, 0x5B0, 0x6B0, 0x7B0,
		0x8B0, 0x9B0, 0xCB0, 0xDB0, 0xEB0, 0xFB0,
		0x4F0
		):
		return 4
	elif (case & 0xFF8) in (
		0x3A0, 0x5A0, 0x7A0, 0x9A0, 0xBA0, 0xCA0, 0xDA0, 0xEA0,
		0x2E0, 0x4E0, 0x5E0, 0x9E0, 0xAE0, 0xCE0
		):
		return 2
	elif (case & 0xFF4) in (0x490, 0x4D0, 0x690, 0x6D0, 0x7D0):
		return 2
	elif (case & 0x2F8) == 0x2F0:
		return 1
	else:
		return 0

def genExpr2():
	quadrant = [
		[ None ]
		for case in xrange(1 << 12)
		]
	casePerm = computeCasePermutation((0, 3, 6, 1, 4, 7, 2, 5, 8))

	for case in xrange(1 << 12):
		w0 = computeZ2S0W0(case)
		w1 = computeZ2S0W1(case)
		w2 = computeZ2S0W1(permuteCase(case, casePerm))
		quadrant[case][0] = simplifyWeights((w0, w1, w2, 16 - w0 - w1 - w2))

	return quadrant

def computeZ3S0W0(case):
	if (case & 0xFF8) in (0x1A8, 0x4A8, 0x5E0, 0x7A0, 0x9E0, 0xEA0):
		return 0
	elif (case & 0x7F8) in (
		0x0A0, 0x0E0, 0x1A0, 0x2A0, 0x2E0, 0x3A0, 0x4A0, 0x4E0, 0x5A0
		):
		return 0
	elif (case & 0x0B0) == 0x000:
		return 0
	elif (case & 0x010) == 0x010:
		return 0
	else:
		return 4

def computeZ3S0W1(case):
	if (case & 0xFF8) in (
		0x0E0, 0x0F0, 0x2A0, 0x2B0, 0x8E0, 0x8F0, 0xAA0, 0xAB0, 0xBB0, 0xCF0
		):
		return 8
	elif (case & 0xFF8) in (
		0x0A0, 0x1A0, 0x4A0, 0x8A0,
		0x1F0, 0x4F0, 0x5F0, 0x9F0, 0xDF0,
		0x0B0, 0x1B0, 0x3B0, 0x4B0, 0x5B0, 0x6B0, 0x7B0,
		0x8B0, 0x9B0, 0xCB0, 0xDB0, 0xEB0, 0xFB0
		):
		return 7
	elif (case & 0xFF1) in (0x130, 0x170, 0x330, 0x370, 0x770):
		return 4
	elif (case & 0xFF8) in (
		0x3A0, 0x5A0, 0x7A0, 0x9A0, 0xBA0, 0xCA0, 0xDA0, 0xEA0,
		0x2E0, 0x4E0, 0x5E0, 0x9E0, 0xAE0, 0xCE0,
		0x2F0, 0x3F0, 0x6F0, 0x7F0, 0xAF0, 0xBF0, 0xEF0, 0xFF0
		):
		return 4
	elif (case & 0x0F0) in (0x000, 0x010, 0x040, 0x050, 0x090, 0x0D0):
		return 4
	else:
		return 0

def computeZ3S1W1(case):
	if (case & 0xFF1) in (0x170, 0x130, 0x330, 0x370, 0x770):
		return 12
	elif (case & 0xFF8) in (0x0E0, 0x0F0, 0x8E0, 0x8F0, 0xCF0):
		return 12
	elif (case & 0xFF1) in (0x920, 0x960, 0xB20, 0xB60, 0xBE0):
		return 4
	elif (case & 0xFF8) in (0x2A0, 0x2B0, 0xAA0, 0xAB0, 0xBB0):
		return 4
	elif (case & 0x020) == 0:
		return 4
	elif (case & 0xFF1) in (
		0x120, 0x160, 0x1E0, 0x320, 0x360, 0x3E0,
		0x520, 0x560, 0x570, 0x5E0, 0x760, 0x7E0,
		0x9E0, 0xD60, 0xDE0, 0xDF0, 0xF60, 0xFE0
		):
		return 2
	elif (case & 0xFF8) in (
		0x0A0, 0x0B0, 0x1B0, 0x3B0, 0x4A0, 0x4B0,
		0x4F0, 0x5B0, 0x6B0, 0x7B0, 0x7F0, 0x8A0,
		0x8B0, 0x9B0, 0xCB0, 0xDB0, 0xEB0, 0xFB0
		):
		return 2
	else:
		return 0

def genExpr3():
	quadrant = [
		[ None ] * 4
		for case in xrange(1 << 12)
		]
	quadrantPerm = (0, 2, 1, 3)
	casePerm = computeCasePermutation((0, 3, 6, 1, 4, 7, 2, 5, 8))

	for case in xrange(1 << 12):
		w0 = computeZ3S0W0(case)
		w1 = computeZ3S0W1(case)
		w2 = computeZ3S0W1(permuteCase(case, casePerm))
		weights = (w0, w1, w2, 16 - w0 - w1 - w2)
		quadrant[case][0] = simplifyWeights(weights)

	for case in xrange(1 << 12):
		w1 = computeZ3S1W1(case)
		weights = (0, w1, 0, 16 - w1)
		quadrant[case][1] = simplifyWeights(weights)

	for case in xrange(1 << 12):
		mirrorCase = permuteCase(case, casePerm)
		quadrant[case][2] = permute(quadrant[mirrorCase][1], quadrantPerm)

	for case in xrange(1 << 12):
		quadrant[case][3] = (0, 0, 0, 1)

	return quadrant

def computeZ4S0W0(case):
	if (case & 0xFF8) in (
		0x1A8, 0x4A8,
		0x0A0, 0x1A0, 0x2A0, 0x3A0, 0x4A0, 0x5A0, 0x7A0,
		0x8A0, 0x9A0, 0xAA0, 0xBA0, 0xCA0, 0xDA0, 0xEA0,
		0x0E0, 0x2E0, 0x4E0, 0x5E0, 0x8E0, 0x9E0, 0xAE0, 0xCE0
		):
		return 0
	elif (case & 0x0B0) == 0:
		return 0
	elif (case & 0x010) == 0x010:
		return 0
	else:
		return 6

def computeZ4S0W1(case):
	if (case & 0xFF8) in (
		0x0A0, 0x1A0, 0x2A0, 0x4A0, 0x8A0, 0xAA0,
		0x0E0, 0x8E0,
		0x0F0, 0x1F0, 0x4F0, 0x5F0, 0x8F0, 0x9F0, 0xCF0, 0xDF0
		):
		return 8
	elif (case & 0x0F8) == 0x0B0:
		return 8
	elif (case & 0xFF4) in (
		0x090, 0x190, 0x290, 0x390, 0x590, 0x790,
		0x890, 0x990, 0xB90, 0xC90, 0xE90, 0xA90, 0xD90, 0xF90,
		0x0D0, 0x1D0, 0x2D0, 0x3D0, 0x5D0,
		0x8D0, 0x9D0, 0xAD0, 0xBD0, 0xCD0, 0xDD0, 0xED0, 0xFD0
		):
		return 6
	elif (case & 0x0B4) == 0x094:
		return 6
	elif (case & 0xFF1) in (
		0x130, 0x170, 0x330, 0x370, 0x770
		):
		return 4
	elif (case & 0xFF8) in (
		0x3A0, 0x5A0, 0x7A0, 0x9A0, 0xBA0, 0xCA0, 0xDA0, 0xEA0,
		0x2E0, 0x4E0, 0x5E0, 0x9E0, 0xAE0, 0xCE0,
		0x2F0, 0x3F0, 0x6F0, 0x7F0, 0xAF0, 0xBF0, 0xEF0, 0xFF0
		):
		return 4
	elif (case & 0x0A0) == 0:
		return 4
	else:
		return 0

def computeZ4S1W0(case):
	if (case & 0xFF8) in (
		0x6A0, 0xFA0,
		0x1E0, 0xDE0, 0x6E0, 0xEE0, 0x3E0, 0x7E0, 0xBE0, 0xFE0,
		0x9A8, 0xCA8, 0x0A8, 0x8A8, 0x5A8, 0xDA8,
		0x2A8, 0x3A8, 0x6A8, 0x7A8, 0xAA8, 0xBA8, 0xEA8, 0xFA8
		):
		return 4
	elif (case & 0x0F8) in (0x020, 0x060, 0x028, 0x068, 0x0E8):
		return 4
	elif (case & 0x0B0) == 0x080:
		return 2
	else:
		return 0

def computeZ4S1W1(case):
	if (case & 0xFF1) in (0x130, 0x170, 0x330, 0x370, 0x770):
		return 12
	elif (case & 0xFF8) in (0x0E0, 0x0F0, 0x8E0, 0x8F0, 0xCF0):
		return 10
	elif (case & 0xFF8) in (
		0x0A0, 0x1A0, 0x2A0, 0x4A0, 0x8A0, 0xAA0,
		0x1F0, 0x4F0, 0x5F0, 0x9F0, 0xDF0
		):
		return 8
	elif (case & 0x0F8) == 0x0B0:
		return 8
	elif (case & 0x0B0) == 0x090:
		return 6
	elif (case & 0xFF8) in (
		0x3A0, 0x5A0, 0x7A0, 0x9A0, 0xBA0, 0xCA0, 0xDA0, 0xEA0,
		0x2E0, 0x4E0, 0x5E0, 0xAE0, 0x9E0, 0xCE0,
		):
		return 4
	elif (case & 0x0B0) in (0x000, 0x010, 0x080):
		return 4
	else:
		return 0

def computeZ4S1W2(case):
	if (case & 0xFF8) in (0x0E0, 0x0F0, 0x8E0, 0x8F0, 0xCF0):
		return 6
	elif (case & 0xFF8) in (0x2A0, 0x2B0, 0xAA0, 0xAB0, 0xBB0):
		return 4
	elif (case & 0xFF1) in (
		0x030, 0x230, 0x430, 0x530, 0x630, 0x730,
		0x830, 0x930, 0xA30, 0xB30, 0xC30, 0xD30, 0xE30, 0xF30,
		0x070, 0x270, 0x470, 0x570, 0x670,
		0x870, 0x970, 0xA70, 0xB70, 0xC70, 0xD70, 0xE70, 0xF70,
		):
		return 2
	elif (case & 0x0B1) in (0x000, 0x001, 0x010, 0x011, 0x031):
		return 2
	else:
		return 0

def computeZ4S3W0(case):
	if (case & 0xFF8) in (
		0x1A8, 0x4A8,
		0x0A0, 0x1A0, 0x2A0, 0x3A0, 0x4A0, 0x5A0, 0x7A0,
		0x8A0, 0x9A0, 0xAA0, 0xBA0, 0xCA0, 0xDA0, 0xEA0,
		0x0E0, 0x2E0, 0x4E0, 0x5E0, 0x8E0, 0x9E0, 0xAE0, 0xCE0,
		):
		return 0
	elif (case & 0x0B0) == 0:
		return 0
	elif (case & 0x010) == 0x010:
		return 0
	else:
		return 2

def computeZ4S3W1(case):
	if (case & 0xFF8) in (
		0x2A0, 0x2B0, 0xAA0,
		0xAB0, 0xBB0,
		0x0E0, 0x8E0,
		0x0F0, 0x8F0, 0xCF0
		):
		return 2
	elif (case & 0x0B0) in (0x000, 0x010, 0x090):
		return 2
	else:
		return 0

def genExpr4():
	quadrant = [
		[ None ] * 4
		for case in xrange(1 << 12)
		]
	quadrantPerm = (0, 2, 1, 3)
	casePerm = computeCasePermutation((0, 3, 6, 1, 4, 7, 2, 5, 8))

	for case in xrange(1 << 12):
		w0 = computeZ4S0W0(case)
		w1 = computeZ4S0W1(case)
		w2 = computeZ4S0W1(permuteCase(case, casePerm))
		quadrant[case][0] = simplifyWeights((w0, w1, w2, 16 - w0 - w1 - w2))

	for case in xrange(1 << 12):
		w0 = computeZ4S1W0(case)
		w1 = computeZ4S1W1(case)
		w2 = computeZ4S1W2(case)
		quadrant[case][1] = simplifyWeights((w0, w1, w2, 16 - w0 - w1 - w2))

	for case in xrange(1 << 12):
		mirrorCase = permuteCase(case, casePerm)
		quadrant[case][2] = permute(quadrant[mirrorCase][1], quadrantPerm)

	for case in xrange(1 << 12):
		w0 = computeZ4S3W0(case)
		w1 = computeZ4S3W1(case)
		w2 = computeZ4S3W1(permuteCase(case, casePerm))
		quadrant[case][3] = simplifyWeights((w0, w1, w2, 16 - w0 - w1 - w2))

	return quadrant
