#!/usr/bin/python

# Usage: 'python makeres.py blender.shader.json'
# Output: blender_resource.json

import os
import sys
import json
import itertools

class Object:
	def to_JSON(self):
		return json.dumps(self, default=lambda o: o.__dict__, sort_keys=True, indent=4)

def writeResource(res, defs, json_data, base_name):
	# Define
	sres = Object()
	res.shader_resources.append(sres)

	shader_id = base_name
	for s in defs:
		shader_id += s

	sres.id = shader_id
	sres.vertex_structure = []
	sres.contexts = []

	# Parse
	for c in json_data['contexts']:
		con = Object()
		sres.contexts.append(con)
		con.id = c['id']
		con.constants = []
		con.texture_units = []

		# Names
		vert_name = c['vertex_shader'].split('.')[0]
		frag_name = c['fragment_shader'].split('.')[0]
		for d in defs:
			vert_name += d
			frag_name += d
		con.vertex_shader = vert_name + '.vert'
		con.fragment_shader = frag_name + '.frag'

		# Params
		for p in c['params']:
			if p['id'] == 'depth_write':
				if p['value'] == 'true':
					con.depth_write = True
				else:
					con.depth_write = False
			elif p['id'] == 'compare_mode':
				con.compare_mode = p['value']
			elif p['id'] == 'cull_mode':
				con.cull_mode = p['value']
			elif p['id'] == 'blend_source':
				con.blend_source = p['value']
			elif p['id'] == 'blend_destination':
				con.blend_destination = p['value']

		# Parse shaders
		vs = open(c['vertex_shader']).read().splitlines()
		fs = open(c['fragment_shader']).read().splitlines()
		parse_shader(sres, c, con, defs, vs, len(sres.contexts) == 1) # Parse attribs for the first vertex shader
		parse_shader(sres, c, con, defs, fs, False)

def parse_shader(sres, c, con, defs, lines, parse_attributes):
	skipTillEndIf = False
	vertex_structure_parsed = False
	vertex_structure_parsing = False
	
	if parse_attributes == False:
		vertex_structure_parsed = True
		
	for line in lines:
		if line.startswith('#ifdef'):
			s = line.split(' ')[1]
			if s != 'GL_ES':
				found = False
				for d in defs:
					if d == s:
						found = True
						break
				if found == False:
					skipTillEndIf = True
				# TODO: Prevent instanced data to go into main verrtex structure
				if s == '_Instancing':
					skipTillEndIf = True
			continue

		if line.startswith('#endif'):
			skipTillEndIf = False
			continue

		if skipTillEndIf == True:
			continue

		if vertex_structure_parsed == False and line.startswith('in '):
			vertex_structure_parsing = True
			vd = Object()
			s = line.split(' ')
			vd.size = int(s[1][-1:])
			vd.name = s[2][:-1]
			sres.vertex_structure.append(vd)
		if vertex_structure_parsing == True and len(line) > 0 and line.startswith('//') == False and line.startswith('in ') == False:
			vertex_structure_parsed = True

		if line.startswith('uniform'):
			s = line.split(' ')
			ctype = s[1]
			cid = s[2][:-1]
			found = False # Unique check
			if ctype == 'sampler2D': # Texture unit
				for tu in con.texture_units:
					if tu.id == cid:
						found = True
						break
				if found == False:
					tu = Object()
					tu.id = cid
					# Check for texture params
					for p in c['texture_params']:
						if p['id'] == cid:
							valid_link = True
							if 'ifdef' in p:
								valid_link = False
								for d in defs:
									if d == p['ifdef']:
										valid_link = True
										break
							if valid_link:
								if 'u_addressing' in p:
									tu.u_addressing = l['u_addressing']
								if 'v_addressing' in p:
									tu.v_addressing = l['v_addressing']
								if 'min_filter' in p:
									tu.min_filter = l['min_filter']
								if 'mag_filter' in p:
									tu.mag_filter = l['mag_filter']
								if 'mipmap' in p:
									tu.mipmap = l['mipmap']
							break
					con.texture_units.append(tu)
			else: # Constant
				if cid.find('[') != -1: # Float arrays
					cid = cid.split('[')[0]
					ctype = 'floats'
				for const in con.constants:
					if const.id == cid:
						found = True
						break
				if found == False:
					const = Object()
					const.type = ctype
					const.id = cid
					# Check for link
					for l in c['links']:
						if l['id'] == cid:
							valid_link = True
							if 'ifdef' in l:
								valid_link = False
								for d in defs:
									if d == l['ifdef']:
										valid_link = True
										break
							if valid_link:
								const.link = l['link']
							break
					con.constants.append(const)

def make(json_name):
	#base_name = sys.argv[1].split('.', 1)[0]
	base_name = json_name.split('.', 1)[0]

	# Make out dir
	#if not os.path.exists('out'):
	#	os.makedirs('out')
	path = '../../compiled/ShaderResources/' + base_name
	if not os.path.exists(path):
		os.makedirs(path)

	# Open json file
	# json_file = open(sys.argv[1]).read()
	json_file = open(json_name).read()
	json_data = json.loads(json_file)

	# Go through every context shaders and gather ifdefs
	defs = []
	for c in json_data['contexts']:
		vs = open(c['vertex_shader']).read().splitlines()
		fs = open(c['fragment_shader']).read().splitlines()
		lines = vs + fs
		for line in lines:
			if line.startswith('#ifdef'):
				d = line.split(' ')[1]
				if d != 'GL_ES':
					defs.append(d)

	# Merge duplicates and sort
	defs = sorted(list(set(defs)))

	# Process #defines
	res = Object()
	res.shader_resources = []
	for L in range(0, len(defs)+1):
		for subset in itertools.combinations(defs, L):
			writeResource(res, subset, json_data, base_name)
			# Save separately
			res_name = base_name
			for s in subset:
				res_name += s
			#with open('out/' + res_name + '.json', 'w') as f:
			with open('../../compiled/ShaderResources/' + base_name + '/' + res_name + '.json', 'w') as f:
				r = Object()
				r.shader_resources = [res.shader_resources[-1]]
				f.write(r.to_JSON())

	# Save combined
	#with open('out/' + base_name + '_resource.json', 'w') as f:
	#	f.write(res.to_JSON())