import ctypes
from OpenGL.GL import *
try:
	import OpenGL.raw.GL
	raw = OpenGL.raw
except ImportError:
	pass
from OpenGL.arrays import GLintArray, GLcharArray, GLsizeiArray, GLcharARBArray
import sys
import gamedata


class shader_manager(object):
	def __init__(self):
		# Fixed Pipeline is always zero
		self.shaderlib = {'ffp': 0}
		self.shaderprograms = {}
		
		self.initshadersources = []
		self.initmode = 'auto'
		self.initialized = False
		
	def use_gl2_shaders(self):
		self.funcs = {
			'create': glCreateShader,
			'source': glShaderSource,
			'compile': glCompileShader,
			'program': glCreateProgram,
			'attach': glAttachShader,
			'link': glLinkProgram,
			'use': glUseProgram,
			'param': glGetShaderiv,
			'uniform': glUniform4f,
			'arraytype': GLcharArray
		}
	def use_raw_shaders(self):
		self.funcs = {
			'create': raw.GL.glCreateShader,
			'source': raw.GL.glShaderSource,
			'compile': raw.GL.glCompileShader,
			'program': raw.GL.glCreateProgram,
			'attach': raw.GL.glAttachShader,
			'link': raw.GL.glLinkProgram,
			'use': raw.GL.glUseProgram,
			'param': raw.GL.glGetShaderiv
		}

	def use_arb_shaders(self):
		from OpenGL.GL.ARB import shader_objects
		if not shader_objects.glInitShaderObjectsARB():
			raise RuntimeError("ARB Shaders failed to initialize")

		self.funcs = {
			'create': shader_objects.glCreateShaderObjectARB,
			'source': shader_objects.glShaderSourceARB,
			'compile': shader_objects.glCompileShaderARB,
			'program': shader_objects.glCreateProgramObjectARB,
			'attach': shader_objects.glAttachObjectARB,
			'link': shader_objects.glLinkProgramARB,
			'use': shader_objects.glUseProgramObjectARB,
			'uniform': shader_objects.glUniform4fARB,
			'param': shader_objects.glGetObjectParameterivARB
		}
	def use_arb_new_shaders(self):
		from OpenGL.GL.ARB import shader_objects_new
		shader_objects = shader_objects_new
		if not shader_objects.glInitShaderObjectsARB():
			raise RuntimeError("ARB New Shaders failed to initialize")

		self.funcs = {
			'create': shader_objects.glCreateShaderObjectARB,
			'source': shader_objects.base_glShaderSourceARB,
			'compile': shader_objects.glCompileShaderARB,
			'program': shader_objects.glCreateProgramObjectARB,
			'attach': shader_objects.glAttachObjectARB,
			'link': shader_objects.glLinkProgramARB,
			'use': shader_objects.glUseProgramObjectARB,
			'param': shader_objects.glGetObjectParameterivARB,
			'arraytype': GLcharARBArray
		}

	def init_gl(self):
		if self.initialized:
			return
			
		self.initialized = True
		import files
		#print glGetString(GL_EXTENSIONS)
		if True:
			self.use_gl2_shaders()
		else:
			self.use_arb_shaders()
			#self.use_gl2_shaders()

		for name, vertex, fragment in self.initshadersources:
			vf = files.mgr.open('shaders/%s.vert' % (vertex,))
			ff = files.mgr.open('shaders/%s.frag' % (fragment,))
			vs = self.funcs['create'](GL_VERTEX_SHADER)
			fs = self.funcs['create'](GL_FRAGMENT_SHADER)
			self.funcs['source'](vs, vf.read())
			self.funcs['source'](fs, ff.read())
			rv = self.funcs['compile'](vs)
			rv = self.funcs['compile'](fs)
			sp = self.funcs['program']()
			self.funcs['attach'](sp, vs)
			self.funcs['attach'](sp, fs)
			rv = self.funcs['link'](sp)
			self.shaderlib[name] = sp
			self.shaderprograms[name] = (vs, fs)
	
	def detect(self):
		shaderlist = [	
						('GL2', self.use_gl2_shaders), 
						('ARB', self.use_arb_shaders), 
						('ARBNEW', self.use_arb_new_shaders),
						('RAW', self.use_raw_shaders)
			]

		workable_shaders = []

		for shadername, shaderinit in shaderlist:
			try:
				shaderinit()
			except:
				print("Shader type %s failed to initialize" % (shadername,))
				continue
			try:
				self.select("ffp")
			except:
				print("Shader type %s failed to access the fixed function pipeline" % (shadername,))
				continue
			try:
				self.select("standard")
			except:
				print("Shader type %s failed to load the \"standard\" vertex and fragment shaders" % (shadername,))
				continue

			workable_shaders.append(shadername)

		return workable_shaders

	def autoinit(self):
		shadertypes = self.detect()
		
		if not shadertypes:
			raise ValueError("No working shaders detected")
		
		self.init_shadertype(shadertypes[0])

	def init_shadertype(self, shadertype):
		if shadertype == "GL2":
			self.use_gl2_shaders()
		elif shadertype == "ARB":
			self.use_arb_shaders()
		elif shadertype == "ARBNEW":
			self.use_arb_new_shaders()
		elif shadertype == "RAW":
			self.use_raw_shaders()

		

	def select(self, shader):
		if self.initshadersources:
			self.init_gl()
			self.initshadersources = []
		if not shader in self.shaderlib:
			self.funcs['use'](0)
			return True
		try:
			self.funcs['use'](self.shaderlib[shader])
		except GLError:
			p = self.shaderlib[shader]
			v, f = self.shaderprograms[shader]
			print("Shader failed to execute: %s" % (shader,))
			print("Vertex shader log:")
			lenarr = GLintArray.zeros(1)
			glGetShaderiv(v, GL_INFO_LOG_LENGTH, lenarr)
			infoarr = GLcharArray.zeros(lenarr[0])
			outsize = GLsizeiArray.zeros(1)
			glGetShaderInfoLog(v, lenarr[0], outsize, infoarr)
			print(''.join([chr(x) for x in infoarr[:outsize[0]]]))
			print("Fragment shader log:")
			lenarr = GLintArray.zeros(1)
			glGetShaderiv(f, GL_INFO_LOG_LENGTH, lenarr)
			infoarr = GLcharArray.zeros(lenarr[0])
			outsize = GLsizeiArray.zeros(1)
			glGetShaderInfoLog(f, lenarr[0], outsize, infoarr)
			print(''.join([chr(x) for x in infoarr[:outsize[0]]]))
			print("Program info log:")
			lenarr = GLintArray.zeros(1)
			glGetProgramiv(p, GL_INFO_LOG_LENGTH, lenarr)
			infoarr = GLcharArray.zeros(lenarr[0])
			outsize = GLsizeiArray.zeros(1)
			glGetProgramInfoLog(p, lenarr[0], outsize, infoarr)
			print(''.join([chr(x) for x in infoarr[:outsize[0]]]))
			glDeleteShader(v)
			glDeleteShader(f)
			glDeleteProgram(p)
			del self.shaderprograms[shader]
			del self.shaderlib[shader]
			glUseProgram(0)
			
			return False

		return True
		
	def load(self):
		shader_data = gamedata.get('shaders')
		self.load_shaders(shader_data)
		
	def load_shaders(self, shaders):
		for shader in shaders.shader:
			self.initshadersources.append((shader['id'], shader['vertex'], shader['fragment']))

def init():
	global mgr
	mgr = shader_manager()
	print("initiated shader mgr: %s" % (mgr,))
		
mgr = None