/*
 Copyright (c) 2013 yvt

 This file is part of OpenSpades.

 OpenSpades is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 OpenSpades is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with OpenSpades.  If not, see <http://www.gnu.org/licenses/>.

 */

#include "GLProgramManager.h"
#include <Core/Debug.h>
#include <Core/Exception.h>
#include <Core/FileManager.h>
#include <Core/Math.h>
#include <Core/Stopwatch.h>
#include "GLDynamicLightShader.h"
#include "GLProgram.h"
#include "GLSettings.h"
#include "GLShader.h"
#include "GLShadowMapShader.h"
#include "GLShadowShader.h"
#include "IGLShadowMapRenderer.h"

namespace spades {
	namespace draw {
		GLProgramManager::GLProgramManager(IGLDevice *d, IGLShadowMapRenderer *smr,
		                                   GLSettings &settings)
		    : device(d), shadowMapRenderer(smr), settings(settings) {
			SPADES_MARK_FUNCTION();
		}

		GLProgramManager::~GLProgramManager() {
			SPADES_MARK_FUNCTION();

			for (std::map<std::string, GLProgram *>::iterator it = programs.begin();
			     it != programs.end(); it++) {
				delete it->second;
			}
			for (std::map<std::string, GLShader *>::iterator it = shaders.begin();
			     it != shaders.end(); it++) {
				delete it->second;
			}
		}

		GLProgram *GLProgramManager::RegisterProgram(const std::string &name) {
			SPADES_MARK_FUNCTION();

			std::map<std::string, GLProgram *>::iterator it;
			it = programs.find(name);
			if (it == programs.end()) {
				GLProgram *prog = CreateProgram(name);
				programs[name] = prog;
				return prog;
			} else {
				return it->second;
			}
		}

		GLShader *GLProgramManager::RegisterShader(const std::string &name) {
			SPADES_MARK_FUNCTION();

			std::map<std::string, GLShader *>::iterator it;
			it = shaders.find(name);
			if (it == shaders.end()) {
				GLShader *prog = CreateShader(name);
				shaders[name] = prog;
				return prog;
			} else {
				return it->second;
			}
		}

		GLProgram *GLProgramManager::CreateProgram(const std::string &name) {
			SPADES_MARK_FUNCTION();

			SPLog("Loading GLSL program '%s'", name.c_str());
			std::string text = FileManager::ReadAllBytes(name.c_str());
			std::vector<std::string> lines = SplitIntoLines(text);

			GLProgram *p = new GLProgram(device, name);

			for (size_t i = 0; i < lines.size(); i++) {
				std::string text = TrimSpaces(lines[i]);
				if (text.empty())
					break;

				if (text == "*shadow*") {
					std::vector<GLShader *> shaders =
					  GLShadowShader::RegisterShader(this, settings, false);
					for (size_t i = 0; i < shaders.size(); i++)
						p->Attach(shaders[i]);
					continue;
				} else if (text == "*shadow-variance*") {
					std::vector<GLShader *> shaders =
					  GLShadowShader::RegisterShader(this, settings, true);
					for (size_t i = 0; i < shaders.size(); i++)
						p->Attach(shaders[i]);
					continue;
				} else if (text == "*dlight*") {
					std::vector<GLShader *> shaders = GLDynamicLightShader::RegisterShader(this);
					for (size_t i = 0; i < shaders.size(); i++)
						p->Attach(shaders[i]);
					continue;
				} else if (text == "*shadowmap*") {
					std::vector<GLShader *> shaders = GLShadowMapShader::RegisterShader(this);
					for (size_t i = 0; i < shaders.size(); i++)
						p->Attach(shaders[i]);
					continue;
				} else if (text[0] == '*') {
					SPRaise("Unknown special shader: %s", text.c_str());
				}
				GLShader *s = CreateShader(text);

				p->Attach(s);
			}

			Stopwatch sw;
			p->Link();
			SPLog("Successfully linked GLSL program '%s' in %.3fms", name.c_str(),
			      sw.GetTime() * 1000.);
			// p->Validate();
			return p;
		}

		GLShader *GLProgramManager::CreateShader(const std::string &name) {
			SPADES_MARK_FUNCTION();

			SPLog("Loading GLSL shader '%s'", name.c_str());
			std::string text = FileManager::ReadAllBytes(name.c_str());
			GLShader::Type type;

			if (name.find(".fs") != std::string::npos)
				type = GLShader::FragmentShader;
			else if (name.find(".vs") != std::string::npos)
				type = GLShader::VertexShader;
			else
				SPRaise("Failed to determine the type of a shader: %s", name.c_str());

			GLShader *s = new GLShader(device, type);

			std::string finalSource;

			if (settings.r_hdr) {
				finalSource += "#define USE_HDR 1\n";
				finalSource += "#define LINEAR_FRAMEBUFFER 1\n";
			} else {
				finalSource += "#define USE_HDR 0\n";
				finalSource += "#define LINEAR_FRAMEBUFFER 0\n";
			}
			if (settings.r_fogShadow) {
				finalSource += "#define USE_VOLUMETRIC_FOG 1\n";
			} else {
				finalSource += "#define USE_VOLUMETRIC_FOG 0\n";
			}

			finalSource += text;

			s->AddSource(finalSource);

			Stopwatch sw;
			s->Compile();
			SPLog("Successfully compiled GLSL program '%s' in %.3fms", name.c_str(),
			      sw.GetTime() * 1000.);
			return s;
		}
	}
}