/*
 * Copyright © 2015 Canonical Ltd.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 3,
 * as published by the Free Software Foundation.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Authored by: Daniel van Vugt <daniel.van.vugt@canonical.com>
 */

#ifndef MIR_RENDERER_GL_PROGRAM_FAMILY_H_
#define MIR_RENDERER_GL_PROGRAM_FAMILY_H_

#include <GLES2/gl2.h>
#include <utility>
#include <map>
#include <unordered_map>

namespace mir
{
namespace renderer
{
namespace gl
{

/**
 * ProgramFamily represents a set of GLSL programs that are closely
 * related. Programs which point to the same shader source strings will be
 * made to share the same compiled shader objects.
 *   A secondary intention is that this class may be extended to allow the
 * different programs within the family to share common patterns of uniform
 * usage too.
 */
class ProgramFamily
{
public:
    ProgramFamily() = default;
    ProgramFamily(ProgramFamily const&) = delete;
    ProgramFamily& operator=(ProgramFamily const&) = delete;
    ~ProgramFamily() noexcept;

    GLuint add_program(const GLchar* const static_vshader_src,
                       const GLchar* const static_fshader_src);

private:
    struct Shader
    {
        GLuint id = 0;
        void init(GLenum type, const GLchar* src);
    };
    typedef std::unordered_map<const GLchar*, Shader> ShaderMap;
    ShaderMap vshader, fshader;

    typedef std::pair<GLuint, GLuint> ShaderPair;
    struct Program
    {
        GLuint id = 0;
    };
    std::map<ShaderPair, Program> program;
};

}
}
}

#endif // MIR_RENDERER_GL_PROGRAM_FAMILY_H_
