#include "renderer_polygon_3d.hpp"

#include <iostream>

#include <glm/gtc/type_ptr.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtx/euler_angles.hpp>

namespace endofthejedi {
    void RendererPolygon3d::setup()
    {
        m_lastTime = -1.0;

        std::cout<<"setup polygon 3d" << std::endl;

        //m_missileModel = new PolygonModel("../data/mesh/quad_screen_coords.stl");

        addModel("../data/mesh/small_atomic_bomb.stl", &m_missileModel);
        addModel("../data/mesh/planet_64.stl",         &m_planetModel);
        addModel("../data/mesh/ship_ufo.stl",          &m_shipModel);

        std::string vss_simple =
          #include "simple.vert"
            ;

        std::string fss_simple =
          #include "simple.frag"
            ;

        std::string vss_game_objects =
          #include "gameobjects.vert"
            ;

        std::string fss_game_objects =
          #include "gameobjects.frag"
            ;

        m_shader.init();

#if 0
        (void) vss_simple;
        (void) fss_simple;
        m_shader.load(vss_simple.c_str(), GL_VERTEX_SHADER);
        m_shader.load(fss_simple.c_str(), GL_FRAGMENT_SHADER);
#else
        (void) vss_game_objects;
        (void) fss_game_objects;
        m_shader.load(vss_game_objects.c_str(), GL_VERTEX_SHADER);
        m_shader.load(fss_game_objects.c_str(), GL_FRAGMENT_SHADER);
#endif
    }

    void RendererPolygon3d::render(const game::State *state)
    {
        if (m_lastTime == -1.0) {
            m_lastTime = state->timestamp();
        }

        float dt = state->timestamp() - m_lastTime;
        if (dt < 0.0) {
            dt = 0.0;
        }

        glClearColor(0.0, 0.0, 0.0, 1.0);

        m_state = state;

        advanceGraphicObjects(dt);

        m_shader.bind();

        renderPlanets();
        renderShips();
        renderMissiles();

        //glDisable(GL_DEPTH_TEST);
        renderParticles();
        //glEnable(GL_DEPTH_TEST);

        //glColor3f(1.0, 0.0, 0.0);
        //glBegin(GL_QUADS);
        //glVertex2f(-1.0f, -1.0f);
        //glVertex2f(1.0f, -1.0f);
        //glVertex2f(1.0f, 1.0f);
        //glVertex2f(-1.0f, 1.0f);
        //glEnd();

        m_lastTime = state->timestamp();
    }

    void RendererPolygon3d::renderParticles()
    {
        for (ParticleBatch *batch : m_particles) {
            batch->bind();
            batch->render();
        }
    }

    void RendererPolygon3d::addExplosionEffect(const glm::vec2 &pos, size_t n, float duration)
    {
        ParticleBatch *batch = new ParticleBatch(n, 0.005, duration);

        for (size_t i=0; i<n; i++) {
            // distribute in a circle
            float t = 4.0 * M_PI * i / (float) n;
            t += 0.2*util::randf_m1_1();

            // with random velocities
            glm::vec2 v = 0.2f*glm::vec2(sin(t), cos(t));
            v *= 0.2+0.8*util::randf_0_1();

            batch->setParticle(i, pos, v);
        }

        batch->upload();

        m_particles.push_back(batch);
    }

    void RendererPolygon3d::advanceGraphicObjects(float dt)
    {
        for (const game::Explosion *expl : m_state->explosions) {
            if (expl->age == 0.0) {
                addExplosionEffect(expl->position, 200, 3.0);
            }
        }

        std::vector<ParticleBatch*> rm;

        for (ParticleBatch *batch : m_particles) {
            batch->tick(dt);
            if (batch->done()) {
                rm.push_back(batch);
            }
        }

        for (ParticleBatch *batch : rm) {
            m_particles.remove(batch);
            delete(batch);
        }
    }

    void RendererPolygon3d::renderPlanets()
    {
        m_planetModel->bind(m_shader);

        for (const game::Planet *planet : m_state->planets) {
            glm::mat4 model = computeModelMatrix(planet);
            glUniformMatrix4fv(m_shader.location("model"), 1, GL_FALSE, glm::value_ptr(model));

            glm::vec3 c = planet->getColor();
            glUniform3f(m_shader.location("color"), c.x, c.y, c.z);
            glUniform3f(m_shader.location("lightpos"), 0.5f, 0.5f, -4.0f);

            m_planetModel->render(m_shader);
        }
    }

    void RendererPolygon3d::renderMissiles()
    {
        m_missileModel->bind(m_shader);

        for (const game::Player *player : m_state->players) {
            for (const game::Missile *missile : player->missiles) {
                glm::vec3 c = glm::vec3(1.0, 1.0, 0.3);
                glUniform3f(m_shader.location("color"), c.x, c.y, c.z);

                glm::mat4 model = computeModelMatrix(missile);
                glUniformMatrix4fv(m_shader.location("model"), 1, GL_FALSE, glm::value_ptr(model));

                m_missileModel->render(m_shader);
            }
        }
    }

    void RendererPolygon3d::renderShips()
    {
        m_shipModel->bind(m_shader);

        for (const game::Ship *ship : m_state->ships) {
            glm::mat4 model = computeModelMatrix(ship);
            glUniformMatrix4fv(m_shader.location("model"), 1, GL_FALSE, glm::value_ptr(model));

            glm::vec3 c = glm::vec3(0.1, 1.0, 0.2);
            glUniform3f(m_shader.location("color"), c.x, c.y, c.z);

            m_shipModel->render(m_shader);
        }
    }

    void RendererPolygon3d::addModel(const std::string &filename, PolygonModel **dest)
    {
        //std::cout<<"adding a model: " << filename << std::endl;

        *dest = new PolygonModel(filename);
        if (!(*dest)->import()) {
            std::cout<<"error: failed to load needed model!!!" << std::endl << std::endl;
            exit(-1);
        }

        (*dest)->uploadToOpenGl();

        m_models.push_back(*dest);
    }

    glm::mat4 RendererPolygon3d::computeModelMatrix(const game::Planet *planet)
    {
        return computeModelMatrix(planet->position, planet->radius);
    }

    glm::mat4 RendererPolygon3d::computeModelMatrix(const game::Missile *missile)
    {
        glm::vec2 vn = glm::normalize(missile->velocity);
        float a = std::atan2(vn.y, vn.x);

        // TODO: which visual size has the rocket? in game its just a point with
        // no size because all others have size.
        return computeModelMatrix(missile->position, 0.03f, a);
    }

    glm::mat4 RendererPolygon3d::computeModelMatrix(const game::Ship *ship)
    {
        // TODO: rotate them before shooting, that looks better
        glm::mat4 mat = computeModelMatrix(ship->position, m_state->shipRadius());
        // XXX model is flipped
        //glm::mat4 mat = computeModelMatrix(ship->position, 0.3);
        mat = glm::rotate(mat, (float) M_PI, glm::vec3(0.0f, 1.0f, 0.0f));
        return mat;
    }

    glm::mat4 RendererPolygon3d::computeModelMatrix(const glm::vec2 &pos, float scale, float angle)
    {
        // init as identity matrix
        glm::mat4 model;

        model = glm::translate(model, glm::vec3(pos, 0.0));

        if (scale != 1.0) {
            model = glm::scale(model, glm::vec3(scale));
        }

        if (angle != 0.0) {
            model = glm::rotate(model, angle, glm::vec3(0.0f, 0.0f, 1.0f));
        }

        return model;
    }
}