#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>
#include <glm/gtc/random.hpp>

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

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

        m_shader.init();

#if 0
        std::string vss_simple = "../data/shader/simple.vert";
        std::string fss_simple = "../data/shader/simple.frag";
        m_shader.loadFile(vss_simple, GL_VERTEX_SHADER);
        m_shader.loadFile(fss_simple, GL_FRAGMENT_SHADER);
#else
        std::string vss_game_objects = "../data/shader/gameobjects.vert";
        std::string fss_game_objects = "../data/shader/gameobjects.frag";
        m_shader.loadFile(vss_game_objects, GL_VERTEX_SHADER);
        m_shader.loadFile(fss_game_objects, GL_FRAGMENT_SHADER);
#endif

        addModel("../data/mesh/small_atomic_bomb.stl", &m_missileModel);
        addModel("../data/mesh/planet_12.stl",         &m_planetModel);
        addModel("../data/mesh/ship_ufo.stl",          &m_shipModel);
    }

    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;
        }

        m_state = state;
        advanceGraphicObjects(dt);

        // TODO: add stars (texture)
        // TODO: add dust particles
        // TODO: add little rocks flying around

        //glClearColor(0.0, 0.0, 0.0, 1.0);
        float s = 0.1;
        glClearColor(s, s, s, 1.0);

        m_shader.bind();

        // TODO: add ONE sun planet
        // TODO: add lights for explosions

        glm::vec3 c = glm::vec3(1.0, 1.0, 0.8);
        glUniform3f(m_shader.location("lightColor"), c.x, c.y, c.z);

		glm::vec3 p = glm::vec3(0.3f, 0.4f, 0.0f);
        glUniform3f(m_shader.location("lightPosition"), p.x, p.y, p.z);

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

        renderParticles();

        //renderTraces();

        //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(size_t id, const glm::vec2 &pos, size_t n, float duration)
    {
        //float particleRadius = 0.005;
        //float particleRadius = 0.003;
        float particleRadius = 0.007;

        // TODO: use this as shader input too and make the area 2x around this
        // so that it stays hot/yellow for 2/3 of the time
        float explCoreSize = 0.02f;
        float maxVelocity  = 0.4f;

        ParticleBatch *batch = new ParticleBatch(id, n, particleRadius, duration);
        batch->setCenter(glm::vec3(pos, 0.0));
        batch->setMaxVelocity(maxVelocity);

        for (size_t i=0; i<n; i++) {
            // distribute in a circle
            //float t = 2.0 * M_PI * i / (float) n;
            //t += 0.2*util::randf_m1_1();

            // with random velocities
            // this is 3d because it looks better if some particles leave/enter
            // the space and they are not all on one plane.
            // especially in 3d this would look bad without 3d velocity vector.
            //glm::vec3 v = 0.5f*glm::vec3(sin(t), cos(t), util::randf_m1_1());

            glm::vec3 v = glm::ballRand(maxVelocity);
            v *= util::randf_0_1() * util::randf_0_1() * util::randf_0_1();

            batch->setParticle(i, glm::vec3(pos, 0.0) + glm::ballRand(explCoreSize), v);
        }

        batch->upload();

        m_particles.push_back(batch);
    }

    void RendererPolygon3d::advanceGraphicObjects(float dt)
    {
        for (const game::Explosion *expl : m_state->explosions) {
            bool gotIt = false;
            for (ParticleBatch *batch : m_particles) {
                if (batch->id() == expl->id) {
                    gotIt = true;
                    break;
                }
            }

            if (!gotIt) {
                addExplosionEffect(expl->id, expl->position, 500, 0.5);
            }
        }

        //if (m_particles.size() == 0) {
        //    addExplosionEffect(0, glm::vec2(0.0, 0.0), 1000, 2.0);
        //}

        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();

        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("materialColor"), c.x, c.y, c.z);
            glUniform3f(m_shader.location("color"), c.x, c.y, c.z);

            m_planetModel->render();
        }
    }

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

        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("materialColor"), 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();
            }
        }
    }

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

        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("materialColor"), c.x, c.y, c.z);

            m_shipModel->render();
        }
    }

    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)->setup(&m_shader);
        (*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());
        glm::mat4 mat = computeModelMatrix(ship->position, 5.0*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;
    }

    void RendererPolygon3d::renderTraces()
    {
        // revert to default
        glUseProgram(0);

        // TODO dont use line mode. make that with own quads
        glPolygonMode(GL_FRONT, GL_LINE);
        for (const game::Trace *trace : m_state->traces) {
            float fade_out = 1.0;
            if (trace->missile == nullptr) {
                fade_out = 1.0 - (trace->age / trace->maxAge);
            }

            glColor3f(0.0, 0.5*fade_out, 0.5*fade_out);
            glBegin(GL_LINE_STRIP);
            for (const game::Trace::TracePoint &tp : trace->points) {
                glVertex2f(tp.position.x, tp.position.y);
            }
            glEnd();
        }
        glPolygonMode(GL_FRONT, GL_FILL);
    }
}