#include "GL/glew.h"
#include "GLFW/glfw3.h"

#include "pwyazh.h"

#include "pwyazh_GL.h"

#include "common.h"

#include <unistd.h>

static S32 global_width = 1024, global_height = 768;
static Input global_input;

void
key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    switch (action)
    {
        case GLFW_PRESS: {
            switch (key)
            {
                case GLFW_KEY_D: {
                    global_input.move_right.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_W: {
                    global_input.move_forward.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_A: {
                    global_input.move_left.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_S: {
                    global_input.move_backward.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_E: {
                    global_input.move_up.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_Q: {
                    global_input.move_down.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_SPACE: {
                    global_input.jump.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_RIGHT: {
                    global_input.action_right.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_LEFT: {
                    global_input.action_left.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_ESCAPE: {
                    global_input.exit.state = KeyState_PRESS;
                } break;
            }
        } break;
        
        case GLFW_RELEASE: {
            switch (key)
            {
                case GLFW_KEY_D: {
                    global_input.move_right.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_W: {
                    global_input.move_forward.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_A: {
                    global_input.move_left.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_S: {
                    global_input.move_backward.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_E: {
                    global_input.move_up.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_Q: {
                    global_input.move_down.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_SPACE: {
                    global_input.jump.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_RIGHT: {
                    global_input.action_right.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_LEFT: {
                    global_input.action_left.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_ESCAPE: {
                    global_input.exit.state = KeyState_RELEASE;
                } break;
            }
        } break;
    }
}

void
window_resize_callback(GLFWwindow* window, int width, int height)
{
    global_width = width;
    global_height = height;
    glViewport(0, 0, global_width, global_height);
}

int
main(void)
{
    GLFWwindow *window;
    Arena *arena = 0;
    F32 target_fps, target_spf,
    last_time, dt;
    MAT4 projection, view, model;
    V3F camera_pos;
    F32 camera_speed, fovx, near, far;
    U32 color_shader;
    
    if (glfwInit() == GLFW_FALSE)
    {
        fprintf(stderr, "[ERROR] Failed to initialize glfw.\n");
        return(1);
    }
    
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_SAMPLES, 4);
    window = glfwCreateWindow(global_width, global_height, "Anti Aliasing (MSAA)", 0, 0);
    if (!window)
    {
        fprintf(stderr, "[ERROR] Failed to create window.\n");
        glfwTerminate();
        return(1);
    }
    
    glfwMakeContextCurrent(window);
    
    glfwSetKeyCallback(window, key_callback);
    glfwSetWindowSizeCallback(window, window_resize_callback);
    
    if (glewInit() != GLEW_OK)
    {
        fprintf(stderr, "[ERROR] Failed to initialize glew.\n");
        glfwTerminate();
        return(1);
    }
    
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_MULTISAMPLE);
    
    arena = arena_alloc(Megabytes(64));
    
    Mesh *cube_mesh = mesh_load_obj(arena, "../../data/models/cube.obj");
    color_shader = create_shader_program("shaders/color.vs",
                                         "shaders/color.fs");
    
    target_fps = 60.0f;
    target_spf = 1.0f/target_fps;
    
    camera_pos = v3f(0.0f, 0.0f, 3.0f);
    camera_speed = 2.0f;
    fovx = 90.0f;
    near = 0.1f;
    far = 1000.0f;
    
    last_time = glfwGetTime();
    
    while (!glfwWindowShouldClose(window))
    {
        glfwPollEvents();
        
        /* NOTE(pryazha): Update */
        if (key_is_pressed(global_input.exit))
            glfwSetWindowShouldClose(window, GLFW_TRUE);
        
        V3F camera_dv = get_dv_camera_orbital(&global_input, camera_pos,
                                              v3f_zero(), dt, camera_speed);
        camera_pos = v3f_add(camera_pos, camera_dv);
        
        projection = perspective(fovx, (F32)global_width/(F32)global_height, near, far);
        view = look_at(camera_pos, v3f_zero(), v3f(0.0f, 1.0f, 0.0f));
        model = mat4_identity();
        
        input_update_last_state(&global_input);
        
        /* NOTE(pryazha): Render */
        glClearColor(0.15f, 0.15f, 0.15f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glUseProgram(color_shader);
        shader_set_mat4fv(color_shader, "projection", projection);
        shader_set_mat4fv(color_shader, "view", view);
        shader_set_mat4fv(color_shader, "model", model);
        mesh_draw(cube_mesh);
        
        glfwSwapBuffers(window);
        
        F32 elapsed = glfwGetTime()-last_time;
        if (elapsed < target_spf)
        {
            U32 sleep_time = (U32)(target_spf-elapsed);
            if (sleep_time > 0)
                sleep(sleep_time);
        }
        F32 current_time = glfwGetTime();
        dt = current_time-last_time;
        last_time = current_time;
    }
    
    arena_release(arena);
    glfwTerminate();
    return(0);
}