#![allow(non_upper_case_globals)]
#![allow(non_snake_case)]

extern crate glfw;

use self::glfw::Context;

extern crate gl;

use self::gl::types::*;

use std::ptr;
use std::mem;
use std::os::raw::c_void;
use std::ffi::CStr;

use common::{process_events, processInput, loadTexture};
use shader::Shader;
use camera::Camera;

use cgmath::{Matrix4, vec3, Deg, perspective, Point3};
use cgmath::prelude::*;

// settings
const SCR_WIDTH: u32 = 1280;
const SCR_HEIGHT: u32 = 720;

pub fn main_4_1_1() {
    let mut camera = Camera {
        Position: Point3::new(0.0, 0.0, 3.0),
        ..Camera::default()
    };

    let mut firstMouse = true;
    let mut lastX: f32 = SCR_WIDTH as f32 / 2.0;
    let mut lastY: f32 = SCR_HEIGHT as f32 / 2.0;

    // timing
    let mut deltaTime: f32; // time between current frame and last frame
    let mut lastFrame: f32 = 0.0;

    // glfw: initialize and configure
    // ------------------------------
    let mut glfw = glfw::init(glfw::FAIL_ON_ERRORS).unwrap();
    glfw.window_hint(glfw::WindowHint::ContextVersion(3, 3));
    glfw.window_hint(glfw::WindowHint::OpenGlProfile(glfw::OpenGlProfileHint::Core));
    #[cfg(target_os = "macos")]
        glfw.window_hint(glfw::WindowHint::OpenGlForwardCompat(true));

    // glfw window creation
    // --------------------
    let (mut window, events) = glfw.create_window(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", glfw::WindowMode::Windowed)
        .expect("Failed to create GLFW window");

    window.make_current();
    window.set_framebuffer_size_polling(true);
    window.set_cursor_pos_polling(true);
    window.set_scroll_polling(true);

    // tell GLFW to capture our mouse
    window.set_cursor_mode(glfw::CursorMode::Disabled);

    // gl: load all OpenGL function pointers
    // ---------------------------------------
    gl::load_with(|symbol| window.get_proc_address(symbol) as *const _);

    let (shader, cubeVBO, cubeVAO, planeVBO, planeVAO, cubeTexture, floorTexture) = unsafe {
        // configure global opengl state
        // -----------------------------
        gl::Enable(gl::DEPTH_TEST);
        gl::DepthFunc(gl::ALWAYS); // always pass the depth test (same effect as glDisable(GL_DEPTH_TEST))

        // build and compile our shader program
        // ------------------------------------
        let shader = Shader::new(
            "src/_4_advanced_opengl/shaders/1.1.depth_testing.vs",
            "src/_4_advanced_opengl/shaders/1.1.depth_testing.fs");

        // set up vertex data (and buffer(s)) and configure vertex attributes
        // ------------------------------------------------------------------
        let cubeVertices: [f32; 180] = [
            // positions       // texture Coords
            -0.5, -0.5, -0.5, 0.0, 0.0,
            0.5, -0.5, -0.5, 1.0, 0.0,
            0.5, 0.5, -0.5, 1.0, 1.0,
            0.5, 0.5, -0.5, 1.0, 1.0,
            -0.5, 0.5, -0.5, 0.0, 1.0,
            -0.5, -0.5, -0.5, 0.0, 0.0,
            -0.5, -0.5, 0.5, 0.0, 0.0,
            0.5, -0.5, 0.5, 1.0, 0.0,
            0.5, 0.5, 0.5, 1.0, 1.0,
            0.5, 0.5, 0.5, 1.0, 1.0,
            -0.5, 0.5, 0.5, 0.0, 1.0,
            -0.5, -0.5, 0.5, 0.0, 0.0,
            -0.5, 0.5, 0.5, 1.0, 0.0,
            -0.5, 0.5, -0.5, 1.0, 1.0,
            -0.5, -0.5, -0.5, 0.0, 1.0,
            -0.5, -0.5, -0.5, 0.0, 1.0,
            -0.5, -0.5, 0.5, 0.0, 0.0,
            -0.5, 0.5, 0.5, 1.0, 0.0,
            0.5, 0.5, 0.5, 1.0, 0.0,
            0.5, 0.5, -0.5, 1.0, 1.0,
            0.5, -0.5, -0.5, 0.0, 1.0,
            0.5, -0.5, -0.5, 0.0, 1.0,
            0.5, -0.5, 0.5, 0.0, 0.0,
            0.5, 0.5, 0.5, 1.0, 0.0,
            -0.5, -0.5, -0.5, 0.0, 1.0,
            0.5, -0.5, -0.5, 1.0, 1.0,
            0.5, -0.5, 0.5, 1.0, 0.0,
            0.5, -0.5, 0.5, 1.0, 0.0,
            -0.5, -0.5, 0.5, 0.0, 0.0,
            -0.5, -0.5, -0.5, 0.0, 1.0,
            -0.5, 0.5, -0.5, 0.0, 1.0,
            0.5, 0.5, -0.5, 1.0, 1.0,
            0.5, 0.5, 0.5, 1.0, 0.0,
            0.5, 0.5, 0.5, 1.0, 0.0,
            -0.5, 0.5, 0.5, 0.0, 0.0,
            -0.5, 0.5, -0.5, 0.0, 1.0
        ];
        let planeVertices: [f32; 30] = [
            // positions       // texture Coords (note we set these higher than 1 (together with GL_REPEAT as texture wrapping mode). this will cause the floor texture to repeat)
            5.0, -0.5, 5.0, 2.0, 0.0,
            -5.0, -0.5, 5.0, 0.0, 0.0,
            -5.0, -0.5, -5.0, 0.0, 2.0,
            5.0, -0.5, 5.0, 2.0, 0.0,
            -5.0, -0.5, -5.0, 0.0, 2.0,
            5.0, -0.5, -5.0, 2.0, 2.0
        ];
        // cube VAO
        let (mut cubeVAO, mut cubeVBO) = (0, 0);
        gl::GenVertexArrays(1, &mut cubeVAO);
        gl::GenBuffers(1, &mut cubeVBO);
        gl::BindVertexArray(cubeVAO);
        gl::BindBuffer(gl::ARRAY_BUFFER, cubeVBO);
        gl::BufferData(gl::ARRAY_BUFFER,
                       (cubeVertices.len() * mem::size_of::<GLfloat>()) as GLsizeiptr,
                       &cubeVertices[0] as *const f32 as *const c_void,
                       gl::STATIC_DRAW);
        let stride = 5 * mem::size_of::<GLfloat>() as GLsizei;
        gl::EnableVertexAttribArray(0);
        gl::VertexAttribPointer(0, 3, gl::FLOAT, gl::FALSE, stride, ptr::null());
        gl::EnableVertexAttribArray(1);
        gl::VertexAttribPointer(1, 2, gl::FLOAT, gl::FALSE, stride, (3 * mem::size_of::<GLfloat>()) as *const c_void);
        gl::BindVertexArray(0);
        // plane VAO
        let (mut planeVAO, mut planeVBO) = (0, 0);
        gl::GenVertexArrays(1, &mut planeVAO);
        gl::GenBuffers(1, &mut planeVBO);
        gl::BindVertexArray(planeVAO);
        gl::BindBuffer(gl::ARRAY_BUFFER, planeVBO);
        gl::BufferData(gl::ARRAY_BUFFER,
                       (planeVertices.len() * mem::size_of::<GLfloat>()) as GLsizeiptr,
                       &planeVertices[0] as *const f32 as *const c_void,
                       gl::STATIC_DRAW);
        gl::EnableVertexAttribArray(0);
        gl::VertexAttribPointer(0, 3, gl::FLOAT, gl::FALSE, stride, ptr::null());
        gl::EnableVertexAttribArray(1);
        gl::VertexAttribPointer(1, 2, gl::FLOAT, gl::FALSE, stride, (3 * mem::size_of::<GLfloat>()) as *const c_void);
        gl::BindVertexArray(0);

        // load textures
        // -------------
        let cubeTexture = loadTexture("resources/textures/marble.jpg");
        let floorTexture = loadTexture("resources/textures/metal.png");

        // shader configuration
        // --------------------
        shader.useProgram();
        shader.setInt(c_str!("texture1"), 0);

        (shader, cubeVBO, cubeVAO, planeVBO, planeVAO, cubeTexture, floorTexture)
    };

    // render loop
    // -----------
    while !window.should_close() {
        // per-frame time logic
        // --------------------
        let currentFrame = glfw.get_time() as f32;
        deltaTime = currentFrame - lastFrame;
        lastFrame = currentFrame;

        // events
        // -----
        process_events(&events, &mut firstMouse, &mut lastX, &mut lastY, &mut camera);

        // input
        // -----
        processInput(&mut window, deltaTime, &mut camera);

        // render
        // ------
        unsafe {
            gl::ClearColor(0.1, 0.1, 0.1, 1.0);
            gl::Clear(gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT);

            shader.useProgram();
            let mut model: Matrix4<f32>;
            let view = camera.GetViewMatrix();
            let projection: Matrix4<f32> = perspective(Deg(camera.Zoom), SCR_WIDTH as f32 / SCR_HEIGHT as f32, 0.1, 100.0);
            shader.setMat4(c_str!("view"), &view);
            shader.setMat4(c_str!("projection"), &projection);
            // cubes
            gl::BindVertexArray(cubeVAO);
            gl::ActiveTexture(gl::TEXTURE0);
            gl::BindTexture(gl::TEXTURE_2D, cubeTexture);
            model = Matrix4::from_translation(vec3(-1.0, 0.0, -1.0));
            shader.setMat4(c_str!("model"), &model);
            gl::DrawArrays(gl::TRIANGLES, 0, 36);
            model = Matrix4::from_translation(vec3(2.0, 0.0, 0.0));
            shader.setMat4(c_str!("model"), &model);
            gl::DrawArrays(gl::TRIANGLES, 0, 36);
            // floor
            gl::BindVertexArray(planeVAO);
            gl::BindTexture(gl::TEXTURE_2D, floorTexture);
            shader.setMat4(c_str!("model"), &Matrix4::identity());
            gl::DrawArrays(gl::TRIANGLES, 0, 6);
            gl::BindVertexArray(0);
        }

        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
        // -------------------------------------------------------------------------------
        window.swap_buffers();
        glfw.poll_events();
    }

    // optional: de-allocate all resources once they've outlived their purpose:
    // ------------------------------------------------------------------------
    unsafe {
        gl::DeleteVertexArrays(1, &cubeVAO);
        gl::DeleteVertexArrays(1, &planeVAO);
        gl::DeleteBuffers(1, &cubeVBO);
        gl::DeleteBuffers(1, &planeVBO);
    }
}
