use winit::{
    event::*,
    event_loop::{ControlFlow, EventLoop},
    window::WindowBuilder,
};

mod camera;
mod commands;
mod handle;
mod mesh;
mod model;
mod pool;
mod procgen;
mod renderer;
mod scene;
mod shader;
mod texture;

use camera::*;
use model::*;
use renderer::Renderer;
use scene::*;
use texture::*;

trait WorldState {
    fn update(&mut self);
    fn render(&self) -> Vec<MeshInstance>;
}

struct Grid {
    meshes: Vec<MeshInstance>,
}

impl Grid {
    fn new(ren: &mut Renderer) -> Self {
        let model = GltfModel::load(ren);
        let mut meshes = Vec::new();
        for x in -5..5 {
            for y in -5..5 {
                let translation = glam::Vec3::new(x as f32, 0.0, y as f32) * 3.0;
                let transform = glam::Mat4::from_translation(translation);
                model.draw(&mut meshes, transform);
            }
        }

        Self { meshes }
    }
}

impl WorldState for Grid {
    fn update(&mut self) {}

    fn render(&self) -> Vec<MeshInstance> {
        self.meshes.clone()
    }
}

struct Metaballs {
    mesh: MeshInstance,
}

impl Metaballs {
    fn new(mut ren: &mut Renderer) -> Self {
        use procgen::marching_cubes::*;

        let metaballs = vec![
            glam::Vec3A::new(-5., -5., 2.),
            glam::Vec3A::new(8., 0.0, -1.),
            glam::Vec3A::new(1., 5., -3.),
        ];

        let field = |x: i32, y: i32, z: i32| {
            let c = glam::Vec3A::new(x as f32, y as f32, z as f32);
            let mut sum = 0.0;
            for ball in metaballs.iter() {
                sum += 1.0 / ball.distance(c);
            }

            sum - 0.4
        };

        let r = 20;
        let domain = MarchDomain {
            min: Vec3::new(-r, -r, -r),
            max: Vec3::new(r, r, r),
        };

        let vertices = marching_cubes(field, &domain);
        let vertices: Vec<mesh::Vertex> = vertices
            .iter()
            .map(|v| mesh::Vertex {
                position: v.position.into(),
                normal: v.normal.into(),
                tex_coords: [0.0; 2],
            })
            .collect();

        let indices = (0..(vertices.len() as u32)).collect();

        let mesh_data = mesh::MeshData {
            vertices, indices
        };

        let zeroed_data = pool::TextureData {
            width: 8,
            height: 8,
            data: vec![0x00; 256],
        };

        let albedo_raw = include_bytes!("assets/brick_moss_001_diff_1k.jpg");
        let albedo_data = load_texture_data(albedo_raw);

        let metalrough_raw = include_bytes!("assets/brick_moss_001_metalrough_1k.jpg");
        let metalrough_data = load_texture_data(metalrough_raw);

        let mesh = ren.load_mesh(&mesh_data);
        let albedo = ren.load_texture(&albedo_data);
        let metalrough = ren.load_texture(&metalrough_data);
        let material = ren.load_material(&pool::MaterialData { albedo, metallic_roughness: metalrough });

        let mesh = scene::MeshInstance {
            mesh, material, transform: glam::Mat4::IDENTITY,
        };

        Self { mesh }
    }
}

impl WorldState for Metaballs {
    fn update(&mut self) {}

    fn render(&self) -> Vec<MeshInstance> {
        vec![self.mesh]
    }
}

struct Planet {
    speed: f32,
    offset: f32,
    radius: f32,
    size: f32,
}

struct Planets {
    start: std::time::Instant,
    planets: Vec<Planet>,
    model: GltfModel,
}

impl Planets {
    fn new(ren: &mut Renderer) -> Self {
        let start = std::time::Instant::now();
        let model = GltfModel::load(ren);

        let mut planets = Vec::new();
        for i in 0..10 {
            let i = i as f32;
            planets.push(Planet {
                speed: 1.618 * 1.5 / i,
                offset: 0.0,
                radius: i * 2.0,
                size: 0.5,
            });
        }

        Self {
            start,
            planets,
            model,
        }
    }
}

impl WorldState for Planets {
    fn update(&mut self) {}

    fn render(&self) -> Vec<MeshInstance> {
        let elapsed = self.start.elapsed().as_secs_f32();

        let mut meshes = Vec::new();
        for planet in self.planets.iter() {
            let translation = glam::Vec3::new(0.0, 0.0, planet.radius);
            let translation = glam::Mat4::from_translation(translation);
            let theta = planet.speed * elapsed + planet.offset;
            let rotation = glam::Mat4::from_rotation_y(theta);
            self.model.draw(&mut meshes, rotation * translation);
        }

        meshes
    }
}

async fn make_window_renderer(window: &winit::window::Window) -> Renderer {
    let size = window.inner_size();

    let instance = wgpu::Instance::new(wgpu::Backends::all());
    let surface = unsafe { instance.create_surface(window) };
    let adapter = instance
        .request_adapter(&wgpu::RequestAdapterOptions {
            power_preference: wgpu::PowerPreference::LowPower,
            compatible_surface: Some(&surface),
            force_fallback_adapter: false,
        })
        .await
        .unwrap();

    let (device, queue) = adapter
        .request_device(
            &wgpu::DeviceDescriptor {
                features: wgpu::Features::empty(),
                limits: wgpu::Limits::default(),
                label: None,
            },
            None,
        )
        .await
        .unwrap();

    let config = wgpu::SurfaceConfiguration {
        usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
        format: surface.get_preferred_format(&adapter).unwrap(),
        width: size.width,
        height: size.height,
        present_mode: wgpu::PresentMode::Fifo,
    };
    surface.configure(&device, &config);

    Renderer::new(size, surface, device, queue, config)
}

fn main() {
    let event_loop = EventLoop::new();
    let window = WindowBuilder::new().build(&event_loop).unwrap();
    let mut camera = Flycam::new(10.0, 0.002);
    let mut is_grabbed = false;
    let mut ren = pollster::block_on(make_window_renderer(&window));
    // let mut state: Box<dyn WorldState> = Box::new(Planets::new(&mut ren));
    // let mut state: Box<dyn WorldState> = Box::new(Grid::new(&mut ren));
    let mut state: Box<dyn WorldState> = Box::new(Metaballs::new(&mut ren));

    let lights = vec![
        PointLight {
            center: glam::Vec3A::new(0.0, 5.0, 0.0),
            intensity: glam::Vec3A::new(100.0, 100.0, 100.0),
        },
        PointLight {
            center: glam::Vec3A::new(-7.0, 5.0, 7.0),
            intensity: glam::Vec3A::new(100.0, 0.0, 0.0),
        },
        PointLight {
            center: glam::Vec3A::new(7.0, 5.0, 7.0),
            intensity: glam::Vec3A::new(0.0, 100.0, 0.0),
        },
        PointLight {
            center: glam::Vec3A::new(0.0, 5.0, -7.0),
            intensity: glam::Vec3A::new(0.0, 0.0, 100.0),
        },
        PointLight {
            center: glam::Vec3A::new(0.0, 50.0, 0.0),
            intensity: glam::Vec3A::new(1000.0, 1000.0, 1000.0),
        },
    ];

    event_loop.run(move |event, _, control_flow| match event {
        Event::RedrawRequested(_) => {
            let scene = Scene {
                meshes: &state.render(),
                point_lights: &lights,
            };
            match ren.render(&camera, &scene) {
                Ok(_) => {}
                Err(wgpu::SurfaceError::Lost) => ren.resize(ren.size),
                Err(wgpu::SurfaceError::OutOfMemory) => *control_flow = ControlFlow::Exit,
                Err(wgpu::SurfaceError::Timeout) => {}
                Err(e) => println!("error: {:?}", e),
            };
        }
        Event::MainEventsCleared => {
            camera.update();
            state.update();
            window.request_redraw();
        }
        Event::DeviceEvent { ref event, .. } => match event {
            DeviceEvent::MouseMotion { delta } => {
                if is_grabbed {
                    camera.process_mouse(delta.0, delta.1);
                }
            }
            _ => {}
        },
        Event::WindowEvent {
            ref event,
            window_id,
        } if window_id == window.id() => match event {
            WindowEvent::KeyboardInput {
                input:
                    KeyboardInput {
                        virtual_keycode: Some(key),
                        state,
                        ..
                    },
                ..
            } => {
                if *state == ElementState::Pressed && *key == VirtualKeyCode::Escape {
                    if is_grabbed {
                        window.set_cursor_grab(false).unwrap();
                        window.set_cursor_visible(true);
                        is_grabbed = false;
                    }
                } else {
                    camera.process_keyboard(*key, *state);
                }
            }
            WindowEvent::MouseInput {
                button: MouseButton::Left,
                state: ElementState::Pressed,
                ..
            } => {
                if !is_grabbed {
                    window.set_cursor_grab(true).unwrap();
                    window.set_cursor_visible(false);
                    is_grabbed = true;
                }
            }
            WindowEvent::CloseRequested => *control_flow = ControlFlow::Exit,
            WindowEvent::Resized(physical_size) => {
                ren.resize(*physical_size);
                camera.resize(physical_size.width, physical_size.height);
            }
            WindowEvent::ScaleFactorChanged { new_inner_size, .. } => {
                ren.resize(**new_inner_size);
                camera.resize(new_inner_size.width, new_inner_size.height);
            }
            _ => {}
        },
        _ => {}
    });
}