use boll::*;
use common::{Point, Dimension};
use core::controller::ControllerManager;
use core::render::Renderer;
use point; // defined in common, but loaded from main...
use rand::Rng;
use sdl2::event::{Event, WindowEvent};
use sdl2::keyboard::Keycode;
use sdl2::rect::Rect as SDLRect;
use sdl2::video::SwapInterval;
use sdl2::{EventPump, VideoSubsystem};
use sprites::SpriteManager;
use std::f32::consts::PI;
use time::{Duration, Instant, prelude::*};

const FPS: u32 = 60;
const NS_PER_FRAME: u32 = 1_000_000_000 / FPS;

#[derive(Default)]
pub struct AppBuilder {
    resolution: Dimension<u16>,
    state: Option<Box<dyn AppState>>,
    title: Option<String>,
}

impl AppBuilder {
    pub fn with_resolution(mut self, width: u16, height: u16) -> Self {
        self.resolution = Dimension { width, height };
        self
    }

    pub fn with_state(mut self, state: Box<dyn AppState>) -> Self {
        self.state = Some(state);
        self
    }

    pub fn with_title(mut self, title: &str) -> Self {
        self.title = Some(title.to_string());
        self
    }

    pub fn build(self) -> Result<App, String> {
        let context = sdl2::init().unwrap();
        sdl2::image::init(sdl2::image::InitFlag::PNG)?;
        let video = context.video()?;
        //self.print_video_display_modes(&video);

        let window = video
            .window(
                &self.title.unwrap(),
                self.resolution.width.into(),
                self.resolution.height.into(),
            )
            .position_centered()
            // .fullscreen()
            // .fullscreen_desktop()
            .opengl()
            .build()
            .unwrap();
        context.mouse().show_cursor(false);

        let canvas = window.into_canvas().build().unwrap();
        let sprites = SpriteManager::new(canvas.texture_creator());
	let screen = canvas.output_size().unwrap();
	let renderer = Renderer::new(canvas);

        video.gl_set_swap_interval(SwapInterval::VSync)?;

        let event_pump = context.event_pump()?;

        Ok(App {
            renderer,
            event_pump,
            sprites,
            states: vec!(self.state.unwrap_or_else(|| Box::new(ActiveState::new(screen)))),
	    ctrl_man: ControllerManager::new(context.joystick()?, context.haptic()?),
        })
    }

    #[allow(dead_code)]
    fn print_video_display_modes(&self, video: &VideoSubsystem) {
        println!("video subsystem: {:?}", video);
        println!("current_video_driver: {:?}", video.current_video_driver());
        for display in 0..video.num_video_displays().unwrap() {
            println!(
                "=== display {} - {} ===",
                display,
                video.display_name(display).unwrap()
            );
            println!(
                " display_bounds: {:?}",
                video.display_bounds(display).unwrap()
            );
            println!(
                " num_display_modes: {:?}",
                video.num_display_modes(display).unwrap()
            );
            println!(
                " desktop_display_mode: {:?}",
                video.desktop_display_mode(display).unwrap()
            );
	    let current = video.current_display_mode(display).unwrap();
            println!(
                " current_display_mode: {:?}",
                current
            );
            for idx in 0..video.num_display_modes(display).unwrap() {
		let mode = video.display_mode(display, idx).unwrap();
                println!(
                    " {}{:2}: {:?}",
		    if mode == current { "*" } else { " " },
                    idx,
                    mode
                );
            }
        }
        println!("swap interval: {:?}", video.gl_get_swap_interval());
    }
}

pub struct App {
    renderer: Renderer,
    event_pump: EventPump,
    sprites: SpriteManager,
    states: Vec<Box<dyn AppState>>,
    pub ctrl_man: ControllerManager,
}

impl App {
    #[allow(clippy::new_ret_no_self)]
    pub fn new() -> AppBuilder {
        Default::default()
    }

    pub fn load_sprites(&mut self, sprites: &[(&str, &str)]) {
        for (name, file) in sprites {
            self.sprites.load(name, file);
        }
    }

    pub fn start(&mut self) {
        let mut last_time = Instant::now();

	self.states[0].enter(&self.ctrl_man);

        loop {
	    if let Some(change) = self.handle_events() {
		self.handle_state_change(change);
	    }

            let duration = Instant::now() - last_time;
	    last_time = Instant::now();

	    self.ctrl_man.update(duration);

	    if let Some(state) = self.states.last_mut() {
		if let Some(change) = state.update(duration) {
		    self.handle_state_change(change);
		}
	    } else {
		break;
	    }

	    self.render();
        }
    }

    fn handle_state_change(&mut self, change: StateChange) {
	match change {
	    StateChange::Push(mut state) => {
		// if let Some(s) = self.states.last_mut() {
		//     s.pause();
		// }
		state.enter(&mut self.ctrl_man);
		self.states.push(state);
	    }
	    StateChange::Pop => {
		if let Some(mut s) = self.states.pop() {
		    s.leave();
		}
	    }
	    StateChange::Exit => {
		while let Some(mut s) = self.states.pop() {
		    s.leave();
		}
	    }
	}
    }

    fn handle_events(&mut self) -> Option<StateChange> {
        for event in self.event_pump.poll_iter() {
	    self.ctrl_man.handle_event(&event);
            match event {
                Event::Quit { .. }
                | Event::KeyDown {
                    keycode: Some(Keycode::Escape),
                    ..
                } => {
		    return Some(StateChange::Pop)
                }
                Event::KeyDown {
                    keycode: Some(Keycode::F11),
                    ..
                } => {
		    self.renderer.toggle_fullscreen();
                }
                Event::Window {
                    win_event: WindowEvent::Resized(x, y),
                    ..
                } => {
                    println!("window resized({}, {})", x, y)
                }
                Event::Window {
                    win_event: WindowEvent::Maximized,
                    ..
                } => {
                    println!("window maximized")
                }
                Event::Window {
                    win_event: WindowEvent::Restored,
                    ..
                } => {
                    println!("window restored")
                }
                Event::Window {
                    win_event: WindowEvent::Enter,
                    ..
                } => {
                    println!("window enter")
                }
                Event::Window {
                    win_event: WindowEvent::Leave,
                    ..
                } => {
                    println!("window leave")
                }
                Event::Window {
                    win_event: WindowEvent::FocusGained,
                    ..
                } => {
                    println!("window focus gained")
                }
                Event::Window {
                    win_event: WindowEvent::FocusLost,
                    ..
                } => {
                    println!("window focus lost")
                }
                _ => {
		    if let Some(state) = self.states.last_mut() {
			if let Some(change) = state.handle_event(event) {
			    return Some(change);
			}
		    } else {
			return Some(StateChange::Exit)
		    }
		},
            }
        }
	None
    }

    fn render(&mut self) {
	self.renderer.clear();
        self.states.last_mut().unwrap().render(&mut self.renderer, &mut self.sprites);
        self.renderer.present();
    }
}

pub enum StateChange {
    Push(Box<dyn AppState>),
    Pop,
    Exit,
}

pub trait AppState {
    fn enter(&mut self, ctrl_man: &ControllerManager);
    fn leave(&mut self);
    fn update(&mut self, dt: Duration) -> Option<StateChange>;
    fn render(&mut self, renderer: &mut Renderer, sprites: &SpriteManager);
    fn handle_event(&mut self, event: Event) -> Option<StateChange>;
}

type Bollar = Vec<Box<dyn Boll>>;

#[derive(Default)]
pub struct ActiveState {
    screen: Dimension<u32>,
    bolls: Bollar,
    boll_size: u32,
    mario_angle: f64,
}

impl ActiveState {
    pub fn new(screen: (u32, u32)) -> ActiveState {
        ActiveState {
            bolls: Bollar::new(),
            boll_size: 1,
	    screen: Dimension::from(screen),
	    ..Default::default()
        }
    }

    fn change_boll_count(&mut self, delta: i32) {
        #[allow(clippy::comparison_chain)]
        if delta > 0 {
            for _i in 0..delta {
                self.add_boll();
            }
        } else if delta < 0 {
            for _i in 0..(-delta) {
                self.bolls.pop();
            }
        }
    }

    fn add_boll(&mut self) {
        let mut rng = rand::thread_rng();
        self.bolls.push(Box::new(SquareBoll {
            pos: point!(
                rng.gen_range(0, self.screen.width) as f64,
                rng.gen_range(0, self.screen.height) as f64
            ),
            vel: point!(rng.gen_range(-2.0, 2.0), rng.gen_range(-2.0, 2.0)),
        }));
    }
}

impl AppState for ActiveState {
    fn enter(&mut self, _ctrl_man: &ControllerManager) {}

    fn update(&mut self, dt: Duration) -> Option<StateChange> {
        for b in &mut self.bolls {
            b.update();
        }

        match dt {
            ns if ns < (NS_PER_FRAME - 90_0000).nanoseconds() => self.change_boll_count(100),
            ns if ns > (NS_PER_FRAME + 90_0000).nanoseconds() => self.change_boll_count(-100),
            _ => {}
        }

	None
    }

    fn render(&mut self, renderer: &mut Renderer, sprites: &SpriteManager) {
        /* draw square of blocks */ {
            let blocks = 20;
            let size = 32;
            let offset = point!(
                (self.screen.width as i32 - (blocks + 1) * size) / 2,
                (self.screen.height as i32 - (blocks + 1) * size) / 2
            );
            let block = sprites.get("block");
            for i in 0..blocks {
                renderer
                    .blit(
                        block,
                        None,
                        SDLRect::new((i) * size + offset.x, offset.y, size as u32, size as u32),
                    );
                renderer
                    .blit(
                        block,
                        None,
                        SDLRect::new(
                            (blocks - i) * size + offset.x,
                            (blocks) * size + offset.y,
                            size as u32,
                            size as u32,
                        ),
                    );
                renderer
                    .blit(
                        block,
                        None,
                        SDLRect::new(
                            offset.x,
                            (blocks - i) * size + offset.y,
                            size as u32,
                            size as u32,
                        ),
                    );
                renderer
                    .blit(
                        block,
                        None,
                        SDLRect::new(
                            (blocks) * size + offset.x,
                            (i) * size + offset.y,
                            size as u32,
                            size as u32,
                        ),
                    );
            }
        }

        /* draw mario */ {
            let size = 64;
            let offset = point!(
                (self.screen.width as i32 - size) / 2,
                (self.screen.height as i32 - size) / 2
            );
            let radius = 110.0 + size as f32 * 0.5;
            let angle = (self.mario_angle as f32 - 90.0) * PI / 180.0;
            let offset2 = point!((angle.cos() * radius) as i32, (angle.sin() * radius) as i32);
            renderer
                .blit_ex(
                    sprites.get("mario"),
                    None,
                    SDLRect::new(
                        offset.x + offset2.x,
                        offset.y + offset2.y,
                        size as u32,
                        size as u32,
                    ),
                    self.mario_angle,
                    sdl2::rect::Point::new(size / 2, size / 2),
                    false,
                    false,
                );
	    self.mario_angle = (self.mario_angle + 1.0) % 360.0;
        }

        /* draw circles and ellipses*/ {
            let p = point!((self.screen.width / 2) as i16, (self.screen.height / 2) as i16);
            renderer.circle(p, 100, (255, 255, 255));
            renderer.circle(p, 110, (255, 255, 255));
            renderer.ellipse(p, (50, 100), (255, 255, 255));
            renderer.ellipse(p, (110, 55), (255, 255, 255));
        }

        for b in &self.bolls {
            b.draw(renderer, self.boll_size);
        }
    }

    fn leave(&mut self) {
        println!("number of bolls: {}", self.bolls.len());
    }

    fn handle_event(&mut self, event: Event) -> Option<StateChange> {
        match event {
            Event::KeyDown {
                keycode: Some(Keycode::KpPlus),
                ..
            } => self.boll_size = std::cmp::min(self.boll_size + 1, 32),
            Event::KeyDown {
                keycode: Some(Keycode::KpMinus),
                ..
            } => self.boll_size = std::cmp::max(self.boll_size - 1, 1),
            Event::MouseMotion { x, y, .. } => self.bolls.push(Box::new(CircleBoll::new(
                point!(x as f64, y as f64),
                point!(0.0, 0.0),
            ))),
            _ => {}
        }
	None
    }
}