use AppState;
use common::Nanoseconds;
use common::Point2D;
use core::controller::Controller;
use core::controller::ControllerManager;
use point;
use sdl2::event::Event;
use sdl2::rect::Rect;
use sdl2::render::Canvas;
use sdl2::video::Window;
use sprites::SpriteManager;
use std::cell::RefCell;
use std::rc::Rc;

////////// GAMESTATE ///////////////////////////////////////////////////////////

#[derive(Default)]
pub struct GameState {
    world: World,
}

impl GameState {
    pub fn new() -> Self {
	GameState {
	    world: World::new(),
	}
    }
}

impl AppState for GameState {
    fn enter(&mut self, ctrl_man: &mut ControllerManager) {
	if let Some(ctrl) = ctrl_man.controllers.get(&0) {
	    self.world.add(Box::new(Character::new(ctrl.clone())));
	}
    }

    fn leave(&mut self) {}

    fn update(&mut self, dt: Nanoseconds) {
	self.world.update(dt);
    }

    fn render(&mut self, canvas: &mut Canvas<Window>, sprites: &mut SpriteManager) {
	self.world.render(canvas, sprites);
    }

    fn handle_event(&mut self, _event: Event) {}
}

////////// WORLD ///////////////////////////////////////////////////////////////

#[derive(Default)]
pub struct World {
    level: Level,
    objects: Objects,
}

impl World {
    pub fn new() -> Self {
	World {
	    level: Level {
		gravity: point!(0.0, 0.1),
		ground: 600.0,
	    },
	    ..Default::default()
	}
    }

    pub fn update(&mut self, dt: Nanoseconds) {
	let mut breeding_ground = vec!();

	for i in (0..self.objects.len()).rev() {
	    if self.objects[i].update(&mut breeding_ground, &self.level, dt) == Dead {
		self.objects.remove(i); // swap_remove is more efficient, but changes the order of the array
	    }
	}

	for o in breeding_ground {
	    self.add(o);
	}
    }

    pub fn render(&mut self, canvas: &mut Canvas<Window>, sprites: &mut SpriteManager) {
	self.level.render(canvas, sprites);
	for o in &mut self.objects {
	    o.render(canvas, sprites);
	}
    }

    pub fn add(&mut self, object: Box<dyn Object>) {
	self.objects.push(object);
    }
}

////////// LEVEL ///////////////////////////////////////////////////////////////

#[derive(Default)]
pub struct Level {
    gravity: Point2D<f64>,
    ground: f64,		// just to have something
}

impl Level {
    pub fn render(&mut self, canvas: &mut Canvas<Window>, _sprites: &mut SpriteManager) {
	let w = canvas.viewport().width() as i32;
	for i in 1..11 {
	    let y = (i * i - 1) as i32 + self.ground as i32;
	    canvas.set_draw_color((255 - i * 20, 255 - i * 20, 0));
	    canvas.draw_line((0, y), (w, y)).unwrap();
	}
    }
}

////////// OBJECT //////////////////////////////////////////////////////////////

type Objects = Vec<Box<dyn Object>>;

pub trait Object {
    fn update(&mut self, objects: &mut Objects, lvl: &Level, dt: Nanoseconds) -> ObjectState;
    fn render(&self, _canvas: &mut Canvas<Window>, _sprites: &mut SpriteManager) {}
}

#[derive(PartialEq)]
pub enum ObjectState { Alive, Dead }
use self::ObjectState::*;


pub trait Physical {}
pub trait Drawable {}

////////// CHARACTER ///////////////////////////////////////////////////////////

pub struct Character {
    ctrl: Rc<RefCell<Controller>>,
    pos: Point2D<f64>,
    vel: Point2D<f64>,
}

impl Character {
    pub fn new(ctrl: Rc<RefCell<Controller>>) -> Self {
	Character {
	    ctrl,
	    pos: point!(100.0, 100.0),
	    vel: point!(0.0, 0.0),
	}
    }
}

impl Object for Character {
    fn update(&mut self, objects: &mut Objects, lvl: &Level, _dt: Nanoseconds) -> ObjectState {
	self.vel += lvl.gravity;
	self.pos += self.vel;

	let ctrl = self.ctrl.borrow();

	if self.pos.y >= lvl.ground {
	    self.pos.y = lvl.ground;
	    self.vel.y = 0.0;
	    self.vel.x *= 0.9;

	    if ctrl.jump.is_pressed {
		self.vel = ctrl.aim.to_point() * 5.0;
	    }
	}

	if ctrl.shoot.is_pressed {
	    use rand::distributions::{Distribution, Normal};
	    let normal = Normal::new(0.0, 0.1);
	    for _i in 0..100 {
		objects.push(Box::new(Boll {
		    pos: self.pos,
		    vel: ctrl.aim.to_adjusted_point() * (3.0 + rand::random::<f64>()) + point!(normal.sample(&mut rand::thread_rng()), normal.sample(&mut rand::thread_rng())) + self.vel,
		    bounces: 2,
		}));
	    }
	    ctrl.rumble(1.0, _dt as u32 / 1_000_000);
	}

	match ctrl.mov.x {
	    v if v < -0.9 => { self.vel.x -= 0.5 }
	    v if v > 0.9 => { self.vel.x += 0.5 }
	    _ => {}
	}

	Alive
    }

    fn render(&self, canvas: &mut Canvas<Window>, sprites: &mut SpriteManager) {
        let block = sprites.get("mario");
	let size = 32;
        canvas.copy(block, None, Rect::new(self.pos.x as i32 - size as i32 / 2, self.pos.y as i32 - size as i32, size, size)).unwrap();

	let ctrl = &self.ctrl.borrow();
	let l = 300.0;
	let pos = (self.pos.x as i32, self.pos.y as i32);
	// axis values
	let p = (self.pos + ctrl.aim.to_point() * l).to_i32().into();
	canvas.set_draw_color((0, 255, 0));
	canvas.draw_line(pos, p).unwrap();
	draw_cross(canvas, p);
	// adjusted values
	let p = (self.pos + ctrl.aim.to_adjusted_point() * l).to_i32().into();
	canvas.set_draw_color((255, 0, 0));
	canvas.draw_line(pos, p).unwrap();
	draw_cross(canvas, p);
	// circle values
	let p = (self.pos + Point2D::from(ctrl.aim.a) * l).to_i32().into();
	canvas.set_draw_color((0, 0, 255));
	canvas.draw_line(pos, p).unwrap();
	draw_cross(canvas, p);
    }
}

fn draw_cross(canvas: &mut Canvas<Window>, p: (i32, i32)) {
    canvas.draw_line((p.0 - 5, p.1), (p.0 + 5, p.1)).unwrap();
    canvas.draw_line((p.0, p.1 - 5), (p.0, p.1 + 5)).unwrap();
}

pub struct Boll {
    pos: Point2D<f64>,
    vel: Point2D<f64>,
    bounces: u8,
}

impl Object for Boll {
    fn update(&mut self, _objects: &mut Objects, lvl: &Level, _dt: Nanoseconds) -> ObjectState {
	self.vel += lvl.gravity;
	self.pos += self.vel;

	if self.pos.y >= lvl.ground {
	    if self.bounces == 0 {
		return Dead
	    } else {
		self.bounces -= 1;
		self.pos.y = lvl.ground;
		self.vel.y = -self.vel.y;
	    }
	}

	Alive
    }

    fn render(&self, canvas: &mut Canvas<Window>, _sprites: &mut SpriteManager) {
        let block = _sprites.get("block");
	let size = 4 + self.bounces * 6;
        canvas.copy(block, None, Rect::new(self.pos.x as i32 - size as i32 / 2, self.pos.y as i32 - size as i32 / 2, size as u32, size as u32)).unwrap();
	// canvas.set_draw_color((0, self.bounces * 100, 255));
	// canvas.draw_point((self.pos.x as i32, self.pos.y as i32)).unwrap();
    }
}