use std::collections::HashMap;

use sfml::window::mouse::Button;

use sfml::system::{
	Vector2f,
	Vector2i
};

use sfml::window::{
	ContextSettings,
	Event,
	Style,
};

use sfml::graphics::{
	RenderWindow,
	RenderTarget,
	View,
};

use sfml::graphics::{
	Texture,
	Image,
	Color,
};

use sfml::graphics::{
	RectangleShape,
	Transformable,
	Rect,
};


#[derive(RustEmbed)]
#[folder = "res/maps"]
pub struct MapAssets;


pub struct Graphics {
	// rendering elements
	window: RenderWindow,
	scenes: Vec<Box<Scene>>,
	current_scene: Box<Scene>,
	// status
	running: bool,
}

impl Graphics {
	pub fn new() -> Graphics {
		let default_window_size = (1280, 720);
		let default_framerate = 80;

		let context_settings = ContextSettings {
			antialiasing_level: 0,
			..Default::default()
		};

		// create window
		let mut window = RenderWindow::new(
			default_window_size,
			"Subconscious",
			Style::DEFAULT,
			&context_settings
		);

		window.set_framerate_limit(default_framerate);
		window.set_vertical_sync_enabled(true);

		let map_scene = Box::new(MapScene::new(&window));

		return Graphics {
			window: window,
			scenes: Vec::new(),
			current_scene: map_scene,
			running: true,
		};
	}

	pub fn is_running(self: &mut Self) -> bool {
		return self.running;
	}

	pub fn update(self: &mut Self) {
		while let Some(event) = self.window.poll_event() {
			match event {
				Event::Closed => {
					self.window.close();
					self.running = false;
				}
				_ => {}
			}

			self.current_scene.event(&mut self.window, event)
		}

	}

	pub fn render(self: &mut Self, state: &crate::game::State) {

		// background
		let bgcolor = match state.map.background_colour {
			Some(color) => Color::rgb(color.red, color.green, color.blue),
			None => Color::BLACK,
		};

		self.window.clear(&bgcolor);
		self.current_scene.render(&mut self.window, state);
		self.window.display();
	}

}

trait Scene {
	fn render(self: &mut Self, window: &mut RenderWindow, state: &crate::game::State);
	fn event(self: &mut Self, window: &mut RenderWindow, event: Event);
}

struct MapScene {
	map_view: View,
	// pan
	panning: bool,
	pan_start: Vector2f,
	// loaded resources
	tilesets: HashMap<u32, Image>,
	textures: HashMap<u32, Texture>,
}

impl MapScene {
	fn new(window: &RenderWindow) -> MapScene {
		return MapScene {
			map_view: window.default_view().to_owned(),
			panning: false,
			pan_start: Vector2f::new(0.0, 0.0),
			tilesets: HashMap::new(),
			textures: HashMap::new()
		};
	}
}

impl MapScene {
	fn load_tilset(self: &mut Self, tmx_tileset: &tiled::Tileset) {
		// load tileset if not loaded yet
		if self.tilesets.contains_key(&tmx_tileset.first_gid) {
			return;
		}

		// TODO: replace with iter or error message
		assert_eq!(tmx_tileset.images.len(), 1);

		// load tileset image
		let tmx_image = &tmx_tileset.images[0];
		let asset = match MapAssets::get(&tmx_image.source) {
			Some(asset) => asset,
			None => {
				panic!("Failed to get asset: {}", &tmx_image.source);
			}
		};


		let image = match Image::from_memory(asset.as_ref()) {
			Some(image) => image,
			None => {
				panic!("Failed load image from asset");
			}
		};

		// load tiles (textures)
		let tileset_width = tmx_image.width as u32 / tmx_tileset.tile_width;
		let tileset_height = tmx_image.height as u32 / tmx_tileset.tile_height;

		for ty in 0 .. tileset_height {
			for tx in 0 .. tileset_width {
				let texture = Texture::from_image_with_rect(
					&image, &Rect::new(
						(tx * tmx_tileset.tile_width) as i32,
						(ty * tmx_tileset.tile_height) as i32,
						tmx_tileset.tile_width as i32,
						tmx_tileset.tile_height as i32
					)
				).unwrap();

				// save tile texture
				self.textures.insert(
					tmx_tileset.first_gid + ty * tileset_width + tx,
					texture
				);
			}
		}

		// save tileset image
		self.tilesets.insert(tmx_tileset.first_gid, image);
	}
}

impl Scene for MapScene {
	fn render(self: &mut Self, window: &mut RenderWindow, state: &crate::game::State) {
		for y in 0 .. state.map.height {
			for x in 0 .. state.map.width {
				// for each layer
				for layer in &state.map.layers {

					let tmx_tile = layer.tiles[y as usize][x as usize];

					// blank tile
					if tmx_tile <= 0 {
						continue;
					}

					let tmx_tileset = match state.map.get_tileset_by_gid(tmx_tile) {
						Some(tileset) => tileset,
						None => {
							// TODO: missing_tile texture
							panic!("Failed to get tileset with get_tileset_by_gid");
						}
					};

					// TODO: load in a separate thread?
					self.load_tilset(tmx_tileset);

					// draw tiles
					// TODO: check map render order
					let texture = &self.textures.get(&tmx_tile).unwrap();
					let mut tile_rect = RectangleShape::with_texture(texture);

					tile_rect.set_size(Vector2f {
						x: tmx_tileset.tile_width as f32,
						y: tmx_tileset.tile_height as f32
					});

					tile_rect.set_position(Vector2f {
						x: (x * tmx_tileset.tile_width) as f32,
						y: (y * tmx_tileset.tile_height) as f32
					});


					window.draw(&tile_rect);
				}
			}
		}
	}

	fn event(self: &mut Self, window: &mut RenderWindow, event: Event) {
		match event {
			Event::MouseWheelScrolled { wheel: _, delta, x: _, y: _ } => {
				// delta is probalby a value between -1 and 1
				let zoom = 1.0 + delta * 0.1;
				self.map_view.zoom(zoom);
				window.set_view(&self.map_view);
			},
			Event::MouseButtonPressed { button, x, y} => {
				match button {
					Button::Right => {},
					Button::Left => {
						// set pan start position
						self.panning = true;
						self.pan_start = window.map_pixel_to_coords_current_view(&Vector2i::new(x, y));
					}
					_ => {},
				}
			},
			Event::MouseButtonReleased { button, x: _, y: _ } => {
				match button {
					Button::Right => {}
					Button::Left => {
						self.panning = false;
					},
					_ => {},
				}
			},
			Event::MouseMoved { x, y } => {
				if self.panning {
					// get delta of vectors
					let delta = self.pan_start - window.map_pixel_to_coords_current_view(&Vector2i::new(x, y));

					// move view by moving the center by delta
					self.map_view.move_(delta);
					window.set_view(&self.map_view);
				}
			}
			_ => {},
		}
	}
}