use sfml::system::Vector2;
use sfml::window::{Event, Key, mouse::Button as MouseButton};
use sfml::graphics::{Color, RectangleShape, RenderTarget, Transformable, Shape};

use crate::engine::renderer::Renderer;
use crate::engine::map::{CollisionTile, Map};
use crate::engine::texture::SPRITE_SIZE_I32;
use crate::engine::font::Font;
use crate::Result;

/// An action caused by a button.
#[derive(Copy, Clone)]
pub enum Action {
    /// Saves the level.
    Save,
}

/// A button that can be clicked.
pub struct Button {
    /// The label of the button.
    pub label: String,

    /// The position of the button.
    pub position: Vector2<f32>,

    /// The size of the button.
    pub size: Vector2<f32>,

    /// The action of the button.
    action: Action,
}

impl Button {
    /// Creates a new button.
    pub fn new(label: &str, action: Action, x: f32, y: f32, w: f32, h: f32) -> Button {
        Button {
            action,
            label: label.to_owned(),
            position: Vector2::new(x, y),
            size: Vector2::new(w, h),
        }
    }

    /// Returns the shape of the button.
    pub fn shape(&self) -> RectangleShape {
        let mut shape = RectangleShape::new();
        shape.set_position(self.position + 0.1 * self.size);
        shape.set_size(self.size - 0.2 * self.size);
        shape.set_fill_color(&Color::rgb(255, 255, 255));
        shape
    }

    /// Draws the button on the renderer.
    pub fn render_on(&self, renderer: &mut Renderer) {
        renderer.window_mut().draw(&self.shape());
        renderer.draw_text(
            &self.label,
            Font::Sansation,
            self.size.y as u32 / 2,
            &Color::rgb(0, 0, 0)
        );
    }

    /// Returns true if the coordinates fall inside the shape of the button.
    pub fn contains(&self, x: f32, y: f32) -> bool {
        let shape = self.shape();
        x > shape.position().x && x < shape.position().x + shape.size().x &&
        y > shape.position().y && y < shape.position().y + shape.size().y
    }
}

/// Represents a level editor.
pub struct Editor {
    /// The renderer used by the editor.
    renderer: Renderer,

    /// The map being currently edited.
    map: Map,

    /// Indicates whether the editor is running or not.
    running: bool,

    /// The size of the left panel.
    left_panel_size: Vector2<f32>,

    /// The size of the top panel.
    top_panel_size: Vector2<f32>,

    /// The buttons of the menu bar.
    menu_bar: Vec<Button>,
}

impl Editor {
    /// Creates a new editor.
    pub fn new() -> Editor {
        let renderer = Renderer::new(800, 600, false);
        let menu_bar = vec![
            Button::new("Save", Action::Save, 0.0, 0.0, 50.0, 50.0),
        ];

        Editor {
            map: Map::new(50, 50),
            running: true,
            top_panel_size: Vector2::new(renderer.window().size().x as f32, 50.0),
            left_panel_size: Vector2::new(100.0, renderer.window().size().y as f32 - 50.0),
            renderer,
            menu_bar,
        }
    }

    /// Runs the main loop of the editor.
    pub fn run(&mut self) {
        while self.running {
            while let Some(event) = self.renderer.poll_event() {
                self.manage_event(event);
            }

            self.render();
        }
    }

    /// Manages the event occuring on the display.
    pub fn manage_event(&mut self, event: Event) {

        match event {
            // Quit the game if window is closed
            Event::Closed => self.running = false,

            // Quit the game if escape is pressed
            Event::KeyPressed {
                code: Key::Escape, ..
            } => self.running = false,

            // A click on the screen
            Event::MouseButtonPressed {
                button: MouseButton::Left, x, y,
            } => {
                if x as f32 >= self.left_panel_size.x && y as f32 >= self.top_panel_size.y {
                    let x = ((x - self.left_panel_size.x as i32) / SPRITE_SIZE_I32) as usize;
                    let y = ((y - self.top_panel_size.y as i32) / SPRITE_SIZE_I32) as usize;

                    if let Some(tile) = self.map.collision_tile(y, x) {
                        if tile.is_empty() {
                            self.map.set_tile(y, x, CollisionTile::full());
                        } else {
                            self.map.set_tile(y, x, CollisionTile::empty());
                        }
                    }
                }

                let mut actions = vec![];
                for button in &self.menu_bar {
                    if button.contains(x as f32, y as f32) {
                        actions.push(button.action);
                    }
                }

                for action in actions {
                    if let Err(e) = self.apply_action(action) {
                        eprintln!("warning: {}", e);
                    }
                }
            },

            _ => (),
        }

    }

    /// Performs the rendering on the screen.
    pub fn render(&mut self) {

        self.renderer.clear();

        // Show the top panel
        let mut top_panel = RectangleShape::with_size(self.top_panel_size);
        top_panel.set_fill_color(&Color::rgb(255, 0, 0));
        self.renderer.window_mut().draw(&top_panel);

        for button in &self.menu_bar {
            button.render_on(&mut self.renderer);
        }

        // Show the left panel
        let mut left_panel = RectangleShape::with_size(self.left_panel_size);
        left_panel.set_position((0.0, self.top_panel_size.y));
        left_panel.set_fill_color(&Color::rgb(0, 255, 0));
        self.renderer.window_mut().draw(&left_panel);

        // Show the map
        for i in 0 .. self.map.rows() {
            for j in 0 .. self.map.cols() {
                let tile = self.map.at(i, j);
                if tile.graphic.is_visible() {
                    self.renderer.translate_and_draw(
                        &tile,
                        (self.left_panel_size.x, self.top_panel_size.y)
                    );
                }
            }
        }

        // Draw the border of the map
        let mut border = RectangleShape::new();
        border.set_size(((
            self.map.cols() * SPRITE_SIZE_I32 as usize) as f32,
            (self.map.rows() * SPRITE_SIZE_I32 as usize) as f32
        ));
        border.set_position((self.left_panel_size.x, self.top_panel_size.y));
        border.set_fill_color(&Color::rgba(0, 0, 0, 0));
        border.set_outline_color(&Color::rgb(0, 0, 0));
        border.set_outline_thickness(2.0);
        self.renderer.window_mut().draw(&border);

        // Display and manage the frame rate
        self.renderer.display();
    }

    /// Saves the level.
    pub fn export(&self) -> Result<()> {
        self.map.save("level.lvl")
    }

    /// Applies the corresponding action.
    pub fn apply_action(&mut self, action: Action) -> Result<()> {
        match action {
            Action::Save => self.export()
        }
    }
}