bracket_terminal::add_wasm_support!();
use bracket_pathfinding::prelude::*;
use bracket_random::prelude::*;
use bracket_terminal::prelude::*;

#[derive(PartialEq, Copy, Clone)]
enum TileType {
    Wall,
    Floor,
}

#[derive(PartialEq, Copy, Clone)]
enum Mode {
    Waiting,
    Moving,
}

struct State {
    map: Vec<TileType>,
    player_position: usize,
    visible: Vec<bool>,
    mode: Mode,
    path: NavigationPath,
}

pub fn xy_idx(x: i32, y: i32) -> usize {
    (y as usize * 80) + x as usize
}

pub fn idx_xy(idx: usize) -> (i32, i32) {
    (idx as i32 % 80, idx as i32 / 80)
}

impl State {
    pub fn new() -> State {
        let mut state = State {
            map: vec![TileType::Floor; 80 * 50],
            player_position: xy_idx(40, 25),
            visible: vec![false; 80 * 50],
            mode: Mode::Waiting,
            path: NavigationPath::new(),
        };

        for x in 0..80 {
            state.map[xy_idx(x, 0)] = TileType::Wall;
            state.map[xy_idx(x, 49)] = TileType::Wall;
        }
        for y in 0..50 {
            state.map[xy_idx(0, y)] = TileType::Wall;
            state.map[xy_idx(79, y)] = TileType::Wall;
        }

        let mut rng = RandomNumberGenerator::new();

        for _ in 0..1400 {
            let x = rng.range(1, 79);
            let y = rng.range(1, 49);
            let idx = xy_idx(x, y);
            if state.player_position != idx {
                state.map[idx] = TileType::Wall;
            }
        }

        state
    }

    pub fn is_exit_valid(&self, x: i32, y: i32) -> bool {
        if x < 1 || x > 79 || y < 1 || y > 49 {
            return false;
        }
        let idx = (y * 80) + x;
        self.map[idx as usize] == TileType::Floor
    }
}

// Implement the game loop
impl GameState for State {
    #[allow(non_snake_case)]
    fn tick(&mut self, ctx: &mut BTerm) {
        // We'll use batched drawing
        let mut draw_batch = DrawBatch::new();

        // Set all tiles to not visible
        for v in &mut self.visible {
            *v = false;
        }

        // Obtain the player's visible tile set, and apply it
        let player_position = self.index_to_point2d(self.player_position);
        let fov = field_of_view_set(player_position, 8, self);

        // Note that the steps above would generally not be run every frame!
        for idx in &fov {
            self.visible[xy_idx(idx.x, idx.y)] = true;
        }

        // Clear the screen
        draw_batch.cls();

        // Iterate the map array, incrementing coordinates as we go.
        let mut y = 0;
        let mut x = 0;
        for (i, tile) in self.map.iter().enumerate() {
            // Render a tile depending upon the tile type; now we check visibility as well!
            let mut fg;
            let mut glyph = ".";

            match tile {
                TileType::Floor => {
                    fg = RGB::from_f32(0.5, 0.5, 0.0);
                }
                TileType::Wall => {
                    fg = RGB::from_f32(0.0, 1.0, 0.0);
                    glyph = "#";
                }
            }
            if !self.visible[i] {
                fg = fg.to_greyscale();
            }
            draw_batch.print_color(
                Point::new(x, y),
                glyph,
                ColorPair::new(fg, RGB::from_f32(0., 0., 0.)),
            );

            // Move the coordinates
            x += 1;
            if x > 79 {
                x = 0;
                y += 1;
            }
        }

        // Either render the proposed path or run along it
        if self.mode == Mode::Waiting {
            // Render a mouse cursor
            let mouse_pos = INPUT.lock().mouse_tile(0);
            let mouse_idx = self.point2d_to_index(mouse_pos);
            draw_batch.print_color(
                mouse_pos,
                "X",
                ColorPair::new(RGB::from_f32(0.0, 1.0, 1.0), RGB::from_f32(0.0, 1.0, 1.0)),
            );
            if self.map[mouse_idx as usize] != TileType::Wall {
                let path = a_star_search(self.player_position, mouse_idx, self);
                if path.success {
                    for loc in path.steps.iter().skip(1) {
                        let x = (loc % 80) as i32;
                        let y = (loc / 80) as i32;
                        draw_batch.print_color(
                            Point::new(x, y),
                            "*",
                            ColorPair::new(RGB::from_f32(1., 0., 0.), RGB::from_f32(0., 0., 0.)),
                        );
                    }

                    if INPUT.lock().is_mouse_button_pressed(0) {
                        self.mode = Mode::Moving;
                        self.path = path;
                    }
                }
            }
        } else {
            self.player_position = self.path.steps[0] as usize;
            self.path.steps.remove(0);
            if self.path.steps.is_empty() {
                self.mode = Mode::Waiting;
            }
        }

        // Render the player @ symbol
        let ppos = idx_xy(self.player_position);
        draw_batch.print_color(
            Point::from_tuple(ppos),
            "@",
            ColorPair::new(RGB::from_f32(1.0, 1.0, 0.0), RGB::from_f32(0., 0., 0.)),
        );

        // Submit the rendering
        draw_batch.submit(0).expect("Batch error");
        render_draw_buffer(ctx).expect("Render error");
    }
}

impl BaseMap for State {
    fn is_opaque(&self, idx: usize) -> bool {
        self.map[idx] == TileType::Wall
    }

    fn get_available_exits(&self, idx: usize) -> SmallVec<[(usize, f32); 10]> {
        let mut exits = SmallVec::new();
        let x = (idx % 80) as i32;
        let y = (idx / 80) as i32;

        // Cardinal directions
        if self.is_exit_valid(x - 1, y) {
            exits.push((idx - 1, 1.0))
        };
        if self.is_exit_valid(x + 1, y) {
            exits.push((idx + 1, 1.0))
        };
        if self.is_exit_valid(x, y - 1) {
            exits.push((idx - 80, 1.0))
        };
        if self.is_exit_valid(x, y + 1) {
            exits.push((idx + 80, 1.0))
        };

        // Diagonals
        if self.is_exit_valid(x - 1, y - 1) {
            exits.push(((idx - 80) - 1, 1.4));
        }
        if self.is_exit_valid(x + 1, y - 1) {
            exits.push(((idx - 80) + 1, 1.4));
        }
        if self.is_exit_valid(x - 1, y + 1) {
            exits.push(((idx + 80) - 1, 1.4));
        }
        if self.is_exit_valid(x + 1, y + 1) {
            exits.push(((idx + 80) + 1, 1.4));
        }

        exits
    }

    fn get_pathing_distance(&self, idx1: usize, idx2: usize) -> f32 {
        let p1 = Point::new(idx1 % 80, idx1 / 80);
        let p2 = Point::new(idx2 % 80, idx2 / 80);
        DistanceAlg::Pythagoras.distance2d(p1, p2)
    }
}

impl Algorithm2D for State {
    fn dimensions(&self) -> Point {
        Point::new(80, 50)
    }
}

fn main() -> BError {
    let context = BTermBuilder::simple80x50()
        .with_title("Bracket Terminal Example - A* Mouse")
        .build()?;
    let gs = State::new();
    main_loop(context, gs)
}