use super::errors::GridError;
use crate::prelude::*;

pub fn grid_start_x(grid_width: u32) -> f32 {
    -(grid_width as f32 * TILE_SIZE) / 2.0 + TILE_SIZE / 2.0
}

pub fn grid_start_y(grid_height: u32) -> f32 {
    -(grid_height as f32 * TILE_SIZE) / 2.0 + TILE_SIZE / 2.0
}

pub fn world_to_grid_coords(
    world_pos: Vec3,
    grid_width: u32,
    grid_height: u32,
) -> Result<(u32, u32), GridError> {
    let start_x = grid_start_x(grid_width);
    let start_y = grid_start_y(grid_height);

    let x = ((world_pos.x - start_x + TILE_SIZE / 2.0) / TILE_SIZE).floor();
    let y = ((world_pos.y - start_y + TILE_SIZE / 2.0) / TILE_SIZE).floor();

    if x >= grid_width as f32 || y >= grid_height as f32 || x < 0.0 || y < 0.0 {
        return Err(GridError::OutOfBounds {
            x: x as i32,
            y: x as i32,
        });
    }

    Ok((x as u32, y as u32))
}

pub fn grid_to_world_coords(
    grid_x: u32,
    grid_y: u32,
    z: Option<f32>,
    grid_width: u32,
    grid_height: u32,
) -> Vec3 {
    Vec3::new(
        grid_start_x(grid_width) + grid_x as f32 * TILE_SIZE,
        grid_start_y(grid_height) + grid_y as f32 * TILE_SIZE,
        z.unwrap_or(0.0),
    )
}