use std::fmt;
use rand;
use rand::distributions::{IndependentSample, Range};
    
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
pub enum Direction {
    North,
    East,
    South,
    West,
}

use Direction::*;

impl fmt::Display for Direction {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_str(
            match self {
                &North => "North",
                &East => "East",
                &South => "South",
                &West => "West"
            }
        )
    }
}

impl Direction {
    pub fn random() -> Direction {
        let mut rng = rand::thread_rng();
        let between = Range::new(0, 4);
        let dir = between.ind_sample(&mut rng);
        match dir {
            0 => North,
            1 => East,
            2 => South,
            3 => West,
            _ => panic!("Invalid number generated by random number generator")
        }
    }
}

#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
pub struct Point {
    pub x: u16,
    pub y: u16
}

impl Point {
    pub fn new(x: u16, y: u16) -> Point {
        Point {
            x: x,
            y: y
        }
    }

    pub fn random(map_size: u16) -> Point {
        let mut rng = rand::thread_rng();
        let between = Range::new(0, map_size);
        let x = between.ind_sample(&mut rng);
        let y = between.ind_sample(&mut rng);
        Point::new(x, y)
    }


    pub fn move_point(&self, direction: Direction, distance: u16, map_size: u16) -> Option<Point> {
        let x = self.x;
        let y = self.y;
        
        match direction {
            South if y < distance => None,
            West if x < distance => None,
            North if y + distance >= map_size => None,
            East if x + distance >= map_size => None,
            South => Some(Point::new(x, y-distance)),
            West => Some(Point::new(x-distance, y)),
            North => Some(Point::new(x, y+distance)),
            East => Some(Point::new(x+distance, y))
        }
    }
}