use std::convert::{From, Into, TryFrom};

#[derive(Debug)]
pub struct Pixmap<T> {
    pub width: u32,
    pub height: u32,
    pub data: Vec<T>,
}

#[derive(Copy, Clone, Debug)]
pub struct MapPoint {
    pub x: u32,
    pub y: u32,
}

impl From<(u32, u32)> for MapPoint {
    fn from((x, y): (u32, u32)) -> MapPoint {
        MapPoint { x, y }
    }
}

impl TryFrom<(i32, i32)> for MapPoint {
    type Error = ();
    fn try_from((x, y): (i32, i32)) -> Result<Self, Self::Error> {
        if x < 0 || y < 0 {
            return Err(());
        } else {
            Ok(MapPoint {
                x: x as u32,
                y: y as u32,
            })
        }
    }
}

impl TryFrom<(i64, i64)> for MapPoint {
    type Error = ();
    fn try_from((x, y): (i64, i64)) -> Result<Self, Self::Error> {
        if x < 0 || y < 0 {
            return Err(());
        } else {
            Ok(MapPoint {
                x: x as u32,
                y: y as u32,
            })
        }
    }
}

impl<T> Pixmap<T>
where
    T: Copy + Clone + Default,
{
    pub fn new(width: u32, height: u32) -> Self {
        let data = vec![Default::default(); (width * height) as usize];
        Pixmap {
            width,
            height,
            data,
        }
    }
    pub fn new_with(width: u32, height: u32, start: T) -> Self {
        let data = vec![start; (width * height) as usize];
        Pixmap {
            width,
            height,
            data,
        }
    }
    pub fn is_inside<P: Into<MapPoint>>(&self, pt: P) -> bool {
        let MapPoint { x, y } = pt.into();
        x < self.width && y < self.height
    }
    pub fn idx<P: Into<MapPoint>>(&self, pt: P) -> usize {
        let MapPoint { x, y } = pt.into();
        (y * self.width + x) as usize
    }
    pub fn get<P: Into<MapPoint>>(&self, pt: P) -> T {
        let idx = self.idx(pt);
        self.data[idx]
    }
    pub fn set<P: Into<MapPoint>>(&mut self, pt: P, new_val: T) -> T {
        let pt = pt.into();
        let old_val = self.get(pt);
        let idx = self.idx(pt);
        self.data[idx] = new_val;
        old_val
    }
}