1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120

use super::Position;
// Utility Enum for storing Negative(N) and Positive(P) as usize
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub(crate) enum N {
    //Negative Number
    N(usize),
    //Positive Number
    P(usize),
}

impl N {
    fn get_number(&self) -> usize {
        match self {
            N::N(n) => *n,
            N::P(n) => *n,
        }
    }

    fn from_isize(n: isize) -> Self {
        if n < 0 {
            return N::N((-n) as usize);
        }
        N::P(n as usize)
    }

    fn from_i32(n: i32) -> Self {
        if n < 0 {
            return N::N((-n) as usize);
        }
        N::P(n as usize)
    }

    pub(crate) fn checked_add_sub(&self, n: usize) -> Option<usize> {
        Some(match self {
            N::N(pn) => n.checked_sub(*pn)?,
            N::P(pn) => n.checked_add(*pn)?,
        })
    }
}

/// A Step or direction to the next position in the grid, always relative to a position.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct Step {
    x: N,
    y: N,
}

impl Step {
    /// Create a new step.
    /// # Example
    /// ```
    /// # use gridit::Step;
    /// let step = Step::new(1, 2);
    /// assert_eq!(step, Step::from((1, 2)));
    /// ```
    pub fn new(x: usize, y: usize) -> Self {
        Step {
            x: N::P(x),
            y: N::P(y),
        }
    }

    /// Negate the x value of the step.
    /// This is usefull when a step is needed with a `x` value larger then `i32`.
    /// ```
    /// # use gridit::Step;
    /// let step = Step::new(2, 2)
    ///                 .negate_x();
    /// assert_eq!(step, Step::from((-2, 2)));
    /// ```
    pub fn negate_x(mut self) -> Self {
        self.x = N::N(self.x.get_number());
        self
    }

    /// Negate the y value of the step.
    /// This is usefull when a step is needed with a `y` value larger then `i32`.
    /// ```
    /// # use gridit::Step;
    /// let step = Step::new(2, 2)
    ///                 .negate_y();
    /// assert_eq!(step, (2, -2).into());
    /// ```
    pub fn negate_y(mut self) -> Self {
        self.y = N::N(self.y.get_number());
        self
    }

    pub(crate) fn take_step_from_position(&self, pos: Position) -> Option<Position> {
        let x = self.x.checked_add_sub(pos.x)?;
        let y = self.y.checked_add_sub(pos.y)?;
        Some((x, y).into())
    }
}

// TODO Create a better impl for all Numbers T -> (T, T)
impl From<(usize, usize)> for Step {
    fn from((x, y): (usize, usize)) -> Self {
        Step::new(x, y)
    }
}

// TODO Create a better impl for all Numbers T -> (T, T) where T: Neg or something likes this
impl From<(isize, isize)> for Step {
    fn from((x, y): (isize, isize)) -> Self {
        Step {
            x: N::from_isize(x),
            y: N::from_isize(y),
        }
    }
}

impl From<(i32, i32)> for Step {
    fn from((x, y): (i32, i32)) -> Self {
        Step {
            x: N::from_i32(x),
            y: N::from_i32(y),
        }
    }
}