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use core::ops::Add;

use crate::Accidental;

/// Music interval in semitones.
#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub struct Interval {
    semitones: u8,
}

impl Interval {
    pub const UNISON: Self = Self::new(0);

    pub const MINOR_SECOND: Self = Self::new(1);

    pub const MAJOR_SECOND: Self = Self::new(2);

    pub const MINOR_THIRD: Self = Self::new(3);

    pub const MAJOR_THIRD: Self = Self::new(4);

    pub const PERFECT_FOURTH: Self = Self::new(5);

    pub const TRITONE: Self = Self::new(6);

    pub const PERFECT_FIFTH: Self = Self::new(7);

    pub const MINOR_SEVENTH: Self = Self::new(10);
    pub const MAJOR_SEVENTH: Self = Self::new(11);

    pub const THIRTEENTH: Self = Self::new(21);

    pub const fn new(semitones: u8) -> Self {
        Self { semitones }
    }

    pub const fn semitones(self) -> u8 {
        self.semitones
    }
}

impl From<Accidental> for Interval {
    fn from(accidental: Accidental) -> Self {
        accidental.interval()
    }
}

impl From<u8> for Interval {
    fn from(semitones: u8) -> Self {
        Self::new(semitones)
    }
}

impl From<Interval> for u8 {
    fn from(interval: Interval) -> Self {
        interval.semitones()
    }
}

impl Add for Interval {
    type Output = Self;

    fn add(self, rhs: Self) -> Self {
        Self::new(self.semitones() + rhs.semitones())
    }
}