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
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158

use crate::constants::{OCTAVE, TONIC};
use rug::integer::IsPrime;
use rug::{Integer, Rational};
use serde::{Deserialize, Serialize};

#[derive(Debug, Deserialize, PartialEq, Serialize)]
pub enum Ordinal {
    Otonal,
    Utonal,
}

#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
pub struct Pitch {
    pub cents: f32,
    pub ratio: Rational,
}

#[derive(Debug, Deserialize, PartialEq, Serialize)]
pub struct LatticeDimension {
    pub limit: usize,
    pub otonal: Vec<Pitch>,
    pub utonal: Vec<Pitch>,
}

impl Pitch {
    pub fn new(ratio: Rational) -> Pitch {
        Pitch {
            cents: ratio.cents(),
            ratio,
        }
    }
}

impl LatticeDimension {
    pub fn new(dimension: usize, steps: usize) -> LatticeDimension {
        LatticeDimension {
            limit: dimension,
            otonal: Rational::from((dimension as i32, 1)).walk(steps),
            utonal: Rational::from((dimension as i32, 1))
                .recip()
                .flatten()
                .walk(steps),
        }
    }
}

pub trait IntExt {
    fn factors(self) -> Vec<i32>;
    fn is_prime(self) -> bool;
    fn is_power_of_two(self) -> bool;
    fn gpf(self) -> i32;
}

pub trait Ratio {
    fn cents(&self) -> f32;
    fn to_list(&self) -> Vec<i32>;
    fn ordinal(&self) -> Ordinal;
    fn invert_ordinal(self) -> Rational;
    fn limit(&self) -> i32;
    fn walk(&self, times: usize) -> Vec<Pitch>;
    fn flatten(self) -> Rational;
}

impl IntExt for i32 {
    fn factors(self) -> Vec<i32> {
        let nums: Vec<_> = (1..=self).collect();
        let mut result: Vec<i32> = Vec::new();
        for n in nums {
            if self % n == 0 {
                result.push(n);
            }
        }

        result
    }

    fn is_prime(self) -> bool {
        let val = Integer::from(self).is_probably_prime(15);
        if let IsPrime::No = val {
            false
        } else {
            true
        }
    }

    fn is_power_of_two(self) -> bool {
        self != 0 && (self & (self - 1)) == 0
    }

    fn gpf(self) -> i32 {
        let mut result: i32 = 0;
        for n in self.factors() {
            if n.is_prime() && n > result {
                result = n;
            }
        }

        result
    }
}

impl Ratio for Rational {
    fn cents(&self) -> f32 {
        (1_200f32 / 2f32.log10()) * self.to_f32().log10()
    }

    fn to_list(&self) -> Vec<i32> {
        let (num, den) = Rational::from(self).into_numer_denom();
        vec![num.to_i32().unwrap(), den.to_i32().unwrap()]
    }

    fn ordinal(&self) -> Ordinal {
        let items = self.to_list();
        let num = items[0].gpf();
        let den = items[1].gpf();

        if num > den {
            Ordinal::Otonal
        } else {
            Ordinal::Utonal
        }
    }

    fn invert_ordinal(self) -> Rational {
        self.recip().flatten()
    }

    fn limit(&self) -> i32 {
        *self.to_list().iter().max().unwrap()
    }

    fn walk(&self, times: usize) -> Vec<Pitch> {
        let tonic = Rational::from(TONIC);
        let mut pitches = vec![Pitch::new(tonic)];

        for _ in 1..times {
            let last_pitch = pitches.last().cloned().unwrap();
            let next_pitch = (last_pitch.ratio * self).flatten();

            pitches.push(Pitch::new(next_pitch));
        }

        pitches
    }

    fn flatten(self) -> Rational {
        let tonic = TONIC;
        let octave = Rational::from(OCTAVE);

        if self > octave {
            (self / octave).flatten()
        } else if self < tonic {
            (self * octave).flatten()
        } else {
            self
        }
    }
}