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
159
160
161
162
163
164
165
166
167
168
169

use std::cmp::max;

use crate::blipbuf::BlipBuf;
use crate::oscillator::Oscillator;
use crate::settings::{
    EFFECT_NONE, MAX_EFFECT, MAX_NOTE, MAX_TONE, MAX_VOLUME, NUM_CHANNELS, TONE_TRIANGLE,
};
use crate::sound::{SharedSound, Sound};
use crate::types::{Effect, Note, Tone, Volume};

pub struct Channel {
    oscillator: Oscillator,
    sounds: Vec<Sound>,
    is_playing: bool,
    should_loop: bool,
    sound_index: u32,
    note_index: u32,
    tick_count: u32,
    pub gain: u8,
}

pub type SharedChannel = shared_type!(Channel);

impl Channel {
    pub fn new() -> SharedChannel {
        new_shared_type!(Self {
            oscillator: Oscillator::new(),
            sounds: Vec::new(),
            is_playing: false,
            should_loop: false,
            sound_index: 0,
            note_index: 0,
            tick_count: 0,
            gain: u8::MAX / NUM_CHANNELS as u8,
        })
    }

    pub fn play_pos(&mut self) -> Option<(u32, u32)> {
        if self.is_playing {
            Some((self.sound_index, self.note_index))
        } else {
            None
        }
    }

    pub fn play(&mut self, sounds: Vec<SharedSound>, start_tick: Option<u32>, should_loop: bool) {
        let sounds: Vec<Sound> = sounds.iter().map(|sound| sound.lock().clone()).collect();
        if sounds.is_empty() || sounds.iter().all(|sound| sound.notes.is_empty()) {
            return;
        }
        self.sounds = sounds;
        self.should_loop = should_loop;
        self.sound_index = 0;
        self.note_index = 0;
        self.tick_count = start_tick.unwrap_or(0);
        loop {
            let sound = &self.sounds[self.sound_index as usize];
            let sound_ticks = sound.notes.len() as u32 * sound.speed;
            if self.tick_count < sound_ticks {
                self.note_index = self.tick_count / sound.speed;
                self.tick_count %= sound.speed;
                break;
            }
            self.tick_count -= sound_ticks;
            self.sound_index += 1;
            if self.sound_index >= self.sounds.len() as u32 {
                if should_loop {
                    self.sound_index = 0;
                } else {
                    return;
                }
            }
        }
        self.is_playing = true;
    }

    pub fn play1(&mut self, sound: SharedSound, start_tick: Option<u32>, should_loop: bool) {
        self.play(vec![sound], start_tick, should_loop);
    }

    pub fn stop(&mut self) {
        self.is_playing = false;
        self.oscillator.stop();
    }

    pub(crate) fn update(&mut self, blip_buf: &mut BlipBuf) {
        if !self.is_playing {
            return;
        }
        let mut sound = &self.sounds[self.sound_index as usize];
        let speed = max(sound.speed, 1);
        if self.tick_count % speed == 0 {
            if self.tick_count > 0 {
                self.note_index += 1;
            }
            while self.note_index >= sound.notes.len() as u32 {
                self.sound_index += 1;
                self.note_index = 0;
                if self.sound_index >= self.sounds.len() as u32 {
                    if self.should_loop {
                        self.sound_index = 0;
                    } else {
                        self.stop();
                        return;
                    }
                }
                sound = &self.sounds[self.sound_index as usize];
            }

            let note = Self::circular_note(&sound.notes, self.note_index);
            assert!(note <= MAX_NOTE, "invalid sound note {}", note);
            let volume = Self::circular_volume(&sound.volumes, self.note_index);
            assert!(volume <= MAX_VOLUME, "invalid sound volume {}", volume);
            let tone = Self::circular_tone(&sound.tones, self.note_index);
            assert!(tone <= MAX_TONE, "invalid sound tone {}", tone);
            let effect = Self::circular_effect(&sound.effects, self.note_index);
            assert!(effect <= MAX_EFFECT, "invalid sound effect {}", effect);
            let speed = max(sound.speed, 1);

            if note >= 0 && volume > 0 {
                self.oscillator.play(
                    note as f64,
                    tone,
                    (self.gain as f64 * volume as f64) / (u8::MAX as f64 * MAX_VOLUME as f64),
                    effect,
                    speed,
                );
            }
        }
        self.oscillator.update(blip_buf);
        self.tick_count += 1;
    }

    const fn circular_note(notes: &[Note], index: u32) -> Note {
        let len = notes.len();
        if len > 0 {
            notes[index as usize % len]
        } else {
            0
        }
    }

    const fn circular_tone(tones: &[Tone], index: u32) -> Tone {
        let len = tones.len();
        if len > 0 {
            tones[index as usize % len]
        } else {
            TONE_TRIANGLE
        }
    }

    const fn circular_volume(volumes: &[Volume], index: u32) -> Volume {
        let len = volumes.len();
        if len > 0 {
            volumes[index as usize % len]
        } else {
            MAX_VOLUME
        }
    }

    const fn circular_effect(effects: &[Effect], index: u32) -> Effect {
        let len = effects.len();
        if len > 0 {
            effects[index as usize % len]
        } else {
            EFFECT_NONE
        }
    }
}