feat: backup and restore of samples using yaml file

[reidevries]

I've run basic tests on my own Volca Sample 2 to confirm the functionality is working, I will probably test more extensively soon.

See #1

[00nktk]

Thanks for the PR! Will give it a look today

[00nktk]

Great feature, thanks!

Got some minor comments. Also, please do a cargo clippy run and fix the issues from its output.

[00nktk]

Please regroup imports the way it's done in other files

// Std
use std::{...};

// External crate
use external_crate::{...};

// This crate
use crate::{...};

[00nktk]

Suggested change

	use super::sample_slots::SampleSlots;
	use serde::{Deserialize, Serialize};
	use serde::{Deserialize, Serialize};
	use super::sample_slots::SampleSlots;

[00nktk]

Too many arguments (clippy). I would split it into two functions: load and upload. Writing processed audio can be inside of "load" I think.

[00nktk]

I believe there's an easier way to achieve this. Smth like

type SampleSlotsInner = BTreeMap<u8, String>; // No need to be public

#[derive(Default, Serialize, Deserialize)]
#[serde(try_from = "SampleSlotsInner")] 
pub struct SampleSlots(pub SampleSlotsInner);

// If you want to restrict sample index
impl TryFrom<SampleSlotsInner> for SampleSlots {
    type Error = anyhow::Error; // or String?

    fn try_from(map: SampleSlotsInner) -> Result<Self, Self::Error> {
        if value.last_key_value().map_or(false, |(&idx, _)| idx >= 200 /* make me const */ ) {
            bail!("Sample idx too big");
        }
    }
}

This way we don't need to implement (and don't have to support) [De-]Serialize, visitors and other stuff. Tough it lacks slot index restriction when the struct is constructed in a way other than through deserialization, but I doubt this is important at this point.

---

Also, this struct feels too big to be stored on stack (nothing critical though). And I can imagine String being replaced with something like this in the future.

struct SampleSlot {
    name: String,
    path: Option<PathBuf>,
    channel: Option<MonoMode>,
    ... // Some other metadata?
}

This is just an idea of how to extend this in the future, so one could have several "volca loadouts" of their sample collection without need to store multiple sample copies.

[00nktk]

Maybe a cli argument for default mode?

[00nktk]

I would make this optional. Imagine swapping sample "slices" or "masks".

[00nktk]

samples would be better, I believe.

If someday pattern-related stuff gets implemented backups could look like

samples:
    ... # sample data
patterns: # or sequences
    ... # pattern data

[00nktk]

Remove this file please.

[00nktk]

I believe yml is also a valid extension. I think you can remove this check and let serde do its job.

[00nktk]

I find this naming ("domain") a little confusing in this crate. While I realise it's more of a personal preference, I think calling this module a "library" and (maybe) reducing nesting (moving BackupData and SampleSlots up) will make it easier to read the code.

[00nktk]

Suggested change

	use serde::de::{Deserialize, Deserializer, MapAccess, Visitor};
	use serde::ser::{Serialize, SerializeMap, Serializer};
	use std::fmt;
	use std::ops::{Index, IndexMut};
	extern crate serde_yaml;
	use std::fmt;
	use std::ops::{Index, IndexMut};
	use serde::de::{Deserialize, Deserializer, MapAccess, Visitor};
	use serde::ser::{Serialize, SerializeMap, Serializer};

extern not needed.