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//! A trait that handles [base58](https://crates.io/crates/base58-monero) encoding and decoding.

use alloc::string::{String, ToString};

use snafu::prelude::*;

use crate::ByteArray;

/// Trait for encoding/decoding to base58.
#[deprecated(since = "0.8.0", note = "please use `MBase58` instead")]
pub trait Base58 {
    /// Convert from base58 string.
    fn from_base58(hex: &str) -> Result<Self, Base58Error>
    where Self: Sized;

    /// Convert to base58 string.
    fn to_base58(&self) -> String;
}

/// Errors for trait Base58.
#[derive(Debug, Snafu)]
#[allow(missing_docs)]
pub enum Base58Error {
    #[snafu(display("Byte array error: `{reason}'"))]
    ByteArrayError { reason: String },
    #[snafu(display("Decode error: `{reason}'"))]
    DecodeError { reason: String },
}

#[allow(deprecated)]
impl<T: ByteArray> Base58 for T {
    fn from_base58(data: &str) -> Result<Self, Base58Error>
    where Self: Sized {
        let bytes = base58_monero::decode(data).map_err(|e| Base58Error::DecodeError { reason: e.to_string() })?;
        Self::from_canonical_bytes(&bytes).map_err(|e| Base58Error::ByteArrayError { reason: e.to_string() })
    }

    fn to_base58(&self) -> String {
        base58_monero::encode(self.as_bytes()).expect("base58_monero::encode is infallible")
    }
}

/// Trait for encoding/decoding to base58.
pub trait MBase58 {
    /// Convert from base58 string.
    fn from_monero_base58(hex: &str) -> Result<Self, Base58Error>
    where Self: Sized;

    /// Convert to base58 string.
    fn to_monero_base58(&self) -> String;
}

impl<T: ByteArray> crate::encoding::MBase58 for T {
    fn from_monero_base58(data: &str) -> Result<Self, Base58Error>
    where Self: Sized {
        let bytes = base58_monero::decode(data).map_err(|e| Base58Error::DecodeError { reason: e.to_string() })?;
        Self::from_canonical_bytes(&bytes)
            .map_err(|e| crate::encoding::Base58Error::ByteArrayError { reason: e.to_string() })
    }

    fn to_monero_base58(&self) -> String {
        base58_monero::encode(self.as_bytes()).expect("base58_monero::encode is infallible")
    }
}

#[cfg(test)]
mod test {
    use alloc::vec::Vec;

    use super::*;

    #[test]
    fn decoding() {
        assert_eq!(Vec::from_monero_base58("111111").unwrap(), vec![0; 4]);
        assert_eq!(Vec::from_monero_base58("11115Q").unwrap(), vec![0, 0, 0, 255]);
        assert!(Vec::from_monero_base58("11111O").is_err());
        assert!(Vec::from_monero_base58("🖖🥴").is_err());
    }

    #[test]
    fn encoding() {
        assert_eq!(vec![0; 4].to_monero_base58(), "111111");
        assert_eq!(vec![0, 2, 250, 39].to_monero_base58(), "111zzz");
    }

    #[test]
    fn inverse_operations() {
        let mut bytes = vec![0; 10];
        getrandom::fill(&mut bytes).unwrap();
        assert_eq!(Vec::from_monero_base58(&bytes.to_monero_base58()).unwrap(), bytes);
    }
}
