cdk/crates/cashu/src/quote_id.rs

//! Quote ID. The specifications only define a string but CDK uses Uuid, so we use an enum to port compatibility.
use std::fmt;
use std::str::FromStr;

use bitcoin::base64::engine::general_purpose;
use bitcoin::base64::Engine as _;
use serde::{de, Deserialize, Deserializer, Serialize};
use thiserror::Error;
use uuid::Uuid;

/// Invalid UUID
#[derive(Debug, Error)]
pub enum QuoteIdError {
    /// UUID Error
    #[error("invalid UUID: {0}")]
    Uuid(#[from] uuid::Error),
    /// Invalid base64
    #[error("invalid base64")]
    Base64,
    /// Invalid quote ID
    #[error("neither a valid UUID nor a valid base64 string")]
    InvalidQuoteId,
}

/// Mint Quote ID
#[derive(Serialize, Debug, Clone, PartialEq, PartialOrd, Ord, Eq, Hash)]
#[serde(untagged)]
pub enum QuoteId {
    /// (Nutshell) base64 quote ID
    BASE64(String),
    /// UUID quote ID
    UUID(Uuid),
}

impl QuoteId {
    /// Create a new UUID-based MintQuoteId
    pub fn new_uuid() -> Self {
        Self::UUID(Uuid::new_v4())
    }
}

impl From<Uuid> for QuoteId {
    fn from(uuid: Uuid) -> Self {
        Self::UUID(uuid)
    }
}

impl fmt::Display for QuoteId {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            QuoteId::BASE64(s) => write!(f, "{s}"),
            QuoteId::UUID(u) => write!(f, "{}", u.hyphenated()),
        }
    }
}

impl FromStr for QuoteId {
    type Err = QuoteIdError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        // Try UUID first
        if let Ok(u) = Uuid::parse_str(s) {
            return Ok(QuoteId::UUID(u));
        }

        // Try base64: decode, then re-encode and compare to ensure canonical form
        // Use the standard (URL/filename safe or standard) depending on your needed alphabet.
        // Here we use standard base64.
        match general_purpose::URL_SAFE.decode(s) {
            Ok(_bytes) => Ok(QuoteId::BASE64(s.to_string())),
            Err(_) => Err(QuoteIdError::InvalidQuoteId),
        }
    }
}

impl<'de> Deserialize<'de> for QuoteId {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        // Deserialize as plain string first
        let s = String::deserialize(deserializer)?;

        // Try UUID first
        if let Ok(u) = Uuid::parse_str(&s) {
            return Ok(QuoteId::UUID(u));
        }

        if general_purpose::URL_SAFE.decode(&s).is_ok() {
            return Ok(QuoteId::BASE64(s));
        }

        // Neither matched — return a helpful error
        Err(de::Error::custom(format!(
            "QuoteId must be either a UUID (e.g. {}) or a valid base64 string; got: {}",
            Uuid::nil(),
            s
        )))
    }
}