zesdex/crates/zesdex-cms/src/domain/error.rs

//! Domain error types for the CMS crate.
//!
//! Typed error enums for repository and service operations.
//! `From` impls connect `std::io::Error` and `serde_json::Error` into
//! `RepositoryError`, and `RepositoryError` into `ServiceError`.
//! Anyhow's blanket `From<E: StdError + Send + Sync + 'static>`
//! covers conversion to `anyhow::Error` for downstream code.

use std::fmt;

// ---------------------------------------------------------------------------
// RepositoryError
// ---------------------------------------------------------------------------

/// Errors from repository / persistence operations in the CMS domain.
#[derive(Debug)]
pub enum RepositoryError {
    /// The requested entity does not exist.
    NotFound(String),
    /// A conflict occurred (e.g. duplicate entry).
    Conflict(String),
    /// An I/O error occurred during persistence.
    Io(std::io::Error),
    /// A serialisation / deserialisation error occurred.
    Serialization(serde_json::Error),
    /// The supplied identifier is invalid (e.g. path traversal attempt).
    InvalidId(String),
    /// An error that could not be downcast to a specific variant.
    Other(String),
}

impl RepositoryError {
    /// Convert an `anyhow::Error` to `RepositoryError` by attempting
    /// downcast to known inner types.
    pub fn from_anyhow(e: anyhow::Error) -> Self {
        if let Some(ioe) = e.downcast_ref::<std::io::Error>() {
            return RepositoryError::Io(std::io::Error::new(ioe.kind(), ioe.to_string()));
        }
        RepositoryError::Other(e.to_string())
    }
}

impl fmt::Display for RepositoryError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            RepositoryError::NotFound(msg) => write!(f, "not found: {msg}"),
            RepositoryError::Conflict(msg) => write!(f, "conflict: {msg}"),
            RepositoryError::Io(e) => write!(f, "I/O error: {e}"),
            RepositoryError::Serialization(e) => write!(f, "serialization error: {e}"),
            RepositoryError::InvalidId(msg) => write!(f, "invalid id: {msg}"),
            RepositoryError::Other(msg) => write!(f, "{msg}"),
        }
    }
}

impl std::error::Error for RepositoryError {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        match self {
            RepositoryError::Io(e) => Some(e),
            RepositoryError::Serialization(e) => Some(e),
            _ => None,
        }
    }
}

impl From<std::io::Error> for RepositoryError {
    fn from(e: std::io::Error) -> Self {
        RepositoryError::Io(e)
    }
}

impl From<serde_json::Error> for RepositoryError {
    fn from(e: serde_json::Error) -> Self {
        RepositoryError::Serialization(e)
    }
}

// ---------------------------------------------------------------------------
// ServiceError
// ---------------------------------------------------------------------------

/// Errors from service / use-case operations in the CMS domain.
#[derive(Debug)]
pub enum ServiceError {
    /// A repository operation failed.
    Repository(RepositoryError),
    /// The provided input is invalid.
    InvalidInput(String),
    /// A generic error with a message.
    Other(String),
}

impl fmt::Display for ServiceError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ServiceError::Repository(e) => write!(f, "repository error: {e}"),
            ServiceError::InvalidInput(msg) => write!(f, "invalid input: {msg}"),
            ServiceError::Other(msg) => write!(f, "{msg}"),
        }
    }
}

impl std::error::Error for ServiceError {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        match self {
            ServiceError::Repository(e) => Some(e),
            _ => None,
        }
    }
}

impl From<RepositoryError> for ServiceError {
    fn from(e: RepositoryError) -> Self {
        ServiceError::Repository(e)
    }
}