//! The HTTP-facing error type returned by fallible handlers.

use axum::http::StatusCode;
use axum::response::{IntoResponse, Response};
use thiserror::Error;

/// Error returned by request handlers.
#[derive(Debug, Error)]
pub enum AppError {
    /// An internal server error wrapping any anyhow error.
    #[error("internal server error: {0}")]
    Internal(#[from] anyhow::Error),

    /// The request was malformed.
    #[error("{0}")]
    BadRequest(String),

    /// The request was unauthenticated or the session was invalid.
    #[error("unauthorized")]
    Unauthorized,

    /// The caller is authenticated but not allowed to do this.
    #[error("forbidden")]
    Forbidden,

    /// Nothing exists at this URL.
    #[error("not found")]
    NotFound,
}

impl IntoResponse for AppError {
    fn into_response(self) -> Response {
        let status = match &self {
            AppError::Internal(_) => StatusCode::INTERNAL_SERVER_ERROR,
            AppError::BadRequest(_) => StatusCode::BAD_REQUEST,
            AppError::Unauthorized => StatusCode::UNAUTHORIZED,
            AppError::Forbidden => StatusCode::FORBIDDEN,
            AppError::NotFound => StatusCode::NOT_FOUND,
        };
        (status, self.to_string()).into_response()
    }
}