// What can go wrong serving a blob, by whose fault it is: each kind is one
// HTTP status, and says how long the answer may be cached.

export class HttpError extends Error {
    readonly status: number;
    /** The Cache-Control the error response carries. */
    readonly cache: string;

    constructor(status: number, message: string, cache: string) {
        super(message);
        this.status = status;
        this.cache = cache;
    }
}

/** The URL can never name a blob: cacheable for a day. */
export class BadRequest extends HttpError {
    constructor(message: string) {
        super(400, message, 'public, max-age=86400');
    }
}

/**
 * The account or the blob does not exist. Cached briefly: a blob may be
 * uploaded moments before the record pointing at it is published.
 */
export class NotFound extends HttpError {
    constructor(message: string) {
        super(404, message, 'public, max-age=300');
    }
}

/** The PDS, the PLC directory or a DID's host failed us. Never cached. */
export class Upstream extends HttpError {
    constructor(message: string) {
        super(502, message, 'no-store');
    }
}