import { defineCodes, SuaveplanError } from "@suaveplan/error";

/**
 * Stable error codes for the `@suaveplan/streams-metadata` package. Every
 * code is reachable from a real call site in `src/`.
 */
export const STREAMS_METADATA_CODES = defineCodes("STREAMS_METADATA", [
    "MIME_FAILED",
    "EXIF_FAILED",
    "INVALID_PAYLOAD",
    "ABORTED",
] as const);

export type StreamsMetadataErrorCode =
    (typeof STREAMS_METADATA_CODES)[keyof typeof STREAMS_METADATA_CODES];

interface ErrorOpts {
    cause?: unknown;
    message?: string;
}

function asErrorCause(c: unknown): Error | undefined {
    return c instanceof Error ? c : undefined;
}

/** Base error class for every `@suaveplan/streams-metadata` failure. */
export class StreamsMetadataError extends SuaveplanError<StreamsMetadataErrorCode> {}

/**
 * Thrown by `MimeTransform` when MIME detection encounters an internal
 * exception. The documented `application/octet-stream` fallback does NOT
 * raise this — it is reserved for engine-level failures.
 */
export class MimeDetectionFailedError extends StreamsMetadataError {
    constructor(opts: ErrorOpts = {}) {
        super(
            STREAMS_METADATA_CODES.MIME_FAILED,
            opts.message ?? "MIME detection failed",
            { cause: asErrorCause(opts.cause) }
        );
    }
}

/**
 * Thrown by `ExifTransform` when `@suaveplan/exif::readMetadata` raises.
 * Preserves the underlying `ExifError` on `cause`.
 */
export class ExifFailedError extends StreamsMetadataError {
    constructor(opts: ErrorOpts = {}) {
        super(
            STREAMS_METADATA_CODES.EXIF_FAILED,
            opts.message ?? "EXIF extraction failed",
            { cause: asErrorCause(opts.cause) }
        );
    }
}

/**
 * Thrown when a transform receives a payload missing the mandatory `bytes`
 * field.
 */
export class InvalidPayloadError extends StreamsMetadataError {
    constructor(opts: ErrorOpts = {}) {
        super(
            STREAMS_METADATA_CODES.INVALID_PAYLOAD,
            opts.message ??
                "Streams-metadata payload is missing required `bytes` Uint8Array"
        );
    }
}

/**
 * Thrown when a transform is invoked with an already-aborted `AbortSignal`
 * by callers that want every error in the streams-metadata namespace.
 * Delegated to from `BaseTransform.assertNotAborted` indirectly when callers
 * opt in to the typed wrapping.
 */
export class MetadataAbortedError extends StreamsMetadataError {
    constructor(opts: ErrorOpts = {}) {
        super(
            STREAMS_METADATA_CODES.ABORTED,
            opts.message ?? "Streams-metadata operation aborted",
            { cause: asErrorCause(opts.cause) }
        );
    }
}