/**

* Media type detection — pure functions for classifying files by MIME or extension.

*

* These replace the inline `isImageFile`, `isVideoFile`, `isAudioFile` helpers

* scattered across `outbound.ts`. Centralizing them here ensures consistent

* detection across both the built-in and standalone versions.

* These replace the inline `isImageFile` and `isVideoFile` helpers scattered

* across `outbound.ts`. Centralizing them here keeps detection consistent.

*/

/** Supported media kind for QQ Bot outbound routing. */

export type MediaKind = "image" | "voice" | "video" | "file";

const IMAGE_EXTENSIONS = new Set([".jpg", ".jpeg", ".png", ".gif", ".webp", ".bmp"]);

const VIDEO_EXTENSIONS = new Set([".mp4", ".mov", ".avi", ".mkv", ".webm", ".flv", ".wmv"]);

const AUDIO_EXTENSIONS = new Set([

".mp3",

".wav",

".ogg",

".flac",

".aac",

".m4a",

".wma",

".opus",

".amr",

".silk",

".slk",

".pcm",

]);

/**

* Extract a lowercase file extension from a path or URL, ignoring query and hash.

}

return VIDEO_EXTENSIONS.has(getCleanExtension(filePath));

}

/** Check whether a file is audio using MIME first and extension as fallback. */

export function isAudioFile(filePath: string, mimeType?: string): boolean {

if (mimeType) {

if (

mimeType.startsWith("audio/") ||

mimeType === "voice" ||

mimeType.includes("silk") ||

mimeType.includes("amr")

) {

return true;

}

}

return AUDIO_EXTENSIONS.has(getCleanExtension(filePath));

}