import type { ReplyPayload } from "../../auto-reply/reply-payload.js";

import { openLocalFileSafely } from "../../infra/fs-safe.js";

import { assertNoWindowsNetworkPath, safeFileURLToPath } from "../../infra/local-file-access.js";

import { estimateBase64DecodedBytes } from "../../media/base64.js";

import { assertLocalMediaAllowed, LocalMediaAccessError } from "../../media/local-media-access.js";

import { isAudioFileName } from "../../media/mime.js";

import { resolveSendableOutboundReplyParts } from "../../plugin-sdk/reply-payload.js";

return MIME_BY_EXT[ext] ?? "audio/mpeg";

}

function estimateBase64DecodedBytes(base64: string): number {

const sanitized = base64.replace(/\s+/g, "");

const padding = sanitized.endsWith("==") ? 2 : sanitized.endsWith("=") ? 1 : 0;

return Math.floor((sanitized.length * 3) / 4) - padding;

function isBase64DataPayload(value: string): boolean {

if (value.length === 0) {

return false;

}

for (let index = 0; index < value.length; index += 1) {

const code = value.charCodeAt(index);

const isBase64Char =

(code >= 0x41 && code <= 0x5a) ||

(code >= 0x61 && code <= 0x7a) ||

(code >= 0x30 && code <= 0x39) ||

code === 0x2b ||

code === 0x2f ||

code === 0x3d;

const isWhitespace =

code === 0x09 ||

code === 0x0a ||

code === 0x0b ||

code === 0x0c ||

code === 0x0d ||

code === 0x20;

if (!isBase64Char && !isWhitespace) {

return false;

}

}

return true;

}

function resolveEmbeddableImageUrl(url: string): string | null {

if (trimmed.length > MAX_WEBCHAT_IMAGE_DATA_URL_CHARS) {

return null;

}

const match = /^data:(image\/[a-z0-9.+-]+);base64,([a-z0-9+/=\s]+)$/i.exec(trimmed);

if (!match) {

const commaIndex = trimmed.indexOf(",");

if (commaIndex < 0) {

return null;

}

const metadata = trimmed.slice(0, commaIndex);

const match = /^data:(image\/[a-z0-9.+-]+);base64$/i.exec(metadata);

const base64Data = trimmed.slice(commaIndex + 1);

if (!match || !isBase64DataPayload(base64Data)) {

return null;

}

const mediaType = normalizeLowercaseStringOrEmpty(match[1]);

const base64Data = match[2];

if (!ALLOWED_WEBCHAT_DATA_IMAGE_MEDIA_TYPES.has(mediaType)) {

return null;

}