// vDeepSeek (stub): multi-modal (image) attachment support.
//
// When a message carries images, DeepSeek V4 models can process them
// natively via the @ai-sdk/deepseek provider. This module provides the
// helper types and functions to detect and convert image attachments.
//
// FULL INTEGRATION requires:
//   1. Storing image data alongside messages (message_parts with kind='image'
//      or a dedicated attachments table with base64-encoded data).
//   2. Extending OpenAiMessage.content from `string | null` to
//      `string | null | Array<{ type: 'text'; text: string } | { type: 'image'; image: string }>`
//      in apps/server/src/services/inference/payload.ts.
//   3. Updating toModelMessages() in stream-phase-adapter.ts to emit AI SDK
//      content arrays with image parts for multimodal user messages.
//
// None of the above is done yet — this file is a type scaffold.

import type { Message } from '../../types/api.js';

/** Shape of a decoded image attachment ready for the AI SDK. */
export interface ImageAttachment {
  /** Base64-encoded image data (no data URI prefix — raw bytes). */
  data: string;
  /** MIME type (e.g. 'image/png', 'image/jpeg', 'image/webp'). */
  mimeType: string;
}

/**
 * Check if a user message has image content that can be forwarded to a
 * multimodal model. Currently a stub — always returns false until the
 * message-pipeline stores image attachments addressably.
 */
export function hasImageAttachments(_message: Message): boolean {
  // TODO(vDeepSeek): scan message_parts for kind='image' or inspect
  // message.content for inline data URIs (data:image/...).
  return false;
}

/**
 * Convert internal image attachments to the format expected by the AI SDK
 * ModelMessage content array.
 *
 * The @ai-sdk/deepseek provider accepts images as:
 *   { type: 'image'; image: 'data:image/png;base64,...' }
 *
 * @param attachments — List of decoded image attachments.
 * @returns AI SDK inline file parts suitable for ModelMessage.content.
 */
export function imageAttachmentsToParts(
  attachments: ImageAttachment[],
): Array<{ type: 'image'; image: string }> {
  return attachments.map((a) => ({
    type: 'image' as const,
    image: `data:${a.mimeType};base64,${a.data}`,
  }));
}