gemini-compat-endpoint

import fs from "fs";
import path from "path";
import { type BuildVisionPromotionPartsParams } from "./promotion";
import { readChatMediaState } from "./chat-media-state";

export async function buildPromotionPartsA(params: BuildVisionPromotionPartsParams): Promise<{ promoParts: any[]; promotedFiles: string[] }> {
  const { chatWd } = params;
  const promoParts: any[] = [];
  const promotedFiles: string[] = [];

  try {
    const state = await readChatMediaState(chatWd).catch(() => ({ attachments: [], variants: [] } as any));
    if (Array.isArray(state.attachments) && state.attachments.length) {
      for (let i = 0; i < state.attachments.length; i++) {
        const a = state.attachments[i];
        const rel = a.filename; // Mode A uses original, not analysis preview
        const abs = path.join(chatWd, rel);
        const exists = await fs.promises.stat(abs).then(() => true).catch(() => false);
        if (exists) {
          const toMime = (fn: string) => (
            /\.jpe?g$/i.test(fn)?'image/jpeg':
            /\.png$/i.test(fn)?'image/png':
            /\.webp$/i.test(fn)?'image/webp':
            /\.gif$/i.test(fn)?'image/gif':
            /\.bmp$/i.test(fn)?'image/bmp':
            /\.svg$/i.test(fn)?'image/svg+xml':
            /\.tiff?$/i.test(fn)?'image/tiff':
            /\.heic$/i.test(fn)?'image/heic':'image/jpeg'
          );
          const buf = await fs.promises.readFile(abs);
          const label = state.attachments.length > 1 ? `Attachment (A${i + 1})` : 'Attachment (A)';
          promoParts.push({ text: label });
          promoParts.push({ inlineData: { data: buf.toString('base64'), mimeType: toMime(rel) } });
          promotedFiles.push(path.basename(abs));
        }
      }
    }
  } catch (e) {
    // Soft-fail: no promotion in Mode A
  }

  return { promoParts, promotedFiles };
}