import { GoogleGenAI, FileState, createPartFromUri, createUserContent, type File } from '@google/genai';
import type { AudioTrack } from './recorder.js';
import { buildPrompt } from './prompt.js';

const ai = new GoogleGenAI({ apiKey: process.env.GEMINI_API_KEY });
const MODEL = process.env.GEMINI_MODEL || 'gemini-2.5-flash';

const sleep = (ms: number) => new Promise((r) => setTimeout(r, ms));

async function upload(track: AudioTrack): Promise<File> {
  let file = await ai.files.upload({ file: track.file, config: { mimeType: 'audio/ogg', displayName: track.name } });
  while (file.state === FileState.PROCESSING) {
    await sleep(2000);
    file = await ai.files.get({ name: file.name! });
  }
  if (file.state === FileState.FAILED) throw new Error(`Gemini no pudo procesar el audio de ${track.name}`);
  return file;
}

export async function generateNotes(tracks: AudioTrack[], startedAt: Date): Promise<string> {
  const files: File[] = [];
  try {
    for (const track of tracks) files.push(await upload(track));

    const parts = tracks.flatMap((track, i) => [
      `Pista ${i + 1}: ${track.name}`,
      createPartFromUri(files[i].uri!, files[i].mimeType!),
    ]);
    const res = await ai.models.generateContent({
      model: MODEL,
      contents: createUserContent([buildPrompt(tracks.map((t) => t.name), startedAt), ...parts]),
    });
    const text = res.text?.trim();
    if (!text) throw new Error('Gemini devolvió una respuesta vacía');
    return text.replace(/^```(?:markdown|md)?\n([\s\S]*)\n```$/, '$1');
  } finally {
    await Promise.allSettled(files.map((f) => ai.files.delete({ name: f.name! })));
  }
}