import { NextRequest, NextResponse } from "next/server";
import { createClient } from "@/lib/supabase/server";
import { checkRateLimit } from "@/lib/rate-limit";
import OpenAI from "openai";

const openai = new OpenAI({
  apiKey: process.env.OPENAI_API_KEY,
});

export async function POST(request: NextRequest) {
  try {
    // Auth check
    const supabase = await createClient();
    const { data: { user }, error: authError } = await supabase.auth.getUser();

    if (authError || !user) {
      return NextResponse.json(
        { error: "Unauthorized" },
        { status: 401 }
      );
    }

    // Rate limiting
    const ip = request.ip ?? request.headers.get("x-forwarded-for") ?? "unknown";
    const rateLimit = await checkRateLimit(ip);

    if (!rateLimit.allowed) {
      return NextResponse.json(
        { error: "Rate limit exceeded. Please try again later." },
        { status: 429 }
      );
    }

    // Parse FormData
    const formData = await request.formData();
    const audioFile = formData.get("audio") as File | null;

    if (!audioFile) {
      return NextResponse.json(
        { error: "No audio file provided" },
        { status: 400 }
      );
    }

    // Validate file type
    const validTypes = ["audio/webm", "audio/mp4", "audio/mpeg", "audio/wav", "audio/ogg"];
    if (!validTypes.includes(audioFile.type)) {
      return NextResponse.json(
        { error: "Invalid audio file type" },
        { status: 400 }
      );
    }

    // Validate file size (max 25MB for Whisper)
    const maxSize = 25 * 1024 * 1024; // 25MB
    if (audioFile.size > maxSize) {
      return NextResponse.json(
        { error: "Audio file too large. Maximum size is 25MB." },
        { status: 400 }
      );
    }

    // Convert File to Buffer for OpenAI
    const bytes = await audioFile.arrayBuffer();
    const buffer = Buffer.from(bytes);

    // Create a File-like object for OpenAI
    const file = new File([buffer], "recording.webm", { type: audioFile.type });

    // Transcribe using Whisper
    const transcription = await openai.audio.transcriptions.create({
      file: file,
      model: "whisper-1",
      language: "en",
    });

    return NextResponse.json({
      transcript: transcription.text,
      remaining: rateLimit.remaining,
    });
  } catch (error) {
    console.error("Transcription error:", error);
    return NextResponse.json(
      { error: "Failed to transcribe audio" },
      { status: 500 }
    );
  }
}