import { NextRequest, NextResponse } from "next/server";
import fs from "fs/promises";
import path from "path";
import { FREE_PLAN } from "@/lib/constants";
import { getSessionUser } from "@/lib/session";
import { getUploadDir } from "@/lib/storage";

const ALLOWED_IMAGE_TYPES = ["image/jpeg", "image/png", "image/webp", "image/gif"];
const ALLOWED_AUDIO_TYPES = [
  "audio/mpeg",
  "audio/mp3",
  "audio/wav",
  "audio/x-wav",
  "audio/ogg",
  "audio/flac",
  "audio/aac",
  "audio/mp4",
  "audio/x-m4a",
];

export async function POST(req: NextRequest) {
  const user = await getSessionUser();
  if (!user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  const formData = await req.formData();
  const file = formData.get("file") as File | null;
  const type = formData.get("type") as string | null;

  if (!file || !type) {
    return NextResponse.json({ error: "Missing file or type" }, { status: 400 });
  }

  if (file.size > FREE_PLAN.maxFileSizeBytes) {
    return NextResponse.json(
      { error: `File exceeds ${FREE_PLAN.maxFileSizeBytes / (1024 * 1024)} MB limit` },
      { status: 400 },
    );
  }

  const allowedTypes = type === "image" ? ALLOWED_IMAGE_TYPES : ALLOWED_AUDIO_TYPES;
  if (!allowedTypes.includes(file.type) && !file.name.match(/\.(mp3|wav|ogg|flac|aac|m4a|jpg|jpeg|png|webp|gif)$/i)) {
    return NextResponse.json({ error: "Invalid file type" }, { status: 400 });
  }

  const sessionDir = path.join(getUploadDir(), user.id, "sessions", Date.now().toString());
  await fs.mkdir(sessionDir, { recursive: true });

  const safeName = file.name.replace(/[^a-zA-Z0-9._-]/g, "_");
  const filePath = path.join(sessionDir, safeName);
  const buffer = Buffer.from(await file.arrayBuffer());
  await fs.writeFile(filePath, buffer);

  return NextResponse.json({
    path: filePath,
    filename: file.name,
    size: file.size,
  });
}