import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";
import { requireSession } from "@/lib/api-auth";
import { createPresignedUploadPost } from "@/lib/storage";
import { checkAndIncrementTierLimit, TierLimitError } from "@/lib/tiers";

const ALLOWED_TYPES = ["image/jpeg", "image/png", "image/webp", "image/avif"] as const;
type AllowedType = (typeof ALLOWED_TYPES)[number];
const MAX_FILE_SIZE = 5 * 1024 * 1024;

const Schema = z.object({
  contentType: z.string().refine((t): t is AllowedType => (ALLOWED_TYPES as readonly string[]).includes(t), {
    message: "Content type must be jpeg, png, webp, or avif",
  }),
  fileSize: z.number().int().positive().max(MAX_FILE_SIZE, "File exceeds 5MB limit"),
});

export async function POST(req: NextRequest) {
  const { session, response } = await requireSession();
  if (response) return response;

  const body = await req.json() as unknown;
  const parsed = Schema.safeParse(body);
  if (!parsed.success) {
    return NextResponse.json({ error: "Validation error", issues: parsed.error.issues }, { status: 400 });
  }

  const { contentType, fileSize } = parsed.data;

  try {
    const sizeMb = Math.ceil(fileSize / (1024 * 1024));
    await checkAndIncrementTierLimit(session!.user.id, session!.user.tier as "free" | "pro" | "family", "storage", sizeMb);
  } catch (err) {
    if (err instanceof TierLimitError) {
      return NextResponse.json({ error: "Storage limit reached for your tier" }, { status: 403 });
    }
    throw err;
  }

  const ext = contentType.split("/")[1] ?? "jpg";
  const key = `user-avatars/${session!.user.id}/${crypto.randomUUID()}.${ext}`;
  const { url, fields } = await createPresignedUploadPost(key, contentType, MAX_FILE_SIZE);

  return NextResponse.json({ url, fields, key });
}