import { NextRequest, NextResponse } from "next/server";
import {
  activateProPlan,
  adminResetUserCredits,
  grantExtraCredits,
  markFreeTopUpPurchased,
} from "@/lib/billing";
import { FREE_TOP_UP_CREDITS } from "@/lib/credits";
import { isBillingDevMock } from "@/lib/stripe";
import { getSessionUser } from "@/lib/session";

/**
 * Local-only billing helpers (no Stripe CLI required).
 * Enabled when NODE_ENV=development (unless BILLING_DEV_MOCK=false) or BILLING_DEV_MOCK=true.
 */
function assertDev() {
  if (!isBillingDevMock()) {
    return NextResponse.json({ error: "Not available outside development mock mode" }, { status: 404 });
  }
  return null;
}

export async function POST(req: NextRequest) {
  const blocked = assertDev();
  if (blocked) return blocked;

  const user = await getSessionUser();
  if (!user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  let body: {
    action?: string;
    credits?: number;
    plan?: "FREE" | "PREMIUM";
  };
  try {
    body = await req.json();
  } catch {
    return NextResponse.json({ error: "Invalid JSON" }, { status: 400 });
  }

  const action = body.action ?? "grant-credits";

  switch (action) {
    case "grant-credits": {
      const credits = Math.floor(Number(body.credits ?? FREE_TOP_UP_CREDITS));
      if (!Number.isFinite(credits) || credits <= 0) {
        return NextResponse.json({ error: "Invalid credits" }, { status: 400 });
      }
      await grantExtraCredits(user.id, credits);
      return NextResponse.json({ ok: true, granted: credits });
    }
    case "free-top-up": {
      await markFreeTopUpPurchased(user.id);
      return NextResponse.json({ ok: true, granted: FREE_TOP_UP_CREDITS });
    }
    case "set-pro": {
      await activateProPlan(user.id, {
        stripeSubscriptionId: `dev_sub_${Date.now()}`,
        cardLast4: "4242",
      });
      return NextResponse.json({ ok: true, plan: "PREMIUM" });
    }
    case "set-free": {
      await adminResetUserCredits(user.id, { plan: "FREE", creditsUsed: 0 });
      return NextResponse.json({ ok: true, plan: "FREE" });
    }
    case "reset-cycle": {
      await adminResetUserCredits(user.id, {
        plan: body.plan,
        creditsUsed: 0,
      });
      return NextResponse.json({ ok: true, reset: true });
    }
    default:
      return NextResponse.json({ error: `Unknown action: ${action}` }, { status: 400 });
  }
}

/** Convenience GET for quick browser testing: /api/dev/grant-credits?action=set-pro */
export async function GET(req: NextRequest) {
  const blocked = assertDev();
  if (blocked) return blocked;

  const action = req.nextUrl.searchParams.get("action") ?? "grant-credits";
  const credits = Number(req.nextUrl.searchParams.get("credits") ?? FREE_TOP_UP_CREDITS);

  const fake = new NextRequest(req.url, {
    method: "POST",
    headers: { "content-type": "application/json", cookie: req.headers.get("cookie") ?? "" },
    body: JSON.stringify({ action, credits }),
  });
  return POST(fake);
}