web/app/api/compare/route.ts

import { NextRequest, NextResponse } from "next/server";
import { createClient } from "@/lib/supabase/server";

const GRADIO_URL = process.env.CLAUSEGUARD_GRADIO_URL || "https://gaurv007-clauseguard.hf.space";

export async function POST(req: NextRequest) {
  try {
    const supabase = await createClient();
    const { data: { user } } = await supabase.auth.getUser();

    if (!user) {
      return NextResponse.json({ error: "Unauthorized. Please log in." }, { status: 401 });
    }

    const body = await req.json();
    let { text_a, text_b } = body;

    if (!text_a || !text_b || text_a.trim().length < 50 || text_b.trim().length < 50) {
      return NextResponse.json(
        { error: "Both contracts must have at least 50 characters." },
        { status: 400 }
      );
    }
    
    // Sanitize basically
    text_a = text_a.replace(/</g, "&lt;").replace(/>/g, "&gt;");
    text_b = text_b.replace(/</g, "&lt;").replace(/>/g, "&gt;");

    // Call Gradio Space API
    const submitRes = await fetch(`${GRADIO_URL}/gradio_api/call/run_comparison`, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ data: [text_a, text_b] }),
    });

    if (!submitRes.ok) {
      throw new Error(`Gradio submit failed: ${submitRes.status}`);
    }

    const { event_id } = await submitRes.json();
    if (!event_id) throw new Error("No event_id from Gradio");

    // Poll for result
    const resultRes = await fetch(
      `${GRADIO_URL}/gradio_api/call/run_comparison/${event_id}`,
      { headers: { Accept: "text/event-stream" } }
    );

    if (!resultRes.ok) {
      throw new Error(`Gradio result failed: ${resultRes.status}`);
    }

    const resultText = await resultRes.text();
    const dataMatch = resultText.match(/event:\s*complete\s*\ndata:\s*(.+)/);
    if (!dataMatch) throw new Error("No complete event from Gradio");

    const gradioData = JSON.parse(dataMatch[1]);
    // gradioData[0] = comparison HTML
    // gradioData[1] = raw JSON comparison data

    const comparisonResult = gradioData[1];
    if (typeof comparisonResult === "object" && comparisonResult !== null) {
      return NextResponse.json(comparisonResult);
    }

    // If it's a string (JSON stringified), parse it
    if (typeof comparisonResult === "string") {
      return NextResponse.json(JSON.parse(comparisonResult));
    }

    throw new Error("Unexpected comparison result format");
  } catch (error: any) {
    console.error("Compare error:", error.message);
    return NextResponse.json({ error: error.message || "Comparison failed" }, { status: 500 });
  }
}