/**
 * Investigation Overview synthesis API route.
 *
 * Route: POST /api/cases/overview
 *
 * Thin route pattern — no overview business logic here.
 */

import { getProvider, getProviderModelName } from "@/lib/llm/provider.js";
import { synthesizeInvestigationOverview } from "@/lib/graph/investigation-overview-synthesis.js";
import { withAuthenticatedApi } from "@/lib/supabase/api-auth.js";

async function post(request) {
  try {
    const body = await request.json();

    if (!body || typeof body !== "object") {
      return Response.json(
        { success: false, stage: "request_validation", error: "Invalid request body" },
        { status: 400 }
      );
    }

    const { situationGraph, findings, plausibleInterpretations } = body;

    if (!situationGraph) {
      return Response.json(
        { success: false, stage: "request_validation", error: "Missing situationGraph" },
        { status: 400 }
      );
    }

    const result = await synthesizeInvestigationOverview(
      { situationGraph, findings, plausibleInterpretations },
      {
        provider: getProvider(),
        modelName: getProviderModelName(),
      }
    );

    return Response.json(
      { success: true, understanding: result.understanding, plausibleInterpretations: result.plausibleInterpretations },
      { status: 200 }
    );
  } catch (error) {
    if (error instanceof SyntaxError) {
      return Response.json(
        { success: false, stage: "request_validation", error: "Invalid JSON request body" },
        { status: 400 }
      );
    }

    if (error.statusCode) {
      return Response.json(
        {
          success: false,
          stage: error.statusCode === 400 ? "request_validation" : "provider",
          error: error.statusCode === 400
            ? "Invalid overview request"
            : "Reasoning request could not be completed.",
        },
        { status: error.statusCode }
      );
    }

    return Response.json(
      { success: false, stage: "internal", error: "Internal server error" },
      { status: 500 }
    );
  }
}

export const POST = withAuthenticatedApi(post);