import { NextFunction, Request, Response, Router } from "express";
import { DEFAULT_MODEL, DEFAULT_OPENAI_BASE_URL } from "../config";
import { OpenAIResponsesClient } from "../services/openaiResponsesClient";
import { ok } from "../utils/http";

export function buildTestConnectionRouter(client: OpenAIResponsesClient): Router {
  const router = Router();

  const handler = async (req: Request, res: Response, next: NextFunction) => {
    try {
      const body = (req.body ?? {}) as Record<string, unknown>;
      const llmProvider = body.llmProvider === "local" ? "local" : "openai";
      const model = String(body.model ?? DEFAULT_MODEL);
      const baseUrl = String(body.baseUrl ?? DEFAULT_OPENAI_BASE_URL);
      const apiKey = String(body.apiKey ?? process.env.OPENAI_API_KEY ?? "");
      const result = await client.testConnection({
        llmProvider,
        apiKey,
        model,
        baseUrl
      });

      let modelFound: boolean | null = null;
      let modelsCount: number | null = null;
      if (llmProvider === "local") {
        try {
          const models = await client.listModels({
            llmProvider,
            apiKey,
            model,
            baseUrl
          });
          modelsCount = models.length;
          modelFound = models.includes(model);
        } catch {
          modelFound = null;
          modelsCount = null;
        }
      }

      ok(res, {
        ok: true,
        provider: llmProvider,
        model: result.model,
        model_found: modelFound,
        models_count: modelsCount,
        timestamp: new Date().toISOString()
      });
    } catch (error) {
      next(error);
    }
  };

  const listModelsHandler = async (req: Request, res: Response, next: NextFunction) => {
    try {
      const body = (req.body ?? {}) as Record<string, unknown>;
      const models = await client.listModels({
        llmProvider: body.llmProvider === "local" ? "local" : "openai",
        apiKey: String(body.apiKey ?? process.env.OPENAI_API_KEY ?? ""),
        model: String(body.model ?? DEFAULT_MODEL),
        baseUrl: String(body.baseUrl ?? DEFAULT_OPENAI_BASE_URL)
      });
      ok(res, {
        ok: true,
        models,
        count: models.length,
        timestamp: new Date().toISOString()
      });
    } catch (error) {
      next(error);
    }
  };

  router.post("/api/llm/test-connection", handler);
  router.post("/api/llm/models", listModelsHandler);
  // Backward-compatible route for old frontend builds.
  router.post("/api/openai/test-connection", handler);
  router.post("/api/openai/models", listModelsHandler);

  return router;
}