import { NestFactory } from "@nestjs/core";
import { AppModule } from "./app.module";
import { ValidationPipe } from "@nestjs/common";
import { DocumentBuilder, SwaggerModule } from "@nestjs/swagger";
import { NestExpressApplication } from "@nestjs/platform-express";
import { join } from "path";
import helmet from "helmet";

async function bootstrap() {
  const app = await NestFactory.create<NestExpressApplication>(AppModule);

  // Serve static files under /public/ for our uploads local bucket
  app.useStaticAssets(join(__dirname, "..", "public"), {
    prefix: "/public/",
  });

  // Set API Prefix and exclude root health check endpoints for container pings
  app.setGlobalPrefix("api", { exclude: ["/", "health"] });

  // Apply Helmet for security headers
  app.use(
    helmet({
      contentSecurityPolicy: false, // Ensure Swagger UI doesn't break
    }),
  );

  // Enable CORS
  const allowedOrigins = process.env.ALLOWED_ORIGINS
    ? process.env.ALLOWED_ORIGINS.split(",")
    : [
        "http://localhost:3000",
        "http://localhost:3001",
        "http://localhost:5173",
      ];

  app.enableCors({
    origin: (origin, callback) => {
      if (
        !origin ||
        allowedOrigins.includes("*") ||
        allowedOrigins.includes(origin)
      ) {
        callback(null, true);
      } else {
        callback(new Error("Not allowed by CORS"));
      }
    },
    methods: "GET,HEAD,PUT,PATCH,POST,DELETE,OPTIONS",
    credentials: true,
  });

  // Global validation pipeline
  app.useGlobalPipes(
    new ValidationPipe({
      whitelist: true,
      transform: true,
      forbidNonWhitelisted: true,
    }),
  );

  // Setup Swagger Open API Docs in development or when explicitly enabled.
  const enableSwagger =
    process.env.NODE_ENV !== "production" ||
    process.env.ENABLE_SWAGGER === "true";
  if (enableSwagger) {
    const config = new DocumentBuilder()
      .setTitle("PhiloMind AI Learning API")
      .setDescription(
        "Immersive AI philosophy learning endpoints including debate, podcasts, and spaced repetition flashcards.",
      )
      .setVersion("1.0.0")
      .addBearerAuth()
      .build();
    const document = SwaggerModule.createDocument(app, config);
    SwaggerModule.setup("docs", app, document);
  }

  // Force port 7860 in Hugging Face Spaces environment to satisfy health check routing, otherwise fallback to PORT or 3001
  const port = process.env.SPACE_ID ? 7860 : process.env.PORT || 3001;
  await app.listen(port, "0.0.0.0");
  console.log(
    `[PhiloMind Backend] Service is running on port ${port} (bind 0.0.0.0)`,
  );
  if (enableSwagger) {
    console.log(
      `[PhiloMind Swagger] Documentation is available at http://localhost:${port}/docs`,
    );
  }
}
bootstrap();