import Fastify, { type FastifyInstance } from 'fastify';
import cors from '@fastify/cors';
import fastifyStatic from '@fastify/static';
import middie from '@fastify/middie';
import { existsSync, readFileSync } from 'node:fs';
import { join } from 'node:path';
import { type LibSQLDatabase } from 'drizzle-orm/libsql';
import type * as schema from '../db/schema/index';
import { appConfig } from '../config/index';
import { authPlugin } from './middleware/auth';
import { errorHandlerPlugin } from './middleware/error-handler';
import { healthRoutes } from './routes/health';
import { systemRoutes } from './routes/system';
import { channelRoutes } from './routes/channel';
import { formatProfileRoutes } from './routes/format-profile';
import { downloadRoutes } from './routes/download';
import { queueRoutes } from './routes/queue';
import { historyRoutes } from './routes/history';
import { contentRoutes } from './routes/content';
import { notificationRoutes } from './routes/notification';
import { platformSettingsRoutes } from './routes/platform-settings';
import { scanRoutes } from './routes/scan';
import { collectRoutes } from './routes/collect';
import { playlistRoutes } from './routes/playlist';
import { adhocDownloadRoutes } from './routes/adhoc-download';
import { mediaServerRoutes } from './routes/media-server';
import { websocketRoutes } from './routes/websocket';
import type { SchedulerService } from '../services/scheduler';
import type { DownloadService } from '../services/download';
import type { QueueService } from '../services/queue';
import type { HealthService } from '../services/health';
import type { DownloadEventBus } from '../services/event-bus';
import type { MissingFileScanner } from '../services/missing-file-scanner';
import type { ViteDevServer } from 'vite';

// Extend Fastify's type system so routes can access the database and scheduler
declare module 'fastify' {
  interface FastifyInstance {
    db: LibSQLDatabase<typeof schema>;
    scheduler: SchedulerService | null;
    downloadService: DownloadService | null;
    queueService: QueueService | null;
    healthService: HealthService | null;
    missingFileScanner: MissingFileScanner | null;
  }
}

export interface BuildServerOptions {
  db: LibSQLDatabase<typeof schema>;
  eventBus?: DownloadEventBus;
  /** Vite dev server instance for HMR in development — omit in production */
  vite?: ViteDevServer;
}

/**
 * Create and configure the Fastify server instance.
 * Registers CORS, auth middleware, error handler, and all route plugins.
 * The database is decorated onto the instance so routes can access it via `fastify.db`.
 */
export async function buildServer(opts: BuildServerOptions): Promise<FastifyInstance> {
  const server = Fastify({
    logger: {
      level: appConfig.logLevel,
      // Redact API key from request logs
      serializers: {
        req(request) {
          return {
            method: request.method,
            url: sanitizeUrl(request.url),
            hostname: request.hostname,
            remoteAddress: request.ip,
          };
        },
      },
    },
  });

  // Decorate with database instance for route access
  server.decorate('db', opts.db);

  // Decorate with scheduler (null until set by startup code)
  server.decorate('scheduler', null);

  // Decorate with download service (null until set by startup code)
  server.decorate('downloadService', null);

  // Decorate with queue service (null until set by startup code)
  server.decorate('queueService', null);

  // Decorate with health service (null until set by startup code)
  server.decorate('healthService', null);

  // Decorate with missing file scanner (null until set by startup code)
  server.decorate('missingFileScanner', null);

  // Register CORS — permissive for development, tightened later
  await server.register(cors, { origin: true });

  // Register centralized error handler
  await server.register(errorHandlerPlugin);

  // Register API key authentication
  await server.register(authPlugin);

  // Register route modules
  await server.register(healthRoutes);
  await server.register(systemRoutes);
  await server.register(channelRoutes);
  await server.register(formatProfileRoutes);
  await server.register(downloadRoutes);
  await server.register(queueRoutes);
  await server.register(historyRoutes);
  await server.register(contentRoutes);
  await server.register(notificationRoutes);
  await server.register(platformSettingsRoutes);
  await server.register(scanRoutes);
  await server.register(collectRoutes);
  await server.register(playlistRoutes);
  await server.register(adhocDownloadRoutes);
  await server.register(mediaServerRoutes);

  // Register WebSocket route (before static file serving so /ws is handled)
  if (opts.eventBus) {
    await server.register(websocketRoutes, { eventBus: opts.eventBus });
  }

  // ── Frontend serving ──
  // Dev mode: Vite middleware handles HMR, module transforms, and index.html
  // Production: @fastify/static serves the built frontend from dist/frontend/
  if (opts.vite) {
    // Register @fastify/middie to support Connect-style middleware
    await server.register(middie);

    // Pipe Vite's dev middleware through Fastify (HMR websocket, module transforms, etc.)
    server.use(opts.vite.middlewares);

    // SPA catch-all: transform and serve index.html through Vite's pipeline
    const vite = opts.vite;
    server.setNotFoundHandler(async (request, reply) => {
      if (
        request.method === 'GET' &&
        !request.url.startsWith('/api/') &&
        request.url !== '/ping'
      ) {
        try {
          const indexPath = join(vite.config.root, 'index.html');
          let html = readFileSync(indexPath, 'utf-8');
          html = await vite.transformIndexHtml(request.url, html);
          return reply.type('text/html').send(html);
        } catch (err) {
          // Let Vite fix the stack trace for better DX
          if (err instanceof Error) vite.ssrFixStacktrace(err);
          throw err;
        }
      }

      return reply.status(404).send({
        statusCode: 404,
        error: 'Not Found',
        message: `Route ${request.method}:${request.url} not found`,
      });
    });
  } else {
    // Production: serve pre-built static frontend
    const frontendDir = join(process.cwd(), 'dist', 'frontend');
    if (existsSync(frontendDir)) {
      await server.register(fastifyStatic, {
        root: frontendDir,
        prefix: '/',
        wildcard: false,
      });

      // SPA catch-all: serve index.html for any GET request that isn't an API route,
      // /ping, or a static file. API and non-GET requests get a standard 404 JSON.
      server.setNotFoundHandler(async (request, reply) => {
        if (
          request.method === 'GET' &&
          !request.url.startsWith('/api/') &&
          request.url !== '/ping'
        ) {
          return reply.sendFile('index.html');
        }

        return reply.status(404).send({
          statusCode: 404,
          error: 'Not Found',
          message: `Route ${request.method}:${request.url} not found`,
        });
      });
    } else {
      // No frontend build — standard 404 for all unknown routes
      server.setNotFoundHandler(async (_request, reply) => {
        return reply.status(404).send({
          statusCode: 404,
          error: 'Not Found',
          message: 'Route not found',
        });
      });
    }
  }

  return server;
}

/**
 * Strip API key query parameters from URLs before logging.
 * Prevents accidental credential leakage in log output.
 */
function sanitizeUrl(url: string): string {
  try {
    // Replace apikey query param value with [REDACTED]
    return url.replace(/([?&])apikey=[^&]*/gi, '$1apikey=[REDACTED]');
  } catch {
    return url;
  }
}