import { Injectable, NestMiddleware, Logger } from '@nestjs/common';
import { FastifyRequest, FastifyReply } from 'fastify';
import { TenantDatabaseService } from './tenant-database.service';

@Injectable()
export class TenantMiddleware implements NestMiddleware {
  private readonly logger = new Logger(TenantMiddleware.name);

  constructor(private readonly tenantDbService: TenantDatabaseService) {}

  async use(
    req: FastifyRequest['raw'],
    res: FastifyReply['raw'],
    next: () => void,
  ) {
    try {
      // Extract subdomain from hostname
      const host = req.headers.host || '';
      const hostname = host.split(':')[0]; // Remove port if present
      
      // Check Origin header to get frontend subdomain (for API calls)
      const origin = req.headers.origin as string;
      const referer = req.headers.referer as string;
      
      let parts = hostname.split('.');

      this.logger.log(`Host header: ${host}, hostname: ${hostname}, origin: ${origin}, referer: ${referer}, parts: ${JSON.stringify(parts)}`);

      // For local development, accept x-tenant-id header
      let tenantId = req.headers['x-tenant-id'] as string;
      let subdomain: string | null = null;

      this.logger.log(`Host header: ${host}, hostname: ${hostname}, parts: ${JSON.stringify(parts)}, x-tenant-id: ${tenantId}`);

      // Try to extract subdomain from Origin header first (for API calls from frontend)
      if (origin) {
        try {
          const originUrl = new URL(origin);
          const originHost = originUrl.hostname;
          parts = originHost.split('.');
          this.logger.log(`Using Origin header hostname: ${originHost}, parts: ${JSON.stringify(parts)}`);
        } catch (error) {
          this.logger.warn(`Failed to parse origin: ${origin}`);
        }
      } else if (referer && !tenantId) {
        // Fallback to Referer if no Origin
        try {
          const refererUrl = new URL(referer);
          const refererHost = refererUrl.hostname;
          parts = refererHost.split('.');
          this.logger.log(`Using Referer header hostname: ${refererHost}, parts: ${JSON.stringify(parts)}`);
        } catch (error) {
          this.logger.warn(`Failed to parse referer: ${referer}`);
        }
      }

      // Extract subdomain (e.g., "tenant1" from "tenant1.routebox.co")
      // For production domains with 3+ parts, extract first part as subdomain
      if (parts.length >= 3) {
        subdomain = parts[0];
        // Ignore www subdomain
        if (subdomain === 'www') {
          subdomain = null;
        }
      }
      // For development (e.g., tenant1.localhost), also check 2 parts
      else if (parts.length === 2 && parts[1] === 'localhost') {
        subdomain = parts[0];
      }

      this.logger.log(`Extracted subdomain: ${subdomain}`);

      // Always attach subdomain to request if present
      if (subdomain) {
        (req as any).subdomain = subdomain;
      }

      // If x-tenant-id is explicitly provided, use it directly but still keep subdomain
      if (tenantId) {
        this.logger.log(`Using explicit x-tenant-id: ${tenantId}`);
        (req as any).tenantId = tenantId;
        next();
        return;
      }

      // Always attach subdomain to request if present
      if (subdomain) {
        (req as any).subdomain = subdomain;
      }

      // Check if this is a central subdomain
      const centralSubdomains = (process.env.CENTRAL_SUBDOMAINS || 'central,admin').split(',');
      const isCentral = subdomain && centralSubdomains.includes(subdomain);

      // If it's a central subdomain, skip tenant resolution
      if (isCentral) {
        this.logger.log(`Central subdomain detected: ${subdomain}, skipping tenant resolution`);
        (req as any).subdomain = subdomain;
        next();
        return;
      }

      // Get tenant by subdomain if available
      if (subdomain) {
        try {
          const tenant = await this.tenantDbService.getTenantByDomain(subdomain);
          if (tenant) {
            tenantId = tenant.id;
            this.logger.log(
              `Tenant identified: ${tenant.name} (${tenant.id}) from subdomain: ${subdomain}`,
            );
          }
        } catch (error) {
          this.logger.warn(`No tenant found for subdomain: ${subdomain}`, error.message);
          // Fall back to using subdomain as tenantId directly if domain lookup fails
          tenantId = subdomain;
          this.logger.log(`Using subdomain as tenantId fallback: ${tenantId}`);
        }
      }

      if (tenantId) {
        // Attach tenant info to request object
        (req as any).tenantId = tenantId;
      } else {
        this.logger.warn(`No tenant identified from host: ${hostname}`);
      }

      next();
    } catch (error) {
      this.logger.error('Error in tenant middleware', error);
      next();
    }
  }
}