events {
    worker_connections 1024;
}

http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;
    
    # Logging
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;
    error_log   /var/log/nginx/error.log   warn;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_types
        application/atom+xml
        application/geo+json
        application/javascript
        application/x-javascript
        application/json
        application/ld+json
        application/manifest+json
        application/rdf+xml
        application/rss+xml
        application/xhtml+xml
        application/xml
        font/eot
        font/otf
        font/ttf
        image/svg+xml
        text/css
        text/javascript
        text/plain
        text/xml;

    # Rate limiting
    limit_req_zone $binary_remote_addr zone=api:10m rate=10r/s;
    limit_req_zone $binary_remote_addr zone=auth:10m rate=5r/m;

    # Security headers
    add_header X-Content-Type-Options nosniff;
    add_header X-Frame-Options DENY;
    add_header X-XSS-Protection "1; mode=block";
    add_header Referrer-Policy "strict-origin-when-cross-origin";
    add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; font-src 'self' https://fonts.gstatic.com; img-src 'self' data: https://*.openstreetmap.org https://server.arcgisonline.com; connect-src 'self' https://api.openweathermap.org https://*.openstreetmap.org https://server.arcgisonline.com;";

    upstream backend {
        server backend:5000;
    }

    upstream frontend {
        server frontend:3000;
    }

    server {
        listen 80;
        server_name localhost;

        # API routes
        location /api/ {
            limit_req zone=api burst=20 nodelay;
            
            proxy_pass http://backend;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            
            # CORS headers for API
            add_header Access-Control-Allow-Origin $http_origin;
            add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS";
            add_header Access-Control-Allow-Headers "Origin, X-Requested-With, Content-Type, Accept, Authorization";
            add_header Access-Control-Allow-Credentials true;
            
            # Handle preflight requests
            if ($request_method = 'OPTIONS') {
                add_header Access-Control-Allow-Origin $http_origin;
                add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS";
                add_header Access-Control-Allow-Headers "Origin, X-Requested-With, Content-Type, Accept, Authorization";
                add_header Access-Control-Allow-Credentials true;
                add_header Content-Length 0;
                add_header Content-Type text/plain;
                return 204;
            }
        }

        # Auth routes with stricter rate limiting
        location /api/auth/ {
            limit_req zone=auth burst=5 nodelay;
            
            proxy_pass http://backend;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
        }

        # Health check endpoint
        location /health {
            proxy_pass http://backend;
            access_log off;
        }

        # Static files and React app
        location / {
            proxy_pass http://frontend;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            
            # Handle React Router
            try_files $uri $uri/ @fallback;
        }

        # Fallback for React Router (SPA)
        location @fallback {
            proxy_pass http://frontend;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
        }

        # Cache static assets
        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
            proxy_pass http://frontend;
            expires 1y;
            add_header Cache-Control "public, immutable";
        }

        # Security - deny access to sensitive files
        location ~ /\. {
            deny all;
            access_log off;
            log_not_found off;
        }

        location ~ ~$ {
            deny all;
            access_log off;
            log_not_found off;
        }
    }
}