# Production Nginx Configuration for GNX Soft
# Place this in /etc/nginx/sites-available/gnxsoft
# Symlink to /etc/nginx/sites-enabled/gnxsoft
#
# DEPLOYMENT NOTES (Host Deployment):
# 1. Frontend: Next.js production build runs on port 1087
#    - Build: cd frontEnd && npm run build
#    - Start: Use start-services.sh script or PM2: PORT=1087 pm2 start npm --name "gnxsoft-frontend" -- start
# 2. Backend: Django runs on port 1086 (internal only)
#    - Use start-services.sh script or PM2: gunicorn gnx.wsgi:application --bind 127.0.0.1:1086 --workers 3
# 3. Database: PostgreSQL on host (port 5433 to avoid conflict with Docker instance on 5432)
# 4. Use install-postgresql.sh to install and configure PostgreSQL
# 5. Use start-services.sh to start both backend and frontend services
#
# NOTE: Rate limiting zones must be defined in the main nginx.conf http context
# Add these lines to /etc/nginx/nginx.conf inside the http {} block:
#   limit_req_zone $binary_remote_addr zone=api_limit:10m rate=10r/s;
#   limit_req_zone $binary_remote_addr zone=general_limit:10m rate=100r/s;

# Frontend - Public facing (Next.js Production Server on port 1087)
upstream frontend {
    server 127.0.0.1:1087;
    keepalive 64;
}

# Backend - Internal only (Django on port 1086)
upstream backend_internal {
    server 127.0.0.1:1086;
    keepalive 64;
}

# Redirect HTTP to HTTPS
server {
    listen 80;
    listen [::]:80;
    server_name gnxsoft.com www.gnxsoft.com;
    
    # Let's Encrypt validation
    location /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }
    
    # Redirect all other traffic to HTTPS
    location / {
        return 301 https://$server_name$request_uri;
    }
}

# HTTPS Frontend
server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name gnxsoft.com www.gnxsoft.com;

    # SSL Configuration
    ssl_certificate /etc/letsencrypt/live/gnxsoft.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/gnxsoft.com/privkey.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-RSA-AES256-GCM-SHA512:DHE-RSA-AES256-GCM-SHA512:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-SHA384;
    ssl_prefer_server_ciphers on;
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 10m;

    # Security Headers
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    add_header Permissions-Policy "camera=(), microphone=(), geolocation=(), interest-cohort=()" always;

    # Rate Limiting (zones must be defined in main nginx.conf http context)
    limit_req_status 429;

    # Client settings
    client_max_body_size 10M;
    client_body_timeout 30s;
    client_header_timeout 30s;

    # Logging
    access_log /var/log/nginx/gnxsoft_access.log;
    error_log /var/log/nginx/gnxsoft_error.log warn;

    # IMPORTANT: More specific location blocks MUST come before location /
    # Order matters in nginx - longest match wins

    # API Proxy - Frontend talks to backend ONLY through this internal proxy
    # Backend port 1086 is BLOCKED from internet by firewall
    location /api/ {
        limit_req zone=api_limit burst=20 nodelay;
        
        # Internal proxy to backend (127.0.0.1:1086)
        # Backend is NOT accessible from public internet
        proxy_pass http://backend_internal/api/;
        proxy_http_version 1.1;
        
        # Add internal API key (must match INTERNAL_API_KEY in Django .env)
        set $api_key "9hZtPwyScigoBAl59Uvcz_9VztSRC6Zt_6L1B2xTM2M";
        proxy_set_header X-Internal-API-Key $api_key;
        
        # Backend sees request as coming from localhost
        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;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Port $server_port;
        
        # Hide backend server info
        proxy_hide_header X-Powered-By;
        proxy_hide_header Server;
        
        # Timeouts
        proxy_connect_timeout 30s;
        proxy_send_timeout 30s;
        proxy_read_timeout 30s;
        
        # CORS headers (if needed)
        add_header Access-Control-Allow-Origin "https://gnxsoft.com" always;
        add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS" always;
        add_header Access-Control-Allow-Headers "Authorization, Content-Type, X-Internal-API-Key" always;
        add_header Access-Control-Allow-Credentials "true" always;
        
        # Handle preflight requests
        if ($request_method = 'OPTIONS') {
            return 204;
        }
    }

    # Media files (served by nginx directly for better performance)
    location /media/ {
        alias /var/www/GNX-WEB/backEnd/media/;
        expires 30d;
        add_header Cache-Control "public, immutable";
        access_log off;
        
        # Security
        location ~ \.(php|py|pl|sh)$ {
            deny all;
        }
    }

    # Static files (served by nginx directly)
    location /static/ {
        alias /var/www/GNX-WEB/backEnd/staticfiles/;
        expires 1y;
        add_header Cache-Control "public, immutable";
        access_log off;
    }

    # Next.js image optimization API - must be proxied to Next.js server
    # Use regex to match /_next/image with query strings
    location ~ ^/_next/image {
        proxy_pass http://frontend;
        proxy_http_version 1.1;
        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;
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Port $server_port;
        
        # Preserve query string
        proxy_pass_request_headers on;
        
        # Timeouts for image processing
        proxy_connect_timeout 30s;
        proxy_send_timeout 30s;
        proxy_read_timeout 30s;
        
        # Buffer settings for image processing
        proxy_buffering on;
        proxy_buffer_size 4k;
        proxy_buffers 8 4k;
        
        # Cache optimized images
        proxy_cache_valid 200 1d;
        add_header Cache-Control "public, max-age=86400";
    }

    # Next.js static files - serve directly from filesystem for better performance
    location /_next/static/ {
        alias /var/www/GNX-WEB/frontEnd/.next/static/;
        expires 1y;
        add_header Cache-Control "public, immutable";
        access_log off;
        
        # Correct MIME types
        types {
            text/css css;
            application/javascript js;
            application/json json;
            font/woff2 woff2;
            font/woff woff;
            font/ttf ttf;
            image/png png;
            image/jpeg jpg jpeg;
            image/webp webp;
            image/svg+xml svg;
        }
    }

    # Frontend public images - use prefix location (must come before root location)
    location /images/ {
        alias /var/www/GNX-WEB/frontEnd/public/images/;
        expires 30d;
        add_header Cache-Control "public, immutable";
        access_log off;
        
        # Ensure proper MIME types
        types {
            image/png png;
            image/jpeg jpg jpeg;
            image/gif gif;
            image/svg+xml svg;
            image/webp webp;
        }
        default_type application/octet-stream;
        
        # Try files, then fallback
        try_files $uri =404;
    }

    # Root location - Frontend (Next.js) - MUST be last
    location / {
        limit_req zone=general_limit burst=50 nodelay;
        
        proxy_pass http://frontend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        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;
        proxy_cache_bypass $http_upgrade;
        
        # Timeouts
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
    }

    # Deny access to hidden files
    location ~ /\. {
        deny all;
        access_log off;
        log_not_found off;
    }

    # Admin panel - Proxy to backend (with IP restriction)
    location /admin/ {
        # IP restriction is handled by Django middleware
        # Add internal API key (must match INTERNAL_API_KEY in Django .env)
        set $api_key "9hZtPwyScigoBAl59Uvcz_9VztSRC6Zt_6L1B2xTM2M";
        proxy_set_header X-Internal-API-Key $api_key;
        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;
        
        proxy_pass http://backend_internal;
        proxy_redirect off;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
        
        # Timeouts
        proxy_connect_timeout 30s;
        proxy_send_timeout 30s;
        proxy_read_timeout 30s;
    }

    # Health check endpoint
    location /health {
        access_log off;
        return 200 "OK\n";
        add_header Content-Type text/plain;
    }
}

# ==============================================================================
# IMPORTANT SECURITY NOTES:
# ==============================================================================
# 1. Backend runs on 127.0.0.1:1086 (internal only)
# 2. Frontend runs on 127.0.0.1:1087 (internal only)
# 3. Firewall BLOCKS external access to ports 1086 and 1087
# 4. Only nginx can reach backend/frontend (internal network)
# 5. Public internet can ONLY access nginx (ports 80, 443)
# 6. All API calls go through nginx proxy (/api/* → 127.0.0.1:1086/api/*)
# 7. Backend IP whitelist middleware ensures only localhost requests
# 8. Rate limiting zones must be added to /etc/nginx/nginx.conf http {} block
# 9. PostgreSQL runs on port 5433 (to avoid conflict with Docker on 5432)
# ==============================================================================