# Document Translation API - Main Server Block
# HTTP to HTTPS redirect and main application routing

# HTTP server - redirect to HTTPS
server {
    listen 80;
    listen [::]:80;
    server_name _;

    # Allow health checks on HTTP
    location /health {
        proxy_pass http://backend/health;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
    }

    # ACME challenge for Let's Encrypt
    location /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }

    # Redirect all other traffic to HTTPS
    location / {
        return 301 https://$host$request_uri;
    }
}

# HTTPS server - main application
server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name _;

    # SSL certificates (replace with your paths)
    ssl_certificate /etc/nginx/ssl/fullchain.pem;
    ssl_certificate_key /etc/nginx/ssl/privkey.pem;
    ssl_trusted_certificate /etc/nginx/ssl/chain.pem;

    # SSL configuration
    ssl_session_timeout 1d;
    ssl_session_cache shared:SSL:50m;
    ssl_session_tickets off;

    # Modern SSL configuration
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384;
    ssl_prefer_server_ciphers off;

    # OCSP Stapling
    ssl_stapling on;
    ssl_stapling_verify on;
    resolver 8.8.8.8 8.8.4.4 valid=300s;
    resolver_timeout 5s;

    # Security headers
    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 Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
    add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self' data:; connect-src 'self' ws: wss:;" always;

    # API routes - proxy to backend
    location /api/ {
        rewrite ^/api/(.*)$ /$1 break;
        
        limit_req zone=api_limit burst=20 nodelay;
        limit_conn conn_limit 10;

        proxy_pass http://backend;
        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 Connection "";
        
        # CORS headers for API
        add_header Access-Control-Allow-Origin $http_origin always;
        add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS" always;
        add_header Access-Control-Allow-Headers "Authorization, Content-Type, X-Requested-With" always;
        add_header Access-Control-Allow-Credentials "true" always;

        if ($request_method = 'OPTIONS') {
            return 204;
        }
    }

    # File upload endpoint - special handling
    location /translate {
        limit_req zone=upload_limit burst=5 nodelay;
        limit_conn conn_limit 5;

        proxy_pass http://backend/translate;
        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;
        
        # Increased timeouts for file processing
        proxy_connect_timeout 60s;
        proxy_send_timeout 600s;
        proxy_read_timeout 600s;
    }

    # Health check endpoint
    location /health {
        proxy_pass http://backend/health;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
    }

    # Admin endpoints
    location /admin {
        limit_req zone=api_limit burst=10 nodelay;
        
        proxy_pass http://backend/admin;
        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;
    }

    # Frontend - Next.js application
    location / {
        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 Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }

    # Static files caching
    location /_next/static/ {
        proxy_pass http://frontend;
        proxy_cache_valid 200 365d;
        add_header Cache-Control "public, max-age=31536000, immutable";
    }

    # Error pages
    error_page 500 502 503 504 /50x.html;
    location = /50x.html {
        root /usr/share/nginx/html;
    }
}