# AniWorld Nginx Configuration
# Reverse proxy configuration for the Flask application

worker_processes auto;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;

events {
    worker_connections 1024;
    use epoll;
    multi_accept on;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    # Logging format
    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;

    # Performance settings
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    server_tokens off;

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types
        text/plain
        text/css
        text/xml
        text/javascript
        application/json
        application/javascript
        application/xml+rss
        application/atom+xml
        image/svg+xml;

    # Rate limiting
    limit_req_zone $binary_remote_addr zone=login:10m rate=5r/m;
    limit_req_zone $binary_remote_addr zone=api:10m rate=30r/m;
    limit_req_zone $binary_remote_addr zone=general:10m rate=60r/m;

    # Upstream backend
    upstream aniworld_backend {
        server aniworld-web:5000 max_fails=3 fail_timeout=30s;
        keepalive 32;
    }

    # HTTP server (redirect to HTTPS if SSL is enabled)
    server {
        listen 80;
        server_name _;

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

        # Redirect to HTTPS if SSL certificate exists
        location / {
            if (-f /etc/nginx/ssl/server.crt) {
                return 301 https://$host$request_uri;
            }
            # If no SSL, proxy directly
            try_files $uri @proxy_to_app;
        }

        location @proxy_to_app {
            proxy_pass http://aniworld_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;
            proxy_connect_timeout 30s;
            proxy_send_timeout 30s;
            proxy_read_timeout 30s;
        }
    }

    # HTTPS server (if SSL certificate is available)
    server {
        listen 443 ssl http2;
        server_name _;

        # SSL configuration (if certificates exist)
        ssl_certificate /etc/nginx/ssl/server.crt;
        ssl_certificate_key /etc/nginx/ssl/server.key;
        ssl_session_cache shared:SSL:1m;
        ssl_session_timeout 5m;
        ssl_ciphers HIGH:!aNULL:!MD5;
        ssl_prefer_server_ciphers on;

        # Security headers
        add_header X-Frame-Options "SAMEORIGIN" always;
        add_header X-XSS-Protection "1; mode=block" always;
        add_header X-Content-Type-Options "nosniff" always;
        add_header Referrer-Policy "no-referrer-when-downgrade" always;
        add_header Content-Security-Policy "default-src 'self' http: https: data: blob: 'unsafe-inline'" always;
        add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;

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

        # Rate limited endpoints
        location /login {
            limit_req zone=login burst=3 nodelay;
            try_files $uri @proxy_to_app;
        }

        location /api/ {
            limit_req zone=api burst=10 nodelay;
            try_files $uri @proxy_to_app;
        }

        # Static files caching
        location ~* \.(css|js|png|jpg|jpeg|gif|ico|svg)$ {
            expires 1y;
            add_header Cache-Control "public, immutable";
            try_files $uri @proxy_to_app;
        }

        # WebSocket support for SocketIO
        location /socket.io/ {
            proxy_pass http://aniworld_backend;
            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;
        }

        # Main application
        location / {
            limit_req zone=general burst=20 nodelay;
            try_files $uri @proxy_to_app;
        }

        location @proxy_to_app {
            proxy_pass http://aniworld_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;
            
            # Timeouts
            proxy_connect_timeout 30s;
            proxy_send_timeout 60s;
            proxy_read_timeout 60s;
            
            # Buffer settings
            proxy_buffering on;
            proxy_buffer_size 4k;
            proxy_buffers 8 4k;
            
            # Error handling
            proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;
        }

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