# Alertmanager Nginx Configuration
# Proxies requests to Alertmanager

# Alertmanager location
location /alertmanager/ {
    # Rate limiting
    limit_req zone=api burst=10 nodelay;
    
    # Remove trailing slash for proxy
    rewrite ^/alertmanager/(.*)$ /$1 break;
    
    # Proxy to Alertmanager
    proxy_pass http://alertmanager_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 30s;
    proxy_read_timeout 30s;
    
    # Buffer settings
    proxy_buffering on;
    proxy_buffer_size 4k;
    proxy_buffers 8 4k;
    
    # Security headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
}

# Alertmanager API
location /api/v1/ {
    # Rate limiting
    limit_req zone=api burst=20 nodelay;
    
    # Proxy to Alertmanager
    proxy_pass http://alertmanager_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
    add_header Access-Control-Allow-Origin "*" always;
    add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS" always;
    add_header Access-Control-Allow-Headers "DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Authorization" always;
    
    # Handle preflight requests
    if ($request_method = 'OPTIONS') {
        add_header Access-Control-Allow-Origin "*";
        add_header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS";
        add_header Access-Control-Allow-Headers "DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range,Authorization";
        add_header Access-Control-Max-Age 1728000;
        add_header Content-Type "text/plain; charset=utf-8";
        add_header Content-Length 0;
        return 204;
    }
}