server {
    listen 80;
    server_name localhost;

    root /usr/share/nginx/html;
    index index.html;

    resolver ${RESOLVER} valid=30s ipv6=off;

    # 静态资源：命中直接返回文件并长时间缓存；缺失返回 404，绝不回退成 HTML，
    # 避免 CDN/网关把误回退的 index.html 当资源缓存造成 MIME 报错。
    location /assets/ {
        try_files $uri =404;
        expires 1y;
        add_header Cache-Control "public, max-age=31536000, immutable";
        access_log off;
    }

    # index.html 不缓存，保证每次回源拿到最新 hash 引用。
    location = /index.html {
        add_header Cache-Control "no-cache";
    }

    location / {
        try_files $uri $uri/ /index.html;
    }

    # The system frontend prefixes canonical /sys paths with /api.
    location /api/sys/ {
        set $backend_host __BACKEND_HOST__;
        set $backend_port __BACKEND_PORT__;
        rewrite ^/api/(.*)$ /$1 break;
        proxy_pass http://$backend_host:$backend_port;
        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 10s;
        proxy_read_timeout 360s;
        proxy_send_timeout 360s;
    }

    # CRM controllers already use /api as part of their canonical path.
    location /api/ {
        set $backend_host __BACKEND_HOST__;
        set $backend_port __BACKEND_PORT__;
        proxy_pass http://$backend_host:$backend_port;
        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 10s;
        proxy_read_timeout 360s;
        proxy_send_timeout 360s;
    }

    location /sys/ {
        set $backend_host __BACKEND_HOST__;
        set $backend_port __BACKEND_PORT__;
        proxy_pass http://$backend_host:$backend_port;
        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 10s;
        proxy_read_timeout 360s;
        proxy_send_timeout 360s;
    }
}