{ pkgs }:
let
  backend = "127.0.0.1:9090";
  socketio = "127.0.0.1:3000";
  frappe_site_name_header = "localhost";
  upstream_real_ip_address = "127.0.0.1";
  upstream_real_ip_header = "X-Forwarded-For";
  upstream_real_ip_recursive = "off";
  client_max_body_size = "50m";
  proxy_read_timeout = "120";
in
pkgs.writeText "erpnext.conf" ''
user  nginx;
worker_processes  auto;

error_log  /tmp/erpnext/logs/nginx/error.log notice;
pid        /tmp/erpnext/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       ${pkgs.nginx}/conf/mime.types;
    default_type  application/octet-stream;

    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  /tmp/erpnext/logs/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    upstream backend-server {
            server ${backend} fail_timeout=0;
    }

    upstream socketio-server {
            server ${socketio} fail_timeout=0;
    }

    # Parse the X-Forwarded-Proto header - if set - defaulting to $scheme.
    map $http_x_forwarded_proto $proxy_x_forwarded_proto {
            default $scheme;
            https https;
    }

    server {
            listen 8080;
            server_name ${frappe_site_name_header};
            root /tmp/erpnext/sites;

            proxy_buffer_size 128k;
            proxy_buffers 4 256k;
            proxy_busy_buffers_size 256k;

            add_header X-Frame-Options "SAMEORIGIN";
            add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload";
            add_header X-Content-Type-Options nosniff;
            add_header X-XSS-Protection "1; mode=block";
            add_header Referrer-Policy "same-origin, strict-origin-when-cross-origin";

            set_real_ip_from ${upstream_real_ip_address};
            real_ip_header ${upstream_real_ip_header};
            real_ip_recursive ${upstream_real_ip_recursive};

            location /assets {
                    try_files $uri =404;
            }

            location ~ ^/protected/(.*) {
                    internal;
                    try_files /${frappe_site_name_header}/$1 =404;
            }

            location /socket.io {
                    proxy_http_version 1.1;
                    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                    proxy_set_header X-Forwarded-Proto $proxy_x_forwarded_proto;
                    proxy_set_header Upgrade $http_upgrade;
                    proxy_set_header Connection "upgrade";
                    proxy_set_header X-Frappe-Site-Name ${frappe_site_name_header};
                    proxy_set_header Origin $scheme://${frappe_site_name_header};
                    proxy_set_header Host $host;

                    proxy_pass http://socketio-server;
            }

            location / {
                    rewrite ^(.+)/$ $proxy_x_forwarded_proto://${frappe_site_name_header}$1 permanent;
                    rewrite ^(.+)/index\.html$ $proxy_x_forwarded_proto://${frappe_site_name_header}$1 permanent;
                    rewrite ^(.+)\.html$ $proxy_x_forwarded_proto://${frappe_site_name_header}$1 permanent;

                    location ~ ^/files/.*.(htm|html|svg|xml) {
                            add_header Content-disposition "attachment";
                            try_files /${frappe_site_name_header}/public/$uri @webserver;
                    }

                    try_files /${frappe_site_name_header}/public/$uri @webserver;
            }

            location @webserver {
                    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                    proxy_set_header X-Forwarded-Proto $proxy_x_forwarded_proto;
                    proxy_set_header X-Frappe-Site-Name ${frappe_site_name_header};
                    proxy_set_header Host $host;
                    proxy_set_header X-Use-X-Accel-Redirect True;
                    proxy_read_timeout ${proxy_read_timeout};
                    proxy_redirect off;

                    proxy_pass  http://backend-server;
            }

            # optimizations
            sendfile on;
            keepalive_timeout 15;
            client_max_body_size ${client_max_body_size};
            client_body_buffer_size 16K;
            client_header_buffer_size 1k;

            # enable gzip compression
            # based on https://mattstauffer.co/blog/enabling-gzip-on-nginx-servers-including-laravel-forge
            gzip on;
            gzip_http_version 1.1;
            gzip_comp_level 5;
            gzip_min_length 256;
            gzip_proxied any;
            gzip_vary on;
            gzip_types
                    application/atom+xml
                    application/javascript
                    application/json
                    application/rss+xml
                    application/vnd.ms-fontobject
                    application/x-font-ttf
                    application/font-woff
                    application/x-web-app-manifest+json
                    application/xhtml+xml
                    application/xml
                    font/opentype
                    image/svg+xml
                    image/x-icon
                    text/css
                    text/plain
                    text/x-component;
                    # text/html is always compressed by HttpGzipModule
    }
}
''