Nginx to server secure and not secure traffic

[hsrmmr]

We have secure and no secure domains for our website  e.g. secure.xyz.com 
and xyz.com

I used following like to make single server handle both port 80 and 443
traffic.

http://nginx.org/en/docs/http/configuring_https_servers.html#single_http_https_server

server {
    listen              80;
    listen              443 ssl;
    server_name      secure.xyz.com  xyz.com;
    ....
    ssl_certificate    secure.xyz.com.crt;
    ssl_certificate_key secure.xyz.com.key;
    ...
}

Every thing works fine except that $_SERVER variables 'SERVER_NAME' is set
to 'secure.xyz.com' .

My question is :
1. Does Nginx always picks the first server from the config ... irrespective
of what client has requested and passes to  proxy (php-fpm)?

2. We have a lot of rules, so if we create two separate server (as per
following) do I need to copy the rules in both places? It there any
maintainable way, like 'include /common_rules.conf'?  


server {
    listen          443;
    server_name     secure.xyz.com;
    ssl             on;
    ssl_certificate   secure.xyz.com.crt;
    ...
    include  common_rules.conf;          ===>???
 }

server {
    listen          80;
    server_name     xyz.com;
    ...
    include common_rules.conf;           ===>???
}

Any help is highly appreciated.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,231295,231295#msg-231295