I am very new in rewriting in nginx but although I've spent 2 days reading on forums, I still can't get some Codeigniter rewrites working ...

server {
    listen *:80;


    server_name artademy.com www.artademy.com;

    root   /var/www/artademy.com/web;

    index index.html index.htm index.php index.cgi index.pl index.xhtml;



    if (!-e $request_filename)
{
    rewrite ^/(.*)$ /index.php?/$1;
}

    if (!-e $request_filename)
{
    rewrite ^/(index.php\?)/(.*)$ /$1/mobile_app last;
    break;
}


    error_log /var/log/ispconfig/httpd/artademy.com/error.log;
    access_log /var/log/ispconfig/httpd/artademy.com/access.log combined;

    ## Disable .htaccess and other hidden files
    location ~ /\. {
        deny all;
        access_log off;
        log_not_found off;
    }

    location = /favicon.ico {
        log_not_found off;
        access_log off;
    } 

    location = /robots.txt {
        allow all;
        log_not_found off;
        access_log off;
    }

    location /stats {
        index index.html index.php;
        auth_basic "Members Only";
        auth_basic_user_file /var/www/clients/client0/web3/.htpasswd_stats;
    }

    location ^~ /awstats-icon {
                     alias /usr/share/awstats/icon;
     }

    location ~ \.php$ {
        try_files $uri =404;
        include /etc/nginx/fastcgi_params;
        fastcgi_pass 127.0.0.1:9012;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param PATH_INFO $fastcgi_script_name;
        fastcgi_intercept_errors on;
    }

 }

Codeigniter settings are: well for uri_protocol: REQUEST_URI;

What i noticed is that from this rule: rewrite ^/(.)$ /index.php?/$1; it works ever if i write it like this: rewrite ^/(.)$ /index.php?; It might be a wild guess but it stops at the question mark... Anyhow what I need are rules as these from .htaccess:

 RewriteCond %{REQUEST_FILENAME} !-f
        RewriteCond %{QUERY_STRING} ^lang=([a-z]{2})$ 
        RewriteRule    ^([a-z]{2})$   index.php?/home_page?lang=$1 [L,QSA]
        RewriteRule    ^([a-z]{2})$   index.php?/home_page?lang=$1 [L,QSA]

        #how_it_works
        RewriteCond %{REQUEST_FILENAME} !-f
        RewriteRule    ^how-it-works/(en)$   index.php?/how_it_works?lang=en [L,QSA]

        #order_status
        RewriteCond %{REQUEST_FILENAME} !-f
        RewriteRule    ^order-status/(en)$   index.php?/order_status?lang=en [L,QSA]

Can anyone tell me what i'm doing wrong and show me a proper way for at least one rule? It would be more than helpful. Thank you in advance! ^^

PS: I made it work on apache by using Path_info for uri_protocol.. if this info is of any help, and i remember having kind of the same problem there too but switching to path_info made it all good.