nginx rewrites with exclusions

I have a site which recently changed its page structure to add the ability for multiple languages (/en/ for English, /fr/ for French). I have the following rewrite rules in my server {} block:

    try_files $uri $uri/ @abc;
    location @abc {
            if ($uri !~ "^/(.*)\/(.*)$") {
                    rewrite ^/(.*)$ /en/$1 permanent;
            }
            rewrite ^/(.*)\/(.*)$ /index.php?lang=$1&page=$2;
    }
    rewrite ^/$ /en/$1 permanent;

It's a little bit of a mess, but I can't seem to accomplish what I need:

• All links accessed should be checked to see if the file exists (works)
• All 'ol开发者_开发技巧d' links such as /abc should be 301'd to /en/abc (works, but seems hackish)
• The root of the site should be redirected to /en/ (works)
• Links in the format /en/abc should be sent to index.php as ?lang=$1&page=$2 (this includes /en/abc/123 where abc/123 is $2 and en is $1). $2 can have any length, such as abc/123/456

What I have 'seems' to work fine, but sub pages abc/123 seem to set $1 to en/abc and $2 to 123 which isn't desired and results in a 404 error as the script can't find the page 123. Thanks in advance for any answers!

Try this

try_files $uri $uri/ @abc;
location @abc {
        if ($uri !~ "^/([^\/]*)\/([^\/]*)$") {
                rewrite ^/(.*)$ /en/$1 permanent;
        }
        rewrite ^/([^\/]*)\/([^\/]*)$ /index.php?lang=$1&page=$2;
}
rewrite ^/$ /en/$1 permanent;

I have replace .* with [^\/]*.