.htaccess vanity urls and clean urls together - .htaccess

Question

I've been able to set up .htaccess to enable vanity urls on my website. However, I'm encountering into a problem when I try to clean other urls on my website. I would give the scenario and my current .htaccess below:
Currently wwww.mywebsite.com/john redirects to profile.php?user=john. In profile.php I check to see user john exist in my database if false I redirect to a custom 404.php page. This work very well. The problem arises when I try to have wwww.mywebsite.com/photo/abcdefg be interpreted as www.mywebsite.com/photo.php?m=abcdefg. For some reason it believes photo is the name of the user and then rewrites it as if its a vanity url. Please see my .htaccess file code below:
ErrorDocument 404 http://www.mywebsite.com/404
RewriteEngine on
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([^\.]+)$ $1.php [NC]
RewriteRule ^([^\.]+)$ profile.php?username=$1 [L]
RewriteCond %{HTTP_HOST} ^(.*)$ [NC]
RewriteCond %{HTTP_HOST} !^(.*)\.(.*)\. [NC]
RewriteRule ^ HTTP%1://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

Answer 1

You need to do your redirect before any internal routing. Then, you need to explcitly match against /photo before you route to profile and change the .php -f:
ErrorDocument 404 http://www.mywebsite.com/404
RewriteEngine on
RewriteCond %{HTTP_HOST} ^(.*)$ [NC]
RewriteCond %{HTTP_HOST} !^(.*)\.(.*)\. [NC]
RewriteRule ^ HTTP%1://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
RewriteRule ^photo/(.+)$ /photo.php?m=$1 [L,QSA]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{DOCUMENT_ROOT}/$1.php -f
RewriteRule ^([^\.]+)$ /$1.php [L]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)$ /profile.php?username=$1 [L]