Options -MultiViews
RewriteEngine On
RewriteBase /

# remove .php; use THE_REQUEST to prevent infinite loops
RewriteCond %{HTTP_HOST} ^arm-admin\.arenacapitals\.com
RewriteCond %{THE_REQUEST} ^GET\ (.*)\.php\ HTTP
RewriteRule (.*)\.php$ $1 [R=301]

# remove index
RewriteRule (.*)index$ $1 [R=301]

# remove slash if not directory
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} /$
RewriteRule (.*)/ $1 [R=301]

# add .php to access file, but don't redirect
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteCond %{REQUEST_URI} !/$
RewriteRule (.*) $1\.php [L]