redirect loop with mod_rewrite - apache

Question

I'm trying to add a language prefix to my pages through mod_rewrite
eg:
https://example.com/ > https://example.com/en/
and internally it need to translate to `https://example.com/?language=en
I've managed to do it for the base url, but when I try to do it with some other redirect implied, it's always end in an infinite loop.
eg:
https://example.com/product-p-22.html > https://example.com/en/product-p-22.html
and internally became `https://example.com/product_info.php?product_id=22&language=en
here is my actual config:
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_URI} !^/(en|fr)/
RewriteCond %{REQUEST_URI} .(php|html) [OR]
RewriteCond %{REQUEST_URI} ^/$
RewriteCond %{QUERY_STRING} !language=
RewriteRule ^(.*)$ en/$1 [L,R=301]
RewriteCond %{REQUEST_URI} !^/example
RewriteRule ^(.*)/$ index.php?language=$1&%{QUERY_STRING}
RewriteRule ^(.*)/(.*)-p-(.*).html$ product_info.php?products_id=$3&language=$1&%{QUERY_STRING}
I've tried many flags like L, END, DPI or some combination of those, but with no luck.
when I look at the debug logs, it seems to find the right url, but then restart parsing the default url:
pass through /var/www/example/product_info.php
init rewrite engine with requested uri /product-p-22.html
pass through /product-p-22.html
any though on what I'm doing wrong here?
Server version: Apache/2.4.41 (Ubuntu)

Answer 1

Based on your shown samples, could you please try following. Please make sure you clear your browser cache before testing your URLs.
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_URI} !^en [NC]
RewriteRule ^(.*)$ en/$1 [NC,R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^ index.php?language=en [NC,QSA,L]
RewriteRule ^([^/]*)/([^-]*)-p-([^.]*)\.html$ product_info.php?products_id=$3&language=$1& [NC,L,QSA]

Answer 2

Have it this way in your site root .htaccess:
RewriteEngine On
RewriteCond %{THE_REQUEST} !\s/+(en|fr)/ [NC]
RewriteRule ^ /en%{REQUEST_URI} [NC,R=301,L]
RewriteRule ^([a-z]{2})/[^-/]+-p-([^./]+)\.html?$ product_info.php?language=$1&products_id=$2 [L,QSA]
RewriteRule ^([a-z]{2})/$ index.php?language=$1 [QSA,L]