Regex to validate an email input with the following rules...

Whole address:

• Up to 254 characters.
• Case insensitive.
• Username and domain separated by @ symbol.
• Only one @ symbol allowed.
• No spaces allowed.

Username:

• 1 to 64 characters.
• Any letter, digit and symbol from these #!%$'&+*-/=?^_.{|}~ are allowed.
• It cannot start or end with a dot.
• It cannot have two (or more) consecutive dots.

Domain:

• Only letters, digits and hyphens (and dots of course) allowed.
• It cannot start or end with a dot.
• Unlimited number of labels separated by one dot allowed.
• No label can start nor end with hyphens.
• It cannot have two (or more) consecutive dots.
• 2 to 63 characters per label.
• It cannot have an all-numerical TLD.