Convert language set iRule to LTM Policy

Here is an LTM Policy I got working that should fit your needs.

ltm policy set_language {
    last-modified 2019-01-31:10:49:10
    requires { http }
    rules {
        set_en {
            actions {
                0 {
                    http-set-cookie
                    response
                    insert
                    name i18next
                    value en
                }
                1 {
                    log
                    response
                    write
                    facility local0
                    message "Set EN Triggered"
                    priority info
                }
            }
            conditions {
                0 {
                    http-cookie
                    name i18next
                    not
                    values { en }
                }
            }
        }
        set_es {
            actions {
                0 {
                    http-set-cookie
                    response
                    insert
                    name i18next
                    value es
                }
                1 {
                    log
                    response
                    write
                    facility local0
                    message "Set ES triggered"
                    priority info
                }
            }
            conditions {
                0 {
                    http-host
                    host
                    contains
                    values { es.test.company.com }
                }
                1 {
                    http-cookie
                    name i18next
                    not
                    values { es }
                }
            }
            ordinal 1
        }
    }
    status published
    strategy all-match
}