#!/bin/bash

# creates trash email for registration for online-services
# email is hashed from domain of service + login-username from linux-system
# or only unhashed service-domain
# this created email-address is added to LDAP target email als dcMailAlias
# also added to pass passwordmanager of user

[ -e ${MSC_BASE}/defaults.conf ] && . ${MSC_BASE}/defaults.conf

LDAP_HOST=${LDAP_HOST_DEFAULT}
BIND_DN=${LDAP_ADMIN_BIND_DN}
PASS_ID=${PASS_ID_LDAP_ADMIN}
OWN_DOMAIN=${TRASHMAIL_OWN_DOMAIN_DEFAULT}
TARGET_MAIL=${TRASHMAIL_TARGET_MAIL_DEFAULT}
HASHED_DEFAULT=${TRASHMAIL_HASHED_DEFAULT}
HASHLENGTH_DEFAULT=8
PWOPTS_DEFAULT="-c -n -s"
PWLENGTH_DEFAULT=50

show_help () {
    cat << EOF

    usage: ${0} <OPTIONS> <URL> [<PWLENGTH>]

    URL:	https://target.domain.tld:8080/path/to/site | target.domain.tld
    PWLENGTH:	Integer, count characters in generated password

    OPTIONS:
        --delete                        delete trashmail from LDAP
        -d				include domain from <URL> in username: 8ee948ae.target.domain.tld@mydomain.tld
        -f|--force			force overwrite existing entry in pass
        -h|--hashed			create hash from domain and linux-login-user (${USER})
        --help				show this help/usage
        -l|--length <INTEGER>|full	cut hashed part of username to <INTGER> characters from start (default: ${HASHLENGHT_DEFAULT})
        -n|--not-hashed			do not hash username from targetdomain and linux-login-user 
        -t|--target-mail <TARGET_MAIL>  Emailadress for which trashmail is created
        -w|--full-hash			do not cut hash (same as »-l full«)
        -y|--symbols			same option as in pwgen. Include at least one special character in the password.


EOF

}

# TODO: how exit main-shell from error in subshell???
getopt -u -o dfhl:nt:wy --long delete,force,hashed,help,not-hashed,hashlength:,whole-hash,symblols,target-mail: -- "$@" || exit $? 
set -- $(getopt -u -o dfhl:nt:wy --long delete,force,hashed,help,not-hashed,hashlength:,whole-hash,symblols,target-mail: -- "$@"|| exit $?)

echo @: $@
while : ; do
    case $1 in
        --delete)
            ACTION=delete
            shift
            ;;
        -d)
            INCLUDE_DOMAIN=true
            shift
            ;;
        -f|--force)
            FORCE=true
            shift
            ;;
        -h|--hashed)
            HASHED=true
            shift
            ;;
        --help)
            show_help
            exit 0
            ;;
        -l|--hashlength)
            HASHLENGTH=$2
            shift; shift;
            ;;
        -n|--not-hashed)
            HASHED=false
            shift
            ;;
        -t|--target-mail)
            TARGET_MAIL=$2
            shift; shift;
            ;;
        -w|--full-hash)
            HASHLENGTH=full
            shift;
            ;;
        -y)
            PWOPTS="${PWOPTS} -y"
            shift
            ;;
        --)
            shift
            break
            ;;
        *)
            echo wrong argument $1 >&2
            show_help
            exit 1
            ;;
    esac
done

# Urlparsing inspired by: https://gist.github.com/joshisa/297b0bc1ec0dcdda0d1625029711fa24
# Referenced and tweaked from http://stackoverflow.com/questions/6174220/parse-url-in-shell-script#6174447

URL=$1
protocol=$(echo "$1" | grep "://" | sed -e's,^\(.*://\).*,\1,g')
# Remove the protocol
url_no_protocol=$(echo "${1/$protocol/}")
# Use tr: Make the protocol lower-case for easy string compare
protocol=$(echo "$protocol" | tr '[:upper:]' '[:lower:]')


# Extract the user and password (if any)
# cut 1: Remove the path part to prevent @ in the querystring from breaking the next cut
# rev: Reverse string so cut -f1 takes the (reversed) rightmost field, and -f2- is what we want
# cut 2: Remove the host:port
# rev: Undo the first rev above 
userpass=$(echo "$url_no_protocol" | grep "@" | cut -d"/" -f1 | rev | cut -d"@" -f2- | rev)
pass=$(echo "$userpass" | grep ":" | cut -d":" -f2)
if [ -n "$pass" ]; then
  user=$(echo "$userpass" | grep ":" | cut -d":" -f1)
else
  user="$userpass"
fi

# Extract the host
hostport=$(echo "${url_no_protocol/$userpass@/}" | cut -d"/" -f1)
host=$(echo "$hostport" | cut -d":" -f1)
port=$(echo "$hostport" | grep ":" | cut -d":" -f2)
path=$(echo "$url_no_protocol" | grep "/" | cut -d"/" -f2-)

echo "Create a trashmail-address for ${host}" >&2


if ${HASHED:-$HASHED_DEFAULT}; then
    case $HASHLENGTH in
        full)
            TRASHUSER="$(echo ${host}${USER}|md5sum -|awk '{print $1}')"
            ;;
        [0-9]|[0-9][0-9])
            TRASHUSER="$(echo ${host}${USER}|md5sum -|awk '{print $1}'|cut -c-${HASHLENGTH})"
            ;;
        *)
            TRASHUSER="$(echo ${host}${USER}|md5sum -|awk '{print $1}'|cut -c-${HASHLENGTH_DEFAULT})"
            ;;
    esac

    if ${INCLUDE_DOMAIN:-false} ;then
        $INCLUDE_DOMAIN && TRASHUSER=${TRASHUSER}.${host}
    fi
    

else
    TRASHUSER=${host}
fi

TRASHMAIL=${TRASHUSER}@${OWN_DOMAIN}
echo $TRASHMAIL

PASS_ENTRY="${PASS_PREFIX%/}${PASS_PREFIX:+/}${host}/${TRASHMAIL}"

case ${ACTION:-create} in
    create)
#set -x
echo "Add new trashmail to LDAP"
cat << EOF |ldapmodify -Z -H ldap://${LDAP_HOST} -D ${BIND_DN} -x -w $(pass ${PASS_ID}|head -n 1)
dn: dcSubMailAddress=${TARGET_MAIL},ou=mailaccounts,dc=schuerz,dc=at
changetype: modify
add: dcMailAlternateAddress
dcMailAlternateAddress: ${TRASHMAIL}
EOF

if [ $? -gt 0 ]; then
    echo pass find ${PASS_ENTRY}
    pass find ${TRASHMAIL}|grep -v "Search Terms"
    case $? in
        1)
            # returncode 1 from grep means, no line selected. so no entry exists, create new one
            echo "Entry not found --> create new pass-entry"
            CREATE=true
            ;;
        0)
            if ${FORCE-false} ; then
                echo "Entry found but enforced to overwrite"
                CREATE=true
            else
                echo
                echo "Current password for ${PASS_ENTRY} is $(pass ${PASS_ENTRY} |head -n1)."
                read -p "Overwrite? [Y|n]: "
                echo ""
                case $REPLY in
                    y|Y)
                        CREATE=true
                        ;;
                    *)
                        CREATE=false
                        ;;
                esac
            fi
            ;;
        *)
            echo "Something went wrong"
            exit 2
            ;;
    esac
else
    CREATE=true
fi

if ${CREATE-false}; then
cat << EOF |pass insert -m ${PASS_ENTRY}
$(pwgen ${PWOPTS_DEFAULT} ${PWOPTS} ${2:-$PWLENGTH_DEFAULT} 1)
email: ${TRASHMAIL}
login: ${TRASHUSER}
url: ${URL}
comment: trashemail autogenerated md5-hash from »${host}${USER}« cut to ${HASHLENGTH}. Delete email, when account deleted!!!
targetmail for this trashmail is ${TARGET_MAIL}
EOF
fi
#set +x
#pass git commit "${PASS_ENTRY}"
pass -c ${PASS_ENTRY}
        ;;
    delete)
        
cat << EOF |ldapmodify -Z -H ldap://${LDAP_HOST} -D ${BIND_DN} -x -w $(pass ${PASS_ID}|head -n 1)
dn: dcSubMailAddress=${TARGET_MAIL},ou=mailaccounts,dc=schuerz,dc=at
changetype: modify
delete: dcMailAlternateAddress
dcMailAlternateAddress: ${TRASHMAIL}
EOF
        ;;
    *)
        echo action $ACTION not known
        exit 1
        ;;
esac