#!/bin/sh
# vim: set sw=4 ts=4 sts=4 et :

pinentry() {
    if [ -n "${TMUX}" ] && [ -z "${DISPLAY}" ]; then
        # We're running in a TMUX pane, launch a new window to handle
        # passphrase/confirmation prompt
        unset t1 t2
        mkfifo "${t1:=$(mktemp -u)}"
        mkfifo "${t2:=$(mktemp -u)}"
        tmux new-window sh -c "exec pinentry -T \$(tty) < '$t1' > '$t2'"
        cat > "$t1"
        cat "$t2"
        rm -f "$t1" "$t2"
        return
    elif [ -n "${SSH_TTY}" ]; then
        # We're in an SSH session, so prompt for the passphrase on the
        # SSH client terminal
        set -- -T "${SSH_TTY}" "$@"
    elif [ -t 0 ]; then
        set -- -T $(tty) "$@"
    elif [ -t 1 ]; then
        set -- -T $(tty <&1) "$@"
    elif [ -t 2 ]; then
        set -- -T $(tty <&2) "$@"
    fi
    command pinentry "$@"
}

prompt_confirm() {
    result=$(pinentry -g <<EOF | grep -E '^(D|ERR)'
SETTITLE ssh-askpass
SETDESC $1
SETOK Yes
SETCANCEL No
CONFIRM
EOF
)
        echo "${result}" >&2
    case "${result}" in
    *cancelled*)
        exit 255
        ;;
    '')
        exit 0
        ;;
    *)
        echo "${result}" >&2
        exit 1
        ;;
    esac
}

prompt_notify() {
    pinentry -g <<EOF || :
SETTITLE ssh-askpass
SETDESC $1
SETTIMEOUT 3
MESSAGE
EOF
}

prompt_passphrase() {
    result=$(pinentry -g <<EOF | grep -E '^(D|ERR)'
SETTITLE ssh-askpass
SETDESC $1
SETPROMPT Passphrase:
GETPIN
EOF
)
    case "${result}" in
    *cancelled*)
        exit 255
        ;;
    D*)
        echo "${result#D }"
        ;;
    *)
        echo "${result}" >&2
        exit 1
        ;;
    esac
}

arg="$(echo "$1" | sed ':a;N;$!ba;s/\n/%0A/g')"
case "${SSH_ASKPASS_PROMPT}" in
confirm)
    prompt_confirm "${arg}"
    ;;
none)
    prompt_notify "${arg}"
    ;;
*)
    prompt_passphrase "${arg}"
    ;;
esac