#!/bin/sh

_main() {
    opts="$@"

    if [ -z "$opts" ] ; then
        _help
    fi

    for o in $opts ; do
        case "$o" in
            g) 
                ARG="${opts#* }" ;
                ARG="${ARG%% *}" ;
                if [ "$o" == "$ARG" ] ; then
                    _err "Option usage: '-$o /path/to/pubkey'"
                    return 1
                fi
                GPG_PUBKEY="$ARG" _install_gpg_pubkey
                ;;
            G) 
                ARG="${opts#* }" ;
                ARG="${ARG%% *}" ;
                if [ "$o" == "$ARG" ] ; then
                    _err "Option usage: '-$o /path/to/seckey'"
                    return 1
                fi
                GPG_SECKEY="$ARG" _install_gpg_seckey
                ;;
            s)
                ARG="${opts#* }" ;
                ARG="${ARG%% *}" ;
                if [ "$o" == "$ARG" ] ; then
                    _err "Option usage: '-$o /path/to/pubkey'"
                    return 1
                fi
                SSH_PUBKEY="$ARG" _install_ssh_pubkey
                ;;
            S)
                ARG="${opts#* }" ;
                ARG="${ARG%% *}" ;
                if [ "$o" == "$ARG" ] ; then
                    _err "Option usage: '-$o /path/to/seckey'"
                    return 1
                fi
                SSH_SECKEY="$ARG" _install_ssh_seckey
                ;;
            h)
                _help
                ;;
            *)
                if [ "$o" != "$ARG" ] ; then
                    _err "Unknown option '-$o'"
                    return 1
                fi
                ;;
        esac
        opts="${opts#* }"
    done
}

_log() {
    printf '\033[34mLog:\033[0m \033[2m%s\033[0m\n' "$1"
}

_warn() {
    printf '\033[33mWarn:\033[0m \033[2m%s\033[0m\n' "$1"
}

_err() {
    printf '\033[31mError:\033[0m \033[2m%s\033[0m\n' "$1" >&2
}

_help() {
    printf '\033[2mUsage:\033[0m \033[36m%s\033[0m \033[34m[OPTION]\033[0m\033[2m...\033[0m \033[35m[ARGUMENT]\033[0m\033[2m...\033[0m
  -g /path/to/pubkey    \033[2mInstall public gpg key\033[0m
  -G /path/to/seckey    \033[2mInstall private gpg key\033[0m
  -s /path/to/pubkey    \033[2mInstall public ssh key\033[0m
  -S /path/to/seckey    \033[2mInstall private ssh key\033[0m
' "$0"
}

_prompt() {
    printf '%s [y/N]: ' "$1"
    read -r opt
    if [ "$opt" == "y" ] ; then
        return 0
    else
        return 1
    fi
}

_missing() {
    missing=
    for p in $(echo "$@" | tr ' ' '\n' | sort -u) ; do
        if ! command -v "$p" >&- 2>&- ; then
            missing="$missing $p"
        fi
    done

    if [ -n "$missing" ] ; then
        echo "${missing# }"
        return 127
    else
        return 0
    fi
}

_install_gpg_pubkey() {
    missing="$(_missing gpg)"
    if [ -n "$missing" ] ; then
        _err "The following commands are missing from PATH: $missing"
        return 127
    fi

    if ! [ -f "$GPG_PUBKEY" ] ; then
        _err "Bad gpg pubkey path"
        return 1
    fi

    if [ -z "$GNUPGHOME" ] ; then
        if ! _prompt '$GNUPGHOME is not defined, continue? (default to ~/.gnupg)' ; then
            return 1
        else
            GNUPGHOME="$HOME/.gnupg"
        fi
    fi

    if ! [ -d "$GNUPGHOME" ] ; then
        mkdir -p "$GNUPGHOME"
        chmod 700 "$GNUPGHOME"
    fi

    key_info="$(gpg -q --show-keys "$GPG_PUBKEY")"

    if [ -z "${key_info//sec*/}" ] ; then
        _err "Failed to import public key $GPG_PUBKEY, appears to be secret key"
        return 1
    fi

    fingerprint="$(echo "$key_info" | sed '/^  *[A-Za-z0-9]*/!d;s/ //g')"

    if [ "$?" != "0" ] ; then
        _err 'Could not get fingerprint'
        return 1
    fi

    gpg -q --batch --import "$GPG_PUBKEY"

    if [ "$?" != "0" ] ; then
        _err 'Could not import public key'
        return 1
    fi

    _log "Imported $GPG_PUBKEY"

    echo "$fingerprint:6:" | gpg -q --batch --import-ownertrust

    if [ "$?" != "0" ] ; then
        _err 'Could not trust public key ultimately'
        return 1
    fi

    _log "Trusted $GPG_PUBKEY ultimately"
}

_install_gpg_seckey() {
    missing="$(_missing gpg)"
    if [ -n "$missing" ] ; then
        _err "The following commands are missing from PATH: $missing"
        return 127
    fi

    if ! [ -f "$GPG_SECKEY" ] ; then
        _err "Bad gpg seckey path"
        return 1
    fi

    if [ -z "$GNUPGHOME" ] ; then
        if ! _prompt '$GNUPGHOME is not defined, continue? (default to ~/.gnupg)' ; then
            return 1
        else
            GNUPGHOME="$HOME/.gnupg"
        fi
    fi

    if ! [ -d "$GNUPGHOME" ] ; then
        mkdir -p "$GNUPGHOME"
        chmod 700 "$GNUPGHOME"
    fi

    key_info="$(gpg -q --show-keys "$GPG_SECKEY")"

    if [ -z "${key_info//pub*/}" ] ; then
        _err "Failed to import secret key $GPG_SECKEY, appears to be public key"
        return 1
    fi

    gpg -q --batch --import "$GPG_SECKEY"

    if [ "$?" != "0" ] ; then
        _err 'Could not import secret key'
        return 1
    fi

    _log "Imported $GPG_SECKEY"
}

_install_ssh_pubkey() {
    if ! [ -f "$SSH_PUBKEY" ] ; then
        _err "Bad ssh pubkey path"
        return 1
    fi

    if [ -z "$SSH_DIR" ] ; then
        if ! _prompt '$SSH_DIR is not defined, continue? (default to ~/.ssh)' ; then
            return 1
        else
            SSH_DIR="$HOME/.ssh"
        fi
    fi

    if ! [ -d "$SSH_DIR" ] ; then
        mkdir -p "$SSH_DIR"
        chmod 700 "$SSH_DIR"
    fi

    if [ -f "$SSH_DIR/${SSH_PUBKEY##*/}" ] ; then
        if ! _prompt "$SSH_DIR/${SSH_PUBKEY##*/} already exists, overwrite?" ; then
            return 1
        fi
    fi

    cp "$SSH_PUBKEY" "$SSH_DIR/${SSH_PUBKEY##*/}"

    if [ "$?" != 0 ] ; then
        _err 'Could not install public ssh key'
        return 1
    fi

    chmod 644 "$SSH_DIR/${SSH_PUBKEY##*/}"

    _log "Imported $SSH_PUBKEY"
}

_install_ssh_seckey() {
    if ! [ -f "$SSH_SECKEY" ] ; then
        _err "Bad ssh seckey path"
        return 1
    fi

    if [ -z "$SSH_DIR" ] ; then
        if ! _prompt '$SSH_DIR is not defined, continue? (default to ~/.ssh)' ; then
            return 1
        else
            SSH_DIR="$HOME/.ssh"
        fi
    fi

    if ! [ -d "$SSH_DIR" ] ; then
        mkdir -p "$SSH_DIR"
        chmod 700 "$SSH_DIR"
    fi

    if [ -f "$SSH_DIR/${SSH_SECKEY##*/}" ] ; then
        if ! _prompt "$SSH_DIR/${SSH_SECKEY##*/} already exists, overwrite?" ; then
            return 1
        fi
    fi

    cp "$SSH_SECKEY" "$SSH_DIR/${SSH_SECKEY##*/}"

    if [ "$?" != 0 ] ; then
        _err 'Could not install public ssh key'
        return 1
    fi

    chmod 600 "$SSH_DIR/${SSH_SECKEY##*/}"

    _log "Imported $SSH_SECKEY"
}

_opts() {
    opts=
    for o in $@ ; do
        if [ -z "${o%%-*}" ] ; then
            opts="$opts $(echo "$o" | sed 's/[A-Za-z0-9]/& /g;s/-//g')"
        else
            opts="$opts $o "
        fi
    done

    opts="${opts% }"
    opts="${opts# }"

    echo "$opts"
}

_main $(_opts $@)

exit "$?"