#!/bin/bash

## Integration at the Bottom

# Copyright (C) 2011 by Wayne Walker <wwalker@solid-constructs.com>
#
# Released under one of the versions of the MIT License.
#
# Copyright (C) 2011 by Wayne Walker <wwalker@solid-constructs.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

_LIVE_AGENT_LIST=""
declare -a _LIVE_AGENT_SOCK_LIST
_LIVE_AGENT_SOCK_LIST=()

_debug_print() {
    if [[ $_DEBUG -gt 0 ]]; then
        printf "%s\n" "$1"
    fi
}

find_all_ssh_agent_sockets() {
    _SSH_AGENT_SOCKETS=$(find /tmp/ -type s -name agent.\* 2>/dev/null | grep '/tmp/ssh-.*/agent.*')
    _debug_print "$_SSH_AGENT_SOCKETS"
}

find_all_gpg_agent_sockets() {
    _GPG_AGENT_SOCKETS=$(find /tmp/ -type s -name S.gpg-agent.ssh 2>/dev/null | grep '/tmp/gpg-.*/S.gpg-agent.ssh')
    _debug_print "$_GPG_AGENT_SOCKETS"
}

find_all_gnome_keyring_agent_sockets() {
    _GNOME_KEYRING_AGENT_SOCKETS=$(find /tmp/ -type s -name "ssh" 2>/dev/null | grep '/tmp/keyring-.*/ssh$')
    _debug_print "$_GNOME_KEYRING_AGENT_SOCKETS"
}

find_all_osx_keychain_agent_sockets() {
    [[ -n "$TMPDIR" ]] || TMPDIR=/tmp
    _OSX_KEYCHAIN_AGENT_SOCKETS=$(find $TMPDIR/ -type s -regex '.*/ssh-.*/agent..*$' 2>/dev/null)
    _debug_print "$_OSX_KEYCHAIN_AGENT_SOCKETS"
}

test_agent_socket() {
    local SOCKET=$1
    SSH_AUTH_SOCK=$SOCKET ssh-add -l 2>/dev/null >/dev/null
    result=$?

    _debug_print $result

    if [[ $result -eq 0 ]]; then
        # contactible and has keys loaded
        _KEY_COUNT=$(SSH_AUTH_SOCK=$SOCKET ssh-add -l | wc -l | tr -d ' ')
    fi

    if [[ $result -eq 1 ]]; then
        # contactible butno keys loaded
        _KEY_COUNT=0
    fi

    if [ $result -eq 0 ] || [ $result -eq 1 ]; then
        if [[ -n "$_LIVE_AGENT_LIST" ]]; then
            _LIVE_AGENT_LIST="${_LIVE_AGENT_LIST} ${SOCKET}:$_KEY_COUNT"
        else
            _LIVE_AGENT_LIST="${SOCKET}:$_KEY_COUNT"
        fi
        return 0
    fi

    return 1
}

find_live_gnome_keyring_agents() {
    for i in $_GNOME_KEYRING_AGENT_SOCKETS; do
        test_agent_socket "$i"
    done
}

find_live_osx_keychain_agents() {
    for i in $_OSX_KEYCHAIN_AGENT_SOCKETS; do
        test_agent_socket "$i"
    done
}

find_live_gpg_agents() {
    for i in $_GPG_AGENT_SOCKETS; do
        test_agent_socket "$i"
    done
}

find_live_ssh_agents() {
    for i in $_SSH_AGENT_SOCKETS; do
        test_agent_socket "$i"
    done
}

function fingerprints() {
    local file="$1"
    while read -r l; do
        [[ -n $l && ${l###} == "$l" ]] && ssh-keygen -l -f /dev/stdin <<<"$l"
    done <"$file"
}

find_all_agent_sockets() {
    _SHOW_IDENTITY=0
    if [ "$1" = "-i" ]; then
        _SHOW_IDENTITY=1
    fi
    _LIVE_AGENT_LIST=
    find_all_ssh_agent_sockets
    find_all_gpg_agent_sockets
    find_all_gnome_keyring_agent_sockets
    find_all_osx_keychain_agent_sockets
    find_live_ssh_agents
    find_live_gpg_agents
    find_live_gnome_keyring_agents
    find_live_osx_keychain_agents
    _debug_print "$_LIVE_AGENT_LIST"
    _LIVE_AGENT_LIST=$(echo "$_LIVE_AGENT_LIST" | tr ' ' '\n' | sort -n -t: -k 2 -k 1 | uniq)
    _LIVE_AGENT_SOCK_LIST=()
    _debug_print "SORTED: $_LIVE_AGENT_LIST"
    if [[ $_SHOW_IDENTITY -gt 0 ]]; then
        i=0
        for a in $_LIVE_AGENT_LIST; do
            sock=${a/:*/}
            _LIVE_AGENT_SOCK_LIST[$i]=$sock
            # technically we could have multiple keys forwarded
            # But I haven't seen anyone do it
            akeys=$(SSH_AUTH_SOCK=$sock ssh-add -l)
            fingerprint=$(echo "${akeys}" | awk '{print $2}')
            if [ -e ~/.ssh/authorized_keys ]; then
                authorized_entry=$(fingerprints ~/.ssh/authorized_keys | grep "$fingerprint")
            fi
            comment=$(echo "${authorized_entry}" | awk '{print $3,$4,$5,$6,$7}')
            printf "export SSH_AUTH_SOCK=%s \t#%i) \t%s\n" "$sock" $((i + 1)) "$comment"
            i=$((i + 1))
        done
    else
        printf "%s\n" "$_LIVE_AGENT_LIST" | sed -e 's/ /\n/g' | sort -n -t: -k 2 -k 1
    fi
}

set_ssh_agent_socket() {
    if [ "$1" = "-c" ] || [ "$1" = "--choose" ]; then
        find_all_agent_sockets -i

        if [ -z "$_LIVE_AGENT_LIST" ]; then
            echo "No agents found"
            return 1
        fi

        echo -n "Choose (1-${#_LIVE_AGENT_SOCK_LIST[@]})? "
        read -r choice
        if [ -n "$choice" ]; then
            n=$((choice - 1))
            if [ -z "${_LIVE_AGENT_SOCK_LIST[$n]}" ]; then
                echo "Invalid choice"
                return 1
            fi
            echo "Setting export SSH_AUTH_SOCK=${_LIVE_AGENT_SOCK_LIST[$n]}"
            export SSH_AUTH_SOCK=${_LIVE_AGENT_SOCK_LIST[$n]}
        fi
    else
        # Choose the first available
        SOCK=$(find_all_agent_sockets | tail -n 1 | awk -F: '{print $1}')
        if [ -z "$SOCK" ]; then
            return 1
        fi
        export SSH_AUTH_SOCK=$SOCK
    fi

    # set agent pid
    if [ -n "$SSH_AUTH_SOCK" ]; then
        export SSH_AGENT_PID=$(($(echo "$SSH_AUTH_SOCK" | cut -d. -f2) + 1))
    fi

    return 0
}

ssh-find-agent() {
    if [ "$1" = "-c" ] || [ "$1" = "--choose" ]; then
        set_ssh_agent_socket -c
        return $?
    elif [ "$1" = "-a" ] || [ "$1" = "--auto" ]; then
        set_ssh_agent_socket
        return $?
    else
        find_all_agent_sockets -i
        return 0
    fi
}

# Automatically add ssh-agent to any new ssh connection
ssh-find-agent -a
if [ -z "$SSH_AUTH_SOCK" ]; then
    eval "$(ssh-agent)" >/dev/null
    ssh-add -l >/dev/null || alias ssh='ssh-add -l >/dev/null || ssh-add && unalias ssh; ssh'
fi