#!/bin/bash

#------------
# SSH-AGENT
#------------
function sshagent_start {
    local key_path="$HOME/.ssh/id_ed25519"
    local lifetime="5d"

    # Parse options
    while getopts "t:k:" opt; do
        case "$opt" in
            t) lifetime="$OPTARG" ;;
            k) key_path="$OPTARG" ;;
            *)
                echo "Usage: sagent_start [-t lifetime] [-k key_path]"
                return 1
                ;;
        esac
    done

    # Convert lifetime to seconds
    local num=${lifetime//[!0-9]/}
    local unit=${lifetime//[0-9]/}
    local seconds=0

    case "$unit" in
        s|"") seconds=$num ;;  # default to seconds
        m)    seconds=$((num * 60)) ;;
        h)    seconds=$((num * 3600)) ;;
        d)    seconds=$((num * 86400)) ;;
        *)
            echo "Invalid time unit. Use s, m, h, or d."
            return 1
            ;;
    esac

    # Clean previous ssh credentials
    (rm -rf /tmp/ssh-* > /dev/null)

    SSH_ENV="$HOME/.ssh/environment"
    printf '\e[1;36m%s\e[m\n' "Initialising new SSH agent..."
    ssh-agent | sed 's/^echo/#echo/' > "${SSH_ENV}"
    chmod 600 "${SSH_ENV}"
    # shellcheck source=/dev/null
    source "${SSH_ENV}" > /dev/null

    if [[ ! -f "$key_path" ]]; then
        printf '\e[1;31m%s\e[m\n' "SSH key not found at $key_path"
        return 1
    fi

    if ssh-add -t "$seconds" "$key_path" >/dev/null 2>&1 ; then
        printf '\e[1;36m%s\e[m\n' "SSH key added successfully: $key_path (lifetime: $lifetime = ${seconds}s)"
    else
        printf '\e[1;31m%s\e[m\n' "Failed to add SSH key"
    fi
}

function sshagent_stop {

    # clean previous ssh credentials
    (rm -rf /tmp/ssh-* > /dev/null)

    ssh-agent -k > /dev/null
}

function sshagent_findsockets {
    find /tmp -uid "$(id -u)" -type s -name agent.\* 2>/dev/null
}

function sshagent_testsocket {
    if [ ! -x "$(command -v ssh-add)" ] ; then
        echo "ssh-add is not available; agent testing aborted"
        return 1
    fi

    if [ X"$1" != X ] ; then
        export SSH_AUTH_SOCK=$1
    fi

    if [ X"$SSH_AUTH_SOCK" = X ] ; then
        return 2
    fi

    if [ -S "$SSH_AUTH_SOCK" ] ; then
        ssh-add -l > /dev/null
        if [ $? = 2 ] ; then
            echo "Socket $SSH_AUTH_SOCK is dead!  Deleting!"
            rm -f "$SSH_AUTH_SOCK"
            return 4
        else
            echo "Found ssh-agent $SSH_AUTH_SOCK"
            return 0
        fi
    else
        echo "$SSH_AUTH_SOCK is not a socket!"
        return 3
    fi
}

function sshagent_reload {
    # ssh agent sockets can be attached to a ssh daemon process or an
    # ssh-agent process.

    AGENTFOUND=0

    # Attempt to find and use the ssh-agent in the current environment
    if sshagent_testsocket ; then AGENTFOUND=1 ; fi

    # If there is no agent in the environment, search /tmp for
    # possible agents to reuse before starting a fresh ssh-agent
    # process.
    if [ $AGENTFOUND = 0 ] ; then
        for agentsocket in $(sshagent_findsockets) ; do
            if [ $AGENTFOUND != 0 ] ; then break ; fi
            if sshagent_testsocket "$agentsocket" ; then AGENTFOUND=1 ; fi
        done
    fi

    # If at this point we still haven't located an agent, it's time to
    # start a new one
    if [ $AGENTFOUND = 0 ] ; then
        eval "$(ssh-agent)"
    fi

    # Clean up
    unset AGENTFOUND
    unset agentsocket

    # Finally, show what keys are currently in the agent
    ssh-add -l
}

if [[ -f "$HOME/.ssh/environment" ]]; then
    sshagent_reload > /dev/null 2>&1
fi

# Alias agents
alias sagent_start="sshagent_start"
alias sagent_stop="sshagent_stop"

# Clean up not global functions
unset -f sshagent_findsockets sshagent_testsocket