#!/usr/bin/env bash

[ -z $SQL_PROXY_HOST ] && SQL_PROXY_HOST="localhost"
CACHE_FILE="$HOME/.cache/sqlproxy_$SQL_PROXY_HOST"

HELP="Usage: myssh [ls|connect]
SUBCOMMANDS:
  ls: list available database hosts
  connect: connect to a database host

SYNTAX connect host [-u user] [-p password] [-c client]
"

ls() {
    echo $(ssh $SQL_PROXY_HOST ls)
}

read_cache() {
    if [ -f $CACHE_FILE ]
    then
        mapfile -t HOST_LIST < $CACHE_FILE
        LAST_CHANGED=$(expr $(date +"%s") - "${HOST_LIST[0]}")
        # Refresh cache if cache is older than a minute
        if [ $LAST_CHANGED -gt 60 ]
        then
            write_cache $(ls)
            read_cache
        fi
    else
        write_cache $(ls)
        read_cache
    fi
}

write_cache() {
    touch $CACHE_FILE
    echo -e $(date +"%s")"\n"$1 > $CACHE_FILE
}

run_client() {
    # wait for port to open
    while ! nc -z localhost 3306 > /dev/null
    do
        sleep 0.1
    done

    if [ $(uname -s) = "Linux" ]
    then
        mysql --protocol=TCP -u $1 -p$2 -h localhost -P 3306
    else
        open "mysql://$1:$2@localhost:3306" -a "Sequel Ace"
    fi
}

MAIN_OPTION=$1
shift

case $MAIN_OPTION in
    ls)
        RESPONSE=$(ls)
        write_cache $RESPONSE
        echo $RESPONSE;;
    connect)
        # Kill open connections on exit
        # https://stackoverflow.com/questions/360201/how-do-i-kill-background-processes-jobs-when-my-shell-script-exits
        trap "trap - SIGTERM && kill -- -$$" SIGINT SIGTERM EXIT

        # check/update cache
        read_cache

        # check if host is valid
        TARGET_HOST=$1
        shift
        tail -n +2 $CACHE_FILE | grep -qe "^$TARGET_HOST$"
        GREP_EXIT_CODE=$?
        if [ $GREP_EXIT_CODE -eq 0 ]
        then
            while getopts "u:p:" o
            do
                case "$o" in
                    u) MYSQL_USERNAME="$OPTARG" ;;
                    p) MYSQL_PASSWORD="$OPTARG" ;;
                esac
            done
            ssh -L 3306:$TARGET_HOST:3306 $SQL_PROXY_HOST > /dev/null 2>&1 &
            if [ ! -z $MYSQL_USERNAME ] && [ ! -z $MYSQL_PASSWORD ]
            then
                run_client $MYSQL_USERNAME $MYSQL_PASSWORD
            else
                echo 'Press CTRL C to quit this connection'
                wait
            fi
        else
            echo "Invalid Hostname: $2."
        fi
        ;;
    *)
        echo -e "Usage: myssh [ls|connect]\n\n";;
esac