#!/bin/bash
source ~/bin/.synccmd.sh
SYNCFILE=~/.syncdir.sync
MYPID=$$
STATUS_RUNNING=RUNNING
STATUS_STOPPED=STOPPED

RED="\e[31m"
GREEN="\e[32m"
ENDCOLOR="\e[0m"

HELP_CMD_NAME='syncdir.sh'
HELP_LOCAL_DIR="/home/$USER/localsync/"
HELP_REMOTE_DIR="remoteuser@server:/home/remoteuser/sync/"

myhelp() {
  echo "Usage: ${HELP_CMD_NAME}  {COMMAND}  [OPTION]"
  echo 'Description: '
  echo -e '\tThis tool allows you to mirror and keep synchronised a folder on a remote server with an arbitrary local folder.'
  echo -e '\tIt has three main commands init, start, stop, remove'
  echo -e "\t${RED}NOTE: you must have configured ssh on your remote server!${ENDCOLOR}"
  echo -e "\tthe typical use is to start a sync with the command"
  echo -e "\t\t${HELP_CMD_NAME} init -l ${HELP_LOCAL_DIR} -r ${HELP_REMOTE_DIR}"
  echo -e "\tAbove command starts to mirror and sync the local folder ${HELP_LOCAL_DIR} with the remote folder ${HELP_REMOTE_DIR}"
}

hastrailingslash() {
  case "$1" in
  */)
      echo true
      ;;
  *)
      echo false
      ;;
  esac
}

syncexists() {
  localpath_hash=$(echo "$1" | md5sum | cut -f1 --delimiter=" " -)
  if [[ $(cat "${SYNCFILE}" | grep "$localpath_hash" | wc -l) -ge 1 ]]; then 
    echo true
  else 
    echo false
  fi
}

initsyncpath() {
  echo 'Starting initial sync...'
  ## write the file with remotepath and localpath for future use
  localpath_hash=$(echo "$1" | md5sum | cut -f1 --delimiter=" " -)
  sync $localpath_hash $2 $1
  ## create sync with status stopped -> after this start the loop
  echo $localpath_hash "p$MYPID" w$(date +%s) $STATUS_STOPPED $1 $2 >> ${SYNCFILE}
  loopsyncpath $1

}

startsyncpath() {
  echo 'Starting sync...'
  ## write the file with remotepath and localpath for future use
  localpath_hash=$(echo "$1" | md5sum | cut -f1 --delimiter=" " -)
  sync $localpath_hash $2 $1
  ## create sync with status stopped -> after this start the loop
  loopsyncpath $1
}

loopsyncpath() {
  echo "loopsyncpath $1"
  #echo $(sed "1q;d" ~/.syncdir.sync) | sed -e "s/STOPPED/RUNNING/"
  re_num='^[0-9]+$'
  if [[ $1 =~ $re_num && $1 -gt 0 ]]; then
    ## $1 is the index of line to substitute
    nline=$1
  else
    ## $1 is the path of sync of line to substitute
    localpath_hash=$(echo "$1" | md5sum | cut -f1 --delimiter=" " -)
    nline=$(grep -n $localpath_hash "$SYNCFILE" | cut -f1 -d ":")
    echo $nline
  fi
  sed -n -s "$nline"p "$SYNCFILE" | while read hash pid when status localpath remotepath; do
    if [ $status = $STATUS_RUNNING ]; then
      echo 'Sync already running do nothing...'
      exit 0
    else
      ## starting loop on background and catch pid
      nohup syncloop.sh $hash $localpath $remotepath 1>~/syncloop_$hash.nohup 2>&1 &
      mypid=$!
      echo "mypid: $mypid"
      when=$(date +%s)
      ## if line exists i must replace with new pid
      sed -i -e "$nline {s/$STATUS_STOPPED/$STATUS_RUNNING/; s/p[0-9]\+/p$mypid/; s/w[0-9]\+/w$when/}" "$SYNCFILE"
    fi
  done
}

nsync() {
  ## find the nline of a sync starting from an hash or a number
  re_num='^[0-9]+$'
  if [[ $1 =~ $re_num && $1 -gt 0 ]]; then
    ## $1 is the index of line to substitute
    nline=$1
  else
    ## $1 is the path of sync of line to substitute
    localpath_hash=$(echo "$1" | md5sum | cut -f1 --delimiter=" " -)
    nline=$(grep -n $1 "$SYNCFILE" | cut -f1 -d ":")
  fi
  echo $nline
}

stoploopsyncpath() {
  echo "stoploopsyncpath $1"
  #echo $(sed "1q;d" ~/.syncdir.sync) | sed -e "s/STOPPED/RUNNING/"
  nline=$(nsync "$1")
  sed -n -s "$nline"p "$SYNCFILE" | while read hash pid when status localpath remotepath; do
    if [ $status = $STATUS_STOPPED ]; then
      echo 'Sync already stopped do nothing...'
      exit 0
    else
      ## stop process and all descendants
      pid=$(echo $pid | cut -c 2-)
      kill $(ps -o pid= --ppid $pid)
      when=$(date +%s)
      sed -i -e "$nline {s/$STATUS_RUNNING/$STATUS_STOPPED/; s/w[0-9]\+/w$when/}" "$SYNCFILE"
    fi
  done
}

removeloopsyncpath() {
  echo "removeloopsyncpath $1"
  #echo $(sed "1q;d" ~/.syncdir.sync) | sed -e "s/STOPPED/RUNNING/"
  nline=$(nsync "$1")
  sed -n -s "$nline"p "$SYNCFILE" | while read hash pid when status localpath remotepath; do
    if [ $status = $STATUS_RUNNING ]; then
      echo 'Sync is running stop it and delete from tasks..'
      stoploopsyncpath $nline
    else
      echo 'Sync is stopped delete it from tasks..'
    fi
    sed -i "$nline"d "$SYNCFILE"
  done
}

emptysyncfile() {
  if [[ $(cat ${SYNCFILE} | wc -l) -eq 0 ]]; then 
    echo true
  else 
    echo false
  fi
}

syncoutofindex() {
  if [[ $1 -gt $(cat ${SYNCFILE} | wc -l) ]]; then 
    echo true
  else 
    echo false
  fi
}

if [ "$1" == '-h' ]; then
  myhelp
  exit 1
fi

case "$1" in 
  init)
    shift
    while getopts ":l:r:" option; do
      case "${option}" in 
        l) echo "l option: ${option} value ${OPTARG}"
           localpath=${OPTARG}
           if [ ! -d "$localpath" ]; then
             echo 'local path to sync not exists... do you want to create it?'
             test_no='^(N|n)[[:alnum:]]+'
             read -r ans
             #no " in regular expression match
             if [[ ${ans} =~ ${test_no} ]]; then 
               echo '... Aborting...'
               exit 1
             fi
             ## create path
             mkdir -p "${localpath}"
           fi
           lhts=$(hastrailingslash $localpath)
           if [ ${lhts} = false ]; then
             localpath="${localpath}"/
           fi
        ;;
        r) echo "r option: ${option} value ${OPTARG}"
          #match an adress in this form username@from_host:/home/test
          remotepath=${OPTARG}
          re_isremote='^[[:alnum:]]+\@([[:alnum:]]+|([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})):/[[:alnum:]]+/?'
          if ! [[ $remotepath =~ $re_isremote ]]; then 
            echo 'Incorrect format for destination path... aborting'
            exit 1
          fi
          if [[ ${localpath} == "" ]]; then
            cpath=$(pwd)
            echo "Setting local path to ${cpath}/"
            localpath=${cpath}/
          fi
          synce=$(syncexists ${localpath})
          if [ ${synce} = true ]; then
            echo 'Folder you have specified is already synched: you can only start, stop or remove sync'
            cat $SYNCFILE
            exit 1
          else
            rhts=$(hastrailingslash $remotepath)
            if [ ${rhts} = false ]; then
              remotepath="${remotepath}"/
            fi
            initsyncpath $localpath $remotepath
          fi

        ;;
        \?) myhelp
            exit 1
        ;;
      esac
    done

    ;;
  start)
    shift
    while getopts ":l:s:" option; do
      case "${option}" in 
        l) localsync=${OPTARG}
           if [[ -d "$localsync" ]]; then
             synce=$(syncexists ${localsync})
             if [ ${synce} = true ]; then
               echo "Sync local folder ${localsync}"
               grep ${localsync} $SYNCFILE | while read hash pid when status localpath remotepath; do
                 startsyncpath ${localpath} ${remotepath}
               done
             else
               echo "local folder ${localsync} not in sync task, please before use init"
             fi
           else
             echo "ATTENTION Folder: $localsync not exists Aborting!"
             exit 2
           fi
        ;;
        s) indexsync=${OPTARG}
           empty=$(emptysyncfile)
           if [ ${empty} = true ]; then
             echo "Sync ${indexsync} not exists, sync file empty, please use init first"
           else
             oi=$(syncoutofindex $indexsync)
             if [ ${oi} = true ]; then
               echo "Sync ${indexsync} out of index"
               exit 1
             else
               sed -n -s "$indexsync"p "$SYNCFILE" | while read hash pid when status localpath remotepath; do
                 startsyncpath ${localpath} ${remotepath}
               done
             fi
           fi
        ;;
        \?) myhelp
            exit 1
        ;;
      esac
    done
    ;;
  stop)
    shift
    while getopts ":l:s:" option; do
      case "${option}" in 
        l) localsync=${OPTARG}
           if [[ -d "$localsync" ]]; then
             #echo "Sync this local folder: $2"
             synce=$(syncexists ${localsync})
             if [ ${synce} = true ]; then
               echo "Stopping Sync local folder ${localsync}"
               stoploopsyncpath ${localsync}
             else
               echo "Can't stop local sync for folder ${localsync}. It is not in sync task, please before use init"
               exit 2
             fi
           else
             echo "ATTENTION Folder: ${localsync} not exists Aborting!"
             exit 2
           fi
        ;;
        s) indexsync=${OPTARG}
           empty=$(emptysyncfile)
           if [ ${empty} = true ]; then
             echo "Sync ${indexsync} not exists, sync file empty, please use init first"
           else
             oi=$(syncoutofindex $indexsync)
             if [ ${oi} = true ]; then
               echo "Sync ${indexsync} out of index"
               exit 1
             else
               stoploopsyncpath $indexsync
               #echo "Starting Sync ${indexsync}"
             fi
           fi
        ;;
        \?) myhelp
            exit 1
        ;;
      esac
    done
    ;;
  list)
    if [ ! -f $SYNCFILE ]; then 
      echo 'Sync file empty'
    else
      if [ $(cat $SYNCFILE | wc -l) -eq 0 ]; then 
        echo 'Sync file empty'
      else
        echo -e "$(cat $SYNCFILE | cat -n | sed -e "s/RUNNING/\\${GREEN}RUNNING\\${ENDCOLOR}/" -e "s/STOPPED/\\${RED}STOPPED\\${ENDCOLOR}/")"
      fi
    fi
    ;;
  remove)
    shift
    while getopts ":l:s:" option; do
      case "${option}" in 
        l) localsync=${OPTARG}
           #echo "Sync this local folder: $2"
           synce=$(syncexists ${localsync})
           if [ ${synce} = true ]; then
             echo "Removing Sync local folder ${localsync}"
             removeloopsyncpath ${localsync}
           else
             echo "Can't remove local sync for folder ${localsync}. It is not in sync task"
             exit 2
           fi
        ;;
        s) indexsync=${OPTARG}
           empty=$(emptysyncfile)
           if [ ${empty} = true ]; then
             echo "Sync ${indexsync} not exists, sync file empty, please use init first"
           else
             oi=$(syncoutofindex $indexsync)
             if [ ${oi} = true ]; then
               echo "Sync ${indexsync} out of index"
               exit 1
             else
               removeloopsyncpath $indexsync
             fi
           fi
        ;;
        \?) myhelp
            exit 1
        ;;
      esac
    done
    ;;
  *) 
    myhelp
    exit 1
esac