#!/bin/sh
###
### Usage: ./optimizer.sh </dev/sgX> <parallelism>
###
###   -h | --help       Shows this message
###
### optimizer.sh
###             Necessary parameters:
###             - sg device of the library
###             - parallelism
###
###             The script checks the parallelism with the available drives of the library/partition, then
###             proceeds with loading *all* the tapes found in the slots. Mailboxes are ignored.
###             It launches several child processes. The `timeout` command tries to unload the drives,
###             it succeeds when the the tape optimization is done.
###
###             Kill switch to stop the running processes: `killall optimizer.sh`
###


help() {
    sed -rn 's/^### ?//;T;p' "$0"
}
if [[ "$1" == "-h" ]] || [[ "$1" == "--help" ]] || [[ "$1" == "" ]]; then
    help
    exit 1
fi

log() {
    echo -e "$(date +'%Y-%m-%d %H:%M:%S')    $1" | tee -a ${LOG_FILE}
}

alive() {
    # $1 "${LIB_SG}"
    # $2 "${SLOT}"
    # $3 "${DRIVE}" 
    # $4 "${BARCODE}"
    echo "${4}" > "${TMP}/.drive${3}.lock"
    local PID_ALIVE='1'
    local WAIT=$((3600 + $RANDOM % 7200)) # from 1 to 2 hours
    local TIMEOUT="600" # 10 minutes wait before dismounting the tape
    while [ $PID_ALIVE -eq 1 ]; do
        log "ALIVE [$$] - Waiting ${WAIT} secondi..."
        sleep "${WAIT}"
        log "ALIVE [$$] - Trying to unload drive ${3} into slot ${2} (Timeout: ${TIMEOUT} seconds)..."
        timeout "${TIMEOUT}" mtx -f "${1}" unload "${2}" "${3}" # Kill after ${TIMEOUT} seconds
        if [[ $(echo $?) == '0' ]]; then
            log "ALIVE [$$] - OK. Drive ${3} unloaded."
            grep -q "$4;drive$3;WIP" "${PROCESSED_BARCODES}" # Check if barcode is WIP
            if [[ $(echo $?) == '0' ]]; then
                log "ALIVE [$$] - Barcode $4 processed."
                sed -i "s/$4;drive$3;WIP/$4;OK/g" "${PROCESSED_BARCODES}"
                rm -f "${TMP}/.drive${3}.lock"
                touch "${TMP}/.drive${3}.ready"
                log "ALIVE [$$] - Drive ${3} newly available. Exit."
                local PID_ALIVE='0'
                return 0 # End Alive
            else
                log "ALIVE [$$] - ERROR. Can't find the barcode among the WIP. Exit."
                return 1
            fi # Barcode processed --> OK
        elif [ -f "${TMP}/.drive${3}.lock" ]; then  # Drive in use
            log "ALIVE [$$] - Unmount drive ${3} failed, still in use (file .lock). Checking the content."
            grep -q "${4}" "${TMP}/.drive${3}.lock"
            if [[ $(echo $?) == '0' ]]; then
                log "ALIVE [$$] - File content OK. Waiting."
                continue
            else
                log "ALIVE [$$] - ERROR. File content of ${TMP}/.drive${3}.lock not coherent. Exit."
                return 1
            fi
        elif [ -f "${TMP}/.drive${3}.ready" ]; then # Drive available
            log "ALIVE [$$] - Found file ${TMP}/.drive${3}.ready. Drive available. Exit."
            local PID_ALIVE='0'
            return 0
        fi
    done
    log "End ALIVE [$$]"
    return 0
}

LIB_SG=$1
PARALLELISM=$2

WAIT=$((300))
TMP='/tmp'
LIB_CONFIG="${TMP}/lib_config.txt"
PROCESSED_SLOTS="${TMP}/processed-slots.txt"
PROCESSED_BARCODES="/root/processed-barcodes.txt"

log "***** New execution *****"

SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
LOG_PATH="${SCRIPT_DIR}/log"
LOG_FILE="${LOG_PATH}/optimizer.log"
if [ ! -d "${LOG_PATH}" ]; then
  echo "Creating the log directory: ${LOG_PATH}"
  mkdir -vp ${LOG_PATH}
fi

mtx -f "${LIB_SG}" status > "${LIB_CONFIG}"

# Check if there are enough ($PARALLELISM) free drives
if [[ $(grep "Data Transfer Element" ${LIB_CONFIG} | grep 'Empty' | wc -l) -lt "${PARALLELISM}" ]]; then
    log "ERROR. Not enough free drives. Exit."
    exit 1
fi

# Clean the WIP barcodes from old executions
sed -i '/WIP/d' "${PROCESSED_BARCODES}"

# Cleaning orphan files
rm -rf ${TMP}/.drive*
rm -rf ${PROCESSED_SLOTS}

for (( i = 0 ; i < ${PARALLELISM} ; i++ )); do
    grep -q "Data Transfer Element ${i}:Empty" ${LIB_CONFIG}
    if [[ $(echo $?) == '0' ]]; then
        if [[ ! -f "${TMP}/.drive${i}.ready" ]]; then
            log "Creating file ${TMP}/.drive${i}.ready"
            touch "${TMP}/.drive${i}.ready"
        fi
    fi
done

# List full slots
SLOTS_FULL="${TMP}/slots_full.txt"
grep 'Storage Element' ${LIB_CONFIG} | grep 'Full' | grep -v IMPORT | grep -v CLN | grep -v "(" > ${SLOTS_FULL}

COUNT=1
OFS=$IFS
IFS="
"
while [ $COUNT -le $(cat ${SLOTS_FULL} | wc -l) ]; do
    RUNNING=$(ls -1q ${TMP}/.drive*.lock | wc -l)
    if [[ "${RUNNING}" -lt "${PARALLELISM}" ]]; then
        SLOT=$(sed "${COUNT}q;d" ${SLOTS_FULL} | awk '{print $3;}' | cut -d ':' -f 1)
        BARCODE=$(sed "${COUNT}q;d" ${SLOTS_FULL} | awk '{print $4;}' | cut -d '=' -f 2)
        grep -q "${SLOT}" "${PROCESSED_SLOTS}" # Check if slot is aready processed
        if [[ $(echo $?) == '0' ]]; then
            echo "Slot ${SLOT} already processed."
            ((COUNT++))
            continue
        fi
        grep -q "${BARCODE};OK" "${PROCESSED_BARCODES}" # Check if barcode is already processed
        if [[ $(echo $?) == '0' ]]; then
            echo "Barcode ${BARCODE} already processed. Skip."
            ((COUNT++))
            continue
        fi
        log "### SLOT ${SLOT} - BARCODE ${BARCODE}"
        for (( i = 0 ; i < ${PARALLELISM} ; i++ )); do # Look for an available drive
            if [ -f "${TMP}/.drive${i}.ready" ]; then   # Look for ".ready" file
                DRIVE=${i}
                mv "${TMP}/.drive${DRIVE}.ready" "${TMP}/.drive${DRIVE}.lock"
                break
            fi
        done
        log "Loading slot ${SLOT} into drive ${DRIVE}."
        mtx -f "${LIB_SG}" load "${SLOT}" "${DRIVE}"
        echo "${BARCODE};drive${DRIVE};WIP" >> "${PROCESSED_BARCODES}" # Barcode  WIP
        echo ${SLOT} >> "${PROCESSED_SLOTS}"
        log "Launching ALIVE with parameters: ${LIB_SG} - ${SLOT} - ${DRIVE} - ${BARCODE}"
        alive "${LIB_SG}" "${SLOT}" "${DRIVE}" "${BARCODE}" &
        RUNNING=$(ls -1q ${TMP}/.drive*.lock | wc -l)
        log "MAIN - RUNNING processes: $RUNNING"
        if [[ "${RUNNING}" -ge "${PARALLELISM}" ]]; then
            log "MAIN (if) - Maximum parallelism. Waiting ${WAIT} seconds…"
            sleep "${WAIT}"
        else
            ((COUNT++))
            log "Waiting 2 minutes to avoid too many commands."
            sleep 120
        fi
    else
        log "MAIN - Maximum parallelism. Waiting ${WAIT} seconds…"
        sleep "${WAIT}"
    fi
done
IFS=$OFS

rm -rf "${LIB_CONFIG}"
rm -rf "${SLOTS_FULL}"
rm -rf "${PROCESSED_SLOTS}"

log "***** End execution *****\n\n"