#!/bin/bash

START_ID=0
END_ID=4000
RANGE_SIZE=500
MAX_PARALLEL=8

export INPUT_DIR="tiffs"
export OUTPUT_PREFIX="disfor"
export RANGE_SIZE

seq $START_ID $RANGE_SIZE $END_ID | parallel -j $MAX_PARALLEL '
    start={}
    end=$((start + RANGE_SIZE - 1))
    [ $end -gt '"$END_ID"' ] && end='"$END_ID"'
    
    dirs=()
    for ((id=$start; id<=$end; id++)); do
        [ -d "$INPUT_DIR/$id" ] && dirs+=("$INPUT_DIR/$id")
    done
    
    [ ${#dirs[@]} -gt 0 ] && tar -I "zstd -9" -cf "$OUTPUT_PREFIX-$start-$end.tar.zst" "${dirs[@]}"
    echo "Completed $OUTPUT_PREFIX-$start-$end.tar.zst"
'