Calculate block height based on a timestamp

blocktime.sh

#!/bin/bash

TIME=$(date -d "$1" +"%s")

function getBlockTime {
  echo $(bitcoin-cli getblockheader $(bitcoin-cli getblockhash $1) | jq -r .time)
}

function binarySearch {
  L=$1
  R=$2

  if ((R >= L));
  then

    BLOCK=$((L + (R - L) / 2))
    BLOCKTIME=$(getBlockTime $BLOCK)

    if ((BLOCKTIME == TIME));
    then
      echo $BLOCK
    elif ((BLOCKTIME > TIME));
    then
      echo $(binarySearch $L $((BLOCK - 1)))
    else
      echo $(binarySearch $((BLOCK + 1)) $R)
    fi
  else
    echo $R
  fi
}

BLOCKS=$(bitcoin-cli getblockchaininfo | jq -r .blocks)
BLOCK=$(binarySearch 0 $BLOCKS)

if ((BLOCK >= 0));
then
  BLOCKTIME=$(getBlockTime $BLOCK)
  echo "Block $BLOCK: $(date -d @$BLOCKTIME -Iseconds)   $((BLOCKTIME - TIME)) seconds"
fi

if ((BLOCKTIME != TIME)) && ((BLOCK < BLOCKS));
then
  NEXTBLOCK=$((BLOCK + 1))
  NEXTBLOCKTIME=$(getBlockTime $NEXTBLOCK)
  echo "Block $NEXTBLOCK: $(date -d @$NEXTBLOCKTIME -Iseconds)   $((NEXTBLOCKTIME - TIME)) seconds"
fi