#!/bin/sh
set -eu

SEALER_ADDRESS="${1:-0x0000000000000000000000000000000000000001}"
PREFUNDED_ADDRESS="${2:-0x0000000000000000000000000000000000000002}"
OUTPUT_FILE="${3:-/genesis.json}"

strip_0x() {
  echo "$1" | sed 's/^0x//; s/^0X//'
}

SEALER_HEX="$(strip_0x "$SEALER_ADDRESS")"
PREFUNDED_HEX="$(strip_0x "$PREFUNDED_ADDRESS")"

if [ ${#SEALER_HEX} -ne 40 ]; then
  echo "Invalid sealer address: $SEALER_ADDRESS" >&2
  exit 1
fi

if [ ${#PREFUNDED_HEX} -ne 40 ]; then
  echo "Invalid pre-funded address: $PREFUNDED_ADDRESS" >&2
  exit 1
fi

VANITY="$(printf '%064s' '' | tr ' ' '0')"
SIGNATURE="$(printf '%0130s' '' | tr ' ' '0')"
EXTRA_DATA="0x${VANITY}${SEALER_HEX}${SIGNATURE}"

cat > "$OUTPUT_FILE" <<EOF
{
  "config": {
    "chainId": 1999,
    "homesteadBlock": 0,
    "eip150Block": 0,
    "eip155Block": 0,
    "eip158Block": 0,
    "byzantiumBlock": 0,
    "constantinopleBlock": 0,
    "petersburgBlock": 0,
    "istanbulBlock": 0,
    "berlinBlock": 0,
    "londonBlock": 0,
    "clique": {
      "period": 5,
      "epoch": 30000
    }
  },
  "nonce": "0x0",
  "timestamp": "0x0",
  "extraData": "${EXTRA_DATA}",
  "gasLimit": "0x1C9C380",
  "difficulty": "0x1",
  "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
  "coinbase": "0x0000000000000000000000000000000000000000",
  "alloc": {
    "${SEALER_HEX}": {
      "balance": "0xD3C21BCECCEDA1000000"
    },
    "${PREFUNDED_HEX}": {
      "balance": "0xD3C21BCECCEDA1000000"
    }
  },
  "number": "0x0",
  "gasUsed": "0x0",
  "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
}
EOF

echo "Wrote genesis to $OUTPUT_FILE"