#!/bin/sh
# Re-reads BMNR's figures on Robinhood Chain and compares them with what pegproof read
# at block 106694507. It only makes eth_calls: read-only, nothing is signed or sent.
# Needs curl and bc. To ask another Robinhood Chain node: PEGPROOF_RPC=https://your-node sh verify.sh

RPC_URL=https://rpc.mainnet.chain.robinhood.com
if [ -n "$PEGPROOF_RPC" ]; then RPC_URL=$PEGPROOF_RPC; fi
TOKEN=0x9a7842eded60b0fe1e03eec342c82a397c821ed0
BLOCK=106694507
BLOCK_HEX=0x65c076b
DIFFERENT=0
UNCHECKED=0

for tool in curl bc; do
  if ! command -v "$tool" >/dev/null 2>&1; then
    echo "This script needs $tool, which is not installed here. Nothing was checked." >&2
    exit 2
  fi
done

# eth_call TO DATA: the hex digits of the result, without 0x; nothing on an error.
eth_call() {
  curl -s "$RPC_URL" -H 'content-type: application/json' \
    -d "{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"eth_call\",\"params\":[{\"to\":\"$1\",\"data\":\"$2\"},\"$BLOCK_HEX\"]}" \
    | tr -d ' \r\n' | sed -n 's/.*"result":"0x\([0-9a-fA-F]*\)".*/\1/p'
}

# word HEX N: the N-th 32-byte word of HEX, counting from 0.
word() {
  printf '%s' "$1" | cut -c "$(($2 * 64 + 1))-$(($2 * 64 + 64))"
}

# dec HEX: the unsigned decimal value of HEX; nothing for nothing.
dec() {
  if [ -z "$1" ]; then return 0; fi
  printf 'ibase=16; %s\n' "$(printf '%s' "$1" | tr 'abcdef' 'ABCDEF')" | bc | tr -d '\\\n'
}

# amount EXPR: EXPR evaluated by bc, on one line, with the leading zero bc leaves out (.5 -> 0.5).
amount() {
  printf '%s\n' "$1" | bc | tr -d '\\\n' | sed 's/^\./0./; s/^-\./-0./'
}

# compare NAME PEGPROOF CHAIN: no answer from the node is NOT CHECKED, never DIFFERS.
compare() {
  got=$3
  if [ -z "$got" ]; then
    got='(no answer: the call failed, or the node has no state at this block)'
    verdict='NOT CHECKED'; UNCHECKED=1
  elif [ "$2" = "$3" ]; then verdict=MATCH
  else verdict=DIFFERS; DIFFERENT=1
  fi
  printf '%s\n  pegproof read: %s\n  chain says:    %s\n  %s\n\n' "$1" "$2" "$got" "$verdict"
}

CHAIN=$(curl -s "$RPC_URL" -H 'content-type: application/json' -d '{"jsonrpc":"2.0","id":1,"method":"eth_chainId","params":[]}' | tr -d ' \r\n' | sed -n 's/.*"result":"\(0x[0-9a-fA-F]*\)".*/\1/p')
case "$CHAIN" in
  0x1237) ;;
  '') echo "No answer from $RPC_URL to eth_chainId. Nothing was checked." >&2; exit 2 ;;
  *) echo "$RPC_URL is not Robinhood Chain (chain id $CHAIN, expected 0x1237). Nothing was checked." >&2; exit 2 ;;
esac

echo "Token $TOKEN at block $BLOCK, asking $RPC_URL"
echo
SUPPLY=$(dec "$(word "$(eth_call "$TOKEN" 0x18160ddd)" 0)")
compare 'totalSupply()' 4193688450000000000000 "$SUPPLY"
MULT=$(dec "$(word "$(eth_call "$TOKEN" 0xa60bf13d)" 0)")
compare 'uiMultiplier()' 1000000000000000000 "$MULT"
if [ -n "$SUPPLY" ] && [ -n "$MULT" ]; then
  RAW=$(amount "$SUPPLY * $MULT / 10^18")
  printf '%s %s\n' "Shares outstanding, from the chain's values:" "$(amount "scale=2; $RAW / 10^18")"
fi
echo
if [ "$DIFFERENT" = 1 ]; then
  echo "Some values differ. Your node returned something other than what pegproof read at block $BLOCK."
  exit 1
elif [ "$UNCHECKED" = 1 ]; then
  echo "Some values could not be checked: the node gave no answer. It may be rate-limiting, or have no state at block $BLOCK (older blocks may need an archive node)."
  exit 2
else
  echo "All values match what pegproof read at block $BLOCK."
fi