type StateRootType = Uint8Array & {
  readonly __tag: "StateRoot";
  readonly length: 32;
};

type StateRootLike = StateRootType | string | Uint8Array;

const SIZE = 32;

import * as StateRoot from './primitives/StateRoot/index.js';

// From hex string
const root = StateRoot.fromHex("0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421");

// From Uint8Array
const bytes = new Uint8Array(32);
const root2 = StateRoot.from(bytes);

const hex = StateRoot.toHex(root);
// "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"

const isEqual = StateRoot.equals(root1, root2);

State Root (32 bytes)
    |
    v
Merkle Patricia Trie
    |
    +-- Address A --> Account State A
    |                   - nonce
    |                   - balance
    |                   - codeHash
    |                   - storageRoot
    |
    +-- Address B --> Account State B
    ...

type BlockHeader = {
  parentHash: Hash;
  stateRoot: StateRoot;    // <-- This represents all state
  transactionsRoot: Hash;
  receiptsRoot: Hash;
  // ...
};

// Empty trie root = keccak256(RLP(null))
const EMPTY_STATE_ROOT = StateRoot.fromHex(
  "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"
);

// Get block header (from trusted source)
const header = await provider.getBlock("latest");

// Get state proof
const proof = await provider.send("eth_getProof", [address, [], "latest"]);

// Verify proof against header's state root
const isValid = verifyStateProof(proof, header.stateRoot);

// Compare state roots between blocks
const block1 = await provider.getBlock(1000000);
const block2 = await provider.getBlock(1000001);

const stateChanged = !StateRoot.equals(
  StateRoot.fromHex(block1.stateRoot),
  StateRoot.fromHex(block2.stateRoot)
);

// Light client stores only block headers
const headers = [header1, header2, ...];

// To verify any state claim, check proof against stateRoot
function verifyBalance(address: string, balance: bigint, proof: StateProof): boolean {
  const header = findHeader(proof.blockNumber);
  return verifyProof(proof, header.stateRoot);
}