import type { Address } from "viem";
import { createNonceManager, jsonRpc, type NonceManager } from "viem/nonce";

/** The identity whose local sends must reach terminal broadcast results in order. */
export interface LocalSendKey {
  readonly address: Address;
  readonly chainId: number;
}

/** Owner-held nonce and send coordination shared by every derived trader. */
export interface WriterRuntime {
  readonly nonceManager: NonceManager;
  readonly runLocalSend: <T>(key: LocalSendKey, task: () => Promise<T>) => Promise<T>;
}

/** Build the writer state owned by one configured Markets client. */
export function makeWriterRuntime(): WriterRuntime {
  const nonceManager = createNonceManager({ source: jsonRpc() });
  const tails = new Map<string, Promise<void>>();

  function runLocalSend<T>({ address, chainId }: LocalSendKey, task: () => Promise<T>): Promise<T> {
    const key = `${chainId}:${address.toLowerCase()}`;
    const previous = tails.get(key) ?? Promise.resolve();
    const result = previous.then(task);
    const tail = result.then(
      () => undefined,
      () => undefined,
    );
    tails.set(key, tail);
    void tail.then(() => {
      if (tails.get(key) === tail) tails.delete(key);
    });
    return result;
  }

  return { nonceManager, runLocalSend };
}