import { CONTRACT_STORAGE_UPDATE_REQUEST_LENGTH } from '@aztec/constants';
import { Fr } from '@aztec/foundation/curves/bn254';
import { BufferReader, FieldReader, serializeToBuffer } from '@aztec/foundation/serialize';
import type { FieldsOf } from '@aztec/foundation/types';

import type { AztecAddress } from '../aztec-address/index.js';

/**
 * Contract storage update request for a slot on a specific contract.
 *
 * Note: Similar to `PublicDataUpdateRequest` but it's from the POV of contract storage so we are not working with
 * public data tree leaf index but storage slot index.
 */
export class ContractStorageUpdateRequest {
  constructor(
    /**
     * Storage slot we are updating.
     */
    public readonly storageSlot: Fr,
    /**
     * New value of the storage slot.
     */
    public readonly newValue: Fr,
    /**
     * Side effect counter tracking position of this event in tx execution.
     */
    public readonly counter: number,
    /**
     * Contract address whose storage is being read.
     */
    public contractAddress?: AztecAddress, // TODO: Should not be optional. This is a temporary hack to silo the storage slot with the correct address for nested executions.
  ) {}

  toBuffer() {
    return serializeToBuffer(this.storageSlot, this.newValue, this.counter);
  }

  static fromBuffer(buffer: Buffer | BufferReader) {
    const reader = BufferReader.asReader(buffer);
    return new ContractStorageUpdateRequest(Fr.fromBuffer(reader), Fr.fromBuffer(reader), reader.readNumber());
  }

  /**
   * Create ContractStorageUpdateRequest from a fields dictionary.
   * @param fields - The dictionary.
   * @returns A ContractStorageUpdateRequest object.
   */
  static from(fields: FieldsOf<ContractStorageUpdateRequest>): ContractStorageUpdateRequest {
    return new ContractStorageUpdateRequest(...ContractStorageUpdateRequest.getFields(fields));
  }

  /**
   * Serialize into a field array. Low-level utility.
   * @param fields - Object with fields.
   * @returns The array.
   */
  static getFields(fields: FieldsOf<ContractStorageUpdateRequest>) {
    return [fields.storageSlot, fields.newValue, fields.counter, fields.contractAddress] as const;
  }

  static empty() {
    return new ContractStorageUpdateRequest(Fr.ZERO, Fr.ZERO, 0);
  }

  isEmpty() {
    return this.storageSlot.isZero() && this.newValue.isZero();
  }

  toFriendlyJSON() {
    return `Slot=${this.storageSlot.toFriendlyJSON()}: ${this.newValue.toFriendlyJSON()}, sideEffectCounter=${
      this.counter
    }`;
  }

  toFields(): Fr[] {
    const fields = [this.storageSlot, this.newValue, new Fr(this.counter)];
    if (fields.length !== CONTRACT_STORAGE_UPDATE_REQUEST_LENGTH) {
      throw new Error(
        `Invalid number of fields for ContractStorageUpdateRequest. Expected ${CONTRACT_STORAGE_UPDATE_REQUEST_LENGTH}, got ${fields.length}`,
      );
    }
    return fields;
  }

  static fromFields(fields: Fr[] | FieldReader): ContractStorageUpdateRequest {
    const reader = FieldReader.asReader(fields);

    const storageSlot = reader.readField();
    const newValue = reader.readField();

    return new ContractStorageUpdateRequest(storageSlot, newValue, reader.readU32());
  }
}