All files / lib/messages DlcAccept.ts

89.11% Statements 180/202
59.34% Branches 54/91
86.21% Functions 25/29
88.94% Lines 177/199

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 6401x 1x 1x   1x 1x   1x 1x 1x 1x 1x 1x         1x 1x                           1x 1x                 33x     33x 33x     33x         33x 33x 33x             33x   33x             33x             33x       33x       33x       33x       33x         33x         33x         33x 33x     33x           33x                     33x   33x                       33x   33x         33x     33x     5230x 5230x               33x                                     55x 55x   55x     55x 55x 55x 55x 55x 55x 55x     55x 55x   55x     55x     55x 55x     55x 55x 55x   55x   52x         52x 52x   3x     55x         55x   55x     55x 55x 55x 55x               55x 222x 221x 221x   221x                     221x 4x   221x 221x                         55x 1x     55x           111x     111x                         111x                                           111x             4x               8x                                                               9x             9x         9x 9x   1x     8x 8x   1x           7x 6x 1x     1x       5x 4x     5x 1x       4x     3x 1x 1x     3x     2x 1x           1x                     18x   18x             18x                           61x 61x     61x 61x 61x 61x 61x 61x 61x     61x   61x   61x     61x 61x 61x 61x 61x     61x       61x       61x           61x 1x 71x       61x       1x                               1x   1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x                                                       1x 2x             4x                               3x   3x   3x 6x   6x 6x   3x                 1x 1x 1x 1x 2x 2x 2x 2x   1x      
import { Script } from '@node-dlc/bitcoin';
import { BufferReader, BufferWriter } from '@node-dlc/bufio';
import { hash160 } from '@node-dlc/crypto';
import { BitcoinNetwork } from 'bitcoin-networks';
import { address } from 'bitcoinjs-lib';
import secp256k1 from 'secp256k1';
 
import { MessageType, PROTOCOL_VERSION } from '../MessageType';
import { deserializeTlv } from '../serialize/deserializeTlv';
import { getTlv } from '../serialize/getTlv';
import { bigIntToNumber, toBigInt } from '../util';
import { BatchFundingGroup } from './BatchFundingGroup';
import {
  CetAdaptorSignatures,
  ICetAdaptorSignaturesJSON,
} from './CetAdaptorSignatures';
import { IDlcMessage } from './DlcMessage';
import { FundingInput, IFundingInputJSON } from './FundingInput';
import {
  INegotiationFieldsV0JSON,
  INegotiationFieldsV1JSON,
  INegotiationFieldsV2JSON,
  NegotiationFields,
} from './NegotiationFields';
 
/**
 * DlcAccept contains information about a node and indicates its
 * acceptance of the new DLC, as well as its CET and refund
 * transaction signatures. This is the second step toward creating
 * the funding transaction and closing transactions.
 * Updated to support dlcspecs PR #163 format.
 */
export class DlcAccept implements IDlcMessage {
  public static type = MessageType.DlcAccept;
 
  /**
   * Creates a DlcAccept from JSON data (e.g., from test vectors)
   * Handles both our internal format and external test vector formats
   * @param json JSON object representing a DLC accept
   */
  // eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types, @typescript-eslint/no-explicit-any
  public static fromJSON(json: any): DlcAccept {
    const instance = new DlcAccept();
 
    // Helper function to parse DER-encoded signature and extract raw r,s values (64 bytes total)
    const parseDerSignature = (hexSig: string): Buffer => {
      const sigBuffer = Buffer.from(hexSig, 'hex');
 
      // If it's already 64 bytes, assume it's raw
      Iif (sigBuffer.length === 64) {
        return sigBuffer;
      }
 
      // Use secp256k1.signatureImport to parse DER signature
      try {
        const rawSig = secp256k1.signatureImport(sigBuffer);
        return Buffer.from(rawSig);
      } catch (ex) {
        throw new Error(`Invalid DER signature: ${ex.message}`);
      }
    };
 
    // Handle both internal and external field naming conventions
    instance.protocolVersion =
      json.protocolVersion || json.protocol_version || PROTOCOL_VERSION;
    instance.temporaryContractId = Buffer.from(
      json.temporaryContractId ||
        json.tempContractId ||
        json.temporary_contract_id,
      'hex',
    );
 
    instance.acceptCollateral = toBigInt(
      json.acceptCollateral ||
        json.acceptCollateralSatoshis ||
        json.accept_collateral,
    );
 
    // Handle field name variations between formats
    instance.fundingPubkey = Buffer.from(
      json.fundingPubkey || json.fundingPubKey || json.funding_pubkey,
      'hex',
    );
    instance.payoutSpk = Buffer.from(
      json.payoutSpk || json.payoutSPK || json.payout_spk,
      'hex',
    );
    instance.payoutSerialId = toBigInt(
      json.payoutSerialId || json.payout_serial_id,
    );
 
    instance.changeSpk = Buffer.from(
      json.changeSpk || json.changeSPK || json.change_spk,
      'hex',
    );
    instance.changeSerialId = toBigInt(
      json.changeSerialId || json.change_serial_id,
    );
 
    // Parse FundingInputs
    instance.fundingInputs = DlcAccept.parseFundingInputsFromJSON(
      json.fundingInputs || json.funding_inputs || [],
    );
 
    // Parse CET adaptor signatures
    instance.cetAdaptorSignatures = DlcAccept.parseCetAdaptorSignaturesFromJSON(
      json.cetAdaptorSignatures || json.cet_adaptor_signatures,
    );
 
    // Parse refund signature - handle DER encoding
    const refundSigHex = json.refundSignature || json.refund_signature;
    instance.refundSignature = parseDerSignature(refundSigHex);
 
    // Parse optional negotiation fields
    Iif (json.negotiationFields || json.negotiation_fields) {
      instance.negotiationFields = DlcAccept.parseNegotiationFieldsFromJSON(
        json.negotiationFields || json.negotiation_fields,
      );
    }
 
    return instance;
  }
 
  /**
   * Parses FundingInputs from JSON
   * @param fundingInputsJson Array of JSON objects representing funding inputs
   */
  private static parseFundingInputsFromJSON(
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    fundingInputsJson: any[],
  ): FundingInput[] {
    return fundingInputsJson.map((inputJson) => {
      // Use the existing FundingInput.fromJSON method which handles all the field mapping correctly
      return FundingInput.fromJSON(inputJson) as FundingInput;
    });
  }
 
  /**
   * Parses CetAdaptorSignatures from JSON
   * @param cetSigsJson JSON object representing CET adaptor signatures
   */
  private static parseCetAdaptorSignaturesFromJSON(
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    cetSigsJson: any,
  ): CetAdaptorSignatures {
    const instance = new CetAdaptorSignatures();
 
    Eif (
      cetSigsJson.ecdsaAdaptorSignatures ||
      cetSigsJson.ecdsa_adaptor_signatures
    ) {
      const ecdsaSigs =
        cetSigsJson.ecdsaAdaptorSignatures ||
        cetSigsJson.ecdsa_adaptor_signatures;
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      instance.sigs = ecdsaSigs.map((sig: any) => {
        // The test vectors use 'signature' field, but our internal format uses encryptedSig/dleqProof
        // Adaptor signatures have different format than regular ECDSA (65 bytes + 97 bytes)
        const sigBuffer = Buffer.from(sig.signature, 'hex');
        return {
          encryptedSig: sigBuffer.slice(0, 65), // First 65 bytes
          dleqProof:
            sigBuffer.length > 65 ? sigBuffer.slice(65, 162) : Buffer.alloc(97), // Next 97 bytes or empty
        };
      });
    }
 
    return instance;
  }
 
  /**
   * Parses NegotiationFields from JSON
   * @param negotiationJson JSON object representing negotiation fields
   */
  private static parseNegotiationFieldsFromJSON(
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    negotiationJson: any,
  ): NegotiationFields {
    return NegotiationFields.fromJSON(negotiationJson);
  }
 
  /**
   * Deserializes an accept_dlc message
   * @param buf
   */
  public static deserialize(buf: Buffer, parseCets = true): DlcAccept {
    const instance = new DlcAccept();
    const reader = new BufferReader(buf);
 
    reader.readUInt16BE(); // read type
 
    // New fields as per dlcspecs PR #163
    instance.protocolVersion = reader.readUInt32BE();
    instance.temporaryContractId = reader.readBytes(32);
    instance.acceptCollateral = reader.readUInt64BE();
    instance.fundingPubkey = reader.readBytes(33);
    const payoutSpkLen = reader.readUInt16BE();
    instance.payoutSpk = reader.readBytes(payoutSpkLen);
    instance.payoutSerialId = reader.readUInt64BE();
 
    // Changed from u16 to bigsize as per dlcspecs PR #163
    const fundingInputsLen = Number(reader.readBigSize());
    for (let i = 0; i < fundingInputsLen; i++) {
      // FundingInput body is serialized directly without TLV wrapper in rust-dlc format
      const fundingInput = FundingInput.deserializeBody(
        reader.buffer.subarray(reader.position),
      );
      instance.fundingInputs.push(fundingInput);
 
      // Skip past the FundingInput we just read
      const fundingInputLength = fundingInput.serializeBody().length;
      reader.position += fundingInputLength;
    }
 
    const changeSpkLen = reader.readUInt16BE();
    instance.changeSpk = reader.readBytes(changeSpkLen);
    instance.changeSerialId = reader.readUInt64BE();
 
    if (parseCets) {
      // Read CET adaptor signatures directly to match serialize format (no TLV wrapping)
      instance.cetAdaptorSignatures = CetAdaptorSignatures.deserialize(
        reader.buffer.subarray(reader.position),
      );
 
      // Skip past the CET adaptor signatures we just read
      const cetLength = instance.cetAdaptorSignatures.serialize().length;
      reader.position += cetLength;
    } else {
      instance.cetAdaptorSignatures = new CetAdaptorSignatures();
    }
 
    instance.refundSignature = reader.readBytes(64);
 
    // negotiation_fields is now optional as per dlcspecs PR #163
    // Check if there's enough data left for the new format fields (backward compatibility)
    // The old format ends exactly after refundSignature. If there's more data, it should be new format.
    const remainingBytes = reader.buffer.length - reader.position;
 
    Eif (remainingBytes > 0) {
      // Only try to parse new fields if we have a reasonable amount of extra data
      // A single stray byte is likely not valid new format data
      Eif (remainingBytes >= 1) {
        try {
          const hasNegotiationFields = reader.readUInt8();
          Iif (hasNegotiationFields === 0x01) {
            instance.negotiationFields = NegotiationFields.deserialize(
              getTlv(reader),
            );
          }
 
          // Parse TLV stream as per dlcspecs PR #163
          // Only continue if there's still data left after the hasNegotiationFields flag
          while (reader.position < reader.buffer.length) {
            const buf = getTlv(reader);
            const tlvReader = new BufferReader(buf);
            const { type } = deserializeTlv(tlvReader);
 
            switch (Number(type)) {
              case MessageType.BatchFundingGroup:
                if (!instance.batchFundingGroups) {
                  instance.batchFundingGroups = [];
                }
                instance.batchFundingGroups.push(
                  BatchFundingGroup.deserialize(buf),
                );
                break;
              default:
                // Store unknown TLVs for future compatibility
                if (!instance.unknownTlvs) {
                  instance.unknownTlvs = [];
                }
                instance.unknownTlvs.push({ type: Number(type), data: buf });
                break;
            }
          }
        } catch (error) {
          // If parsing new format fails, assume it's old format and ignore the extra bytes
          // This provides backward compatibility for malformed or old format data
          // Silently ignore parsing errors for backward compatibility
        }
      }
    }
 
    // Auto-detect single funded DLCs based on minimal acceptCollateral
    // In single funded DLCs, acceptCollateral is typically 0 or very small
    if (instance.acceptCollateral === BigInt(0)) {
      instance.singleFunded = true;
    }
 
    return instance;
  }
 
  /**
   * The type for accept_dlc message. accept_dlc = 42780
   */
  public type = DlcAccept.type;
 
  // New fields as per dlcspecs PR #163
  public protocolVersion: number = PROTOCOL_VERSION; // Default to current protocol version
 
  // Existing fields
  public temporaryContractId: Buffer;
 
  public acceptCollateral: bigint;
 
  public fundingPubkey: Buffer;
 
  public payoutSpk: Buffer;
 
  public payoutSerialId: bigint;
 
  public fundingInputs: FundingInput[] = [];
 
  public changeSpk: Buffer;
 
  public changeSerialId: bigint;
 
  public cetAdaptorSignatures: CetAdaptorSignatures;
 
  public refundSignature: Buffer;
 
  // negotiation_fields is now optional
  public negotiationFields?: NegotiationFields;
 
  public batchFundingGroups?: BatchFundingGroup[];
 
  // Store unknown TLVs for forward compatibility
  public unknownTlvs?: Array<{ type: number; data: Buffer }>;
 
  /**
   * Flag to indicate if this is a single funded DLC
   * In single funded DLCs, the acceptor provides minimal or no collateral
   */
  public singleFunded = false;
 
  /**
   * Marks this DLC accept as single funded
   * For single funded DLCs, acceptCollateral is typically 0 or minimal
   */
  public markAsSingleFunded(): void {
    this.singleFunded = true;
  }
 
  /**
   * Checks if this DLC accept is for a single funded DLC
   * @returns True if this is a single funded DLC
   */
  public isSingleFunded(): boolean {
    return this.singleFunded;
  }
 
  /**
   * Get funding, change and payout address from DlcAccept
   * @param network Bitcoin Network
   * @returns {IDlcAcceptAddresses}
   */
  public getAddresses(network: BitcoinNetwork): IDlcAcceptAddresses {
    const fundingSPK = Script.p2wpkhLock(hash160(this.fundingPubkey))
      .serialize()
      .slice(1);
    const fundingAddress = address.fromOutputScript(fundingSPK, network);
    const changeAddress = address.fromOutputScript(this.changeSpk, network);
    const payoutAddress = address.fromOutputScript(this.payoutSpk, network);
 
    return {
      fundingAddress,
      changeAddress,
      payoutAddress,
    };
  }
 
  /**
   * Validates correctness of all fields
   * Updated validation rules as per dlcspecs PR #163
   * https://github.com/discreetlogcontracts/dlcspecs/blob/master/Protocol.md#the-accept_dlc-message
   * @throws Will throw an error if validation fails
   */
  public validate(): void {
    // 1. Type is set automatically in class
    // 2. protocol_version validation
    Iif (this.protocolVersion !== PROTOCOL_VERSION) {
      throw new Error(
        `Unsupported protocol version: ${this.protocolVersion}, expected: ${PROTOCOL_VERSION}`,
      );
    }
 
    // 3. temporary_contract_id must match the one from offer_dlc
    Iif (!this.temporaryContractId || this.temporaryContractId.length !== 32) {
      throw new Error('temporaryContractId must be 32 bytes');
    }
 
    // 4. payout_spk and change_spk must be standard script pubkeys
    try {
      address.fromOutputScript(this.payoutSpk);
    } catch (e) {
      throw new Error('payoutSpk is invalid');
    }
 
    try {
      address.fromOutputScript(this.changeSpk);
    } catch (e) {
      throw new Error('changeSpk is invalid');
    }
 
    // 5. funding_pubkey must be a valid secp256k1 pubkey in compressed format
    // https://github.com/bitcoin/bips/blob/master/bip-0137.mediawiki#background-on-ecdsa-signatures
 
    if (secp256k1.publicKeyVerify(Buffer.from(this.fundingPubkey))) {
      if (this.fundingPubkey[0] != 0x02 && this.fundingPubkey[0] != 0x03) {
        throw new Error('fundingPubkey must be in compressed format');
      }
    } else {
      throw new Error('fundingPubkey is not a valid secp256k1 key');
    }
 
    // 6. inputSerialId must be unique for each input
    const inputSerialIds = this.fundingInputs.map(
      (input: FundingInput) => input.inputSerialId,
    );
 
    if (new Set(inputSerialIds).size !== inputSerialIds.length) {
      throw new Error('inputSerialIds must be unique');
    }
 
    // 7. Ensure funding inputs are segwit
    this.fundingInputs.forEach((input: FundingInput) => input.validate());
 
    // 8. validate funding amount
    const fundingAmount = this.fundingInputs.reduce((acc, fundingInput) => {
      const input = fundingInput as FundingInput;
      return acc + input.prevTx.outputs[input.prevTxVout].value.sats;
    }, BigInt(0));
 
    if (this.isSingleFunded()) {
      // For single funded DLCs, acceptor may provide minimal or no collateral
      // fundingAmount should be >= acceptCollateral (allowing for 0 collateral case)
      if (this.acceptCollateral > 0 && fundingAmount < this.acceptCollateral) {
        throw new Error(
          'For single funded DLCs, fundingAmount must be at least acceptCollateral',
        );
      }
    } else {
      // For regular DLCs, funding amount must be greater than accept collateral
      Iif (this.acceptCollateral >= fundingAmount) {
        throw new Error('fundingAmount must be greater than acceptCollateral');
      }
    }
  }
 
  /**
   * Converts accept_dlc to JSON (canonical rust-dlc format)
   */
  public toJSON(): IDlcAcceptJSON {
    // Convert raw signature back to DER format for canonical rust-dlc JSON
    const derRefundSignature = secp256k1.signatureExport(this.refundSignature);
 
    return {
      protocolVersion: this.protocolVersion,
      temporaryContractId: this.temporaryContractId.toString('hex'),
      acceptCollateral: bigIntToNumber(this.acceptCollateral),
      fundingPubkey: this.fundingPubkey.toString('hex'), // lowercase 'k'
      payoutSpk: this.payoutSpk.toString('hex'), // lowercase
      payoutSerialId: bigIntToNumber(this.payoutSerialId),
      fundingInputs: this.fundingInputs.map((input) => input.toJSON()),
      changeSpk: this.changeSpk.toString('hex'), // lowercase
      changeSerialId: bigIntToNumber(this.changeSerialId),
      cetAdaptorSignatures: this.cetAdaptorSignatures.toJSON(),
      refundSignature: Buffer.from(derRefundSignature).toString('hex'),
      negotiationFields: this.negotiationFields?.toJSON(),
    };
  }
 
  /**
   * Serializes the accept_dlc message into a Buffer
   * Updated serialization format as per dlcspecs PR #163
   */
  public serialize(): Buffer {
    const writer = new BufferWriter();
    writer.writeUInt16BE(this.type);
 
    // New fields as per dlcspecs PR #163
    writer.writeUInt32BE(this.protocolVersion);
    writer.writeBytes(this.temporaryContractId);
    writer.writeUInt64BE(this.acceptCollateral);
    writer.writeBytes(this.fundingPubkey);
    writer.writeUInt16BE(this.payoutSpk.length);
    writer.writeBytes(this.payoutSpk);
    writer.writeUInt64BE(this.payoutSerialId);
 
    // Changed from u16 to bigsize as per dlcspecs PR #163
    writer.writeBigSize(this.fundingInputs.length);
 
    for (const fundingInput of this.fundingInputs) {
      // Use serializeBody() to match rust-dlc behavior - funding inputs in vec are serialized without TLV wrapper
      writer.writeBytes(fundingInput.serializeBody());
    }
 
    writer.writeUInt16BE(this.changeSpk.length);
    writer.writeBytes(this.changeSpk);
    writer.writeUInt64BE(this.changeSerialId);
    writer.writeBytes(this.cetAdaptorSignatures.serialize());
    writer.writeBytes(this.refundSignature);
 
    // negotiation_fields is now optional as per dlcspecs PR #163
    Iif (this.negotiationFields) {
      writer.writeUInt8(0x01); // present
      writer.writeBytes(this.negotiationFields.serialize());
    } else {
      writer.writeUInt8(0x00); // absent
    }
 
    // TLV stream as per dlcspecs PR #163
    Iif (this.batchFundingGroups)
      this.batchFundingGroups.forEach((fundingInfo) =>
        writer.writeBytes(fundingInfo.serialize()),
      );
 
    // Write unknown TLVs for forward compatibility
    if (this.unknownTlvs) {
      this.unknownTlvs.forEach((tlv) => {
        writer.writeBytes(tlv.data);
      });
    }
 
    return writer.toBuffer();
  }
 
  public withoutSigs(): DlcAcceptWithoutSigs {
    return new DlcAcceptWithoutSigs(
      this.protocolVersion,
      this.temporaryContractId,
      this.acceptCollateral,
      this.fundingPubkey,
      this.payoutSpk,
      this.payoutSerialId,
      this.fundingInputs,
      this.changeSpk,
      this.changeSerialId,
      this.negotiationFields,
      this.batchFundingGroups,
    );
  }
}
 
export class DlcAcceptWithoutSigs {
  constructor(
    readonly protocolVersion: number,
    readonly temporaryContractId: Buffer,
    readonly acceptCollateral: bigint,
    readonly fundingPubkey: Buffer,
    readonly payoutSpk: Buffer,
    readonly payoutSerialId: bigint,
    readonly fundingInputs: FundingInput[],
    readonly changeSpk: Buffer,
    readonly changeSerialId: bigint,
    readonly negotiationFields?: NegotiationFields,
    readonly batchFundingGroups?: BatchFundingGroup[],
  ) {}
}
 
export interface IDlcAcceptJSON {
  protocolVersion: number;
  temporaryContractId: string;
  acceptCollateral: number;
  fundingPubkey: string;
  payoutSpk: string;
  payoutSerialId: number;
  fundingInputs: IFundingInputJSON[];
  changeSpk: string;
  changeSerialId: number;
  cetAdaptorSignatures: ICetAdaptorSignaturesJSON;
  refundSignature: string;
  negotiationFields?: // Now optional
  | INegotiationFieldsV0JSON
    | INegotiationFieldsV1JSON
    | INegotiationFieldsV2JSON;
}
 
export interface IDlcAcceptAddresses {
  fundingAddress: string;
  changeAddress: string;
  payoutAddress: string;
}
 
export class DlcAcceptContainer {
  private accepts: DlcAccept[] = [];
 
  /**
   * Adds a DlcAccept to the container.
   * @param accept The DlcAccept to add.
   */
  public addAccept(accept: DlcAccept): void {
    this.accepts.push(accept);
  }
 
  /**
   * Returns all DlcAccepts in the container.
   * @returns An array of DlcAccept instances.
   */
  public getAccepts(): DlcAccept[] {
    return this.accepts;
  }
 
  /**
   * Serializes all DlcAccepts in the container to a Buffer.
   * @returns A Buffer containing the serialized DlcAccepts.
   */
  public serialize(): Buffer {
    const writer = new BufferWriter();
    // Write the number of accepts in the container first.
    writer.writeBigSize(this.accepts.length);
    // Serialize each accept and write it.
    this.accepts.forEach((accept) => {
      const serializedAccept = accept.serialize();
      // Optionally, write the length of the serialized accept for easier deserialization.
      writer.writeBigSize(serializedAccept.length);
      writer.writeBytes(serializedAccept);
    });
    return writer.toBuffer();
  }
 
  /**
   * Deserializes a Buffer into a DlcAcceptContainer with DlcAccepts.
   * @param buf The Buffer to deserialize.
   * @returns A DlcAcceptContainer instance.
   */
  public static deserialize(buf: Buffer, parseCets = true): DlcAcceptContainer {
    const reader = new BufferReader(buf);
    const container = new DlcAcceptContainer();
    const acceptsCount = reader.readBigSize();
    for (let i = 0; i < acceptsCount; i++) {
      const acceptLength = reader.readBigSize();
      const acceptBuf = reader.readBytes(Number(acceptLength));
      const accept = DlcAccept.deserialize(acceptBuf, parseCets);
      container.addAccept(accept);
    }
    return container;
  }
}