Build

import {
  AccountRole,
  Address,
  address,
  AddressesByLookupTableAddress,
  appendTransactionMessageInstructions,
  Base64EncodedBytes,
  Blockhash,
  compileTransaction,
  compressTransactionMessageUsingAddressLookupTables,
  createKeyPairSignerFromBytes,
  createSolanaRpc,
  createTransactionMessage,
  getBase58Decoder,
  getBase58Encoder,
  getBase64Codec,
  getBase64EncodedWireTransaction,
  AccountMeta,
  Instruction,
  pipe,
  setTransactionMessageFeePayer,
  setTransactionMessageLifetimeUsingBlockhash,
  signTransaction,
} from "@solana/kit";
import { getTransferSolInstruction } from "@solana-program/system"; // For adding custom instructions

// ── Config ──────────────────────────────────────────────────────────────────
const COMPUTE_BUDGET_PROGRAM: Address = address(
  "ComputeBudget111111111111111111111111111111",
);
const COMPUTE_UNIT_LIMIT_MAX = 1_400_000;

// ── Instruction types ───────────────────────────────────────────────────────

type Account = {
  pubkey: Address;
  isSigner: boolean;
  isWritable: boolean;
};

type ApiInstruction = {
  programId: Address;
  accounts: Account[];
  data: Base64EncodedBytes;
};

function createInstruction(ix: ApiInstruction): Instruction {
  return {
    programAddress: ix.programId,
    accounts: ix.accounts.map((acc) => ({
      address: acc.pubkey,
      role: acc.isSigner && acc.isWritable
        ? AccountRole.WRITABLE_SIGNER
        : acc.isSigner
          ? AccountRole.READONLY_SIGNER
          : acc.isWritable
            ? AccountRole.WRITABLE
            : AccountRole.READONLY,
    })),
    data: Uint8Array.from(getBase64Codec().encode(ix.data)),
  };
}

// ── Build response type ─────────────────────────────────────────────────────

type BuildResponse = {
  inputMint: string;
  outputMint: string;
  inAmount: string;
  outAmount: string;
  otherAmountThreshold: string;
  swapMode: string;
  slippageBps: number;
  routePlan: {
    percent: number;
    bps: number;
    swapInfo: {
      ammKey: string;
      label: string;
      inputMint: string;
      outputMint: string;
      inAmount: string;
      outAmount: string;
    };
  }[];
  computeBudgetInstructions: ApiInstruction[];
  setupInstructions: ApiInstruction[];
  swapInstruction: ApiInstruction;
  cleanupInstruction: ApiInstruction | null;
  otherInstructions: ApiInstruction[];
  tipInstruction: ApiInstruction | null;
  addressesByLookupTableAddress: Record<string, string[]> | null;
  blockhashWithMetadata: {
    blockhash: number[];
    lastValidBlockHeight: number;
  };
};

// ── Helpers ──────────────────────────────────────────────────────────────────

function makeSetComputeUnitLimitIx(units: number): ApiInstruction {
  const data = Buffer.alloc(5);
  data.writeUInt8(0x02, 0);
  data.writeUInt32LE(units, 1);
  return {
    programId: COMPUTE_BUDGET_PROGRAM,
    accounts: [],
    data: data.toString("base64") as ApiInstruction["data"],
  };
}

function transformBlockhash(meta: BuildResponse["blockhashWithMetadata"]): {
  blockhash: Blockhash;
  lastValidBlockHeight: bigint;
} {
  return {
    blockhash: getBase58Decoder().decode(
      Uint8Array.from(meta.blockhash),
    ) as Blockhash,
    lastValidBlockHeight: BigInt(meta.lastValidBlockHeight),
  };
}

function transformALTs(
  raw: Record<string, string[]> | null,
): AddressesByLookupTableAddress {
  if (!raw) return {};
  return Object.fromEntries(
    Object.entries(raw).map(([key, addrs]) => [
      address(key),
      addrs.map((a) => address(a)),
    ]),
  );
}

function buildTransaction(
  ixs: Instruction[],
  blockhash: { blockhash: Blockhash; lastValidBlockHeight: bigint },
  alts: AddressesByLookupTableAddress,
  feePayer: Address,
) {
  return pipe(
    createTransactionMessage({ version: 0 }),
    (msg) => appendTransactionMessageInstructions(ixs, msg),
    (msg) => compressTransactionMessageUsingAddressLookupTables(msg, alts),
    (msg) => setTransactionMessageFeePayer(feePayer, msg),
    (msg) => setTransactionMessageLifetimeUsingBlockhash(blockhash, msg),
    (msg) => compileTransaction(msg),
  );
}