import { PublicKey, TransactionInstruction, SystemProgram } from "@solana/web3.js";
import type { PitProgram } from "../program.js";
import { getRegistryAddress } from "../accounts/pda.js";

/**
 * Parameters for creating an initialize_registry instruction
 */
interface InitializeRegistryParams {
  /** Operator's public key (must match hardcoded OPERATOR) */
  operator: PublicKey;
}

/**
 * Create an initialize_registry instruction
 *
 * This instruction is operator-only and should be called once before
 * any markets are initialized. It creates the singleton registry account
 * that tracks all active market week numbers.
 *
 * @param program - Anchor Program instance
 * @param params - Initialize registry parameters
 * @returns Promise resolving to TransactionInstruction
 *
 * @example
 * ```typescript
 * import { createProgram, createInitializeRegistryInstruction } from "@pit-protocol/sdk";
 *
 * const program = createProgram(provider);
 * const ix = await createInitializeRegistryInstruction(program, {
 *   operator: operatorKeypair.publicKey,
 * });
 *
 * const tx = new Transaction().add(ix);
 * await sendAndConfirmTransaction(connection, tx, [operatorKeypair]);
 * ```
 */
export async function createInitializeRegistryInstruction(
  program: PitProgram,
  params: InitializeRegistryParams
): Promise<TransactionInstruction> {
  const { operator } = params;

  const registry = getRegistryAddress();

  return await program.methods
    .initializeRegistry()
    .accountsPartial({
      registry,
      operator,
      systemProgram: SystemProgram.programId,
    })
    .instruction();
}