import {
  PublicKey,
  SYSVAR_CLOCK_PUBKEY,
  TransactionInstruction,
} from "@solana/web3.js";

import * as BufferLayout from "@solana/buffer-layout";
import * as Layout from "../../serialization/layout";
import BN from "bn.js";
import { TOKEN_PROGRAM_ID } from "@solana/spl-token";
import { LendingInstruction } from "./instruction";
import { PORT_LENDING, PORT_STAKING } from "../../constants";

// Repay borrowed liquidity to a reserve to receive collateral at a discount from an unhealthy
// obligation. Requires a refreshed obligation and reserves.
//
// Accounts expected by this instruction:
//
//   0. `[writable]` Source liquidity token account.
//                     Minted by repay reserve liquidity mint.
//                     $authority can transfer $liquidity_amount.
//   1. `[writable]` Destination collateral token account.
//                     Minted by withdraw reserve collateral mint.
//   2. `[writable]` Repay reserve account - refreshed.
//   3. `[writable]` Repay reserve liquidity supply SPL Token account.
//   4. `[]` Withdraw reserve account - refreshed.
//   5. `[writable]` Withdraw reserve collateral supply SPL Token account.
//   6. `[writable]` Obligation account - refreshed.
//   7. `[]` Lending market account.
//   8. `[]` Derived lending market authority.
//   9. `[signer]` User transfer authority ($authority).
//   10 `[]` Clock sysvar.
//   11 `[]` Token program id.
export const liquidateObligationInstruction = (
  liquidityAmount: number | BN,
  sourceLiquidity: PublicKey,
  destinationCollateral: PublicKey,
  repayReserve: PublicKey,
  repayReserveLiquiditySupply: PublicKey,
  withdrawReserve: PublicKey,
  withdrawReserveCollateralSupply: PublicKey,
  obligation: PublicKey,
  lendingMarket: PublicKey,
  lendingMarketAuthority: PublicKey,
  transferAuthority: PublicKey,
  lendingProgramId: PublicKey = PORT_LENDING,
  stakingPool?: PublicKey,
  stakeAccount?: PublicKey,
  stakingProgramId: PublicKey = PORT_STAKING
): TransactionInstruction => {
  const dataLayout = BufferLayout.struct([
    BufferLayout.u8("instruction"),
    Layout.uint64("liquidityAmount"),
  ]);

  const data = Buffer.alloc(dataLayout.span);
  dataLayout.encode(
    {
      instruction: LendingInstruction.LiquidateObligation,
      liquidityAmount: new BN(liquidityAmount),
    },
    data
  );

  let keys = [
    { pubkey: sourceLiquidity, isSigner: false, isWritable: true },
    { pubkey: destinationCollateral, isSigner: false, isWritable: true },
    { pubkey: repayReserve, isSigner: false, isWritable: true },
    { pubkey: repayReserveLiquiditySupply, isSigner: false, isWritable: true },
    { pubkey: withdrawReserve, isSigner: false, isWritable: false },
    {
      pubkey: withdrawReserveCollateralSupply,
      isSigner: false,
      isWritable: true,
    },
    { pubkey: obligation, isSigner: false, isWritable: true },
    { pubkey: lendingMarket, isSigner: false, isWritable: false },
    { pubkey: lendingMarketAuthority, isSigner: false, isWritable: false },
    { pubkey: transferAuthority, isSigner: true, isWritable: false },
    { pubkey: SYSVAR_CLOCK_PUBKEY, isSigner: false, isWritable: false },
    { pubkey: TOKEN_PROGRAM_ID, isSigner: false, isWritable: false },
  ];
  if (stakingPool !== undefined && stakeAccount !== undefined) {
    keys = keys.concat([
      { pubkey: stakeAccount, isSigner: false, isWritable: true },
      { pubkey: stakingPool, isSigner: false, isWritable: true },
      { pubkey: stakingProgramId, isSigner: false, isWritable: false },
    ]);
  }

  return new TransactionInstruction({
    keys,
    programId: lendingProgramId,
    data,
  });
};