# src/stake-program.js

    // @flow

    import * as BufferLayout from 'buffer-layout';

    import {encodeData, decodeData} from './instruction';
    import * as Layout from './layout';
    import {PublicKey} from './publickey';
    import {SystemProgram} from './system-program';
    import {
      SYSVAR_CLOCK_PUBKEY,
      SYSVAR_RENT_PUBKEY,
      SYSVAR_STAKE_HISTORY_PUBKEY,
    } from './sysvar';
    import {Transaction, TransactionInstruction} from './transaction';

    export const STAKE_CONFIG_ID = new PublicKey(
      'StakeConfig11111111111111111111111111111111',
    );

    export class Authorized {
      staker: PublicKey;
      withdrawer: PublicKey;

      /**
       * Create a new Authorized object
       */
      constructor(staker: PublicKey, withdrawer: PublicKey) {
        this.staker = staker;
        this.withdrawer = withdrawer;
      }
    }

    export class Lockup {
      unixTimestamp: number;
      epoch: number;
      custodian: PublicKey;

      /**
       * Create a new Lockup object
       */
      constructor(unixTimestamp: number, epoch: number, custodian: PublicKey) {
        this.unixTimestamp = unixTimestamp;
        this.epoch = epoch;
        this.custodian = custodian;
      }
    }

    /**
     * Create stake account transaction params
     * @typedef {Object} CreateStakeAccountParams
     * @property {PublicKey} fromPubkey
     * @property {PublicKey} stakePubkey
     * @property {Authorized} authorized
     * @property {Lockup} lockup
     * @property {number} lamports
     */
    export type CreateStakeAccountParams = {|
      fromPubkey: PublicKey,
      stakePubkey: PublicKey,
      authorized: Authorized,
      lockup: Lockup,
      lamports: number,
    |};

    /**
     * Create stake account with seed transaction params
     * @typedef {Object} CreateStakeAccountWithSeedParams
     * @property {PublicKey} fromPubkey
     * @property {PublicKey} stakePubkey
     * @property {PublicKey} basePubkey
     * @property {string} seed
     * @property {Authorized} authorized
     * @property {Lockup} lockup
     * @property {number} lamports
     */
    export type CreateStakeAccountWithSeedParams = {|
      fromPubkey: PublicKey,
      stakePubkey: PublicKey,
      basePubkey: PublicKey,
      seed: string,
      authorized: Authorized,
      lockup: Lockup,
      lamports: number,
    |};

    /**
     * Initialize stake instruction params
     * @typedef {Object} InitializeStakeParams
     * @property {PublicKey} stakePubkey
     * @property {Authorized} authorized
     * @property {Lockup} lockup
     */
    export type InitializeStakeParams = {|
      stakePubkey: PublicKey,
      authorized: Authorized,
      lockup: Lockup,
    |};

    /**
     * Delegate stake instruction params
     * @typedef {Object} DelegateStakeParams
     * @property {PublicKey} stakePubkey
     * @property {PublicKey} authorizedPubkey
     * @property {PublicKey} votePubkey
     */
    export type DelegateStakeParams = {|
      stakePubkey: PublicKey,
      authorizedPubkey: PublicKey,
      votePubkey: PublicKey,
    |};

    /**
     * Authorize stake instruction params
     * @typedef {Object} AuthorizeStakeParams
     * @property {PublicKey} stakePubkey
     * @property {PublicKey} authorizedPubkey
     * @property {PublicKey} newAuthorizedPubkey
     * @property {StakeAuthorizationType} stakeAuthorizationType
     */
    export type AuthorizeStakeParams = {|
      stakePubkey: PublicKey,
      authorizedPubkey: PublicKey,
      newAuthorizedPubkey: PublicKey,
      stakeAuthorizationType: StakeAuthorizationType,
    |};

    /**
     * Authorize stake instruction params using a derived key
     * @typedef {Object} AuthorizeWithSeedStakeParams
     * @property {PublicKey} stakePubkey
     * @property {PublicKey} authorityBase
     * @property {string} authoritySeed
     * @property {PublicKey} authorityOwner
     * @property {PublicKey} newAuthorizedPubkey
     * @property {StakeAuthorizationType} stakeAuthorizationType
     */
    export type AuthorizeWithSeedStakeParams = {|
      stakePubkey: PublicKey,
      authorityBase: PublicKey,
      authoritySeed: string,
      authorityOwner: PublicKey,
      newAuthorizedPubkey: PublicKey,
      stakeAuthorizationType: StakeAuthorizationType,
    |};

    /**
     * Split stake instruction params
     * @typedef {Object} SplitStakeParams
     * @property {PublicKey} stakePubkey
     * @property {PublicKey} authorizedPubkey
     * @property {PublicKey} splitStakePubkey
     * @property {number} lamports
     */
    export type SplitStakeParams = {|
      stakePubkey: PublicKey,
      authorizedPubkey: PublicKey,
      splitStakePubkey: PublicKey,
      lamports: number,
    |};

    /**
     * Withdraw stake instruction params
     * @typedef {Object} WithdrawStakeParams
     * @property {PublicKey} stakePubkey
     * @property {PublicKey} authorizedPubkey
     * @property {PublicKey} toPubkey
     * @property {number} lamports
     */
    export type WithdrawStakeParams = {|
      stakePubkey: PublicKey,
      authorizedPubkey: PublicKey,
      toPubkey: PublicKey,
      lamports: number,
    |};

    /**
     * Deactivate stake instruction params
     * @typedef {Object} DeactivateStakeParams
     * @property {PublicKey} stakePubkey
     * @property {PublicKey} authorizedPubkey
     */
    export type DeactivateStakeParams = {|
      stakePubkey: PublicKey,
      authorizedPubkey: PublicKey,
    |};

    /**
     * Stake Instruction class
     */
    export class StakeInstruction {
      /**
       * Decode a stake instruction and retrieve the instruction type.
       */
      static decodeInstructionType(
        instruction: TransactionInstruction,
      ): StakeInstructionType {
        this.checkProgramId(instruction.programId);

        const instructionTypeLayout = BufferLayout.u32('instruction');
        const typeIndex = instructionTypeLayout.decode(instruction.data);

        let type;
        for (const t of Object.keys(STAKE_INSTRUCTION_LAYOUTS)) {
          if (STAKE_INSTRUCTION_LAYOUTS[t].index == typeIndex) {
            type = t;
          }
        }

        if (!type) {
          throw new Error('Instruction type incorrect; not a StakeInstruction');
        }

        return type;
      }

      /**
       * Decode a initialize stake instruction and retrieve the instruction params.
       */
      static decodeInitialize(
        instruction: TransactionInstruction,
      ): InitializeStakeParams {
        this.checkProgramId(instruction.programId);
        this.checkKeyLength(instruction.keys, 2);

        const {authorized, lockup} = decodeData(
          STAKE_INSTRUCTION_LAYOUTS.Initialize,
          instruction.data,
        );

        return {
          stakePubkey: instruction.keys[0].pubkey,
          authorized: new Authorized(
            new PublicKey(authorized.staker),
            new PublicKey(authorized.withdrawer),
          ),
          lockup: new Lockup(
            lockup.unixTimestamp,
            lockup.epoch,
            new PublicKey(lockup.custodian),
          ),
        };
      }

      /**
       * Decode a delegate stake instruction and retrieve the instruction params.
       */
      static decodeDelegate(
        instruction: TransactionInstruction,
      ): DelegateStakeParams {
        this.checkProgramId(instruction.programId);
        this.checkKeyLength(instruction.keys, 6);
        decodeData(STAKE_INSTRUCTION_LAYOUTS.Delegate, instruction.data);

        return {
          stakePubkey: instruction.keys[0].pubkey,
          votePubkey: instruction.keys[1].pubkey,
          authorizedPubkey: instruction.keys[5].pubkey,
        };
      }

      /**
       * Decode an authorize stake instruction and retrieve the instruction params.
       */
      static decodeAuthorize(
        instruction: TransactionInstruction,
      ): AuthorizeStakeParams {
        this.checkProgramId(instruction.programId);
        this.checkKeyLength(instruction.keys, 3);
        const {newAuthorized, stakeAuthorizationType} = decodeData(
          STAKE_INSTRUCTION_LAYOUTS.Authorize,
          instruction.data,
        );

        return {
          stakePubkey: instruction.keys[0].pubkey,
          authorizedPubkey: instruction.keys[2].pubkey,
          newAuthorizedPubkey: new PublicKey(newAuthorized),
          stakeAuthorizationType: {
            index: stakeAuthorizationType,
          },
        };
      }

      /**
       * Decode an authorize-with-seed stake instruction and retrieve the instruction params.
       */
      static decodeAuthorizeWithSeed(
        instruction: TransactionInstruction,
      ): AuthorizeWithSeedStakeParams {
        this.checkProgramId(instruction.programId);
        this.checkKeyLength(instruction.keys, 2);
        const {
          newAuthorized,
          stakeAuthorizationType,
          authoritySeed,
          authorityOwner,
        } = decodeData(
          STAKE_INSTRUCTION_LAYOUTS.AuthorizeWithSeed,
          instruction.data,
        );

        return {
          stakePubkey: instruction.keys[0].pubkey,
          authorityBase: instruction.keys[1].pubkey,
          authoritySeed: authoritySeed,
          authorityOwner: new PublicKey(authorityOwner),
          newAuthorizedPubkey: new PublicKey(newAuthorized),
          stakeAuthorizationType: {
            index: stakeAuthorizationType,
          },
        };
      }

      /**
       * Decode a split stake instruction and retrieve the instruction params.
       */
      static decodeSplit(instruction: TransactionInstruction): SplitStakeParams {
        this.checkProgramId(instruction.programId);
        this.checkKeyLength(instruction.keys, 3);
        const {lamports} = decodeData(
          STAKE_INSTRUCTION_LAYOUTS.Split,
          instruction.data,
        );

        return {
          stakePubkey: instruction.keys[0].pubkey,
          splitStakePubkey: instruction.keys[1].pubkey,
          authorizedPubkey: instruction.keys[2].pubkey,
          lamports,
        };
      }

      /**
       * Decode a withdraw stake instruction and retrieve the instruction params.
       */
      static decodeWithdraw(
        instruction: TransactionInstruction,
      ): WithdrawStakeParams {
        this.checkProgramId(instruction.programId);
        this.checkKeyLength(instruction.keys, 5);
        const {lamports} = decodeData(
          STAKE_INSTRUCTION_LAYOUTS.Withdraw,
          instruction.data,
        );

        return {
          stakePubkey: instruction.keys[0].pubkey,
          toPubkey: instruction.keys[1].pubkey,
          authorizedPubkey: instruction.keys[4].pubkey,
          lamports,
        };
      }

      /**
       * Decode a deactivate stake instruction and retrieve the instruction params.
       */
      static decodeDeactivate(
        instruction: TransactionInstruction,
      ): DeactivateStakeParams {
        this.checkProgramId(instruction.programId);
        this.checkKeyLength(instruction.keys, 3);
        decodeData(STAKE_INSTRUCTION_LAYOUTS.Deactivate, instruction.data);

        return {
          stakePubkey: instruction.keys[0].pubkey,
          authorizedPubkey: instruction.keys[2].pubkey,
        };
      }

      /**
       * @private
       */
      static checkProgramId(programId: PublicKey) {
        if (!programId.equals(StakeProgram.programId)) {
          throw new Error('invalid instruction; programId is not StakeProgram');
        }
      }

      /**
       * @private
       */
      static checkKeyLength(keys: Array<any>, expectedLength: number) {
        if (keys.length < expectedLength) {
          throw new Error(
            `invalid instruction; found ${keys.length} keys, expected at least ${expectedLength}`,
          );
        }
      }
    }

    /**
     * An enumeration of valid StakeInstructionType's
     * @typedef { 'Initialize' | 'Authorize' | 'AuthorizeWithSeed' | 'Delegate' | 'Split' | 'Withdraw'
     | 'Deactivate' } StakeInstructionType
     */
    export type StakeInstructionType = $Keys<typeof STAKE_INSTRUCTION_LAYOUTS>;

    /**
     * An enumeration of valid stake InstructionType's
     */
    export const STAKE_INSTRUCTION_LAYOUTS = Object.freeze({
      Initialize: {
        index: 0,
        layout: BufferLayout.struct([
          BufferLayout.u32('instruction'),
          Layout.authorized(),
          Layout.lockup(),
        ]),
      },
      Authorize: {
        index: 1,
        layout: BufferLayout.struct([
          BufferLayout.u32('instruction'),
          Layout.publicKey('newAuthorized'),
          BufferLayout.u32('stakeAuthorizationType'),
        ]),
      },
      Delegate: {
        index: 2,
        layout: BufferLayout.struct([BufferLayout.u32('instruction')]),
      },
      Split: {
        index: 3,
        layout: BufferLayout.struct([
          BufferLayout.u32('instruction'),
          BufferLayout.ns64('lamports'),
        ]),
      },
      Withdraw: {
        index: 4,
        layout: BufferLayout.struct([
          BufferLayout.u32('instruction'),
          BufferLayout.ns64('lamports'),
        ]),
      },
      Deactivate: {
        index: 5,
        layout: BufferLayout.struct([BufferLayout.u32('instruction')]),
      },
      AuthorizeWithSeed: {
        index: 8,
        layout: BufferLayout.struct([
          BufferLayout.u32('instruction'),
          Layout.publicKey('newAuthorized'),
          BufferLayout.u32('stakeAuthorizationType'),
          Layout.rustString('authoritySeed'),
          Layout.publicKey('authorityOwner'),
        ]),
      },
    });

    /**
     * @typedef {Object} StakeAuthorizationType
     * @property (index} The Stake Authorization index (from solana-stake-program)
     */
    export type StakeAuthorizationType = {|
      index: number,
    |};

    /**
     * An enumeration of valid StakeAuthorizationLayout's
     */
    export const StakeAuthorizationLayout = Object.freeze({
      Staker: {
        index: 0,
      },
      Withdrawer: {
        index: 1,
      },
    });

    /**
     * Factory class for transactions to interact with the Stake program
     */
    export class StakeProgram {
      /**
       * Public key that identifies the Stake program
       */
      static get programId(): PublicKey {
        return new PublicKey('Stake11111111111111111111111111111111111111');
      }

      /**
       * Max space of a Stake account
       */
      static get space(): number {
        return 4008;
      }

      /**
       * Generate an Initialize instruction to add to a Stake Create transaction
       */
      static initialize(params: InitializeStakeParams): TransactionInstruction {
        const {stakePubkey, authorized, lockup} = params;
        const type = STAKE_INSTRUCTION_LAYOUTS.Initialize;
        const data = encodeData(type, {
          authorized: {
            staker: authorized.staker.toBuffer(),
            withdrawer: authorized.withdrawer.toBuffer(),
          },
          lockup: {
            unixTimestamp: lockup.unixTimestamp,
            epoch: lockup.epoch,
            custodian: lockup.custodian.toBuffer(),
          },
        });
        const instructionData = {
          keys: [
            {pubkey: stakePubkey, isSigner: false, isWritable: true},
            {pubkey: SYSVAR_RENT_PUBKEY, isSigner: false, isWritable: false},
          ],
          programId: this.programId,
          data,
        };
        return new TransactionInstruction(instructionData);
      }

      /**
       * Generate a Transaction that creates a new Stake account at
       *   an address generated with `from`, a seed, and the Stake programId
       */
      static createAccountWithSeed(
        params: CreateStakeAccountWithSeedParams,
      ): Transaction {
        let transaction = SystemProgram.createAccountWithSeed({
          fromPubkey: params.fromPubkey,
          newAccountPubkey: params.stakePubkey,
          basePubkey: params.basePubkey,
          seed: params.seed,
          lamports: params.lamports,
          space: this.space,
          programId: this.programId,
        });

        const {stakePubkey, authorized, lockup} = params;
        return transaction.add(this.initialize({stakePubkey, authorized, lockup}));
      }

      /**
       * Generate a Transaction that creates a new Stake account
       */
      static createAccount(params: CreateStakeAccountParams): Transaction {
        let transaction = SystemProgram.createAccount({
          fromPubkey: params.fromPubkey,
          newAccountPubkey: params.stakePubkey,
          lamports: params.lamports,
          space: this.space,
          programId: this.programId,
        });

        const {stakePubkey, authorized, lockup} = params;
        return transaction.add(this.initialize({stakePubkey, authorized, lockup}));
      }

      /**
       * Generate a Transaction that delegates Stake tokens to a validator
       * Vote PublicKey. This transaction can also be used to redelegate Stake
       * to a new validator Vote PublicKey.
       */
      static delegate(params: DelegateStakeParams): Transaction {
        const {stakePubkey, authorizedPubkey, votePubkey} = params;

        const type = STAKE_INSTRUCTION_LAYOUTS.Delegate;
        const data = encodeData(type);

        return new Transaction().add({
          keys: [
            {pubkey: stakePubkey, isSigner: false, isWritable: true},
            {pubkey: votePubkey, isSigner: false, isWritable: false},
            {pubkey: SYSVAR_CLOCK_PUBKEY, isSigner: false, isWritable: false},
            {
              pubkey: SYSVAR_STAKE_HISTORY_PUBKEY,
              isSigner: false,
              isWritable: false,
            },
            {pubkey: STAKE_CONFIG_ID, isSigner: false, isWritable: false},
            {pubkey: authorizedPubkey, isSigner: true, isWritable: false},
          ],
          programId: this.programId,
          data,
        });
      }

      /**
       * Generate a Transaction that authorizes a new PublicKey as Staker
       * or Withdrawer on the Stake account.
       */
      static authorize(params: AuthorizeStakeParams): Transaction {
        const {
          stakePubkey,
          authorizedPubkey,
          newAuthorizedPubkey,
          stakeAuthorizationType,
        } = params;

        const type = STAKE_INSTRUCTION_LAYOUTS.Authorize;
        const data = encodeData(type, {
          newAuthorized: newAuthorizedPubkey.toBuffer(),
          stakeAuthorizationType: stakeAuthorizationType.index,
        });

        return new Transaction().add({
          keys: [
            {pubkey: stakePubkey, isSigner: false, isWritable: true},
            {pubkey: SYSVAR_CLOCK_PUBKEY, isSigner: false, isWritable: true},
            {pubkey: authorizedPubkey, isSigner: true, isWritable: false},
          ],
          programId: this.programId,
          data,
        });
      }

      /**
       * Generate a Transaction that authorizes a new PublicKey as Staker
       * or Withdrawer on the Stake account.
       */
      static authorizeWithSeed(params: AuthorizeWithSeedStakeParams): Transaction {
        const {
          stakePubkey,
          authorityBase,
          authoritySeed,
          authorityOwner,
          newAuthorizedPubkey,
          stakeAuthorizationType,
        } = params;

        const type = STAKE_INSTRUCTION_LAYOUTS.AuthorizeWithSeed;
        const data = encodeData(type, {
          newAuthorized: newAuthorizedPubkey.toBuffer(),
          stakeAuthorizationType: stakeAuthorizationType.index,
          authoritySeed: authoritySeed,
          authorityOwner: authorityOwner.toBuffer(),
        });

        return new Transaction().add({
          keys: [
            {pubkey: stakePubkey, isSigner: false, isWritable: true},
            {pubkey: authorityBase, isSigner: true, isWritable: false},
          ],
          programId: this.programId,
          data,
        });
      }

      /**
       * Generate a Transaction that splits Stake tokens into another stake account
       */
      static split(params: SplitStakeParams): Transaction {
        const {stakePubkey, authorizedPubkey, splitStakePubkey, lamports} = params;

        let transaction = SystemProgram.createAccount({
          fromPubkey: authorizedPubkey,
          newAccountPubkey: splitStakePubkey,
          lamports: 0,
          space: this.space,
          programId: this.programId,
        });
        const type = STAKE_INSTRUCTION_LAYOUTS.Split;
        const data = encodeData(type, {lamports});

        return transaction.add({
          keys: [
            {pubkey: stakePubkey, isSigner: false, isWritable: true},
            {pubkey: splitStakePubkey, isSigner: false, isWritable: true},
            {pubkey: authorizedPubkey, isSigner: true, isWritable: false},
          ],
          programId: this.programId,
          data,
        });
      }

      /**
       * Generate a Transaction that withdraws deactivated Stake tokens.
       */
      static withdraw(params: WithdrawStakeParams): Transaction {
        const {stakePubkey, authorizedPubkey, toPubkey, lamports} = params;
        const type = STAKE_INSTRUCTION_LAYOUTS.Withdraw;
        const data = encodeData(type, {lamports});

        return new Transaction().add({
          keys: [
            {pubkey: stakePubkey, isSigner: false, isWritable: true},
            {pubkey: toPubkey, isSigner: false, isWritable: true},
            {pubkey: SYSVAR_CLOCK_PUBKEY, isSigner: false, isWritable: false},
            {
              pubkey: SYSVAR_STAKE_HISTORY_PUBKEY,
              isSigner: false,
              isWritable: false,
            },
            {pubkey: authorizedPubkey, isSigner: true, isWritable: false},
          ],
          programId: this.programId,
          data,
        });
      }

      /**
       * Generate a Transaction that deactivates Stake tokens.
       */
      static deactivate(params: DeactivateStakeParams): Transaction {
        const {stakePubkey, authorizedPubkey} = params;
        const type = STAKE_INSTRUCTION_LAYOUTS.Deactivate;
        const data = encodeData(type);

        return new Transaction().add({
          keys: [
            {pubkey: stakePubkey, isSigner: false, isWritable: true},
            {pubkey: SYSVAR_CLOCK_PUBKEY, isSigner: false, isWritable: false},
            {pubkey: authorizedPubkey, isSigner: true, isWritable: false},
          ],
          programId: this.programId,
          data,
        });
      }
    }