import { PublicKey, Connection } from '@solana/web3.js';
import BN from 'bn.js'; // eslint-disable-line @typescript-eslint/no-unused-vars
import * as borsh from '@project-serum/borsh'; // eslint-disable-line @typescript-eslint/no-unused-vars
import * as types from '../types'; // eslint-disable-line @typescript-eslint/no-unused-vars
import { WHIRLPOOL_PROGRAM_ID } from '../programId';

export interface FeeTierFields {
  whirlpoolsConfig: PublicKey;
  tickSpacing: number;
  defaultFeeRate: number;
}

export interface FeeTierJSON {
  whirlpoolsConfig: string;
  tickSpacing: number;
  defaultFeeRate: number;
}

export class FeeTier {
  readonly whirlpoolsConfig: PublicKey;
  readonly tickSpacing: number;
  readonly defaultFeeRate: number;

  static readonly discriminator = Buffer.from([56, 75, 159, 76, 142, 68, 190, 105]);

  static readonly layout = borsh.struct([
    borsh.publicKey('whirlpoolsConfig'),
    borsh.u16('tickSpacing'),
    borsh.u16('defaultFeeRate'),
  ]);

  constructor(fields: FeeTierFields) {
    this.whirlpoolsConfig = fields.whirlpoolsConfig;
    this.tickSpacing = fields.tickSpacing;
    this.defaultFeeRate = fields.defaultFeeRate;
  }

  static async fetch(c: Connection, address: PublicKey): Promise<FeeTier | null> {
    const info = await c.getAccountInfo(address);

    if (info === null) {
      return null;
    }
    if (!info.owner.equals(WHIRLPOOL_PROGRAM_ID)) {
      throw new Error("account doesn't belong to this program");
    }

    return this.decode(info.data);
  }

  static async fetchMultiple(c: Connection, addresses: PublicKey[]): Promise<Array<FeeTier | null>> {
    const infos = await c.getMultipleAccountsInfo(addresses);

    return infos.map((info) => {
      if (info === null) {
        return null;
      }
      if (!info.owner.equals(WHIRLPOOL_PROGRAM_ID)) {
        throw new Error("account doesn't belong to this program");
      }

      return this.decode(info.data);
    });
  }

  static decode(data: Buffer): FeeTier {
    if (!data.slice(0, 8).equals(FeeTier.discriminator)) {
      throw new Error('invalid account discriminator');
    }

    const dec = FeeTier.layout.decode(data.slice(8));

    return new FeeTier({
      whirlpoolsConfig: dec.whirlpoolsConfig,
      tickSpacing: dec.tickSpacing,
      defaultFeeRate: dec.defaultFeeRate,
    });
  }

  toJSON(): FeeTierJSON {
    return {
      whirlpoolsConfig: this.whirlpoolsConfig.toString(),
      tickSpacing: this.tickSpacing,
      defaultFeeRate: this.defaultFeeRate,
    };
  }

  static fromJSON(obj: FeeTierJSON): FeeTier {
    return new FeeTier({
      whirlpoolsConfig: new PublicKey(obj.whirlpoolsConfig),
      tickSpacing: obj.tickSpacing,
      defaultFeeRate: obj.defaultFeeRate,
    });
  }
}