import { BufferReader, BufferWriter } from '@node-dlc/bufio';
import { BitField } from '@node-dlc/common';

import { QueryChannelRangeFlags } from '../flags/QueryChannelRangeFlags';
import { MessageType } from '../MessageType';
import { readTlvs } from '../serialize/readTlvs';
import { IWireMessage } from './IWireMessage';

export class QueryChannelRangeMessage implements IWireMessage {
  public static deserialize(payload: Buffer): QueryChannelRangeMessage {
    const instance = new QueryChannelRangeMessage();
    const reader = new BufferReader(payload);

    reader.readUInt16BE(); // read type bytes
    instance.chainHash = reader.readBytes(32);
    instance.firstBlocknum = reader.readUInt32BE();
    instance.numberOfBlocks = reader.readUInt32BE();

    // Parse any TLVs that might exist
    readTlvs(reader, (type: bigint, valueReader: BufferReader) => {
      switch (type) {
        case BigInt(1): {
          const options = valueReader.readBigSize();
          const bitfield = new BitField<QueryChannelRangeFlags>(options);
          instance.timestamps = bitfield.isSet(
            QueryChannelRangeFlags.timestamps,
          );
          instance.checksums = bitfield.isSet(QueryChannelRangeFlags.checksums);
          return true;
        }
        default:
          return false;
      }
    });

    return instance;
  }

  /**
   * Type 263
   */
  public type: MessageType = MessageType.QueryChannelRange;

  /**
   * 32-byte hash that uniquely identifies the chain that the reply
   * should refer to
   */
  public chainHash: Buffer;

  /**
   * The first block it wants to know channels for
   */
  public firstBlocknum: number;

  /**
   * Number of blocks to return, must be 1 or greater
   */
  public numberOfBlocks: number;

  /**
   * When gossip_queries_ex is enabled, this asks the remote node to include
   * the timestamps of update messages.
   */
  public timestamps: boolean;

  /**
   * When gossip_queries_ex is enabled, this asks the remote node to include
   * checksums of update messages.
   */
  public checksums: boolean;

  public serialize(): Buffer {
    const writer = new BufferWriter();
    writer.writeUInt16BE(MessageType.QueryChannelRange);
    writer.writeBytes(this.chainHash);
    writer.writeUInt32BE(this.firstBlocknum);
    writer.writeUInt32BE(this.numberOfBlocks);

    // write the options TLV
    if (this.timestamps || this.checksums) {
      const bitfield = new BitField<QueryChannelRangeFlags>();
      if (this.timestamps) bitfield.set(QueryChannelRangeFlags.timestamps);
      if (this.checksums) bitfield.set(QueryChannelRangeFlags.checksums);
      writer.writeBigSize(1);
      writer.writeBigSize(BufferReader.bigSizeBytes(bitfield.value));
      writer.writeBigSize(bitfield.value);
    }

    return writer.toBuffer();
  }
}