/*
 * This file is part of the Flowee project
 * Copyright (C) 2019-2020 Tom Zander <tomz@freedommail.ch>
 * Copyright (C) 2020 James Zuccon <zuccon@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
const Message = require('./message');

/**
  * Blockchain information service.
  * @param {Flowee} instance Instance of Flowee
  */
class BlockchainService {
  constructor(network) {
    this.network = network;
  }

  /**
   * Get Blockchain Information
   * @example
   * let blockChainInfo = await flowee.getBlockChainInfo();
   */
  async getBlockChainInfo() {
    let reply = await this.network.sendMessage(new Message(1, 0));
    return {
      difficulty: reply[64],
      medianTime: reply[65],
      chainWork: reply["66str"],
      chain: reply[67],
      blocks: reply[68],
      headers: reply[69],
      bestBlockHash: reply[70],
      bestBlockId: reply["70str"],
    };
  }

  /**
   * Get the best block hash available
   * @returns The an object with the block hash as string and buffer.
   * @example
   * let bestBlockHash = await flowee.getBestBlockHash();
   */
  async getBestBlockHash() {
    let reply = await this.network.sendMessage(new Message(1, 2));
    return {
      blockId: reply["1str"],
      blockHash: reply[1],
    }
  }

  /**
   * Get Block height
   * @returns {number} The block height
   * @example
   * let blockCount = await flowee.getBlockCount();
   */
  async getBlockCount() {
    let reply = await this.network.sendMessage(new Message(1, 10));
    return reply.body[7]; // Block Height (is equal to count since genesis is height=0)
  }

  /**
   * Get Block
   * @param param (Number or Hash) The block height
   * @returns {number} Object containing details about block
   * @example
   * let blockHeader = await flowee.getBlock(500000);
   */
  async getBlock(param) {
    let message = new Message(1, 4);
    message.body[44] = true; // Include_OffsetInBlock
    message.body[45] = false; // Include_FullTxData

    if (typeof param === 'number') {
      message.body[7] =  param;
    } else if (param * 1 == parseInt(param)) { // is really a number
      message.body[7] =  parseInt(param);
    } else if (typeof param === 'string') {
      message.body[5] = Buffer.from(param, 'hex').reverse();
      if (message.body[5].length != 32)
        throw "Invalid argument, not blockId";
    } else if (typeof param == 'undefined') {
        throw "Missing argument";
    } else {
      message.body[5] = param;
    }

    let reply = await this.network.sendMessage(message);
    let answer = {
      blockId: reply["5str"],
      blockHash: reply[5],
      blockHeight: reply[7],
      transactions: []
    }
    let tx = null;
    for (let prop of reply.body) {
        if (prop.key == 0) {
            if (tx != null)
                answer.transactions.push(tx);
            tx = null;
        }
        else if (prop.key == 8) {
            tx = {};
            tx.offset = prop.value;
        }
    }

    return answer;
  }

  async getRawTransaction(blockHeight, offsetInBlock) {
    if (blockHeight * 1 == parseInt(blockHeight)) { // is really a number
      blockHeight = blockHeight * 1;
    }
    if (typeof blockHeight === 'string') {
      // assume this is a txid
      var search = await this.network.search({
        jobs: [{
            value: blockHeight,
            type: this.network.Job.FetchTx,
            txFilter: [ this.network.IncludeFullTxData ]
        }]});
      return search.transactions[0].fullTxData;
    }

    if (typeof blockHeight === 'number' && typeof offsetInBlock === 'number') {
      let message = new Message(1, 12);
      message.body[7] =  blockHeight;
      message.body[8] =  offsetInBlock;
      message.body[45] = true; // Include_FullTxData

      let reply = await this.network.sendMessage(message);
      return reply["1"];
    }
    else
      throw "Missing arguments";
  }

  async getBlockHeader(blockHeight) {
    if (blockHeight * 1 == parseInt(blockHeight)) { // is really a number
      blockHeight = blockHeight * 1;
    }
    let message = new Message(1, 8);
    if (typeof blockHeight === 'number') {
      message.body[7] =  blockHeight;
    } else if (typeof blockHeight === 'string') {
      message.body[5] = Buffer.from(param, 'hex').reverse();
      if (message.body[5].length != 32)
        throw "Invalid argument, not blockId";
    }
    else
      throw "Missing arguments";

    let reply = await this.network.sendMessage(message);
    return {
      blockId: reply["5str"],
      blockHash: reply[5],
      confirmations: reply[72],
      blockHeight: reply[7],
      version: reply[62],
      merkleRoot: reply[73],
      merkleRootHex: reply["73str"],
      time: reply[63],
      medianTime: reply[65],
      nonce: reply[74],
      bits: reply[75],
      difficulty: reply[64],
      prevBlockHash: reply["76str"],
      nextBlockHash: reply["77str"]
    };
  }
}

module.exports = BlockchainService;