'use strict';

var assert = require('assert');
var async = require('async');
var BaseService = require('../../service');
var inherits = require('util').inherits;
var Encoding = require('./encoding');
var levelup = require('levelup');

function TransactionService(options) {
  BaseService.call(this, options);
  this._db = this.node.services.db;
  this._mempool = this.node.services._mempool;
  this._block = this.node.services.block;
  this._p2p = this.node.services.p2p;
}

inherits(TransactionService, BaseService);

TransactionService.dependencies = [
  'p2p',
  'db',
  'block',
  'timestamp',
  'mempool'
];

/*

1. getAddressSummary
2. getAddressUnspentOutputs
3. bitcoind.height
4. getBlockHeader
5. getDetailedTransaction
6. getTransaction
7. sendTransaction
8. getInfo
9. bitcoind.tiphash
10. getBestBlockHash
11. isSynced
12. getAddressHistory
13. getBlock
14. getRawBlock
15. getBlockHashesByTimestamp
16. estimateFee
17. getBlockOverview
18. syncPercentage

*/
TransactionService.prototype.getAPIMethods = function() {
  return [
    ['getRawTransaction', this, this.getRawTransaction, 1],
    ['getTransaction', this, this.getTransaction, 1],
    ['getDetailedTransaction', this, this.getDetailedTransaction, 1],
    ['sendTransaction', this, this.sendTransaction, 1],
    ['syncPercentage', this, this.syncPercentage, 0]
  ];
};


TransactionService.prototype.getTransaction = function(txid, options, callback) {

  var self = this;

  var queryMempool = _.isUndefined(options.queryMempool) ? true : options.queryMempool;

  var key = self.encoding.encodeTransactionKey(txid);
  this._db.get(key, function(err, tx) {

    if(err) {
      return callback(err);
    }

    if (queryMempool && !tx) {

      this._mempool.getTransaction(tx, function(err, memTx) {

        if(err) {
          return callback(err);
        }

        if (memTx) {
          return callback(null, { tx: memTx, confirmations: 0});
        }
        return callback();

      });

    } else {

      if (tx) {
        return callback(null, { tx: tx, confirmations: this._p2p.getBestHeight - tx.__height });
      }
      return callback();

    }

  });


};

TransactionService.prototype._onBlock = function(block, connectBlock, callback) {
  var self = this;
  var action = 'put';
  var reverseAction = 'del';
  if (!connectBlock) {
    action = 'del';
    reverseAction = 'put';
  }

  var operations = [];

  this.currentTransactions = {};

  async.series([
    function(next) {
      self.node.services.timestamp.getTimestamp(block.hash, function(err, timestamp) {
        if(err) {
          return next(err);
        }
        block.__timestamp = timestamp;
        next();
      });
    }, function(next) {
      async.eachSeries(block.transactions, function(tx, next) {
        tx.__timestamp = block.__timestamp;
        tx.__height = block.__height;

        self._getInputValues(tx, function(err, inputValues) {
          if(err) {
            return next(err);
          }
          tx.__inputValues = inputValues;
          self.currentTransactions[tx.id] = tx;

          operations.push({
            type: action,
            key: self.encoding.encodeTransactionKey(tx.id),
            value: self.encoding.encodeTransactionValue(tx)
          });
          next();
        });
      }, function(err) {
        if(err) {
          return next(err);
        }
        next();
      });
    }], function(err) {
        if(err) {
          return callback(err);
        }
        callback(null, operations);
    });

};

TransactionService.prototype.sendTransaction = function(tx, callback) {
  this._p2p.sendTransaction(tx, callback);
};

TransactionService.prototype._setListeners = function() {

  var self = this;

  self._db.on('error', self._onDbError.bind(self));
  self.on('reorg', self._onReorg.bind(self));

};

TransactionService.prototype._onDbError = function(error) {
};

TransactionService.prototype._onReorg = function(commonAncestor, newBlockList) {
};

TransactionService.prototype.start = function(callback) {

  var self = this;
  self._setListeners();

  self._db.getPrefix(self.name, function(err, prefix) {

    if(err) {
      return callback(err);
    }

    self._db.getServiceTip(self.name, function(err, tip) {

      if (err) {
        return callback(err);
      }

      self._tip = tip;
      self.prefix = prefix;
      self._encoding = new Encoding(self.prefix);
      self._startSubscriptions();
      callback();

    });
  });
};

TransactionService.prototype._onTransaction = function(transaction) {
};

TransactionService.prototype._startSubscriptions = function() {

  if (this._subscribed) {
    return;
  }

  this._subscribed = true;
  if (!this._bus) {
    this._bus = this.node.openBus({remoteAddress: 'localhost'});
  }

  this._bus.on('block/block', this._onTransaction.bind(this));
  this._bus.subscribe('block/block');
};

TransactionService.prototype.stop = function(callback) {
  setImmediate(callback);
};

TransactionService.prototype.syncPercentage = function(callback) {

};

TransactionService.prototype._getMissingInputValues = function(tx, callback) {

  var self = this;

  if (tx.isCoinbase()) {
    return callback(null, []);
  }

  async.eachOf(tx.inputs, function(input, index, next) {
    if (tx.__inputValues[index]) {
      return next();
    }
    self.getTransaction(input.prevTxId.toString('hex'), {}, function(err, prevTx) {
      if(err) {
        return next(err);
      }
      if (!prevTx) {
        return next(new Error('previous Tx missing.'));
      }
      if (!prevTx.outputs[input.outputIndex]) {
        return next(new Error('Input did not have utxo.'));
      }
      var satoshis = prevTx.outputs[input.outputIndex].satoshis;
      tx.__inputValues[index] = satoshis;
      next();
    });
  }, callback);

};

TransactionService.prototype._getInputValues = function(tx, callback) {
  var self = this;

  if (tx.isCoinbase()) {
    return callback(null, []);
  }

  async.mapLimit(tx.inputs, this.concurrency, function(input, next) {
    self.getTransaction(input.prevTxId.toString('hex'), {}, function(err, prevTx) {
      if(err) {
        return next(err);
      }
      if (!prevTx.outputs[input.outputIndex]) {
        return next(new Error('Input did not have utxo: ' + prevTx.id + ' for tx: ' + tx.id));
      }
      var satoshis = prevTx.outputs[input.outputIndex].satoshis;
      next(null, satoshis);
    });
  }, callback);
};

module.exports = TransactionService;