'use strict';

var util = require('util');
var bitcore = require('bitcore-lib');
var zmq = require('zmq');
var async = require('async');
var BitcoinRPC = require('bitcoind-rpc');
var $ = bitcore.util.preconditions;
var _  = bitcore.deps._;

var index = require('../../');
var errors = index.errors;
var log = index.log;
var Service = require('../../service');

function Bitcoin(options) {
  if (!(this instanceof Bitcoin)) {
    return new Bitcoin(options);
  }

  Service.call(this, options);
  this.options = options;

  this.subscriptions = {};
  this.subscriptions.rawtransaction = [];
  this.subscriptions.hashblock = [];

  this._initClients();

  this._process = options.process || process;

  this.on('error', function(err) {
    log.error(err.stack);
  });
}

util.inherits(Bitcoin, Service);

Bitcoin.dependencies = [];

Bitcoin.prototype._initClients = function() {
  var self = this;
  this.nodes = [];
  this.nodesIndex = 0;
  Object.defineProperty(this, 'client', {
    get: function() {
      var client = self.nodes[self.nodesIndex].client;
      self.nodesIndex = (self.nodesIndex + 1) % self.nodes.length;
      return client;
    },
    enumerable: true,
    configurable: false
  });
};

Bitcoin.prototype.getAPIMethods = function() {
  var methods = [
    ['getBlock', this, this.getBlock, 1]
  ];
  return methods;
};

Bitcoin.prototype.getPublishEvents = function() {
  return [
    {
      name: 'bitcoind/rawtransaction',
      scope: this,
      subscribe: this.subscribe.bind(this, 'rawtransaction'),
      unsubscribe: this.unsubscribe.bind(this, 'rawtransaction')
    },
    {
      name: 'bitcoind/hashblock',
      scope: this,
      subscribe: this.subscribe.bind(this, 'hashblock'),
      unsubscribe: this.unsubscribe.bind(this, 'hashblock')
    }
  ];
};

Bitcoin.prototype.subscribe = function(name, emitter) {
  this.subscriptions[name].push(emitter);
  log.info(emitter.remoteAddress, 'subscribe:', 'bitcoind/' + name, 'total:', this.subscriptions[name].length);
};

Bitcoin.prototype.unsubscribe = function(name, emitter) {
  var index = this.subscriptions[name].indexOf(emitter);
  if (index > -1) {
    this.subscriptions[name].splice(index, 1);
  }
  log.info(emitter.remoteAddress, 'unsubscribe:', 'bitcoind/' + name, 'total:', this.subscriptions[name].length);
};

Bitcoin.prototype._tryAllClients = function(func, callback) {
  var self = this;
  var nodesIndex = this.nodesIndex;
  var retry = function(done) {
    var client = self.nodes[nodesIndex].client;
    nodesIndex = (nodesIndex + 1) % self.nodes.length;
    func(client, done);
  };
  async.retry({times: this.nodes.length, interval: this.tryAllInterval || 1000}, retry, callback);
};

Bitcoin.prototype._wrapRPCError = function(errObj) {
  var err = new errors.RPCError(errObj.message);
  err.code = errObj.code;
  return err;
};

Bitcoin.prototype._initChain = function(callback) {
  var self = this;

  self.client.getBestBlockHash(function(err, response) {
    if (err) {
      return callback(self._wrapRPCError(err));
    }

    self.tiphash = response.result;

    self.client.getBlock(response.result, function(err, response) {
      if (err) {
        return callback(self._wrapRPCError(err));
      }

      self.height = response.result.height;

      self.client.getBlockHash(0, function(err, response) {
        if (err) {
          return callback(self._wrapRPCError(err));
        }
        var blockhash = response.result;
        self.getRawBlock(blockhash, function(err, blockBuffer) {
          if (err) {
            return callback(err);
          }
          self.genesisBuffer = blockBuffer;
          self.emit('ready');
          log.info('Bitcoin Daemon Ready');
          callback();
        });
      });
    });
  });
};

Bitcoin.prototype._zmqBlockHandler = function(node, message) {
  var self = this;
  self._rapidProtectedUpdateTip(node, message);
  self.emit('block', message);

  for (var i = 0; i < this.subscriptions.hashblock.length; i++) {
    this.subscriptions.hashblock[i].emit('bitcoind/hashblock', message.toString('hex'));
  }
};

Bitcoin.prototype._rapidProtectedUpdateTip = function(node, message) {
  var self = this;

  if (new Date() - self.lastTip > 1000) {
    self.lastTip = new Date();
    self._updateTip(node, message);
  } else {
    clearTimeout(self.lastTipTimeout);
    self.lastTipTimeout = setTimeout(function() {
      self._updateTip(node, message);
    }, 1000);
  }
};

Bitcoin.prototype._updateTip = function(node, message) {
  var self = this;

  var hex = message.toString('hex');
  if (hex !== self.tiphash) {
    self.tiphash = message.toString('hex');
    node.client.getBlock(self.tiphash, function(err, response) {
      if (err) {
        var error = self._wrapRPCError(err);
        self.emit('error', error);
      } else {
        self.height = response.result.height;
        $.checkState(self.height >= 0);
        self.emit('tip', self.height);
      }
    });
  }
};


Bitcoin.prototype._zmqTransactionHandler = function(node, message) {
  var self = this;
  self.emit('tx', message);
  for (var i = 0; i < this.subscriptions.rawtransaction.length; i++) {
    this.subscriptions.rawtransaction[i].emit('bitcoind/rawtransaction', message.toString('hex'));
  }
};

Bitcoin.prototype._checkSyncedAndSubscribeZmqEvents = function(node) {
  var self = this;
  var interval;

  function checkAndSubscribe(callback) {
    node.client.getBestBlockHash(function(err, response) {
      if (err) {
        return callback(self._wrapRPCError(err));
      }
      var blockhash = new Buffer(response.result, 'hex');
      self.emit('block', blockhash);
      self._updateTip(node, blockhash);

      node.client.getBlockchainInfo(function(err, response) {
        if (err) {
          return callback(self._wrapRPCError(err));
        }
        var progress = response.result.verificationprogress;
        if (progress >= self.zmqSubscribeProgress) {
          self._subscribeZmqEvents(node);
          clearInterval(interval);
          callback(null, true);
        } else {
          callback(null, false);
        }
      });
    });
  }

  checkAndSubscribe(function(err, synced) {
    if (err) {
      log.error(err);
    }
    if (!synced) {
      interval = setInterval(function() {
        if (self.node.stopping) {
          return clearInterval(interval);
        }
        checkAndSubscribe(function(err) {
          if (err) {
            log.error(err);
          }
        });
      }, node._tipUpdateInterval || Bitcoin.DEFAULT_TIP_UPDATE_INTERVAL);
    }
  });

};

Bitcoin.prototype._subscribeZmqEvents = function(node) {
  var self = this;
  node.zmqSubSocket.subscribe('hashblock');
  node.zmqSubSocket.subscribe('rawtx');
  node.zmqSubSocket.on('message', function(topic, message) {
    var topicString = topic.toString('utf8');
    if (topicString === 'rawtx') {
      self._zmqTransactionHandler(node, message);
    } else if (topicString === 'hashblock') {
      self._zmqBlockHandler(node, message);
    }
  });
};

Bitcoin.prototype._initZmqSubSocket = function(node, zmqUrl) {
  node.zmqSubSocket = zmq.socket('sub');

  node.zmqSubSocket.on('connect', function(fd, endPoint) {
    log.info('ZMQ connected to:', endPoint);
  });

  node.zmqSubSocket.on('connect_delay', function(fd, endPoint) {
    if (this.zmqDelayWarningMultiplierCouunt++ >= this.zmqDelayWarningMultiplier) {
      log.warn('ZMQ connection delay:', endPoint);
      this.zmqDelayWarningMultiplierCouunt = 0;
    }
  });

  node.zmqSubSocket.on('disconnect', function(fd, endPoint) {
    log.warn('ZMQ disconnect:', endPoint);
  });

  node.zmqSubSocket.on('monitor_error', function(err) {
    log.error('Error in monitoring: %s, will restart monitoring in 5 seconds', err);
    setTimeout(function() {
      node.zmqSubSocket.monitor(500, 0);
    }, 5000);
  });

  node.zmqSubSocket.monitor(100, 0);
  node.zmqSubSocket.connect(zmqUrl);
};

Bitcoin.prototype._loadTipFromNode = function(node, callback) {
  var self = this;
  node.client.getBestBlockHash(function(err, response) {
    if (err && err.code === -28) {
      log.warn(err.message);
      return callback(self._wrapRPCError(err));
    } else if (err) {
      return callback(self._wrapRPCError(err));
    }
    node.client.getBlock(response.result, function(err, response) {
      if (err) {
        return callback(self._wrapRPCError(err));
      }
      self.height = response.result.height;
      $.checkState(self.height >= 0);
      self.emit('tip', self.height);
      callback();
    });
  });
};

Bitcoin.prototype._connectProcess = function(config, callback) {
  var self = this;
  var node = {};
  var exitShutdown = false;

  async.retry({times: 60, interval: self.startRetryInterval}, function(done) {
    if (self.node.stopping) {
      exitShutdown = true;
      return done();
    }

    node.client = new BitcoinRPC({
      protocol: config.rpcprotocol || 'http',
      host: config.rpchost || '127.0.0.1',
      port: config.rpcport,
      user: config.rpcuser,
      pass: config.rpcpassword,
      rejectUnauthorized: _.isUndefined(config.rpcstrict) ? true : config.rpcstrict
    });

    self._loadTipFromNode(node, done);

  }, function(err) {
    if (err) {
      return callback(err);
    }
    if (exitShutdown) {
      return callback(new Error('Stopping while trying to connect to bitcoind.'));
    }

    self._initZmqSubSocket(node, config.zmqpubrawtx);
    self._subscribeZmqEvents(node);

    callback(null, node);
  });
};

Bitcoin.prototype.start = function(callback) {
  var self = this;

  async.series([
    function(next) {
      if (self.options.spawn) {
        self._spawnChildProcess(function(err, node) {
          if (err) {
            return next(err);
          }
          self.nodes.push(node);
          next();
        });
      } else {
        next();
      }
    },
    function(next) {
      if (self.options.connect) {
        async.map(self.options.connect, self._connectProcess.bind(self), function(err, nodes) {
          if (err) {
            return callback(err);
          }
          for(var i = 0; i < nodes.length; i++) {
            self.nodes.push(nodes[i]);
          }
          next();
        });
      } else {
        next();
      }
    }
  ], function(err) {
    if (err) {
      return callback(err);
    }
    if (self.nodes.length === 0) {
      return callback(new Error('Bitcoin configuration options "spawn" or "connect" are expected'));
    }
    self._initChain(callback);
  });

};

Bitcoin.prototype._getAddressDetailsForOutput = function(output, outputIndex, result, addressStrings) {
  if (!output.address) {
    return;
  }
  var address = output.address;
  if (addressStrings.indexOf(address) >= 0) {
    if (!result.addresses[address]) {
      result.addresses[address] = {
        inputIndexes: [],
        outputIndexes: [outputIndex]
      };
    } else {
      result.addresses[address].outputIndexes.push(outputIndex);
    }
    result.satoshis += output.satoshis;
  }
};

Bitcoin.prototype._maybeGetBlockHash = function(blockArg, callback) {
  var self = this;
  if (_.isNumber(blockArg) || (blockArg.length < 40 && /^[0-9]+$/.test(blockArg))) {
    self._tryAllClients(function(client, done) {
      client.getBlockHash(blockArg, function(err, response) {
        if (err) {
          return done(self._wrapRPCError(err));
        }
        done(null, response.result);
      });
    }, callback);
  } else {
    callback(null, blockArg);
  }
};


Bitcoin.prototype.getRawBlock = function(blockArg, callback) {
  var self = this;

  function queryBlock(err, blockhash) {
    if (err) {
      return callback(err);
    }
    self._tryAllClients(function(client, done) {
      self.client.getBlock(blockhash, false, function(err, response) {
        if (err) {
          return done(self._wrapRPCError(err));
        }
        var buffer = new Buffer(response.result, 'hex');
        done(null, buffer);
      });
    }, callback);
  }

  self._maybeGetBlockHash(blockArg, queryBlock);
};

Bitcoin.prototype.getBlock = function(blockArg, callback) {
  var self = this;

  function queryBlock(err, blockhash) {
    if (err) {
      return callback(err);
    }
    self._tryAllClients(function(client, done) {
      client.getBlock(blockhash, false, function(err, response) {
        if (err) {
          return done(self._wrapRPCError(err));
        }
        var blockObj = bitcore.Block.fromString(response.result);
        done(null, blockObj);
      });
    }, callback);
  }
  self._maybeGetBlockHash(blockArg, queryBlock);
};

Bitcoin.prototype.stop = function(callback) {
  callback();
};

module.exports = Bitcoin;