'use strict';

var pg = require('pg');
var PG_ERRORS = {
  23505: 'uniqueViolation'
};

var PostgresqlInterface = function (conString) {
  if (!conString) {
    throw new Error('Postgres connection string is required');
  }

  this.client = new pg.Client(conString);

  // TODO better logging
  this.client.on('error', function (err) { console.log(err); });

  this.client.connect();
};
PostgresqlInterface.factory = function factory(conString) { return new PostgresqlInterface(conString); };
module.exports = PostgresqlInterface;

PostgresqlInterface.prototype.summonTransaction = 
  function summonTransaction(deviceFingerprint, tx, cb) {
  // First do an INSERT
  // If it worked, go ahead with transaction
  // If duplicate, fetch status and return
  var self = this;
  this.client.query('INSERT INTO transactions (id, status, deviceFingerprint, ' +
      'toAddress, satoshis, currencyCode, fiat) ' + 
      'VALUES ($1, $2, $3, $4, $5, $6, $7)', [tx.txId, 'pending', deviceFingerprint,
      tx.toAddress, tx.satoshis, tx.currencyCode, tx.fiat], 
      function (err) {
    if (err && PG_ERRORS[err.code] === 'uniqueViolation')
      return self._fetchTransaction(tx.txId, cb);
    if (err) return cb(err);
    cb(null, true);
  });
};

PostgresqlInterface.prototype.reportTransactionError = 
  function reportTransactionError(tx, err) {
  this.client.query('UPDATE transactions SET status=$1, error=$2 WHERE id=$3', 
    ['failed', err.message, tx.txId]);
};

PostgresqlInterface.prototype.completeTransaction = 
  function completeTransaction(tx, txHash) {
  if (txHash)
    this.client.query('UPDATE transactions SET txHash=$1, status=$2, completed=now() WHERE id=$3', 
      [txHash, 'completed', tx.txId]);
  else
    this.client.query('UPDATE transactions SET status=$1, error=$2 WHERE id=$3', 
      ['failed', 'No txHash received', tx.txId]);    
};

PostgresqlInterface.prototype._fetchTransaction = 
    function _fetchTransaction(txId, cb) {
  this.client.query('SELECT status, txHash FROM transaction WHERE id=$1', 
      [txId], function (err, rows) {
    if (err) return cb(err);

    // This should never happen, since we already checked for existence
    if (rows === 0) return cb(new Error('Couldn\'t find transaction.')); 

    var result = rows[0];
    cb(null, false, result.txHash);
  });
};