'use strict';

var imports       = require('soop').imports();

var config        = imports.config || require('../config/config');
var networks      = require('bitcore/networks');
var async         = require('async');

var syncId = 0;

function Sync(opts) {
  this.id = syncId++;
  this.opts = opts || {};
  this.bDb = require('./BlockDb').default();
  this.txDb =  require('./TransactionDb').default();
  this.network = config.network === 'testnet' ? networks.testnet : networks.livenet;
}

Sync.prototype.close = function(cb) {
  var self = this;
  self.txDb.close(function() {
    self.bDb.close(cb);
  });
};


Sync.prototype.destroy = function(next) {
  var self = this;
  async.series([

    function(b) {
      self.bDb.drop(b);
    },
    function(b) {
      self.txDb.drop(b);
    },
  ], next);
};

/*
  * Arrives a NEW block, which is the new TIP
  *
  * Case 0) Simple case
  *    A-B-C-D-E(TIP)-NEW
  *
  * Case 1)
  *    A-B-C-D-E(TIP)
  *        \
  *         NEW
  *
  *  1) Declare D-E orphans (and possible invalidate TXs on them)
  *
  * Case 2)
  *    A-B-C-D-E(TIP)
  *        \
  *         F-G-NEW
  *  1) Set F-G as connected (mark TXs as valid)
  *  2) Declare D-E orphans (and possible invalidate TXs on them)
  *
  *
  * Case 3)
  *
  *    A-B-C-D-E(TIP) ...  NEW
  *
  *    NEW is ignored (if allowReorgs is false)
  *
  *
  */

Sync.prototype.storeTipBlock = function(b, allowReorgs, cb) {

  if (typeof allowReorgs === 'function') {
    cb = allowReorgs;
    allowReorgs = true;
  }
  if (!b) return cb();

  var self = this;
  var oldTip, oldNext, needReorg = false;
  var newPrev = b.previousblockhash;

  async.series([

      function(c) {
        self.bDb.has(b.hash, function(err, val) {
          return c(err ||
            (val ? new Error('WARN: Ignoring already existing block:' + b.hash) : null));
        });
      },
      function(c) {
        if (!allowReorgs) return c();
        self.bDb.has(newPrev, function(err, val) {
          if (!val && newPrev.match(/^0+$/)) return c();

          return c(err ||
            (!val ? new Error('NEED_SYNC Ignoring block with non existing prev:' + b.hash) : null));
        });
      },
      function(c) {
        self.txDb.createFromBlock(b, function(err) {
          return c(err);
        });
      },
      function(c) {
        if (!allowReorgs) return c();
        self.bDb.getTip(function(err, val) {
          oldTip = val;
          if (oldTip && newPrev !== oldTip) needReorg = true;
          return c();
        });
      },
      function(c) {
        if (!needReorg) return c();
        self.bDb.getNext(newPrev, function(err, val) {
          if (err) return c(err);
          oldNext = val;
          return c();
        });
      },
      function(c) {
        self.bDb.add(b, c);
      },
      function(c) {
        if (!needReorg) return c();
        console.log('NEW TIP: %s NEED REORG (old tip: %s)', b.hash, oldTip);
        self.processReorg(oldTip, oldNext, newPrev, c);
      },
      function(c) {
        if (!allowReorgs) return c();
        self.bDb.setTip(b.hash, function(err) {
          return c(err);
        });
      },
      function(c) {
        self.bDb.setNext(newPrev, b.hash, function(err) {
          return c(err);
        });
      }

    ],
    function(err) {
      if (err && err.toString().match(/WARN/)) {
        err = null;
      }
      return cb(err);
    });
};



Sync.prototype.processReorg = function(oldTip, oldNext, newPrev, cb) {
  var self = this;

  var orphanizeFrom;

  async.series([

      function(c) {
        self.bDb.isMain(newPrev, function(err, val) {
          if (!val) return c();

          console.log('# Reorg Case 1)');
          // case 1
          orphanizeFrom = oldNext;
          return c(err);
        });
      },
      function(c) {
        if (orphanizeFrom) return c();

        console.log('# Reorg Case 2)');
        self.setBranchConnectedBackwards(newPrev, function(err, yHash, newYHashNext) {
          if (err) return c(err);
          self.bDb.getNext(yHash, function(err, yHashNext) {
            orphanizeFrom = yHashNext;
            self.bDb.setNext(yHash, newYHashNext, function(err) {
              return c(err);
            });
          });
        });
      },
      function(c) {
        if (!orphanizeFrom) return c();
        self.setBranchOrphan(orphanizeFrom, function(err) {
          return c(err);
        });
      },
    ],
    function(err) {
      return cb(err);
    });
};

Sync.prototype.setBlockMain = function(hash, isMain, cb) {
  var self = this;
  self.bDb.setMain(hash, isMain, function(err) {
    if (err) return cb(err);
    return self.txDb.handleBlockChange(hash, isMain, cb);
  });
};

Sync.prototype.setBranchOrphan = function(fromHash, cb) {
  var self = this,
    hashInterator = fromHash;

  async.whilst(
    function() {
      return hashInterator;
    },
    function(c) {
      self.setBlockMain(hashInterator, false, function(err) {
        if (err) return cb(err);
        self.bDb.getNext(hashInterator, function(err, val) {
          hashInterator = val;
          return c(err);
        });
      });
    }, cb);
};

Sync.prototype.setBranchConnectedBackwards = function(fromHash, cb) {
  var self = this,
    hashInterator = fromHash,
    lastHash = fromHash,
    isMain;

  async.doWhilst(
    function(c) {
      self.setBlockMain(hashInterator, true, function(err) {
        if (err) return c(err);
        self.bDb.getPrev(hashInterator, function(err, val) {
          if (err) return c(err);
          lastHash = hashInterator;
          hashInterator = val;
          self.bDb.isMain(hashInterator, function(err, val) {
            isMain = val;
            return c();
          });
        });
      });
    },
    function() {
      return hashInterator && !isMain;
    },
    function(err) {
      console.log('\tFound yBlock:', hashInterator);
      return cb(err, hashInterator, lastHash);
    }
  );
};


Sync.prototype.storeTxs = function(txs, cb) {
  var self = this;
  self.txDb.createFromArray(txs, null, function(err) {
    if (err) return cb(err);
    return cb(err);
  });
};


module.exports = require('soop')(Sync);