"use strict";
  module.exports = function(Promise,
                            PromiseArray,
                            apiRejection,
                            tryConvertToPromise,
                            INTERNAL,
                            debug) {
  var getDomain = Promise._getDomain;
  var util = require("./util");
  var tryCatch = util.tryCatch;
  
  function ReductionPromiseArray(promises, fn, initialValue, _each) {
      this.constructor$(promises);
      var domain = getDomain();
      this._fn = domain === null ? fn : util.domainBind(domain, fn);
      if (initialValue !== undefined) {
          initialValue = Promise.resolve(initialValue);
          initialValue._attachCancellationCallback(this);
      }
      this._initialValue = initialValue;
      this._currentCancellable = null;
      if(_each === INTERNAL) {
          this._eachValues = Array(this._length);
      } else if (_each === 0) {
          this._eachValues = null;
      } else {
          this._eachValues = undefined;
      }
      this._promise._captureStackTrace();
      this._init$(undefined, -5);
  }
  util.inherits(ReductionPromiseArray, PromiseArray);
  
  ReductionPromiseArray.prototype._gotAccum = function(accum) {
      if (this._eachValues !== undefined && 
          this._eachValues !== null && 
          accum !== INTERNAL) {
          this._eachValues.push(accum);
      }
  };
  
  ReductionPromiseArray.prototype._eachComplete = function(value) {
      if (this._eachValues !== null) {
          this._eachValues.push(value);
      }
      return this._eachValues;
  };
  
  ReductionPromiseArray.prototype._init = function() {};
  
  ReductionPromiseArray.prototype._resolveEmptyArray = function() {
      this._resolve(this._eachValues !== undefined ? this._eachValues
                                                   : this._initialValue);
  };
  
  ReductionPromiseArray.prototype.shouldCopyValues = function () {
      return false;
  };
  
  ReductionPromiseArray.prototype._resolve = function(value) {
      this._promise._resolveCallback(value);
      this._values = null;
  };
  
  ReductionPromiseArray.prototype._resultCancelled = function(sender) {
      if (sender === this._initialValue) return this._cancel();
      if (this._isResolved()) return;
      this._resultCancelled$();
      if (this._currentCancellable instanceof Promise) {
          this._currentCancellable.cancel();
      }
      if (this._initialValue instanceof Promise) {
          this._initialValue.cancel();
      }
  };
  
  ReductionPromiseArray.prototype._iterate = function (values) {
      this._values = values;
      var value;
      var i;
      var length = values.length;
      if (this._initialValue !== undefined) {
          value = this._initialValue;
          i = 0;
      } else {
          value = Promise.resolve(values[0]);
          i = 1;
      }
  
      this._currentCancellable = value;
  
      if (!value.isRejected()) {
          for (; i < length; ++i) {
              var ctx = {
                  accum: null,
                  value: values[i],
                  index: i,
                  length: length,
                  array: this
              };
              value = value._then(gotAccum, undefined, undefined, ctx, undefined);
          }
      }
  
      if (this._eachValues !== undefined) {
          value = value
              ._then(this._eachComplete, undefined, undefined, this, undefined);
      }
      value._then(completed, completed, undefined, value, this);
  };
  
  Promise.prototype.reduce = function (fn, initialValue) {
      return reduce(this, fn, initialValue, null);
  };
  
  Promise.reduce = function (promises, fn, initialValue, _each) {
      return reduce(promises, fn, initialValue, _each);
  };
  
  function completed(valueOrReason, array) {
      if (this.isFulfilled()) {
          array._resolve(valueOrReason);
      } else {
          array._reject(valueOrReason);
      }
  }
  
  function reduce(promises, fn, initialValue, _each) {
      if (typeof fn !== "function") {
          return apiRejection("expecting a function but got " + util.classString(fn));
      }
      var array = new ReductionPromiseArray(promises, fn, initialValue, _each);
      return array.promise();
  }
  
  function gotAccum(accum) {
      this.accum = accum;
      this.array._gotAccum(accum);
      var value = tryConvertToPromise(this.value, this.array._promise);
      if (value instanceof Promise) {
          this.array._currentCancellable = value;
          return value._then(gotValue, undefined, undefined, this, undefined);
      } else {
          return gotValue.call(this, value);
      }
  }
  
  function gotValue(value) {
      var array = this.array;
      var promise = array._promise;
      var fn = tryCatch(array._fn);
      promise._pushContext();
      var ret;
      if (array._eachValues !== undefined) {
          ret = fn.call(promise._boundValue(), value, this.index, this.length);
      } else {
          ret = fn.call(promise._boundValue(),
                                this.accum, value, this.index, this.length);
      }
      if (ret instanceof Promise) {
          array._currentCancellable = ret;
      }
      var promiseCreated = promise._popContext();
      debug.checkForgottenReturns(
          ret,
          promiseCreated,
          array._eachValues !== undefined ? "Promise.each" : "Promise.reduce",
          promise
      );
      return ret;
  }
  };