var assignMergeValue = require('./_assignMergeValue'),

cloneBuffer = require('./_cloneBuffer'),
cloneTypedArray = require('./_cloneTypedArray'),
copyArray = require('./_copyArray'),
initCloneObject = require('./_initCloneObject'),
isArguments = require('./isArguments'),
isArray = require('./isArray'),
isArrayLikeObject = require('./isArrayLikeObject'),
isBuffer = require('./isBuffer'),
isFunction = require('./isFunction'),
isObject = require('./isObject'),
isPlainObject = require('./isPlainObject'),
isTypedArray = require('./isTypedArray'),
safeGet = require('./_safeGet'),
toPlainObject = require('./toPlainObject');

/**

* A specialized version of `baseMerge` for arrays and objects which performs
* deep merges and tracks traversed objects enabling objects with circular
* references to be merged.
*
* @private
* @param {Object} object The destination object.
* @param {Object} source The source object.
* @param {string} key The key of the value to merge.
* @param {number} srcIndex The index of `source`.
* @param {Function} mergeFunc The function to merge values.
* @param {Function} [customizer] The function to customize assigned values.
* @param {Object} [stack] Tracks traversed source values and their merged
*  counterparts.
*/

function baseMergeDeep(object, source, key, srcIndex, mergeFunc, customizer, stack) {

var objValue = safeGet(object, key),
    srcValue = safeGet(source, key),
    stacked = stack.get(srcValue);

if (stacked) {
  assignMergeValue(object, key, stacked);
  return;
}
var newValue = customizer
  ? customizer(objValue, srcValue, (key + ''), object, source, stack)
  : undefined;

var isCommon = newValue === undefined;

if (isCommon) {
  var isArr = isArray(srcValue),
      isBuff = !isArr && isBuffer(srcValue),
      isTyped = !isArr && !isBuff && isTypedArray(srcValue);

  newValue = srcValue;
  if (isArr || isBuff || isTyped) {
    if (isArray(objValue)) {
      newValue = objValue;
    }
    else if (isArrayLikeObject(objValue)) {
      newValue = copyArray(objValue);
    }
    else if (isBuff) {
      isCommon = false;
      newValue = cloneBuffer(srcValue, true);
    }
    else if (isTyped) {
      isCommon = false;
      newValue = cloneTypedArray(srcValue, true);
    }
    else {
      newValue = [];
    }
  }
  else if (isPlainObject(srcValue) || isArguments(srcValue)) {
    newValue = objValue;
    if (isArguments(objValue)) {
      newValue = toPlainObject(objValue);
    }
    else if (!isObject(objValue) || isFunction(objValue)) {
      newValue = initCloneObject(srcValue);
    }
  }
  else {
    isCommon = false;
  }
}
if (isCommon) {
  // Recursively merge objects and arrays (susceptible to call stack limits).
  stack.set(srcValue, newValue);
  mergeFunc(newValue, srcValue, srcIndex, customizer, stack);
  stack['delete'](srcValue);
}
assignMergeValue(object, key, newValue);

}

module.exports = baseMergeDeep;