var LazyWrapper = require('./_LazyWrapper'),
    LodashWrapper = require('./_LodashWrapper'),
    baseLodash = require('./_baseLodash'),
    isArray = require('./isArray'),
    isObjectLike = require('./isObjectLike'),
    wrapperClone = require('./_wrapperClone');

/** Used for built-in method references. */
var objectProto = Object.prototype;

/** Used to check objects for own properties. */
var hasOwnProperty = objectProto.hasOwnProperty;

/**
 * Creates a `lodash` object which wraps `value` to enable implicit method
 * chaining. Methods that operate on and return arrays, collections, and
 * functions can be chained together. Methods that retrieve a single value or
 * may return a primitive value will automatically end the chain sequence and
 * return the unwrapped value. Otherwise, the value must be unwrapped with
 * `_#value`.
 *
 * Explicit chaining, which must be unwrapped with `_#value` in all cases,
 * may be enabled using `_.chain`.
 *
 * The execution of chained methods is lazy, that is, it's deferred until
 * `_#value` is implicitly or explicitly called.
 *
 * Lazy evaluation allows several methods to support shortcut fusion. Shortcut
 * fusion is an optimization to merge iteratee calls; this avoids the creation
 * of intermediate arrays and can greatly reduce the number of iteratee executions.
 * Sections of a chain sequence qualify for shortcut fusion if the section is
 * applied to an array of at least two hundred elements and any iteratees
 * accept only one argument. The heuristic for whether a section qualifies
 * for shortcut fusion is subject to change.
 *
 * Chaining is supported in custom builds as long as the `_#value` method is
 * directly or indirectly included in the build.
 *
 * In addition to lodash methods, wrappers have `Array` and `String` methods.
 *
 * The wrapper `Array` methods are:
 * `concat`, `join`, `pop`, `push`, `shift`, `sort`, `splice`, and `unshift`
 *
 * The wrapper `String` methods are:
 * `replace` and `split`
 *
 * The wrapper methods that support shortcut fusion are:
 * `at`, `compact`, `drop`, `dropRight`, `dropWhile`, `filter`, `find`,
 * `findLast`, `head`, `initial`, `last`, `map`, `reject`, `reverse`, `slice`,
 * `tail`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, and `toArray`
 *
 * The chainable wrapper methods are:
 * `after`, `ary`, `assign`, `assignIn`, `assignInWith`, `assignWith`, `at`,
 * `before`, `bind`, `bindAll`, `bindKey`, `castArray`, `chain`, `chunk`,
 * `commit`, `compact`, `concat`, `conforms`, `constant`, `countBy`, `create`,
 * `curry`, `debounce`, `defaults`, `defaultsDeep`, `defer`, `delay`,
 * `difference`, `differenceBy`, `differenceWith`, `drop`, `dropRight`,
 * `dropRightWhile`, `dropWhile`, `extend`, `extendWith`, `fill`, `filter`,
 * `flatten`, `flattenDeep`, `flattenDepth`, `flip`, `flow`, `flowRight`,
 * `fromPairs`, `functions`, `functionsIn`, `groupBy`, `initial`, `intersection`,
 * `intersectionBy`, `intersectionWith`, `invert`, `invertBy`, `invokeMap`,
 * `iteratee`, `keyBy`, `keys`, `keysIn`, `map`, `mapKeys`, `mapValues`,
 * `matches`, `matchesProperty`, `memoize`, `merge`, `mergeWith`, `method`,
 * `methodOf`, `mixin`, `negate`, `nthArg`, `omit`, `omitBy`, `once`, `orderBy`,
 * `over`, `overArgs`, `overEvery`, `overSome`, `partial`, `partialRight`,
 * `partition`, `pick`, `pickBy`, `plant`, `property`, `propertyOf`, `pull`,
 * `pullAll`, `pullAllBy`, `pullAllWith`, `pullAt`, `push`, `range`,
 * `rangeRight`, `rearg`, `reject`, `remove`, `rest`, `reverse`, `sampleSize`,
 * `set`, `setWith`, `shuffle`, `slice`, `sort`, `sortBy`, `splice`, `spread`,
 * `tail`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `tap`, `throttle`,
 * `thru`, `toArray`, `toPairs`, `toPairsIn`, `toPath`, `toPlainObject`,
 * `transform`, `unary`, `union`, `unionBy`, `unionWith`, `uniq`, `uniqBy`,
 * `uniqWith`, `unset`, `unshift`, `unzip`, `unzipWith`, `update`, `values`,
 * `valuesIn`, `without`, `wrap`, `xor`, `xorBy`, `xorWith`, `zip`, `zipObject`,
 * `zipObjectDeep`, and `zipWith`
 *
 * The wrapper methods that are **not** chainable by default are:
 * `add`, `attempt`, `camelCase`, `capitalize`, `ceil`, `clamp`, `clone`,
 * `cloneDeep`, `cloneDeepWith`, `cloneWith`, `deburr`, `each`, `eachRight`,
 * `endsWith`, `eq`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`,
 * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `first`, `floor`,
 * `forEach`, `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`,
 * `get`, `gt`, `gte`, `has`, `hasIn`, `head`, `identity`, `includes`,
 * `indexOf`, `inRange`, `invoke`, `isArguments`, `isArray`, `isArrayBuffer`,
 * `isArrayLike`, `isArrayLikeObject`, `isBoolean`, `isBuffer`, `isDate`,
 * `isElement`, `isEmpty`, `isEqual`, `isEqualWith`, `isError`, `isFinite`,
 * `isFunction`, `isInteger`, `isLength`, `isMap`, `isMatch`, `isMatchWith`,
 * `isNaN`, `isNative`, `isNil`, `isNull`, `isNumber`, `isObject`, `isObjectLike`,
 * `isPlainObject`, `isRegExp`, `isSafeInteger`, `isSet`, `isString`,
 * `isUndefined`, `isTypedArray`, `isWeakMap`, `isWeakSet`, `join`, `kebabCase`,
 * `last`, `lastIndexOf`, `lowerCase`, `lowerFirst`, `lt`, `lte`, `max`,
 * `maxBy`, `mean`, `min`, `minBy`, `noConflict`, `noop`, `now`, `pad`,
 * `padEnd`, `padStart`, `parseInt`, `pop`, `random`, `reduce`, `reduceRight`,
 * `repeat`, `result`, `round`, `runInContext`, `sample`, `shift`, `size`,
 * `snakeCase`, `some`, `sortedIndex`, `sortedIndexBy`, `sortedLastIndex`,
 * `sortedLastIndexBy`, `startCase`, `startsWith`, `subtract`, `sum`, `sumBy`,
 * `template`, `times`, `toInteger`, `toJSON`, `toLength`, `toLower`,
 * `toNumber`, `toSafeInteger`, `toString`, `toUpper`, `trim`, `trimEnd`,
 * `trimStart`, `truncate`, `unescape`, `uniqueId`, `upperCase`, `upperFirst`,
 * `value`, and `words`
 *
 * @name _
 * @constructor
 * @category Seq
 * @param {*} value The value to wrap in a `lodash` instance.
 * @returns {Object} Returns the new `lodash` wrapper instance.
 * @example
 *
 * function square(n) {
 *   return n * n;
 * }
 *
 * var wrapped = _([1, 2, 3]);
 *
 * // Returns an unwrapped value.
 * wrapped.reduce(_.add);
 * // => 6
 *
 * // Returns a wrapped value.
 * var squares = wrapped.map(square);
 *
 * _.isArray(squares);
 * // => false
 *
 * _.isArray(squares.value());
 * // => true
 */
function lodash(value) {
  if (isObjectLike(value) && !isArray(value) && !(value instanceof LazyWrapper)) {
    if (value instanceof LodashWrapper) {
      return value;
    }
    if (hasOwnProperty.call(value, '__wrapped__')) {
      return wrapperClone(value);
    }
  }
  return new LodashWrapper(value);
}

// Ensure wrappers are instances of `baseLodash`.
lodash.prototype = baseLodash.prototype;
lodash.prototype.constructor = lodash;

module.exports = lodash;