/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
import { isListLikeIterable, iterateListLike } from '../../facade/collection';
import { BaseException } from '../../facade/exceptions';
import { getMapKey, isArray, isBlank, isPresent, looseIdentical, stringify } from '../../facade/lang';
/* @ts2dart_const */
export class DefaultIterableDifferFactory {
    constructor() {
    }
    supports(obj) { return isListLikeIterable(obj); }
    create(cdRef, trackByFn) {
        return new DefaultIterableDiffer(trackByFn);
    }
}
var trackByIdentity = (index, item) => item;
/**
 * @stable
 */
export class DefaultIterableDiffer {
    constructor(_trackByFn) {
        this._trackByFn = _trackByFn;
        this._length = null;
        this._collection = null;
        // Keeps track of the used records at any point in time (during & across `_check()` calls)
        this._linkedRecords = null;
        // Keeps track of the removed records at any point in time during `_check()` calls.
        this._unlinkedRecords = null;
        this._previousItHead = null;
        this._itHead = null;
        this._itTail = null;
        this._additionsHead = null;
        this._additionsTail = null;
        this._movesHead = null;
        this._movesTail = null;
        this._removalsHead = null;
        this._removalsTail = null;
        // Keeps track of records where custom track by is the same, but item identity has changed
        this._identityChangesHead = null;
        this._identityChangesTail = null;
        this._trackByFn = isPresent(this._trackByFn) ? this._trackByFn : trackByIdentity;
    }
    get collection() { return this._collection; }
    get length() { return this._length; }
    forEachItem(fn) {
        var record;
        for (record = this._itHead; record !== null; record = record._next) {
            fn(record);
        }
    }
    forEachPreviousItem(fn) {
        var record;
        for (record = this._previousItHead; record !== null; record = record._nextPrevious) {
            fn(record);
        }
    }
    forEachAddedItem(fn) {
        var record;
        for (record = this._additionsHead; record !== null; record = record._nextAdded) {
            fn(record);
        }
    }
    forEachMovedItem(fn) {
        var record;
        for (record = this._movesHead; record !== null; record = record._nextMoved) {
            fn(record);
        }
    }
    forEachRemovedItem(fn) {
        var record;
        for (record = this._removalsHead; record !== null; record = record._nextRemoved) {
            fn(record);
        }
    }
    forEachIdentityChange(fn) {
        var record;
        for (record = this._identityChangesHead; record !== null; record = record._nextIdentityChange) {
            fn(record);
        }
    }
    diff(collection) {
        if (isBlank(collection))
            collection = [];
        if (!isListLikeIterable(collection)) {
            throw new BaseException(`Error trying to diff '${collection}'`);
        }
        if (this.check(collection)) {
            return this;
        }
        else {
            return null;
        }
    }
    onDestroy() { }
    // todo(vicb): optim for UnmodifiableListView (frozen arrays)
    check(collection) {
        this._reset();
        var record = this._itHead;
        var mayBeDirty = false;
        var index;
        var item;
        var itemTrackBy;
        if (isArray(collection)) {
            var list = collection;
            this._length = collection.length;
            for (index = 0; index < this._length; index++) {
                item = list[index];
                itemTrackBy = this._trackByFn(index, item);
                if (record === null || !looseIdentical(record.trackById, itemTrackBy)) {
                    record = this._mismatch(record, item, itemTrackBy, index);
                    mayBeDirty = true;
                }
                else {
                    if (mayBeDirty) {
                        // TODO(misko): can we limit this to duplicates only?
                        record = this._verifyReinsertion(record, item, itemTrackBy, index);
                    }
                    if (!looseIdentical(record.item, item))
                        this._addIdentityChange(record, item);
                }
                record = record._next;
            }
        }
        else {
            index = 0;
            iterateListLike(collection, (item /** TODO #9100 */) => {
                itemTrackBy = this._trackByFn(index, item);
                if (record === null || !looseIdentical(record.trackById, itemTrackBy)) {
                    record = this._mismatch(record, item, itemTrackBy, index);
                    mayBeDirty = true;
                }
                else {
                    if (mayBeDirty) {
                        // TODO(misko): can we limit this to duplicates only?
                        record = this._verifyReinsertion(record, item, itemTrackBy, index);
                    }
                    if (!looseIdentical(record.item, item))
                        this._addIdentityChange(record, item);
                }
                record = record._next;
                index++;
            });
            this._length = index;
        }
        this._truncate(record);
        this._collection = collection;
        return this.isDirty;
    }
    /* CollectionChanges is considered dirty if it has any additions, moves, removals, or identity
     * changes.
     */
    get isDirty() {
        return this._additionsHead !== null || this._movesHead !== null ||
            this._removalsHead !== null || this._identityChangesHead !== null;
    }
    /**
     * Reset the state of the change objects to show no changes. This means set previousKey to
     * currentKey, and clear all of the queues (additions, moves, removals).
     * Set the previousIndexes of moved and added items to their currentIndexes
     * Reset the list of additions, moves and removals
     *
     * @internal
     */
    _reset() {
        if (this.isDirty) {
            var record;
            var nextRecord;
            for (record = this._previousItHead = this._itHead; record !== null; record = record._next) {
                record._nextPrevious = record._next;
            }
            for (record = this._additionsHead; record !== null; record = record._nextAdded) {
                record.previousIndex = record.currentIndex;
            }
            this._additionsHead = this._additionsTail = null;
            for (record = this._movesHead; record !== null; record = nextRecord) {
                record.previousIndex = record.currentIndex;
                nextRecord = record._nextMoved;
            }
            this._movesHead = this._movesTail = null;
            this._removalsHead = this._removalsTail = null;
            this._identityChangesHead = this._identityChangesTail = null;
        }
    }
    /**
     * This is the core function which handles differences between collections.
     *
     * - `record` is the record which we saw at this position last time. If null then it is a new
     *   item.
     * - `item` is the current item in the collection
     * - `index` is the position of the item in the collection
     *
     * @internal
     */
    _mismatch(record, item, itemTrackBy, index) {
        // The previous record after which we will append the current one.
        var previousRecord;
        if (record === null) {
            previousRecord = this._itTail;
        }
        else {
            previousRecord = record._prev;
            // Remove the record from the collection since we know it does not match the item.
            this._remove(record);
        }
        // Attempt to see if we have seen the item before.
        record = this._linkedRecords === null ? null : this._linkedRecords.get(itemTrackBy, index);
        if (record !== null) {
            // We have seen this before, we need to move it forward in the collection.
            // But first we need to check if identity changed, so we can update in view if necessary
            if (!looseIdentical(record.item, item))
                this._addIdentityChange(record, item);
            this._moveAfter(record, previousRecord, index);
        }
        else {
            // Never seen it, check evicted list.
            record = this._unlinkedRecords === null ? null : this._unlinkedRecords.get(itemTrackBy);
            if (record !== null) {
                // It is an item which we have evicted earlier: reinsert it back into the list.
                // But first we need to check if identity changed, so we can update in view if necessary
                if (!looseIdentical(record.item, item))
                    this._addIdentityChange(record, item);
                this._reinsertAfter(record, previousRecord, index);
            }
            else {
                // It is a new item: add it.
                record =
                    this._addAfter(new CollectionChangeRecord(item, itemTrackBy), previousRecord, index);
            }
        }
        return record;
    }
    /**
     * This check is only needed if an array contains duplicates. (Short circuit of nothing dirty)
     *
     * Use case: `[a, a]` => `[b, a, a]`
     *
     * If we did not have this check then the insertion of `b` would:
     *   1) evict first `a`
     *   2) insert `b` at `0` index.
     *   3) leave `a` at index `1` as is. <-- this is wrong!
     *   3) reinsert `a` at index 2. <-- this is wrong!
     *
     * The correct behavior is:
     *   1) evict first `a`
     *   2) insert `b` at `0` index.
     *   3) reinsert `a` at index 1.
     *   3) move `a` at from `1` to `2`.
     *
     *
     * Double check that we have not evicted a duplicate item. We need to check if the item type may
     * have already been removed:
     * The insertion of b will evict the first 'a'. If we don't reinsert it now it will be reinserted
     * at the end. Which will show up as the two 'a's switching position. This is incorrect, since a
     * better way to think of it is as insert of 'b' rather then switch 'a' with 'b' and then add 'a'
     * at the end.
     *
     * @internal
     */
    _verifyReinsertion(record, item, itemTrackBy, index) {
        var reinsertRecord = this._unlinkedRecords === null ? null : this._unlinkedRecords.get(itemTrackBy);
        if (reinsertRecord !== null) {
            record = this._reinsertAfter(reinsertRecord, record._prev, index);
        }
        else if (record.currentIndex != index) {
            record.currentIndex = index;
            this._addToMoves(record, index);
        }
        return record;
    }
    /**
     * Get rid of any excess {@link CollectionChangeRecord}s from the previous collection
     *
     * - `record` The first excess {@link CollectionChangeRecord}.
     *
     * @internal
     */
    _truncate(record) {
        // Anything after that needs to be removed;
        while (record !== null) {
            var nextRecord = record._next;
            this._addToRemovals(this._unlink(record));
            record = nextRecord;
        }
        if (this._unlinkedRecords !== null) {
            this._unlinkedRecords.clear();
        }
        if (this._additionsTail !== null) {
            this._additionsTail._nextAdded = null;
        }
        if (this._movesTail !== null) {
            this._movesTail._nextMoved = null;
        }
        if (this._itTail !== null) {
            this._itTail._next = null;
        }
        if (this._removalsTail !== null) {
            this._removalsTail._nextRemoved = null;
        }
        if (this._identityChangesTail !== null) {
            this._identityChangesTail._nextIdentityChange = null;
        }
    }
    /** @internal */
    _reinsertAfter(record, prevRecord, index) {
        if (this._unlinkedRecords !== null) {
            this._unlinkedRecords.remove(record);
        }
        var prev = record._prevRemoved;
        var next = record._nextRemoved;
        if (prev === null) {
            this._removalsHead = next;
        }
        else {
            prev._nextRemoved = next;
        }
        if (next === null) {
            this._removalsTail = prev;
        }
        else {
            next._prevRemoved = prev;
        }
        this._insertAfter(record, prevRecord, index);
        this._addToMoves(record, index);
        return record;
    }
    /** @internal */
    _moveAfter(record, prevRecord, index) {
        this._unlink(record);
        this._insertAfter(record, prevRecord, index);
        this._addToMoves(record, index);
        return record;
    }
    /** @internal */
    _addAfter(record, prevRecord, index) {
        this._insertAfter(record, prevRecord, index);
        if (this._additionsTail === null) {
            // todo(vicb)
            // assert(this._additionsHead === null);
            this._additionsTail = this._additionsHead = record;
        }
        else {
            // todo(vicb)
            // assert(_additionsTail._nextAdded === null);
            // assert(record._nextAdded === null);
            this._additionsTail = this._additionsTail._nextAdded = record;
        }
        return record;
    }
    /** @internal */
    _insertAfter(record, prevRecord, index) {
        // todo(vicb)
        // assert(record != prevRecord);
        // assert(record._next === null);
        // assert(record._prev === null);
        var next = prevRecord === null ? this._itHead : prevRecord._next;
        // todo(vicb)
        // assert(next != record);
        // assert(prevRecord != record);
        record._next = next;
        record._prev = prevRecord;
        if (next === null) {
            this._itTail = record;
        }
        else {
            next._prev = record;
        }
        if (prevRecord === null) {
            this._itHead = record;
        }
        else {
            prevRecord._next = record;
        }
        if (this._linkedRecords === null) {
            this._linkedRecords = new _DuplicateMap();
        }
        this._linkedRecords.put(record);
        record.currentIndex = index;
        return record;
    }
    /** @internal */
    _remove(record) {
        return this._addToRemovals(this._unlink(record));
    }
    /** @internal */
    _unlink(record) {
        if (this._linkedRecords !== null) {
            this._linkedRecords.remove(record);
        }
        var prev = record._prev;
        var next = record._next;
        // todo(vicb)
        // assert((record._prev = null) === null);
        // assert((record._next = null) === null);
        if (prev === null) {
            this._itHead = next;
        }
        else {
            prev._next = next;
        }
        if (next === null) {
            this._itTail = prev;
        }
        else {
            next._prev = prev;
        }
        return record;
    }
    /** @internal */
    _addToMoves(record, toIndex) {
        // todo(vicb)
        // assert(record._nextMoved === null);
        if (record.previousIndex === toIndex) {
            return record;
        }
        if (this._movesTail === null) {
            // todo(vicb)
            // assert(_movesHead === null);
            this._movesTail = this._movesHead = record;
        }
        else {
            // todo(vicb)
            // assert(_movesTail._nextMoved === null);
            this._movesTail = this._movesTail._nextMoved = record;
        }
        return record;
    }
    /** @internal */
    _addToRemovals(record) {
        if (this._unlinkedRecords === null) {
            this._unlinkedRecords = new _DuplicateMap();
        }
        this._unlinkedRecords.put(record);
        record.currentIndex = null;
        record._nextRemoved = null;
        if (this._removalsTail === null) {
            // todo(vicb)
            // assert(_removalsHead === null);
            this._removalsTail = this._removalsHead = record;
            record._prevRemoved = null;
        }
        else {
            // todo(vicb)
            // assert(_removalsTail._nextRemoved === null);
            // assert(record._nextRemoved === null);
            record._prevRemoved = this._removalsTail;
            this._removalsTail = this._removalsTail._nextRemoved = record;
        }
        return record;
    }
    /** @internal */
    _addIdentityChange(record, item) {
        record.item = item;
        if (this._identityChangesTail === null) {
            this._identityChangesTail = this._identityChangesHead = record;
        }
        else {
            this._identityChangesTail = this._identityChangesTail._nextIdentityChange = record;
        }
        return record;
    }
    toString() {
        var list = [];
        this.forEachItem((record /** TODO #9100 */) => list.push(record));
        var previous = [];
        this.forEachPreviousItem((record /** TODO #9100 */) => previous.push(record));
        var additions = [];
        this.forEachAddedItem((record /** TODO #9100 */) => additions.push(record));
        var moves = [];
        this.forEachMovedItem((record /** TODO #9100 */) => moves.push(record));
        var removals = [];
        this.forEachRemovedItem((record /** TODO #9100 */) => removals.push(record));
        var identityChanges = [];
        this.forEachIdentityChange((record /** TODO #9100 */) => identityChanges.push(record));
        return 'collection: ' + list.join(', ') + '\n' +
            'previous: ' + previous.join(', ') + '\n' +
            'additions: ' + additions.join(', ') + '\n' +
            'moves: ' + moves.join(', ') + '\n' +
            'removals: ' + removals.join(', ') + '\n' +
            'identityChanges: ' + identityChanges.join(', ') + '\n';
    }
}
/**
 * @stable
 */
export class CollectionChangeRecord {
    constructor(item, trackById) {
        this.item = item;
        this.trackById = trackById;
        this.currentIndex = null;
        this.previousIndex = null;
        /** @internal */
        this._nextPrevious = null;
        /** @internal */
        this._prev = null;
        /** @internal */
        this._next = null;
        /** @internal */
        this._prevDup = null;
        /** @internal */
        this._nextDup = null;
        /** @internal */
        this._prevRemoved = null;
        /** @internal */
        this._nextRemoved = null;
        /** @internal */
        this._nextAdded = null;
        /** @internal */
        this._nextMoved = null;
        /** @internal */
        this._nextIdentityChange = null;
    }
    toString() {
        return this.previousIndex === this.currentIndex ? stringify(this.item) :
            stringify(this.item) + '[' +
                stringify(this.previousIndex) + '->' + stringify(this.currentIndex) + ']';
    }
}
// A linked list of CollectionChangeRecords with the same CollectionChangeRecord.item
class _DuplicateItemRecordList {
    constructor() {
        /** @internal */
        this._head = null;
        /** @internal */
        this._tail = null;
    }
    /**
     * Append the record to the list of duplicates.
     *
     * Note: by design all records in the list of duplicates hold the same value in record.item.
     */
    add(record) {
        if (this._head === null) {
            this._head = this._tail = record;
            record._nextDup = null;
            record._prevDup = null;
        }
        else {
            // todo(vicb)
            // assert(record.item ==  _head.item ||
            //       record.item is num && record.item.isNaN && _head.item is num && _head.item.isNaN);
            this._tail._nextDup = record;
            record._prevDup = this._tail;
            record._nextDup = null;
            this._tail = record;
        }
    }
    // Returns a CollectionChangeRecord having CollectionChangeRecord.trackById == trackById and
    // CollectionChangeRecord.currentIndex >= afterIndex
    get(trackById, afterIndex) {
        var record;
        for (record = this._head; record !== null; record = record._nextDup) {
            if ((afterIndex === null || afterIndex < record.currentIndex) &&
                looseIdentical(record.trackById, trackById)) {
                return record;
            }
        }
        return null;
    }
    /**
     * Remove one {@link CollectionChangeRecord} from the list of duplicates.
     *
     * Returns whether the list of duplicates is empty.
     */
    remove(record) {
        // todo(vicb)
        // assert(() {
        //  // verify that the record being removed is in the list.
        //  for (CollectionChangeRecord cursor = _head; cursor != null; cursor = cursor._nextDup) {
        //    if (identical(cursor, record)) return true;
        //  }
        //  return false;
        //});
        var prev = record._prevDup;
        var next = record._nextDup;
        if (prev === null) {
            this._head = next;
        }
        else {
            prev._nextDup = next;
        }
        if (next === null) {
            this._tail = prev;
        }
        else {
            next._prevDup = prev;
        }
        return this._head === null;
    }
}
class _DuplicateMap {
    constructor() {
        this.map = new Map();
    }
    put(record) {
        // todo(vicb) handle corner cases
        var key = getMapKey(record.trackById);
        var duplicates = this.map.get(key);
        if (!isPresent(duplicates)) {
            duplicates = new _DuplicateItemRecordList();
            this.map.set(key, duplicates);
        }
        duplicates.add(record);
    }
    /**
     * Retrieve the `value` using key. Because the CollectionChangeRecord value may be one which we
     * have already iterated over, we use the afterIndex to pretend it is not there.
     *
     * Use case: `[a, b, c, a, a]` if we are at index `3` which is the second `a` then asking if we
     * have any more `a`s needs to return the last `a` not the first or second.
     */
    get(trackById, afterIndex = null) {
        var key = getMapKey(trackById);
        var recordList = this.map.get(key);
        return isBlank(recordList) ? null : recordList.get(trackById, afterIndex);
    }
    /**
     * Removes a {@link CollectionChangeRecord} from the list of duplicates.
     *
     * The list of duplicates also is removed from the map if it gets empty.
     */
    remove(record) {
        var key = getMapKey(record.trackById);
        // todo(vicb)
        // assert(this.map.containsKey(key));
        var recordList = this.map.get(key);
        // Remove the list of duplicates when it gets empty
        if (recordList.remove(record)) {
            this.map.delete(key);
        }
        return record;
    }
    get isEmpty() { return this.map.size === 0; }
    clear() { this.map.clear(); }
    toString() { return '_DuplicateMap(' + stringify(this.map) + ')'; }
}
//# sourceMappingURL=default_iterable_differ.js.map