/**
 * @license
 * Copyright Google LLC 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 {ZoneType} from '../zone-impl';

export function patchResizeObserver(Zone: ZoneType): void {
  Zone.__load_patch('ResizeObserver', (global: any, Zone: any, api: _ZonePrivate) => {
    const ResizeObserver = global['ResizeObserver'];
    if (!ResizeObserver) {
      return;
    }

    const resizeObserverSymbol = api.symbol('ResizeObserver');

    api.patchMethod(global, 'ResizeObserver', (delegate: Function) => (self: any, args: any[]) => {
      const callback = args.length > 0 ? args[0] : null;
      if (callback) {
        args[0] = function (entries: any, observer: any) {
          const zones: {[zoneName: string]: any} = {};
          const currZone = Zone.current;
          for (let entry of entries) {
            let zone = entry.target[resizeObserverSymbol];
            if (!zone) {
              zone = currZone;
            }
            let zoneEntriesInfo = zones[zone.name];
            if (!zoneEntriesInfo) {
              zones[zone.name] = zoneEntriesInfo = {entries: [], zone: zone};
            }
            zoneEntriesInfo.entries.push(entry);
          }

          Object.keys(zones).forEach((zoneName) => {
            const zoneEntriesInfo = zones[zoneName];
            if (zoneEntriesInfo.zone !== Zone.current) {
              zoneEntriesInfo.zone.run(
                callback,
                this,
                [zoneEntriesInfo.entries, observer],
                'ResizeObserver',
              );
            } else {
              callback.call(this, zoneEntriesInfo.entries, observer);
            }
          });
        };
      }
      return args.length > 0 ? new ResizeObserver(args[0]) : new ResizeObserver();
    });

    api.patchMethod(
      ResizeObserver.prototype,
      'observe',
      (delegate: Function) => (self: any, args: any[]) => {
        const target = args.length > 0 ? args[0] : null;
        if (!target) {
          return delegate.apply(self, args);
        }
        let targets = self[resizeObserverSymbol];
        if (!targets) {
          targets = self[resizeObserverSymbol] = [];
        }
        targets.push(target);
        target[resizeObserverSymbol] = Zone.current;
        return delegate.apply(self, args);
      },
    );

    api.patchMethod(
      ResizeObserver.prototype,
      'unobserve',
      (delegate: Function) => (self: any, args: any[]) => {
        const target = args.length > 0 ? args[0] : null;
        if (!target) {
          return delegate.apply(self, args);
        }
        let targets = self[resizeObserverSymbol];
        if (targets) {
          for (let i = 0; i < targets.length; i++) {
            if (targets[i] === target) {
              targets.splice(i, 1);
              break;
            }
          }
        }
        target[resizeObserverSymbol] = undefined;
        return delegate.apply(self, args);
      },
    );

    api.patchMethod(
      ResizeObserver.prototype,
      'disconnect',
      (delegate: Function) => (self: any, args: any[]) => {
        const targets = self[resizeObserverSymbol];
        if (targets) {
          targets.forEach((target: any) => {
            target[resizeObserverSymbol] = undefined;
          });
          self[resizeObserverSymbol] = undefined;
        }
        return delegate.apply(self, args);
      },
    );
  });
}
