/**
 * @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 {CommonModule, SlicePipe} from '@angular/common';
import {Component} from '@angular/core';
import {TestBed, waitForAsync} from '@angular/core/testing';
import {expect} from '@angular/platform-browser/testing/src/matchers';

{
  describe('SlicePipe', () => {
    let list: number[];
    let str: string;
    let pipe: SlicePipe;

    beforeEach(() => {
      list = [1, 2, 3, 4, 5];
      str = 'tuvwxyz';
      pipe = new SlicePipe();
    });

    describe('supports', () => {
      it('should support strings', () => {
        expect(() => pipe.transform(str, 0)).not.toThrow();
      });
      it('should support lists', () => {
        expect(() => pipe.transform(list, 0)).not.toThrow();
      });
      it('should support readonly lists', () => {
        expect(() => pipe.transform(list as ReadonlyArray<number>, 0)).not.toThrow();
      });

      it('should not support other objects',
         // this would not compile
         // so we cast as `any` to check that it throws for unsupported objects
         () => {
           expect(() => pipe.transform({} as any, 0)).toThrow();
         });
    });

    describe('transform', () => {
      it('should return null if the value is null', () => {
        expect(pipe.transform(null, 1)).toBe(null);
      });

      it('should return null if the value is undefined', () => {
        expect(pipe.transform(undefined, 1)).toBe(null);
      });

      it('should return all items after START index when START is positive and END is omitted',
         () => {
           expect(pipe.transform(list, 3)).toEqual([4, 5]);
           expect(pipe.transform(str, 3)).toEqual('wxyz');
         });

      it('should return last START items when START is negative and END is omitted', () => {
        expect(pipe.transform(list, -3)).toEqual([3, 4, 5]);
        expect(pipe.transform(str, -3)).toEqual('xyz');
      });

      it('should return all items between START and END index when START and END are positive',
         () => {
           expect(pipe.transform(list, 1, 3)).toEqual([2, 3]);
           expect(pipe.transform(str, 1, 3)).toEqual('uv');
         });

      it('should return all items between START and END from the end when START and END are negative',
         () => {
           expect(pipe.transform(list, -4, -2)).toEqual([2, 3]);
           expect(pipe.transform(str, -4, -2)).toEqual('wx');
         });

      it('should return an empty value if START is greater than END', () => {
        expect(pipe.transform(list, 4, 2)).toEqual([]);
        expect(pipe.transform(str, 4, 2)).toEqual('');
      });

      it('should return an empty value if START greater than input length', () => {
        expect(pipe.transform(list, 99)).toEqual([]);
        expect(pipe.transform(str, 99)).toEqual('');
      });

      it('should return entire input if START is negative and greater than input length', () => {
        expect(pipe.transform(list, -99)).toEqual([1, 2, 3, 4, 5]);
        expect(pipe.transform(str, -99)).toEqual('tuvwxyz');
      });

      it('should not modify the input list', () => {
        expect(pipe.transform(list, 2)).toEqual([3, 4, 5]);
        expect(list).toEqual([1, 2, 3, 4, 5]);
      });
    });

    describe('integration', () => {
      @Component({selector: 'test-comp', template: '{{(data | slice:1).join(",") }}'})
      class TestComp {
        data: any;
      }

      beforeEach(() => {
        TestBed.configureTestingModule({declarations: [TestComp], imports: [CommonModule]});
      });

      it('should work with mutable arrays', waitForAsync(() => {
           const fixture = TestBed.createComponent(TestComp);
           const mutable: number[] = [1, 2];
           fixture.componentInstance.data = mutable;
           fixture.detectChanges();
           expect(fixture.nativeElement).toHaveText('2');

           mutable.push(3);
           fixture.detectChanges();
           expect(fixture.nativeElement).toHaveText('2,3');
         }));
    });
  });
}
