/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    Tests to make sure that the `DreamListViewControllerModel` type correctly

                constructs a diff.

*/

import XCTest

class DreamListViewControllerModelDiffTests: XCTestCase {

    func testDiffingEqualModels() {

        let dream1 = Dream(description: "foo", creature: .unicorn(.pink), effects: [.fireBreathing])

        let dream2 = Dream(description: "bar", creature: .unicorn(.yellow), effects: [.rain])

        let model1 = DreamListViewControllerModel(favoriteCreature: .unicorn(.pink), dreams: [

            dream1,

            dream2

        ])

        let model2 = DreamListViewControllerModel(favoriteCreature: .unicorn(.pink), dreams: [

            dream1,

            dream2

        ])

        let diff = model1.diffed(with: model2)

        XCTAssertFalse(diff.hasAnyDreamChanges)

        XCTAssertFalse(diff.hasAnyDreamChanges)

        XCTAssertFalse(diff.favoriteCreatureChanged)

        XCTAssertEqual(diff.from, model1)

        XCTAssertEqual(diff.to, model2)

        XCTAssertNil(diff.dreamChange)

    }

    func testDiffRemovingDreamFromModel() {

        let dream1 = Dream(description: "foo", creature: .unicorn(.pink), effects: [.fireBreathing])

        let dream2 = Dream(description: "bar", creature: .unicorn(.white), effects: [.laserFocus, .fireflies])

        let dream3 = Dream(description: "baz", creature: .unicorn(.white), effects: [.laserFocus, .fireflies])

        let model1 = DreamListViewControllerModel(favoriteCreature: .unicorn(.pink), dreams: [

            dream1,

            dream2,

            dream3

        ])

        let model2 = DreamListViewControllerModel(favoriteCreature: .unicorn(.pink), dreams: [

            dream1,

            dream2

        ])

        let diff = model1.diffed(with: model2)

        XCTAssertEqual(diff.dreamChange, .removed(dream3))

    }

    func testDiffAppendingDreamFromModel() {

        let dream1 = Dream(description: "foo", creature: .unicorn(.pink), effects: [.fireBreathing])

        let dream2 = Dream(description: "bar", creature: .unicorn(.white), effects: [.laserFocus, .fireflies])

        let dream3 = Dream(description: "baz", creature: .unicorn(.white), effects: [.laserFocus, .fireflies])

        let model1 = DreamListViewControllerModel(favoriteCreature: .unicorn(.pink), dreams: [

            dream1,

            dream2

        ])

        let model2 = DreamListViewControllerModel(favoriteCreature: .unicorn(.pink), dreams: [

            dream1,

            dream2,

            dream3

        ])

        let diff = model1.diffed(with: model2)

        XCTAssertEqual(diff.dreamChange, .inserted(dream3))

    }

    func testDiffFavoriteCreatureChanged() {

        let model1 = DreamListViewControllerModel(favoriteCreature: .unicorn(.pink), dreams: [])

        let model2 = DreamListViewControllerModel(favoriteCreature: .unicorn(.yellow), dreams: [])

        let diff = model1.diffed(with: model2)

        XCTAssertTrue(diff.favoriteCreatureChanged)

    }

}