// Copyright 2018-present the Material Components for iOS authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import XCTest
import MaterialComponents.MaterialButtonBar
import MaterialComponents.MaterialButtons

class ButtonBarObservationTests: XCTestCase {

  var buttonBar: MDCButtonBar!

  override func setUp() {
    buttonBar = MDCButtonBar()
  }

  // Create a solid color image for testing purposes.
  private func createImage(colored color: UIColor) -> UIImage {
    UIGraphicsBeginImageContextWithOptions(CGSize(width: 64, height: 64), true, 1)
    color.setFill()
    UIRectFill(CGRect(x: 0, y: 0, width: 64, height: 64))
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image!
  }

  // MARK: Initial state

  func testInitialTextButtonStateMatchesItemState() {
    // Given
    let item = UIBarButtonItem(title: "LEFT", style: .plain, target: nil, action: nil)

    // When
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // Then
    let titles = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap {
      $0.title(for: .normal)
    }
    XCTAssertEqual(titles, [item.title!])
  }

  func testInitialImageButtonStateMatchesItemState() {
    // Given
    let image1 = createImage(colored: .red)
    let item = UIBarButtonItem(image: image1, style: .plain, target: nil, action: nil)

    // When
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // Then
    let images =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.image(for: .normal) }
    XCTAssertEqual(images, [item.image!])
  }

  func testInitialGeneralStateMatchesItemState() {
    // Given
    let item = UIBarButtonItem(title: "Title", style: .plain, target: nil, action: nil)

    // When
    item.accessibilityHint = "Hint"
    item.accessibilityIdentifier = "Identifier"
    item.accessibilityLabel = "Label"
    item.accessibilityValue = "Value"
    item.isEnabled = true
    item.tag = 100
    item.tintColor = .blue
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // Then
    let accessibilityHints =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityHint }
    XCTAssertEqual(accessibilityHints, [item.accessibilityHint!])
    let accessibilityIdentifiers =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityIdentifier }
    XCTAssertEqual(accessibilityIdentifiers, [item.accessibilityIdentifier!])
    let accessibilityLabels =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityLabel }
    XCTAssertEqual(accessibilityLabels, [item.accessibilityLabel!])
    let accessibilityValues =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityValue }
    XCTAssertEqual(accessibilityValues, [item.accessibilityValue!])
    let enabled = buttonBar.subviews.compactMap { $0 as? MDCButton }.map { $0.isEnabled }
    XCTAssertEqual(enabled, [item.isEnabled])
    let tags = buttonBar.subviews.compactMap { $0 as? MDCButton }.map { $0.tag }
    XCTAssertEqual(tags, [item.tag])
    let tintColors = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.tintColor }
    XCTAssertEqual(tintColors, [item.tintColor!])
  }

  // MARK: KVO observation

  func testAccessibilityHintChangesAreObserved() {
    // Given
    let item = UIBarButtonItem(title: "Title", style: .plain, target: nil, action: nil)
    item.accessibilityHint = "Hint"
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.accessibilityHint = "Other hint"

    // Then
    let accessibilityLabels =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityHint }
    XCTAssertEqual(accessibilityLabels, [item.accessibilityHint!])
  }

  func testAccessibilityIdentifierChangesAreObserved() {
    // Given
    let item = UIBarButtonItem(title: "Title", style: .plain, target: nil, action: nil)
    item.accessibilityIdentifier = "Identifier"
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.accessibilityIdentifier = "Other identifier"

    // Then
    let accessibilityIdentifiers =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityIdentifier }
    XCTAssertEqual(accessibilityIdentifiers, [item.accessibilityIdentifier!])
  }

  func testAccessibilityLabelChangesAreObserved() {
    // Given
    let item = UIBarButtonItem(title: "Title", style: .plain, target: nil, action: nil)
    item.accessibilityLabel = "Label"
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.accessibilityLabel = "Other label"

    // Then
    let accessibilityLabels =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityLabel }
    XCTAssertEqual(accessibilityLabels, [item.accessibilityLabel!])
  }

  func testAccessibilityValueChangesAreObserved() {
    // Given
    let item = UIBarButtonItem(title: "Title", style: .plain, target: nil, action: nil)
    item.accessibilityValue = "Value"
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.accessibilityValue = "Other value"

    // Then
    let accessibilityValues =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityValue }
    XCTAssertEqual(accessibilityValues, [item.accessibilityValue!])
  }

  func testEnabledChangesAreObserved() {
    // Given
    let item = UIBarButtonItem(title: "Title", style: .plain, target: nil, action: nil)
    item.isEnabled = true
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.isEnabled = false

    // Then
    let enabled = buttonBar.subviews.compactMap { $0 as? MDCButton }.map { $0.isEnabled }
    XCTAssertEqual(enabled, [item.isEnabled])
  }

  func testImageChangesAreObserved() {
    // Given
    let image1 = createImage(colored: .red)
    let item = UIBarButtonItem(image: image1, style: .plain, target: nil, action: nil)
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.image = createImage(colored: .blue)

    // Then
    let images =
      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.image(for: .normal) }
    XCTAssertEqual(images, [item.image!])
  }

  func testTagChangesAreObserved() {
    // Given
    let item = UIBarButtonItem(title: "Title", style: .plain, target: nil, action: nil)
    item.tag = 100
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.tag = 50

    // Then
    let tags = buttonBar.subviews.compactMap { $0 as? MDCButton }.map { $0.tag }
    XCTAssertEqual(tags, [item.tag])
  }

  func testTintColorChangesAreObserved() {
    // Given
    let item = UIBarButtonItem(title: "Title", style: .plain, target: nil, action: nil)
    item.tintColor = .blue
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.tintColor = .red

    // Then
    let tintColors = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.tintColor }
    XCTAssertEqual(tintColors, [item.tintColor!])

    // Verify that the tint color reverts to the default
    item.tintColor = nil

    do {
      let tintColors = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap {
        $0.tintColor
      }
      XCTAssertEqual(tintColors, [buttonBar.tintColor])
    }
  }

  func testTintColorChangeToNilIsObservedAndReset() {
    // Given
    let item = UIBarButtonItem(title: "Title", style: .plain, target: nil, action: nil)
    item.tintColor = .blue
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.tintColor = nil

    // Then
    let tintColors = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.tintColor }
    XCTAssertEqual(tintColors, [buttonBar.tintColor])
  }

  func testTitleChangesAreObserved() {
    // Given
    let item = UIBarButtonItem(title: "LEFT", style: .plain, target: nil, action: nil)
    buttonBar.items = [item]
    buttonBar.layoutSubviews()

    // When
    item.title = "NEW TITLE"

    // Then
    let titles = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap {
      $0.title(for: .normal)
    }
    XCTAssertEqual(titles, [item.title!])
  }

}