//

// STScanView.swift

// STBaseProject

//

// Created by 寒江孤影 on 2018/3/14.

//

import UIKit

/// Safe-area adaptation toggle for `STScanView`.

public enum STSafeAreaAdaptation: Sendable, Equatable {

case enabled

case disabled

public var isEnabled: Bool { self == .enabled }

}

public struct STScanViewConfiguration {

public var scanAreaMargin: CGFloat = 60.0

public var scanLineHeight: CGFloat = 5.0

public var maskAlpha: CGFloat = 0.6

public var borderColor: UIColor = .white

public var cornerColor: UIColor = UIColor(red: 0.110, green: 0.659, blue: 0.894, alpha: 1.0)

public var cornerSize: CGSize = CGSize(width: 15.0, height: 15.0)

public var cornerLineWidth: CGFloat = 4.0

public var tipText: String = "将二维码放入框内,即可自动扫描"

public var tipTextColor: UIColor = .white

public var tipTextFont: UIFont = UIFont.systemFont(ofSize: 13)

public var animationDuration: TimeInterval = 1.5

public var animationInterval: TimeInterval = 0.3

public var automaticSafeAreaAdaptation: Bool = true

public init() {}

}

public enum STScanViewTheme {

case light

case dark

case custom(STScanViewConfiguration)

fileprivate var configuration: STScanViewConfiguration {

switch self {

case .light:

var config = STScanViewConfiguration()

config.maskAlpha = 0.4

config.borderColor = .black

config.tipTextColor = .black

return config

case .dark:

return STScanViewConfiguration()

case .custom(let config):

return config

}

}

}

public class STScanView: UIView {

// MARK: - Public Properties

public var scanType: STScanType = .qrCode {

didSet { updateScanType() }

}

public var theme: STScanViewTheme = .dark {

didSet {

configuration = theme.configuration

// configuration.didSet 已调用 setNeedsDisplay()，此处不需再次触发

}

}

public var configuration: STScanViewConfiguration = STScanViewConfiguration() {

didSet { updateConfiguration() }

}

public var isAnimating: Bool {

return !isAnimationStopped && scanType != .barCode

}

// MARK: - Private Properties

private var isAnimationStopped: Bool = false

private var heightScale: CGFloat = 1.0

private var animationStartWorkItem: DispatchWorkItem?

private var tipLabel: UILabel?

private var scanLineView: UIImageView?

// MARK: - Lifecycle

deinit {

stopAnimation()

}

public override init(frame: CGRect) {

super.init(frame: frame)

setupView()

}

required public init?(coder aDecoder: NSCoder) {

super.init(coder: aDecoder)

setupView()

}

public override func layoutSubviews() {

super.layoutSubviews()

updateScanLineFrame()

updateTipLabelFrame()

}

public override func safeAreaInsetsDidChange() {

super.safeAreaInsetsDidChange()

if self.configuration.automaticSafeAreaAdaptation {

setNeedsDisplay()

setNeedsLayout()

}

}

// MARK: - Setup

private func setupView() {

backgroundColor = .clear

isAnimationStopped = false

setupScanLine()

setupTipLabel()

setupAccessibility()

}

private func setupScanLine() {

let view = UIImageView()

view.contentMode = .scaleToFill

view.image = makeScanLineImage()

view.alpha = 0

addSubview(view)

self.scanLineView = view

}

private func setupTipLabel() {

let label = UILabel()

label.numberOfLines = 0

label.textAlignment = .center

label.layer.zPosition = 1

addSubview(label)

bringSubviewToFront(label)

self.tipLabel = label

updateTipLabelAppearance()

}

private func setupAccessibility() {

isAccessibilityElement = true

accessibilityTraits = .staticText

accessibilityLabel = "扫码区域"

accessibilityHint = self.configuration.tipText

}

// MARK: - Public Methods

public func st_configScanType(scanType: STScanType) {

self.scanType = scanType

}

public func st_startAnimating() {

startAnimation()

}

public func st_stopAnimating() {

stopAnimation()

}

// MARK: - Private Methods

private func updateScanType() {

switch self.scanType {

case .barCode:

heightScale = 3.0

stopAnimation()

case .qrCode, .all:

heightScale = 1.0

// 使用 DispatchWorkItem 以便在 scanType 快速切换时可取消旧的待执行动画

let item = DispatchWorkItem { [weak self] in

self?.startAnimation()

}

self.animationStartWorkItem = item

DispatchQueue.main.asyncAfter(deadline: .now() + 0.5, execute: item)

}

setNeedsDisplay()

setNeedsLayout()

}

private func updateConfiguration() {

updateTipLabelAppearance()

updateScanLineImage()

setNeedsDisplay()

setupAccessibility()

}

private func updateTipLabelAppearance() {

self.tipLabel?.text = self.configuration.tipText

self.tipLabel?.textColor = self.configuration.tipTextColor

self.tipLabel?.font = self.configuration.tipTextFont

}

/// 每次按当前 configuration 重新生成扫描线图像，避免 lazy 缓存导致样式不跟随配置更新

private func makeScanLineImage() -> UIImage {

let size = CGSize(width: 1, height: self.configuration.scanLineHeight)

let renderer = UIGraphicsImageRenderer(size: size)

return renderer.image { ctx in

let colors = [UIColor.clear.cgColor,

self.configuration.cornerColor.cgColor,

UIColor.clear.cgColor] as CFArray

let locations: [CGFloat] = [0, 0.5, 1]

guard let gradient = CGGradient(

colorsSpace: CGColorSpaceCreateDeviceRGB(),

colors: colors,

locations: locations

) else { return }

ctx.cgContext.drawLinearGradient(

gradient,

start: .zero,

end: CGPoint(x: 0, y: size.height),

options: []

)

}

}

private func updateScanLineImage() {

self.scanLineView?.image = makeScanLineImage()

}

private func updateScanLineFrame() {

guard let scanLineView = self.scanLineView else { return }

let scanRect = calculateScanAreaRect()

let scanSize = calculateScanAreaSize()

scanLineView.frame = CGRect(

x: scanRect.minX + 2,

y: scanRect.minY + 2,

width: scanSize.width - 4,

height: self.configuration.scanLineHeight

)

}

private func updateTipLabelFrame() {

guard let tipLabel = self.tipLabel else { return }

let scanRect = calculateScanAreaRect()

tipLabel.frame = CGRect(

x: 0,

y: scanRect.maxY + 15,

width: bounds.width,

height: 50

)

}

private func startAnimation() {

guard self.scanType != .barCode && !isAnimationStopped else { return }

stopAnimation()

isAnimationStopped = false

guard let scanLineView = self.scanLineView else { return }

let scanRect = calculateScanAreaRect()

let startY = scanRect.minY + 2

let endY = scanRect.maxY - self.configuration.scanLineHeight - 2

var frame = scanLineView.frame

frame.origin.y = startY

scanLineView.frame = frame

scanLineView.alpha = 1.0

UIView.animate(

withDuration: self.configuration.animationDuration,

delay: 0,

options: [.curveEaseInOut],

animations: {

var newFrame = scanLineView.frame

newFrame.origin.y = endY

scanLineView.frame = newFrame

}

) { [weak self] _ in

guard let self, !self.isAnimationStopped else { return }

UIView.animate(withDuration: 0.2, animations: {

scanLineView.alpha = 0

}) { _ in

guard !self.isAnimationStopped else { return }

let item = DispatchWorkItem { [weak self] in

self?.startAnimation()

}

self.animationStartWorkItem = item

DispatchQueue.main.asyncAfter(deadline: .now() + self.configuration.animationInterval, execute: item)

}

}

}

private func stopAnimation() {

isAnimationStopped = true

self.animationStartWorkItem?.cancel()

self.animationStartWorkItem = nil

self.scanLineView?.layer.removeAllAnimations()

self.scanLineView?.alpha = 0

}

// MARK: - Drawing

public override func draw(_ rect: CGRect) {

super.draw(rect)

drawScanRect()

}

private func drawScanRect() {

guard let context = UIGraphicsGetCurrentContext() else { return }

let scanRect = calculateScanAreaRect()

drawMask(context: context, scanRect: scanRect)

drawBorder(context: context, scanRect: scanRect)

drawCorners(context: context, scanRect: scanRect)

}

private func calculateScanAreaSize() -> CGSize {

let margin = getEffectiveMargin()

let width = bounds.width - margin * 2

return CGSize(width: width, height: width / heightScale)

}

private func calculateScanAreaRect() -> CGRect {

let margin = getEffectiveMargin()

let scanSize = calculateScanAreaSize()

let x = margin

var y = bounds.height / 2.0 - scanSize.height / 2.0

if self.configuration.automaticSafeAreaAdaptation {

let safeAreaInsets = self.safeAreaInsets

let availableHeight = bounds.height - safeAreaInsets.top - safeAreaInsets.bottom

y = safeAreaInsets.top + (availableHeight - scanSize.height) / 2.0

}

return CGRect(x: x, y: y, width: scanSize.width, height: scanSize.height)

}

private func getEffectiveMargin() -> CGFloat {

var margin = self.configuration.scanAreaMargin / heightScale

if self.configuration.automaticSafeAreaAdaptation {

let safeAreaInsets = self.safeAreaInsets

margin = max(margin, safeAreaInsets.left + 20, safeAreaInsets.right + 20)

}

return margin

}

private func drawMask(context: CGContext, scanRect: CGRect) {

context.setFillColor(red: 0, green: 0, blue: 0, alpha: self.configuration.maskAlpha)

context.fill(CGRect(x: 0, y: 0, width: bounds.width, height: scanRect.minY))

context.fill(CGRect(x: 0, y: scanRect.minY, width: scanRect.minX, height: scanRect.height))

// 右侧宽度使用 bounds.width - scanRect.maxX，语义正确，不依赖左右对称假设

context.fill(CGRect(x: scanRect.maxX, y: scanRect.minY, width: bounds.width - scanRect.maxX, height: scanRect.height))

context.fill(CGRect(x: 0, y: scanRect.maxY, width: bounds.width, height: bounds.height - scanRect.maxY))

}

private func drawBorder(context: CGContext, scanRect: CGRect) {

context.setStrokeColor(self.configuration.borderColor.cgColor)

context.setLineWidth(1.0)

context.addRect(scanRect)

context.strokePath()

}

private func drawCorners(context: CGContext, scanRect: CGRect) {

context.setStrokeColor(self.configuration.cornerColor.cgColor)

context.setLineWidth(self.configuration.cornerLineWidth)

let cornerSize = self.configuration.cornerSize

let lineWidth = self.configuration.cornerLineWidth

let offset = lineWidth / 3.0

let points: [(CGPoint, [(CGFloat, CGFloat)])] = [

(CGPoint(x: scanRect.minX - offset, y: scanRect.minY - offset),

[(0, -lineWidth/2), (cornerSize.width, 0), (0, cornerSize.height)]),

(CGPoint(x: scanRect.maxX + offset, y: scanRect.minY - offset),

[(0, -lineWidth/2), (-cornerSize.width, 0), (0, cornerSize.height)]),

(CGPoint(x: scanRect.minX - offset, y: scanRect.maxY + offset),

[(0, lineWidth/2), (cornerSize.width, 0), (0, -cornerSize.height)]),

(CGPoint(x: scanRect.maxX + offset, y: scanRect.maxY + offset),

[(0, lineWidth/2), (-cornerSize.width, 0), (0, -cornerSize.height)])

]

for (startPoint, offsets) in points {

context.move(to: CGPoint(x: startPoint.x + offsets[0].0, y: startPoint.y + offsets[0].1))

context.addLine(to: CGPoint(x: startPoint.x + offsets[1].0, y: startPoint.y + offsets[1].1))

context.move(to: startPoint)

context.addLine(to: CGPoint(x: startPoint.x + offsets[2].0, y: startPoint.y + offsets[2].1))

}

context.strokePath()

}

}

// MARK: - Convenience Initializers

extension STScanView {

public convenience init(frame: CGRect, theme: STScanViewTheme) {

self.init(frame: frame)

self.theme = theme

}

public convenience init(frame: CGRect, configuration: STScanViewConfiguration) {

self.init(frame: frame)

self.configuration = configuration

}

}

// MARK: - Additional Public APIs

extension STScanView {

public func updateTipText(_ text: String) {

self.configuration.tipText = text

self.tipLabel?.text = text

setupAccessibility()

}

public func setSafeAreaAdaptation(_ adaptation: STSafeAreaAdaptation) {

self.configuration.automaticSafeAreaAdaptation = adaptation.isEnabled

setNeedsDisplay()

setNeedsLayout()

}

public func getScanAreaRect() -> CGRect {

return calculateScanAreaRect()

}

public func resetToDefault() {

self.theme = .dark

self.scanType = .qrCode

}

}