//
//  SOSReceiveAlertView.swift
//  QuickLocation
//

import UIKit

/// Full-screen SOS alert shown above the currently visible application page.
final class SOSReceiveAlertView: UIView {

    var onAcknowledged: (() -> Void)?

    private let gradientLayer = CAGradientLayer()
    private let primaryAvatarView = UIImageView()
    private let primaryAvatarRingView = UIView()
    private let alarmIconView = UIImageView(image: UIImage(named: "SOS/sos_receive_alarm"))
    private let nameLabel = UILabel()
    private let messageLabel = UILabel()
    private let titleImageView = UIImageView(image: UIImage(named: "SOS/sos_receive_title"))
    private let acknowledgeButton = UIButton(type: .custom)
    private let extraBadge = UILabel()
    private let rippleLayers = [CAShapeLayer(), CAShapeLayer()]

    private var primaryMemberID = ""
    private var secondaryMembers: [GroupMemberModel] = []
    private var secondaryAvatarViews: [String: UIImageView] = [:]
    private var hasStartedAnimations = false

    private static let rippleKey = "sos.receive.ripple"
    private static let backgroundFlashKey = "sos.receive.background.flash"
    private static let alarmFlashKey = "sos.receive.alarm.flash"
    private static let secondaryOffsets: [CGPoint] = [
        CGPoint(x: -112, y: -60),
        CGPoint(x: 118, y: 8),
        CGPoint(x: -124, y: 26),
        CGPoint(x: 108, y: 96),
        CGPoint(x: -105, y: 100),
        CGPoint(x: -60, y: -116),
        CGPoint(x: 55, y: -120),
        CGPoint(x: 0, y: 136)
    ]

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupView()
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func layoutSubviews() {
        super.layoutSubviews()

        gradientLayer.frame = bounds

        let side = min(bounds.width, 414)
        let avatarSide = min(side * 0.38, 150)
        let avatarCenter = CGPoint(
            x: bounds.midX,
            y: min(bounds.height * 0.35, 292)
        )
        primaryAvatarRingView.bounds = CGRect(x: 0, y: 0, width: avatarSide, height: avatarSide)
        primaryAvatarRingView.center = avatarCenter
        primaryAvatarRingView.layer.cornerRadius = avatarSide / 2
        primaryAvatarView.frame = primaryAvatarRingView.bounds.insetBy(dx: 7, dy: 7)
        primaryAvatarView.layer.cornerRadius = primaryAvatarView.bounds.height / 2

        let alarmSide = min(max(avatarSide * 0.46, 58), 72)
        alarmIconView.bounds = CGRect(x: 0, y: 0, width: alarmSide, height: alarmSide)
        alarmIconView.center = CGPoint(
            x: avatarCenter.x + avatarSide * 0.43,
            y: avatarCenter.y - avatarSide * 0.47
        )

        let rippleCenter = avatarCenter
        let rippleRadius = avatarSide / 2
        let rippleDiameter = rippleRadius * 2
        rippleLayers.forEach { layer in
            layer.bounds = CGRect(x: 0, y: 0, width: rippleDiameter, height: rippleDiameter)
            layer.position = rippleCenter
            layer.path = UIBezierPath(
                arcCenter: CGPoint(x: rippleRadius, y: rippleRadius),
                radius: rippleRadius,
                startAngle: 0,
                endAngle: .pi * 2,
                clockwise: true
            ).cgPath
        }

        let buttonWidth = min(bounds.width - 60, 345)
        let buttonHeight: CGFloat = 56
        let bottomInset = max(safeAreaInsets.bottom + 64, 64)
        acknowledgeButton.frame = CGRect(
            x: bounds.midX - buttonWidth / 2,
            y: bounds.height - bottomInset - buttonHeight,
            width: buttonWidth,
            height: buttonHeight
        )

        let nameTop = min(
            avatarCenter.y + avatarSide / 2 + 104,
            max(avatarCenter.y + avatarSide / 2 + 48, acknowledgeButton.frame.minY - 190)
        )
        nameLabel.frame = CGRect(x: 20, y: nameTop, width: bounds.width - 40, height: 40)
        messageLabel.frame = CGRect(x: 20, y: nameLabel.frame.maxY + 10, width: bounds.width - 40, height: 44)

        let titleWidth = min(bounds.width * 0.34, 128)
        let titleHeight = titleImageView.image.map { titleWidth * $0.size.height / $0.size.width } ?? 40
        titleImageView.frame = CGRect(
            x: bounds.midX - titleWidth / 2,
            y: messageLabel.frame.maxY + 16,
            width: titleWidth,
            height: titleHeight
        )

        let hasOverflow = secondaryMembers.count > Self.secondaryOffsets.count
        let visibleCount = hasOverflow ? Self.secondaryOffsets.count - 1 : min(secondaryMembers.count, Self.secondaryOffsets.count)
        let extraCount = hasOverflow ? secondaryMembers.count - visibleCount : 0
        for (index, member) in secondaryMembers.enumerated() {
            guard let imageView = secondaryAvatarViews[member.user_id] else { continue }
            imageView.isHidden = index >= visibleCount
            guard index < Self.secondaryOffsets.count else { continue }
            let offset = Self.secondaryOffsets[index]
            imageView.bounds = CGRect(x: 0, y: 0, width: 44, height: 44)
            imageView.center = CGPoint(x: avatarCenter.x + offset.x, y: avatarCenter.y + offset.y)
            imageView.layer.cornerRadius = 22
        }

        extraBadge.isHidden = extraCount == 0
        if extraCount > 0 {
            let offset = Self.secondaryOffsets[Self.secondaryOffsets.count - 1]
            extraBadge.bounds = CGRect(x: 0, y: 0, width: 44, height: 44)
            extraBadge.center = CGPoint(x: avatarCenter.x + offset.x, y: avatarCenter.y + offset.y)
            extraBadge.text = "+\(extraCount)"
        }

        bringSubviewToFront(primaryAvatarRingView)
        bringSubviewToFront(alarmIconView)
        bringSubviewToFront(nameLabel)
        bringSubviewToFront(messageLabel)
        bringSubviewToFront(titleImageView)
        bringSubviewToFront(acknowledgeButton)
    }

    override func didMoveToWindow() {
        super.didMoveToWindow()
        if window == nil {
            stopAnimations()
        } else if !isHidden {
            startAnimationsIfNeeded()
        }
    }

    func show(primary member: GroupMemberModel) {
        primaryMemberID = member.user_id
        secondaryMembers.removeAll()
        secondaryAvatarViews.values.forEach { $0.removeFromSuperview() }
        secondaryAvatarViews.removeAll()
        extraBadge.isHidden = true

        let image = member.userIcon.size == .zero
            ? UIImage(named: "Common/default_avatar")
            : member.userIcon
        primaryAvatarView.image = image
        nameLabel.text = member.nick_name.isEmpty ? "圈子成员" : member.nick_name
        isHidden = false
        setNeedsLayout()
        layoutIfNeeded()
        startAnimationsIfNeeded()
    }

    func appendSecondary(_ member: GroupMemberModel) {
        guard !member.user_id.isEmpty,
              member.user_id != primaryMemberID,
              !secondaryMembers.contains(where: { $0.user_id == member.user_id }) else { return }

        secondaryMembers.append(member)
        let imageView = makeSecondaryAvatar(member)
        secondaryAvatarViews[member.user_id] = imageView
        addSubview(imageView)
        setNeedsLayout()
    }

    func dismiss() {
        stopAnimations()
        secondaryAvatarViews.values.forEach { $0.removeFromSuperview() }
        secondaryAvatarViews.removeAll()
        secondaryMembers.removeAll()
        primaryMemberID = ""
        removeFromSuperview()
    }

    private func setupView() {
        backgroundColor = .white
        isAccessibilityElement = false
        accessibilityViewIsModal = true

        gradientLayer.type = .radial
        gradientLayer.colors = [
            UIColor.white.cgColor,
            UIColor(hexStr: "#FFF4F4").cgColor,
            UIColor(hexStr: "#FFB7BA").cgColor
        ]
        gradientLayer.locations = [0, 0.58, 1]
        gradientLayer.startPoint = CGPoint(x: 0.5, y: 0.5)
        gradientLayer.endPoint = CGPoint(x: 1, y: 1)
        layer.insertSublayer(gradientLayer, at: 0)

        rippleLayers.forEach {
            $0.fillColor = UIColor.clear.cgColor
            $0.strokeColor = UIColor(hexStr: "#FF7378").cgColor
            $0.lineWidth = 1.5
            $0.opacity = 0
            layer.addSublayer($0)
        }

        primaryAvatarRingView.backgroundColor = .white
        primaryAvatarRingView.layer.cornerRadius = 75
        primaryAvatarRingView.layer.shadowColor = UIColor.black.withAlphaComponent(0.14).cgColor
        primaryAvatarRingView.layer.shadowOpacity = 1
        primaryAvatarRingView.layer.shadowRadius = 8
        primaryAvatarRingView.layer.shadowOffset = CGSize(width: 0, height: 3)
        addSubview(primaryAvatarRingView)

        primaryAvatarView.contentMode = .scaleAspectFill
        primaryAvatarView.clipsToBounds = true
        primaryAvatarView.layer.masksToBounds = true
        primaryAvatarRingView.addSubview(primaryAvatarView)

        alarmIconView.contentMode = .scaleAspectFit
        addSubview(alarmIconView)

        nameLabel.textColor = UIColor(hexStr: "#273246")
        nameLabel.font = .systemFont(ofSize: 28, weight: .regular)
        nameLabel.textAlignment = .center
        addSubview(nameLabel)

        messageLabel.text = "正在向您紧急求助"
        messageLabel.textColor = UIColor(hexStr: "#273246")
        messageLabel.font = .systemFont(ofSize: 32, weight: .regular)
        messageLabel.textAlignment = .center
        messageLabel.adjustsFontSizeToFitWidth = true
        messageLabel.minimumScaleFactor = 0.72
        addSubview(messageLabel)

        titleImageView.contentMode = .scaleAspectFit
        addSubview(titleImageView)

        extraBadge.backgroundColor = UIColor(hexStr: "#FF5A5F")
        extraBadge.textColor = .white
        extraBadge.font = .systemFont(ofSize: 13, weight: .semibold)
        extraBadge.textAlignment = .center
        extraBadge.layer.cornerRadius = 22
        extraBadge.layer.borderWidth = 3
        extraBadge.layer.borderColor = UIColor.white.cgColor
        extraBadge.clipsToBounds = true
        extraBadge.isHidden = true
        addSubview(extraBadge)

        acknowledgeButton.backgroundColor = UIColor(hexStr: "#FF5050")
        acknowledgeButton.cornerRadius = 20
        acknowledgeButton.setTitle("我知道了", for: .normal)
        acknowledgeButton.setTitleColor(.white, for: .normal)
        acknowledgeButton.titleLabel?.font = FontManager.boboBold(18)
        acknowledgeButton.addTarget(self, action: #selector(handleAcknowledged), for: .touchUpInside)
        acknowledgeButton.accessibilityLabel = "我知道了"
        addSubview(acknowledgeButton)
    }

    private func makeSecondaryAvatar(_ member: GroupMemberModel) -> UIImageView {
        let imageView = UIImageView()
        imageView.image = member.userIcon.size == .zero
            ? UIImage(named: "Common/default_avatar")
            : member.userIcon
        imageView.contentMode = .scaleAspectFill
        imageView.clipsToBounds = true
        imageView.layer.borderWidth = 4
        imageView.layer.borderColor = UIColor.white.cgColor
        imageView.layer.shadowColor = UIColor.black.withAlphaComponent(0.18).cgColor
        imageView.layer.shadowOpacity = 1
        imageView.layer.shadowRadius = 4
        imageView.layer.shadowOffset = CGSize(width: 0, height: 2)
        return imageView
    }

    private func startAnimationsIfNeeded() {
        guard !hasStartedAnimations,
              window != nil,
              !UIAccessibility.isReduceMotionEnabled else { return }
        hasStartedAnimations = true

        let flash = CAKeyframeAnimation(keyPath: "opacity")
        flash.values = [0.42, 1.0, 0.42]
        flash.keyTimes = [0, 0.5, 1]
        flash.duration = 1.15
        flash.repeatCount = .infinity
        flash.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)
        flash.isRemovedOnCompletion = false
        gradientLayer.add(flash, forKey: Self.backgroundFlashKey)

        let alarmOpacity = CAKeyframeAnimation(keyPath: "opacity")
        alarmOpacity.values = [1.0, 0.25, 1.0]
        alarmOpacity.keyTimes = [0, 0.5, 1]
        alarmOpacity.duration = 0.7
        alarmOpacity.repeatCount = .infinity
        alarmOpacity.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)

        let alarmScale = CAKeyframeAnimation(keyPath: "transform.scale")
        alarmScale.values = [1.0, 1.08, 1.0]
        alarmScale.keyTimes = [0, 0.5, 1]
        alarmScale.duration = 0.7
        alarmScale.repeatCount = .infinity
        alarmScale.timingFunction = CAMediaTimingFunction(name: .easeInEaseOut)

        let alarmGroup = CAAnimationGroup()
        alarmGroup.animations = [alarmOpacity, alarmScale]
        alarmGroup.duration = 0.7
        alarmGroup.repeatCount = .infinity
        alarmIconView.layer.add(alarmGroup, forKey: Self.alarmFlashKey)

        let travelDuration = 1.35
        let staggerDuration = travelDuration * 0.85
        let cycleDuration = staggerDuration * Double(rippleLayers.count)
        let travelProgress = NSNumber(value: travelDuration / cycleDuration)
        let baseTime = CACurrentMediaTime()
        for (index, rippleLayer) in rippleLayers.enumerated() {
            let scale = CAKeyframeAnimation(keyPath: "transform.scale")
            scale.values = [1.0, 2.1, 2.1]
            scale.keyTimes = [0, travelProgress, 1]

            let opacity = CAKeyframeAnimation(keyPath: "opacity")
            opacity.values = [0.58, 0, 0]
            opacity.keyTimes = [0, travelProgress, 1]

            let group = CAAnimationGroup()
            group.animations = [scale, opacity]
            group.duration = cycleDuration
            group.beginTime = baseTime + Double(index) * staggerDuration
            group.repeatCount = .infinity
            group.isRemovedOnCompletion = false
            rippleLayer.add(group, forKey: Self.rippleKey)
        }
    }

    private func stopAnimations() {
        hasStartedAnimations = false
        gradientLayer.removeAnimation(forKey: Self.backgroundFlashKey)
        gradientLayer.opacity = 1
        alarmIconView.layer.removeAnimation(forKey: Self.alarmFlashKey)
        rippleLayers.forEach { $0.removeAnimation(forKey: Self.rippleKey) }
    }

    @objc private func handleAcknowledged() {
        onAcknowledged?()
    }
}