import SnapKit
import UIKit

/// 注销页面共用的轻量视觉组件，仅负责颜色、字号和布局，不包含业务状态。
@MainActor
enum StoreAccountDeregistrationStyle {
    /// 注销流程独立视觉令牌，与设计稿保持一致且不修改全局主题。
    static let primary = UIColor(hex: 0x1677FF)
    static let pageBackground = UIColor(hex: 0xF5F7FA)
    static let textPrimary = UIColor(hex: 0x172033)
    static let textSecondary = UIColor(hex: 0x7A8496)
    static let border = UIColor(hex: 0xE7ECF3)
    static let infoBackground = UIColor(hex: 0xEEF5FF)
    static let danger = UIColor(hex: 0xE5484D)

    /// 创建支持多行的系统字体标签。
    static func label(_ text: String = "", size: CGFloat = 15, weight: UIFont.Weight = .regular,
                      color: UIColor? = nil) -> UILabel {
        let label = UILabel()
        label.text = text
        label.font = .systemFont(ofSize: size, weight: weight)
        label.textColor = color ?? textPrimary
        label.numberOfLines = 0
        return label
    }

    /// 创建统一间距的纵向内容组。
    static func stack(_ views: [UIView], spacing: CGFloat = 12) -> UIStackView {
        let stack = UIStackView(arrangedSubviews: views)
        stack.axis = .vertical
        stack.spacing = spacing
        return stack
    }

    /// 白色圆角卡片，内容由页面提供。
    static func card(_ content: UIView, background: UIColor = .white) -> UIView {
        let card = UIView()
        card.backgroundColor = background
        card.layer.cornerRadius = 16
        card.layer.borderWidth = background == .white ? 0.5 : 0
        card.layer.borderColor = border.cgColor
        card.addSubview(content)
        content.snp.makeConstraints { $0.edges.equalToSuperview().inset(16) }
        return card
    }

    /// 统一主次按钮；禁用态及加载期间不依赖系统默认的灰底样式。
    static func button(_ title: String, id: String, primary: Bool = true) -> UIButton {
        let button = UIButton(type: .system)
        button.accessibilityIdentifier = id
        configure(button, title: title, primary: primary)
        button.snp.makeConstraints { $0.height.greaterThanOrEqualTo(50) }
        return button
    }

    /// 更新按钮角色和文案，保留清晰的主次关系。
    static func configure(_ button: UIButton, title: String, primary: Bool = true) {
        var config = primary ? UIButton.Configuration.filled() : .plain()
        config.title = title
        config.baseBackgroundColor = StoreAccountDeregistrationStyle.primary
        config.baseForegroundColor = primary ? .white : StoreAccountDeregistrationStyle.primary
        config.background.cornerRadius = 12
        if !primary {
            config.background.strokeColor = StoreAccountDeregistrationStyle.primary
            config.background.strokeWidth = 1
        }
        config.contentInsets = .init(top: 14, leading: 16, bottom: 14, trailing: 16)
        config.titleTextAttributesTransformer = UIConfigurationTextAttributesTransformer { attributes in
            var attributes = attributes
            attributes.font = UIFont.systemFont(ofSize: 16, weight: .semibold)
            return attributes
        }
        button.configuration = config
        button.configurationUpdateHandler = { button in
            let enabled = button.isEnabled
            var updated = button.configuration
            updated?.background.backgroundColorTransformer = UIConfigurationColorTransformer { _ in
                primary ? (enabled ? StoreAccountDeregistrationStyle.primary : StoreAccountDeregistrationStyle.primary.withAlphaComponent(0.12)) : .clear
            }
            updated?.titleTextAttributesTransformer = UIConfigurationTextAttributesTransformer { attributes in
                var attributes = attributes
                attributes.font = UIFont.systemFont(ofSize: 16, weight: .semibold)
                attributes.foregroundColor = enabled ? (primary ? .white : StoreAccountDeregistrationStyle.primary) : StoreAccountDeregistrationStyle.textSecondary
                return attributes
            }
            button.configuration = updated
        }
    }

    /// 以统一的SF Symbol展示提示图标，不加载额外图片资源。
    static func icon(_ name: String, size: CGFloat = 22) -> UIImageView {
        let image = UIImageView(image: UIImage(systemName: name,
                                              withConfiguration: UIImage.SymbolConfiguration(pointSize: size, weight: .medium)))
        image.tintColor = primary
        image.contentMode = .scaleAspectFit
        image.setContentHuggingPriority(.required, for: .horizontal)
        return image
    }

    /// 带浅色圆形底的状态图标，用于冷静期和身份信息强调。
    static func iconBadge(_ name: String, iconSize: CGFloat = 30, diameter: CGFloat = 88) -> UIView {
        let container = UIView()
        container.backgroundColor = infoBackground
        container.layer.cornerRadius = diameter / 2
        let image = icon(name, size: iconSize)
        container.addSubview(image)
        container.snp.makeConstraints { $0.width.height.equalTo(diameter) }
        image.snp.makeConstraints { $0.center.equalToSuperview(); $0.width.height.equalTo(iconSize + 8) }
        return container
    }

    /// 为危险确认操作应用红色实心按钮样式。
    static func configureDestructive(_ button: UIButton, title: String) {
        var config = UIButton.Configuration.filled()
        config.title = title
        config.baseBackgroundColor = danger
        config.baseForegroundColor = .white
        config.background.cornerRadius = 12
        config.contentInsets = .init(top: 13, leading: 16, bottom: 13, trailing: 16)
        config.titleTextAttributesTransformer = UIConfigurationTextAttributesTransformer { attributes in
            var attributes = attributes
            attributes.font = .systemFont(ofSize: 16, weight: .semibold)
            return attributes
        }
        button.configuration = config
    }
}

/// 注销资产及最终提交共用的高保真底部确认弹层。
@MainActor
final class StoreAccountDeregistrationConfirmationSheetViewController: UIViewController {
    /// 弹层展示的一行摘要数据。
    struct Summary {
        let icon: String
        let title: String
        let value: String
    }

    private typealias Style = StoreAccountDeregistrationStyle
    private let sheetTitle: String
    private let summaries: [Summary]
    private let notices: [(icon: String, text: String, danger: Bool)]
    private let cancelTitle: String
    private let confirmTitle: String
    private let onConfirm: () -> Void
    private let cancelButton = UIButton(type: .system)
    private let confirmButton = UIButton(type: .system)
    private let contentStack = UIStackView()

    /// 创建只在用户明确确认后回调的弹层；下拉或取消不会触发业务请求。
    init(title: String, summaries: [Summary], notices: [(String, String, Bool)],
         cancelTitle: String, confirmTitle: String, onConfirm: @escaping () -> Void) {
        sheetTitle = title
        self.summaries = summaries
        self.notices = notices
        self.cancelTitle = cancelTitle
        self.confirmTitle = confirmTitle
        self.onConfirm = onConfirm
        super.init(nibName: nil, bundle: nil)
        modalPresentationStyle = .pageSheet
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        let titleLabel = Style.label(sheetTitle, size: 20, weight: .semibold)
        titleLabel.textAlignment = .center
        let summaryStack = Style.stack([], spacing: 0)
        for (index, summary) in summaries.enumerated() {
            let icon = Style.icon(summary.icon, size: 18)
            icon.snp.makeConstraints { $0.width.equalTo(24) }
            let title = Style.label(summary.title, size: 14, color: Style.textSecondary)
            let value = Style.label(summary.value, size: 15, weight: .semibold)
            value.textAlignment = .right
            let row = UIStackView(arrangedSubviews: [icon, title, UIView(), value])
            row.axis = .horizontal
            row.alignment = .center
            row.spacing = 8
            row.snp.makeConstraints { $0.height.greaterThanOrEqualTo(48) }
            summaryStack.addArrangedSubview(row)
            if index < summaries.count - 1 {
                let divider = UIView()
                divider.backgroundColor = Style.border
                divider.snp.makeConstraints { $0.height.equalTo(0.5) }
                summaryStack.addArrangedSubview(divider)
            }
        }
        let summaryCard = Style.card(summaryStack)
        summaryCard.layer.cornerRadius = 12

        let noticeStack = Style.stack([], spacing: 12)
        for notice in notices {
            let icon = Style.icon(notice.icon, size: 16)
            icon.tintColor = notice.danger ? Style.danger : Style.primary
            icon.snp.makeConstraints { $0.width.equalTo(22) }
            let text = Style.label(notice.text, size: 13,
                                   color: notice.danger ? Style.danger : Style.textSecondary)
            let row = UIStackView(arrangedSubviews: [icon, text])
            row.axis = .horizontal
            row.alignment = .top
            row.spacing = 8
            noticeStack.addArrangedSubview(row)
        }

        Style.configure(cancelButton, title: cancelTitle, primary: false)
        Style.configureDestructive(confirmButton, title: confirmTitle)
        cancelButton.accessibilityIdentifier = "deregister.sheet.cancel"
        confirmButton.accessibilityIdentifier = "deregister.sheet.confirm"
        cancelButton.addTarget(self, action: #selector(cancelTapped), for: .touchUpInside)
        confirmButton.addTarget(self, action: #selector(confirmTapped), for: .touchUpInside)
        let actions = UIStackView(arrangedSubviews: [cancelButton, confirmButton])
        actions.axis = .horizontal
        actions.distribution = .fillEqually
        actions.spacing = 12
        actions.snp.makeConstraints { $0.height.equalTo(50) }

        contentStack.axis = .vertical
        contentStack.spacing = 16
        contentStack.addArrangedSubview(titleLabel)
        contentStack.addArrangedSubview(summaryCard)
        if !notices.isEmpty { contentStack.addArrangedSubview(noticeStack) }
        contentStack.addArrangedSubview(actions)
        view.addSubview(contentStack)
        contentStack.snp.makeConstraints {
            $0.top.equalTo(view.safeAreaLayoutGuide).offset(28)
            $0.leading.trailing.equalToSuperview().inset(16)
            $0.bottom.lessThanOrEqualTo(view.safeAreaLayoutGuide).inset(12)
        }
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        guard let sheet = sheetPresentationController else { return }
        view.layoutIfNeeded()
        let sheetWidth = presentingViewController?.view.bounds.width ?? view.bounds.width
        let contentWidth = max(0, sheetWidth - 32)
        let contentHeight = contentStack.systemLayoutSizeFitting(
            CGSize(width: contentWidth, height: UIView.layoutFittingCompressedSize.height),
            withHorizontalFittingPriority: .required,
            verticalFittingPriority: .fittingSizeLevel
        ).height
        // 自定义 detent 会由系统计入底部安全区，这里只计算内容和视觉间距，避免重复留白。
        let preferredHeight = ceil(28 + contentHeight + 12)
        let identifier = UISheetPresentationController.Detent.Identifier("accountDeregistrationConfirmation")
        sheet.detents = [.custom(identifier: identifier) { context in
            min(preferredHeight, context.maximumDetentValue)
        }]
        sheet.selectedDetentIdentifier = identifier
        sheet.prefersGrabberVisible = true
        sheet.prefersScrollingExpandsWhenScrolledToEdge = false
        sheet.preferredCornerRadius = 22
        preferredContentSize.height = preferredHeight
    }

    @objc private func cancelTapped() { dismiss(animated: true) }

    @objc private func confirmTapped() {
        confirmButton.isEnabled = false
        dismiss(animated: true) { [onConfirm] in onConfirm() }
    }
}