suixinkan_ios_new/suixinkan/Core/Design/AppContentUnavailableView.swift

//
//  AppContentUnavailableView.swift
//  suixinkan
//
//  Created by Codex on 2026/6/26.
//

import SwiftUI

/// iOS 16 兼容的空状态视图；iOS 17+ 自动使用系统 ContentUnavailableView。
struct AppContentUnavailableView<LabelContent: View, DescriptionContent: View, ActionsContent: View>: View {
    private let label: LabelContent
    private let description: DescriptionContent
    private let actions: ActionsContent

    init(
        @ViewBuilder label: () -> LabelContent,
        @ViewBuilder description: () -> DescriptionContent,
        @ViewBuilder actions: () -> ActionsContent
    ) {
        self.label = label()
        self.description = description()
        self.actions = actions()
    }

    var body: some View {
        if #available(iOS 17.0, *) {
            ContentUnavailableView {
                label
            } description: {
                description
            } actions: {
                actions
            }
        } else {
            VStack(spacing: AppMetrics.Spacing.small) {
                label
                    .font(.system(size: AppMetrics.FontSize.title3, weight: .semibold))
                    .foregroundStyle(AppDesign.textPrimary)
                description
                    .font(.system(size: AppMetrics.FontSize.subheadline))
                    .foregroundStyle(AppDesign.textSecondary)
                    .multilineTextAlignment(.center)
                actions
                    .padding(.top, AppMetrics.Spacing.xSmall)
            }
            .frame(maxWidth: .infinity)
            .padding(AppMetrics.Spacing.large)
        }
    }
}

extension AppContentUnavailableView where LabelContent == Label<Text, Image>, DescriptionContent == EmptyView, ActionsContent == EmptyView {
    init(_ title: String, systemImage: String) {
        self.init {
            Label(title, systemImage: systemImage)
        } description: {
            EmptyView()
        } actions: {
            EmptyView()
        }
    }
}

extension AppContentUnavailableView where LabelContent == Label<Text, Image>, DescriptionContent == Text, ActionsContent == EmptyView {
    init(_ title: String, systemImage: String, description: Text) {
        self.init {
            Label(title, systemImage: systemImage)
        } description: {
            description
        } actions: {
            EmptyView()
        }
    }
}