//
//  CustomMainTabBar.swift
//  suixinkan
//
//  Created by Codex on 2026/6/23.
//

import SwiftUI

/// 自定义主 TabBar，展示四个一级入口和中间扫码核销按钮。
struct CustomMainTabBar: View {
    @Binding var selectedTab: AppTab

    let orderBadgeText: String?
    let onScanTap: () -> Void

    private let items = CustomMainTabItem.defaultItems

    var body: some View {
        HStack(alignment: .center, spacing: 0) {
            CustomMainTabBarItem(
                item: items[0],
                selectedTab: $selectedTab,
                badgeText: nil
            )
            CustomMainTabBarItem(
                item: items[1],
                selectedTab: $selectedTab,
                badgeText: orderBadgeText
            )
            CustomMainTabBarCenterAction(onScanTap: onScanTap)
                .frame(width: 74)
            CustomMainTabBarItem(
                item: items[2],
                selectedTab: $selectedTab,
                badgeText: nil
            )
            CustomMainTabBarItem(
                item: items[3],
                selectedTab: $selectedTab,
                badgeText: nil
            )
        }
        .frame(maxWidth: .infinity)
        .frame(height: 72)
        .padding(.horizontal, 22)
        .background(.white)
        .overlay(alignment: .top) {
            Rectangle()
                .fill(Color.black.opacity(0.04))
                .frame(height: 0.5)
        }
    }
}

/// 自定义 TabBar 单个入口的静态配置。
private struct CustomMainTabItem {
    let tab: AppTab
    let title: String
    let selectedImage: String
    let unselectedImage: String

    static let defaultItems: [CustomMainTabItem] = [
        .init(tab: .home, title: "首页", selectedImage: "TabHomeSelected", unselectedImage: "TabHomeUnselected"),
        .init(tab: .orders, title: "订单", selectedImage: "TabOrderSelected", unselectedImage: "TabOrderUnselected"),
        .init(tab: .statistics, title: "数据", selectedImage: "TabDataSelected", unselectedImage: "TabDataUnselected"),
        .init(tab: .profile, title: "我的", selectedImage: "TabProfileSelected", unselectedImage: "TabProfileUnselected")
    ]
}

/// 自定义 TabBar 的普通入口按钮。
private struct CustomMainTabBarItem: View {
    let item: CustomMainTabItem
    @Binding var selectedTab: AppTab
    let badgeText: String?

    private var isSelected: Bool {
        selectedTab == item.tab
    }

    var body: some View {
        Button {
            selectedTab = item.tab
        } label: {
            VStack(spacing: 3) {
                ZStack(alignment: .topTrailing) {
                    Image(isSelected ? item.selectedImage : item.unselectedImage)
                        .renderingMode(.original)
                        .resizable()
                        .scaledToFit()
                        .frame(width: 24, height: 24)

                    if let badgeText {
                        CustomMainTabBadge(text: badgeText)
                    }
                }
                Text(item.title)
                    .font(.system(size: 12, weight: isSelected ? .medium : .regular))
                    .foregroundStyle(isSelected ? AppDesign.primary : Color(hex: 0x7D8DA3))
                    .lineLimit(1)
                    .minimumScaleFactor(0.8)
            }
            .frame(maxWidth: .infinity)
            .frame(height: 58)
            .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
        .accessibilityLabel(item.title)
        .accessibilityIdentifier("main.tab.\(item.tab.rawValue)")
    }
}

/// 自定义 TabBar 中间的扫码核销按钮。
private struct CustomMainTabBarCenterAction: View {
    let onScanTap: () -> Void

    var body: some View {
        Button(action: onScanTap) {
            ZStack {
                Circle()
                    .fill(AppDesign.primary)
                    .frame(width: 58, height: 58)
                Image(systemName: "qrcode.viewfinder")
                    .font(.system(size: 30, weight: .bold))
                    .foregroundStyle(.white)
            }
            .frame(width: 70, height: 64)
            .contentShape(Circle())
        }
        .buttonStyle(.plain)
        .accessibilityLabel("扫码核销")
        .accessibilityIdentifier("main.scan")
    }
}

/// 自定义 TabBar 的订单数量角标。
private struct CustomMainTabBadge: View {
    let text: String

    var body: some View {
        Text(text)
            .font(.system(size: 9, weight: .bold))
            .foregroundStyle(.white)
            .frame(minWidth: 15, minHeight: 15)
            .padding(.horizontal, 2)
            .background(Color(hex: 0xEF4444), in: Capsule())
            .offset(x: 9, y: -7)
    }
}

#Preview {
    CustomMainTabBar(
        selectedTab: .constant(.orders),
        orderBadgeText: "8",
        onScanTap: {}
    )
}