import SwiftUI

enum TjTab: String, Hashable, CaseIterable {
    case home, trend, me
    var label: String {
        switch self {
        case .home:  return "首页"
        case .trend: return "趋势"
        case .me:    return "我的"
        }
    }
    var icon: String {
        switch self {
        case .home:  return "house"
        case .trend: return "chart.line.uptrend.xyaxis"
        case .me:    return "person.circle"
        }
    }
}

enum ActiveFlow: Identifiable {
    case quick, archive
    var id: String { String(describing: self) }
}

struct RootView: View {
    @State private var tab: TjTab = .home
    @State private var showRecordSheet = false
    @State private var activeFlow: ActiveFlow?

    var body: some View {
        VStack(spacing: 0) {
            Group {
                switch tab {
                case .home:  HomeView(onTapArchive: {})
                case .trend: TrendsView()
                case .me:    MeView()
                }
            }
            .frame(maxWidth: .infinity, maxHeight: .infinity)

            TabBar(active: tab,
                   onTap: { tab = $0 },
                   onTapRecord: { showRecordSheet = true })
        }
        .background(Tj.Palette.sand.ignoresSafeArea())
        .sheet(isPresented: $showRecordSheet) {
            RecordSheet { kind in
                showRecordSheet = false
                DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
                    switch kind {
                    case .quick:   activeFlow = .quick
                    case .archive: activeFlow = .archive
                    case .diary:   break
                    }
                }
            }
        }
#if os(iOS)
        .fullScreenCover(item: $activeFlow) { flow in
            switch flow {
            case .quick:
                QuickCaptureFlow(onClose: { activeFlow = nil })
            case .archive:
                ArchiveFlow(onClose: { activeFlow = nil })
            }
        }
#else
        .sheet(item: $activeFlow) { flow in
            switch flow {
            case .quick:
                QuickCaptureFlow(onClose: { activeFlow = nil })
            case .archive:
                ArchiveFlow(onClose: { activeFlow = nil })
            }
        }
#endif
    }
}

private struct TabBar: View {
    let active: TjTab
    let onTap: (TjTab) -> Void
    let onTapRecord: () -> Void

    var body: some View {
        HStack(spacing: 0) {
            tabItem(.home)
            Color.clear.frame(width: 60, height: 1)
            tabItem(.trend)
            tabItem(.me)
        }
        .padding(.horizontal, 12)
        .padding(.top, 10)
        .padding(.bottom, 4)
        .background(
            Tj.Palette.paper
                .overlay(alignment: .top) {
                    Rectangle()
                        .fill(Tj.Palette.lineSoft)
                        .frame(height: 1)
                }
        )
        .overlay(alignment: .top) {
            recordButton.offset(y: -22)
        }
    }

    private func tabItem(_ t: TjTab) -> some View {
        Button { onTap(t) } label: {
            VStack(spacing: 4) {
                Image(systemName: t.icon)
                    .font(.system(size: 20, weight: .regular))
                    .frame(width: 26, height: 26)
                Text(t.label)
                    .font(.system(size: 11))
            }
            .foregroundStyle(active == t ? Tj.Palette.ink : Tj.Palette.text3)
            .frame(maxWidth: .infinity)
            .padding(.vertical, 4)
            .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
    }

    private var recordButton: some View {
        Button(action: onTapRecord) {
            VStack(spacing: 4) {
                ZStack {
                    Circle()
                        .fill(Tj.Palette.ink)
                        .shadow(color: Color(red: 0.157, green: 0.216, blue: 0.176).opacity(0.25),
                                radius: 12, x: 0, y: 4)
                    Image(systemName: "plus")
                        .font(.system(size: 20, weight: .semibold))
                        .foregroundStyle(Tj.Palette.paper)
                }
                .frame(width: 52, height: 52)

                Text("记录")
                    .font(.system(size: 11))
                    .foregroundStyle(Tj.Palette.ink)
            }
        }
        .buttonStyle(.plain)
    }
}

#Preview {
    RootView()
}