import SwiftUI

struct MainTabView: View {
    @EnvironmentObject var appState: AppState
    @StateObject private var realtime = RealtimeService()
    @State private var selectedTab = 0
    @State private var showCompose = false
    @State private var showSettings = false

    var body: some View {
        ZStack(alignment: .bottom) {
            Color.nightBase.ignoresSafeArea()

            // Content
            TabContent(
                selectedTab: selectedTab,
                realtime: realtime
            )
            .environmentObject(appState)

            // Floating Tab Bar
            FloatingTabBar(
                selectedTab: $selectedTab,
                windowState: appState.windowState,
                onCompose: { showCompose = true },
                onSettings: { showSettings = true }
            )
        }
        .ignoresSafeArea(edges: .bottom)
        .sheet(isPresented: $showCompose) {
            ComposeView().environmentObject(appState)
        }
        .sheet(isPresented: $showSettings) {
            SettingsView().environmentObject(appState)
        }
        .onDisappear {
            Task { await realtime.stopListening() }
        }
    }
}

// MARK: - Tab Content

private struct TabContent: View {
    let selectedTab: Int
    @ObservedObject var realtime: RealtimeService
    @EnvironmentObject var appState: AppState

    var body: some View {
        ZStack {
            FeedView(realtime: realtime)
                .environmentObject(appState)
                .opacity(selectedTab == 0 ? 1 : 0)
                .allowsHitTesting(selectedTab == 0)

            DiaryView()
                .environmentObject(appState)
                .opacity(selectedTab == 1 ? 1 : 0)
                .allowsHitTesting(selectedTab == 1)

            ProfileView(
                user: appState.currentUser ?? .preview,
                isCurrentUser: true
            )
            .environmentObject(appState)
            .opacity(selectedTab == 2 ? 1 : 0)
            .allowsHitTesting(selectedTab == 2)
        }
    }
}

// MARK: - Floating Tab Bar

struct FloatingTabBar: View {
    @Binding var selectedTab: Int
    let windowState: AppState.WindowState
    let onCompose: () -> Void
    let onSettings: () -> Void

    var body: some View {
        HStack(spacing: 0) {
            // Feed
            TabIcon(icon: "moon.stars", activeIcon: "moon.stars.fill", isSelected: selectedTab == 0) {
                selectedTab = 0
            }

            Spacer()

            // Diary
            TabIcon(icon: "book.closed", activeIcon: "book.closed.fill", isSelected: selectedTab == 1) {
                selectedTab = 1
            }

            Spacer()

            // Center: Compose
            ComposeTabButton(windowState: windowState, onTap: onCompose)

            Spacer()

            // Profile
            TabIcon(icon: "person", activeIcon: "person.fill", isSelected: selectedTab == 2) {
                selectedTab = 2
            }

            Spacer()

            // Settings
            TabIcon(icon: "gearshape", activeIcon: "gearshape.fill", isSelected: false) {
                onSettings()
            }
        }
        .padding(.horizontal, 20)
        .padding(.vertical, 10)
        .padding(.bottom, 18)
        .background(
            Rectangle()
                .fill(.ultraThinMaterial.opacity(0.8))
                .background(Color.nightBase.opacity(0.85))
                .ignoresSafeArea()
        )
        .overlay(
            Rectangle().fill(Color.nightBorder).frame(height: 1),
            alignment: .top
        )
    }
}

struct TabIcon: View {
    let icon: String
    let activeIcon: String
    let isSelected: Bool
    let action: () -> Void

    var body: some View {
        Button(action: action) {
            Image(systemName: isSelected ? activeIcon : icon)
                .font(.system(size: 21))
                .foregroundColor(isSelected ? .nightPrimary : .nightSecondary)
                .frame(width: 44, height: 44)
        }
    }
}

struct ComposeTabButton: View {
    let windowState: AppState.WindowState
    let onTap: () -> Void
    @State private var glow = false

    var body: some View {
        Button {
            guard windowState == .open else { return }
            onTap()
        } label: {
            ZStack {
                if windowState == .open {
                    Circle()
                        .fill(Color.nightPurple.opacity(0.18))
                        .frame(width: 62, height: 62)
                        .scaleEffect(glow ? 1.15 : 1.0)
                        .animation(.easeInOut(duration: 2.2).repeatForever(autoreverses: true), value: glow)
                }
                Circle()
                    .fill(buttonFill)
                    .frame(width: 50, height: 50)
                Image(systemName: buttonIcon)
                    .font(.system(size: 19, weight: .semibold))
                    .foregroundColor(.white)
            }
        }
        .onAppear { glow = true }
        .animation(.easeInOut(duration: 0.4), value: windowState)
    }

    var buttonFill: AnyShapeStyle {
        switch windowState {
        case .open:
            return AnyShapeStyle(LinearGradient(
                colors: [Color(hex: "8B5CF6"), Color(hex: "6D28D9")],
                startPoint: .topLeading, endPoint: .bottomTrailing
            ))
        case .posted:
            return AnyShapeStyle(LinearGradient(
                colors: [Color(hex: "059669"), Color(hex: "047857")],
                startPoint: .top, endPoint: .bottom
            ))
        default:
            return AnyShapeStyle(Color.nightRaised)
        }
    }

    var buttonIcon: String {
        switch windowState {
        case .open:   return "plus"
        case .posted: return "checkmark"
        default:      return "moon.zzz"
        }
    }
}