//
//  ContentView.swift
//  Keging
//
//  첫 화면 — 큰 시작 버튼 + 구석의 세팅·설정 버튼. 아래로 스와이프하면 통계.
//

import SwiftUI

struct ContentView: View {
    @EnvironmentObject private var engine: KegelEngine
    @EnvironmentObject private var settings: SettingsStore

    @State private var showTimerSettings = false
    @State private var showAppSettings = false
    @State private var showStats = false

    var body: some View {
        ZStack {
            AppTheme.background.ignoresSafeArea()
            mainScreen
            if showStats {
                StatsView(onClose: closeStats)
                    .transition(.move(edge: .top))
                    .zIndex(2)
            }
        }
        .sheet(isPresented: $showTimerSettings) { TimerSettingsView() }
        .sheet(isPresented: $showAppSettings) { AppSettingsView() }
        .fullScreenCover(isPresented: workoutPresented) { WorkoutView() }
        .onReceive(NotificationCenter.default.publisher(for: .startWorkoutRequested)) { _ in
            startFromShortcut()
        }
        .onAppear {
            if AppLaunchState.shared.startRequested { startFromShortcut() }
            #if DEBUG
            if CommandLine.arguments.contains("-openStats") { showStats = true }
            if CommandLine.arguments.contains("-autoStart") { WorkoutCoordinator.shared.startWorkout() }
            #endif
        }
    }

    // MARK: 첫 화면

    private var mainScreen: some View {
        VStack(spacing: 0) {
            HStack(alignment: .top) {
                cornerButton(symbol: "gearshape.fill", label: "설정") { showAppSettings = true }
                Spacer()
                Button {
                    openStats()
                } label: {
                    VStack(spacing: 2) {
                        Capsule().fill(.secondary.opacity(0.5)).frame(width: 36, height: 5)
                        Image(systemName: "chevron.compact.down")
                            .font(.body)
                            .foregroundStyle(.secondary)
                    }
                    .padding(.top, 10)
                }
                .buttonStyle(.plain)
                .accessibilityLabel("통계 보기")
                Spacer()
                cornerButton(symbol: "slider.horizontal.3", label: "운동 세팅") { showTimerSettings = true }
            }
            .padding(.horizontal, 20)
            .padding(.top, 8)

            Spacer()

            Button {
                WorkoutCoordinator.shared.startWorkout()
            } label: {
                startButtonLabel
            }
            .buttonStyle(.plain)
            .accessibilityLabel("케겔 운동 시작")

            Button {
                showTimerSettings = true
            } label: {
                Text(settings.config.summaryText)
                    .font(.subheadline)
                    .foregroundStyle(.secondary)
            }
            .buttonStyle(.plain)
            .padding(.top, 30)
            .accessibilityLabel("운동 세팅 열기 — 현재 \(settings.config.summaryText)")

            Spacer()
            Spacer()
        }
        .contentShape(Rectangle())
        .gesture(
            DragGesture(minimumDistance: 25)
                .onEnded { value in
                    if value.translation.height > 60, abs(value.translation.width) < 100 {
                        openStats()
                    }
                }
        )
    }

    private var startButtonLabel: some View {
        ZStack {
            Circle()
                .fill(
                    RadialGradient(
                        colors: [AppTheme.green.opacity(0.22), .clear],
                        center: .center, startRadius: 100, endRadius: 165
                    )
                )
                .frame(width: 330, height: 330)
            Circle()
                .fill(
                    LinearGradient(
                        colors: [AppTheme.green, AppTheme.green.opacity(0.82)],
                        startPoint: .top, endPoint: .bottom
                    )
                )
                .frame(width: 236, height: 236)
                .shadow(color: AppTheme.green.opacity(0.35), radius: 24, x: 0, y: 10)
            VStack(spacing: 8) {
                Image(systemName: "play.fill").font(.system(size: 40, weight: .bold))
                Text("시작").font(.title.bold())
            }
            .foregroundStyle(startButtonForeground)
        }
        .frame(width: 330, height: 330)
    }

    /// 다크의 세이지 민트 버튼 위에는 흰 글자가 묻혀서 짙은 그린 틴트 글자로
    private var startButtonForeground: Color {
        Color(light: .white, dark: Color(hex: "#0F2018"))
    }

    private func cornerButton(symbol: String, label: String, action: @escaping () -> Void) -> some View {
        Button(action: action) {
            Image(systemName: symbol)
                .font(.title3)
                .foregroundStyle(.secondary)
                .frame(width: 44, height: 44)
                .background(AppTheme.surface, in: Circle())
        }
        .buttonStyle(.plain)
        .accessibilityLabel(label)
    }

    // MARK: 통계·운동 전환

    private func openStats() {
        withAnimation(.spring(duration: 0.35)) { showStats = true }
    }

    private func closeStats() {
        withAnimation(.spring(duration: 0.35)) { showStats = false }
    }

    private var workoutPresented: Binding<Bool> {
        Binding(
            get: { engine.state != .idle },
            set: { presented in if !presented { engine.acknowledgeFinish() } }
        )
    }

    private func startFromShortcut() {
        AppLaunchState.shared.startRequested = false
        showStats = false
        WorkoutCoordinator.shared.startWorkout()
    }
}