import SwiftUI

struct ContentView: View {
    @EnvironmentObject var engine: PlayerEngine
    @State private var columnVisibility: NavigationSplitViewVisibility = .all
    @State private var showURLInput = false
    @State private var urlInput = ""
    
    var body: some View {
        Group {
            if engine.isFullscreen {
                PlayerView()
                    .onTapGesture(count: 2) {
                        engine.toggleFullscreen()
                    }
            } else {
                NavigationSplitView(columnVisibility: $columnVisibility) {
                    playlistSidebar
                } detail: {
                    PlayerView()
                }
                .navigationSplitViewStyle(.balanced)
                .navigationSplitViewColumnWidth(min: 240, ideal: 300, max: 400)
            }
        }
        .alert("添加流媒体 URL", isPresented: $showURLInput) {
            TextField("M3U8 或其他流媒体 URL", text: $urlInput)
            Button("添加") {
                addStreamURL()
            }
            Button("取消", role: .cancel) {}
        } message: {
            Text("输入 M3U8、MP4 或其他流媒体地址")
        }
        .keyboardShortcut(.escape, action: {
            if engine.isFullscreen { engine.toggleFullscreen() }
        })
    }
    
    // MARK: - 侧边栏
    
    private var playlistSidebar: some View {
        VStack(spacing: 0) {
            PlaylistView()
            
            Divider()
            
            // 底部工具栏: 添加流URL + 循环模式
            HStack(spacing: 12) {
                Button {
                    urlInput = ""
                    showURLInput = true
                } label: {
                    Label("添加流 URL", systemImage: "link")
                        .font(.caption)
                }
                .buttonStyle(.bordered)
                .controlSize(.small)
                
                Spacer()
                
                // 循环模式
                Button {
                    engine.repeatMode = engine.repeatMode.next
                } label: {
                    HStack(spacing: 4) {
                        Image(systemName: engine.repeatMode.icon)
                        Text(repeatModeText)
                    }
                    .font(.caption)
                    .foregroundStyle(engine.repeatMode == .none ? .secondary : .blue)
                }
                .buttonStyle(.plain)
            }
            .padding(.horizontal, 16)
            .padding(.vertical, 10)
        }
    }
    
    private var repeatModeText: String {
        switch engine.repeatMode {
        case .none: return "不循环"
        case .single: return "单曲"
        case .all: return "列表"
        }
    }
    
    private func addStreamURL() {
        guard !urlInput.isEmpty, let url = URL(string: urlInput) else { return }
        engine.addToQueue(urls: [url])
    }
}

// ESC 快捷键辅助
extension View {
    func keyboardShortcut(_ key: KeyEquivalent, action: @escaping () -> Void) -> some View {
        self.background(
            KeyboardShortcutView(key: key, action: action)
        )
    }
}

struct KeyboardShortcutView: View {
    let key: KeyEquivalent
    let action: () -> Void
    
    var body: some View {
        Button(action: action) {
            EmptyView()
        }
        .keyboardShortcut(key, modifiers: [])
        .hidden()
    }
}