import SwiftUI
import CoreData
import CoreImage

// MARK: - 二维码创建界面
struct CreateQRCodeView: View {
    @Environment(\.dismiss) private var dismiss
    @StateObject private var coreDataManager = CoreDataManager.shared
    
    // 从类型选择界面传入的参数
    let selectedQRCodeType: QRCodeType
    
    @State private var content = ""
    @State private var showingAlert = false
    @State private var alertMessage = ""
    
    // 输入焦点，确保进入页面自动弹出键盘
    @FocusState private var isContentFieldFocused: Bool
    
    var body: some View {
        VStack(spacing: 0) {
            inputAndPreviewSection
        }
        .navigationTitle(selectedQRCodeType.displayName)
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .navigationBarTrailing) {
                Button("创建") { createQRCode() }
                    .disabled(content.isEmpty)
                    .font(.system(size: 16, weight: .semibold))
            }
        }
        .alert("提示", isPresented: $showingAlert) {
            Button("确定") { }
        } message: { Text(alertMessage) }
        .onAppear {
            // 稍延迟以确保进入页面时自动聚焦
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
                isContentFieldFocused = true
            }
        }
        .onTapGesture {
            // 点击外部关闭键盘
            isContentFieldFocused = false
        }
    }
    
    // MARK: - UI Components
    

    
    private var inputAndPreviewSection: some View {
        ScrollView {
            VStack(spacing: 24) {
                // 输入提示
                VStack(spacing: 12) {
                    HStack {
                        Image(systemName: "info.circle")
                            .font(.caption)
                            .foregroundColor(.blue)
                        
                        Text(getContentHint())
                            .font(.caption)
                            .foregroundColor(.secondary)
                            .lineLimit(nil)
                        
                        Spacer()
                    }
                    .padding(.horizontal, 12)
                    .padding(.vertical, 8)
                    .background(
                        RoundedRectangle(cornerRadius: 8)
                            .fill(Color.blue.opacity(0.1))
                    )
                }
                .padding(.horizontal, 20)
                
                // 内容输入区域
                VStack(spacing: 16) {
                    HStack {
                        Text("输入内容")
                            .font(.headline)
                            .foregroundColor(.primary)
                        
                        Spacer()
                    }
                    
                    // 多行输入框
                    VStack(spacing: 8) {
                        ZStack {
                            // 输入框主体
                            TextEditor(text: $content)
                                .frame(minHeight: 120)
                                .padding(8)
                                .background(Color(.systemBackground))
                                .cornerRadius(8)
                                .overlay(
                                    RoundedRectangle(cornerRadius: 8)
                                        .stroke(isContentFieldFocused ? Color.blue : Color(.systemGray4), lineWidth: 1)
                                )
                                .focused($isContentFieldFocused)
                                .onChange(of: content) { newValue in
                                    // 限制最大字符数为150
                                    if newValue.count > 150 {
                                        content = String(newValue.prefix(150))
                                    }
                                }
                                .toolbar {
                                    ToolbarItemGroup(placement: .keyboard) {
                                        Spacer()
                                        Button("完成") {
                                            isContentFieldFocused = false
                                        }
                                        .foregroundColor(.blue)
                                        .font(.system(size: 16, weight: .medium))
                                    }
                                }
                            
                            // 占位符文本 - 左上角对齐
                            if content.isEmpty && !isContentFieldFocused {
                                VStack {
                                    HStack {
                                        Text(getPlaceholderText())
                                            .foregroundColor(.secondary)
                                            .font(.body)
                                        Spacer()
                                    }
                                    Spacer()
                                }
                                .padding(16)
                                .allowsHitTesting(false)
                                .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .topLeading)
                            }
                        }
                        
                        // 字符计数和限制提示 - 输入框底下
                        HStack {
                            Spacer()
                            
                            VStack(alignment: .trailing, spacing: 4) {
                                // 字符限制提示
                                if content.count >= 150 {
                                    HStack(spacing: 4) {
                                        Image(systemName: "exclamationmark.triangle")
                                            .font(.caption)
                                            .foregroundColor(.orange)
                                        
                                        Text("已达到最大字符数")
                                            .font(.caption)
                                            .foregroundColor(.orange)
                                    }
                                } else if content.count >= 140 {
                                    HStack(spacing: 4) {
                                        Image(systemName: "info.circle")
                                            .font(.caption)
                                            .foregroundColor(.blue)
                                        
                                        Text("接近字符限制")
                                            .font(.caption)
                                            .foregroundColor(.blue)
                                    }
                                }
                                
                                // 字符计数
                                Text("\(content.count)/150")
                                    .font(.caption)
                                    .foregroundColor(getCharacterCountColor())
                            }
                        }
                    }
                }
                .padding(.horizontal, 20)
                
                // 预览区域
                if !content.isEmpty {
                    VStack(spacing: 16) {
                        HStack {
                            Text("预览")
                                .font(.headline)
                                .foregroundColor(.primary)
                            
                            Spacer()
                            
                            Button(action: {
                                // 可以添加分享功能
                            }) {
                                Image(systemName: "square.and.arrow.up")
                                    .font(.system(size: 16))
                                    .foregroundColor(.blue)
                            }
                        }
                        
                        VStack(spacing: 16) {
                            // 二维码图片
                            if let qrCodeImage = generateQRCodeImage() {
                                Image(uiImage: qrCodeImage)
                                    .interpolation(.none)
                                    .resizable()
                                    .scaledToFit()
                                    .frame(width: 200, height: 200)
                                    .background(Color.white)
                                    .cornerRadius(12)
                                    .shadow(color: .black.opacity(0.1), radius: 8, x: 0, y: 4)
                            }
                            
                            // 内容预览卡片
                            VStack(alignment: .leading, spacing: 8) {
                                HStack {
                                    Text("内容")
                                        .font(.caption)
                                        .foregroundColor(.secondary)
                                    
                                    Spacer()
                                    
                                    Text(selectedQRCodeType.displayName)
                                        .font(.caption)
                                        .padding(.horizontal, 6)
                                        .padding(.vertical, 2)
                                        .background(Color.orange.opacity(0.1))
                                        .foregroundColor(.orange)
                                        .cornerRadius(4)
                                }
                                
                                Text(formatContentForQRCodeType())
                                    .font(.body)
                                    .foregroundColor(.primary)
                                    .textSelection(.enabled)
                            }
                            .padding()
                            .background(Color(.systemGray6))
                            .cornerRadius(8)
                        }
                        .padding()
                        .background(Color(.systemBackground))
                        .cornerRadius(12)
                        .shadow(color: .black.opacity(0.05), radius: 4, x: 0, y: 2)
                    }
                    .padding(.horizontal, 20)
                }
                
                Spacer(minLength: 100)
            }
            .padding(.top, 20)
        }
        .background(Color(.systemGroupedBackground))
    }
    

    
    // MARK: - Helper Methods
    
    private func getCharacterCountColor() -> Color {
        if content.count >= 150 {
            return .orange
        } else if content.count >= 140 {
            return .blue
        } else {
            return .secondary
        }
    }
    
    private func getContentHint() -> String {
        switch selectedQRCodeType {
        case .text:
            return "输入任意文本内容"
        case .url:
            return "输入网址，如：https://www.example.com"
        case .mail:
            return "输入邮箱地址，如：user@example.com"
        case .phone:
            return "输入电话号码，如：+86 138 0013 8000"
        case .sms:
            return "输入短信内容，如：Hello World"
        case .wifi:
            return "输入WiFi信息，如：SSID:MyWiFi,Password:12345678"
        case .vcard:
            return "输入联系人信息"
        case .mecard:
            return "输入联系人信息（简化版）"
        case .location:
            return "输入地理位置，如：40.7128,-74.0060"
        case .calendar:
            return "输入日历事件信息"
        case .instagram:
            return "输入Instagram用户名或链接"
        case .facebook:
            return "输入Facebook用户名或链接"
        case .spotify:
            return "输入Spotify歌曲或播放列表链接"
        case .twitter:
            return "输入Twitter用户名或链接"
        case .whatsapp:
            return "输入WhatsApp消息内容"
        case .viber:
            return "输入Viber消息内容"
        case .snapchat:
            return "输入Snapchat用户名"
        case .tiktok:
            return "输入TikTok用户名或链接"
        }
    }
    
    private func getPlaceholderText() -> String {
        switch selectedQRCodeType {
        case .text:
            return "输入文本内容"
        case .url:
            return "输入网址"
        case .mail:
            return "输入邮箱地址"
        case .phone:
            return "输入电话号码"
        case .sms:
            return "输入短信内容"
        case .wifi:
            return "输入WiFi信息"
        case .vcard:
            return "输入联系人信息"
        case .mecard:
            return "输入联系人信息"
        case .location:
            return "输入地理位置坐标"
        case .calendar:
            return "输入日历事件信息"
        case .instagram:
            return "输入Instagram信息"
        case .facebook:
            return "输入Facebook信息"
        case .spotify:
            return "输入Spotify链接"
        case .twitter:
            return "输入Twitter信息"
        case .whatsapp:
            return "输入WhatsApp消息"
        case .viber:
            return "输入Viber消息"
        case .snapchat:
            return "输入Snapchat用户名"
        case .tiktok:
            return "输入TikTok信息"
        }
    }
    
    private func generateQRCodeImage() -> UIImage? {
        guard !content.isEmpty else { return nil }
        
        // 根据二维码类型格式化内容
        let formattedContent = formatContentForQRCodeType()
        
        // 生成二维码
        let data = formattedContent.data(using: .utf8)
        let qrFilter = CIFilter.qrCodeGenerator()
        qrFilter.setValue(data, forKey: "inputMessage")
        qrFilter.setValue("H", forKey: "inputCorrectionLevel") // 高纠错级别
        
        guard let outputImage = qrFilter.outputImage else { return nil }
        
        // 转换为UIImage
        let context = CIContext()
        guard let cgImage = context.createCGImage(outputImage, from: outputImage.extent) else { return nil }
        
        return UIImage(cgImage: cgImage)
    }
    
    private func formatContentForQRCodeType() -> String {
        switch selectedQRCodeType {
        case .text:
            return content
        case .url:
            return content.hasPrefix("http") ? content : "https://\(content)"
        case .mail:
            return "mailto:\(content)"
        case .phone:
            return "tel:\(content)"
        case .sms:
            return "sms:\(content)"
        case .wifi:
            return "WIFI:T:WPA;S:\(content);P:password;;"
        case .vcard:
            return "BEGIN:VCARD\nVERSION:3.0\nFN:\(content)\nEND:VCARD"
        case .mecard:
            return "MECARD:N:\(content);;"
        case .location:
            return "geo:\(content)"
        case .calendar:
            return "BEGIN:VEVENT\nSUMMARY:\(content)\nEND:VEVENT"
        case .instagram:
            return "https://instagram.com/\(content)"
        case .facebook:
            return "https://facebook.com/\(content)"
        case .spotify:
            return content.hasPrefix("http") ? content : "https://open.spotify.com/track/\(content)"
        case .twitter:
            return "https://twitter.com/\(content)"
        case .whatsapp:
            return "https://wa.me/\(content)"
        case .viber:
            return "viber://chat?number=\(content)"
        case .snapchat:
            return "https://snapchat.com/add/\(content)"
        case .tiktok:
            return "https://tiktok.com/@\(content)"
        }
    }
    
    private func createQRCode() {
        guard !content.isEmpty else { return }
        
        let context = coreDataManager.container.viewContext
        let historyItem = HistoryItem(context: context)
        historyItem.id = UUID()
        historyItem.content = content
        historyItem.dataType = DataType.qrcode.rawValue
        historyItem.dataSource = DataSource.created.rawValue
        historyItem.createdAt = Date()
        historyItem.isFavorite = false
        historyItem.qrCodeType = selectedQRCodeType.rawValue
        
        do {
            try context.save()
            alertMessage = "二维码创建成功！"
            showingAlert = true
            // 创建成功后返回
            DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) { 
                dismiss()
            }
        } catch {
            alertMessage = "保存失败：\(error.localizedDescription)"
            showingAlert = true
        }
    }
}

#Preview {
    NavigationView {
        CreateQRCodeView(selectedQRCodeType: .text)
    }
}