import Foundation
import EventKit
import Combine

// MARK: - 日历管理器
class CalendarManager: ObservableObject {
    static let shared = CalendarManager()
    
    private let eventStore = EKEventStore()
    @Published var objectWillChange = ObservableObjectPublisher()
    
    private init() {}
    
    // MARK: - 添加事件到日历
    func addEventToCalendar(calendarDetails: CalendarDetails, completion: @escaping (Bool, String?) -> Void) {
        // 检查权限
        if #available(iOS 17.0, *) {
            // iOS 17+ 使用新的权限API
            switch EKEventStore.authorizationStatus(for: .event) {
            case .fullAccess, .writeOnly:
                performAddEvent(calendarDetails: calendarDetails, completion: completion)
            case .notDetermined:
                requestCalendarAccess { [weak self] granted in
                    if granted {
                        self?.performAddEvent(calendarDetails: calendarDetails, completion: completion)
                    } else {
                        DispatchQueue.main.async {
                            completion(false, "calendar_permission_denied".localized)
                        }
                    }
                }
            case .denied, .restricted:
                DispatchQueue.main.async {
                    completion(false, "calendar_permission_denied".localized)
                }
            @unknown default:
                DispatchQueue.main.async {
                    completion(false, "calendar_permission_unknown".localized)
                }
            }
        } else {
            // iOS 16及以下使用旧权限API
            switch EKEventStore.authorizationStatus(for: .event) {
            case .authorized:
                performAddEvent(calendarDetails: calendarDetails, completion: completion)
            case .notDetermined:
                requestCalendarAccess { [weak self] granted in
                    if granted {
                        self?.performAddEvent(calendarDetails: calendarDetails, completion: completion)
                    } else {
                        DispatchQueue.main.async {
                            completion(false, "calendar_permission_denied".localized)
                        }
                    }
                }
            case .denied, .restricted:
                DispatchQueue.main.async {
                    completion(false, "calendar_permission_denied".localized)
                }
            case .fullAccess:
                performAddEvent(calendarDetails: calendarDetails, completion: completion)
            case .writeOnly:
                performAddEvent(calendarDetails: calendarDetails, completion: completion)
            @unknown default:
                DispatchQueue.main.async {
                    completion(false, "calendar_permission_unknown".localized)
                }
            }
        }
    }
    
    // MARK: - 请求日历权限
    private func requestCalendarAccess(completion: @escaping (Bool) -> Void) {
        if #available(iOS 17.0, *) {
            Task {
                do {
                    let granted = try await eventStore.requestWriteOnlyAccessToEvents()
                    DispatchQueue.main.async {
                        completion(granted)
                    }
                } catch {
                    DispatchQueue.main.async {
                        completion(false)
                    }
                }
            }
        } else {
            eventStore.requestAccess(to: .event) { granted, error in
                DispatchQueue.main.async {
                    completion(granted)
                }
            }
        }
    }
    
    // MARK: - 执行添加事件
    private func performAddEvent(calendarDetails: CalendarDetails, completion: @escaping (Bool, String?) -> Void) {
        let event = EKEvent(eventStore: eventStore)
        
        // 设置事件标题
        event.title = calendarDetails.summary.isEmpty ? "calendar_event".localized : calendarDetails.summary
        
        // 设置事件描述
        if !calendarDetails.description.isEmpty {
            event.notes = calendarDetails.description
        }
        
        // 设置事件位置
        if !calendarDetails.location.isEmpty {
            event.location = calendarDetails.location
        }
        
        // 设置开始时间
        if let startDate = parseCalendarDate(calendarDetails.startTime) {
            event.startDate = startDate
        } else {
            DispatchQueue.main.async {
                completion(false, "calendar_invalid_start_time".localized)
            }
            return
        }
        
        // 设置结束时间
        if let endDate = parseCalendarDate(calendarDetails.endTime) {
            event.endDate = endDate
        } else {
            // 如果没有结束时间，设置为开始时间后1小时
            event.endDate = event.startDate.addingTimeInterval(3600)
        }
        
        // 设置日历（使用默认日历）
        event.calendar = eventStore.defaultCalendarForNewEvents
        
        // 设置提醒（15分钟前）
        let alarm = EKAlarm(relativeOffset: -900) // -15分钟
        event.addAlarm(alarm)
        
        // 保存事件
        do {
            try eventStore.save(event, span: .thisEvent)
            DispatchQueue.main.async {
                completion(true, nil)
            }
        } catch {
            DispatchQueue.main.async {
                completion(false, "calendar_save_failed".localized)
            }
        }
    }
    
    // MARK: - 解析日历日期
    private func parseCalendarDate(_ dateString: String) -> Date? {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyyMMdd'T'HHmmss"
        
        if let date = dateFormatter.date(from: dateString) {
            return date
        }
        
        // 尝试其他格式
        dateFormatter.dateFormat = "yyyyMMdd"
        return dateFormatter.date(from: dateString)
    }
}