import Foundation
import CoreData
import SwiftUI
import Combine

class CoreDataManager: ObservableObject {
    static let shared = CoreDataManager()
    
    let container: NSPersistentContainer
    
    init() {
        container = NSPersistentContainer(name: "MyQrCode")
        
        container.loadPersistentStores { description, error in
            if let error = error {
                print(String(format: "core_data_load_failed".localized, error.localizedDescription))
                
                // 如果是架构不匹配错误，删除数据库文件并重新创建
                if let nsError = error as NSError?,
                   nsError.domain == NSCocoaErrorDomain && (nsError.code == 134030 || nsError.code == 134140) {
                    print("architecture_mismatch_detected".localized)
                    self.deleteDatabaseFiles()
                    
                    // 重新加载持久化存储
                    self.container.loadPersistentStores { _, reloadError in
                        if let reloadError = reloadError {
                            print(String(format: "core_data_reload_failed".localized, reloadError.localizedDescription))
                        } else {
                            print("core_data_reload_success".localized)
                        }
                    }
                }
            }
        }
        
        // 启用自动合并更改
        container.viewContext.automaticallyMergesChangesFromParent = true
        container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
    }
    
    // 保存上下文
    func save() {
        let context = container.viewContext
        
        if context.hasChanges {
            do {
                try context.save()
                print("core_data_save_success".localized)
            } catch {
                print(String(format: "core_data_save_failed".localized, error.localizedDescription))
                print(String(format: "error_details".localized, "\(error)"))
                
                // 如果是NSError，打印更多信息
                if let nsError = error as NSError? {
                    print(String(format: "error_domain".localized, nsError.domain))
                    print("❌ Error code: \(nsError.code)")
                    print("❌ User info: \(nsError.userInfo)")
                    
                    // 检查是否是Transformable属性错误
                    if nsError.domain == NSCocoaErrorDomain && nsError.code == 134030 {
                        print("❌ May be Transformable property encoding error")
                    }
                }
            }
        } else {
            print("ℹ️ No changes to save")
        }
    }
    
    // 分页大小
    private let pageSize = 20
    
    // 获取历史记录（分页加载）
    func fetchHistoryItems(page: Int = 0) -> [HistoryItem] {
        let request: NSFetchRequest<HistoryItem> = HistoryItem.fetchRequest()
        request.sortDescriptors = [NSSortDescriptor(keyPath: \HistoryItem.createdAt, ascending: false)]
        request.fetchLimit = pageSize
        request.fetchOffset = page * pageSize
        
        do {
            return try container.viewContext.fetch(request)
        } catch {
            print("Failed to fetch history: \(error.localizedDescription)")
            return []
        }
    }
    
    // 获取所有历史记录（用于兼容性）
    func fetchAllHistoryItems() -> [HistoryItem] {
        let request: NSFetchRequest<HistoryItem> = HistoryItem.fetchRequest()
        request.sortDescriptors = [NSSortDescriptor(keyPath: \HistoryItem.createdAt, ascending: false)]
        
        do {
            return try container.viewContext.fetch(request)
        } catch {
            print("Failed to fetch all history: \(error.localizedDescription)")
            return []
        }
    }
    
    // 获取历史记录总数
    func fetchHistoryItemsCount() -> Int {
        let request: NSFetchRequest<HistoryItem> = HistoryItem.fetchRequest()
        
        do {
            return try container.viewContext.count(for: request)
        } catch {
            print("Failed to count history: \(error.localizedDescription)")
            return 0
        }
    }
    
    // 添加历史记录
    func addHistoryItem(_ item: HistoryItem) {
        container.viewContext.insert(item)
        save()
    }
    
    // 删除历史记录
    func deleteHistoryItem(_ item: HistoryItem) {
        container.viewContext.delete(item)
        save()
    }
    
    // 清空所有历史记录
    func clearAllHistory() {
        let request: NSFetchRequest<NSFetchRequestResult> = HistoryItem.fetchRequest()
        let deleteRequest = NSBatchDeleteRequest(fetchRequest: request)
        
        do {
            try container.viewContext.execute(deleteRequest)
            save()
        } catch {
            print("Failed to clear history: \(error.localizedDescription)")
        }
    }
    
    // 删除数据库文件
    private func deleteDatabaseFiles() {
        let fileManager = FileManager.default
        
        // 获取应用支持目录
        guard let appSupportURL = fileManager.urls(for: .applicationSupportDirectory, in: .userDomainMask).first else {
            print("❌ 无法获取应用支持目录")
            return
        }
        
        // 删除MyQrCode.sqlite及其相关文件
        let databaseName = "MyQrCode"
        let possibleFiles = [
            appSupportURL.appendingPathComponent("\(databaseName).sqlite"),
            appSupportURL.appendingPathComponent("\(databaseName).sqlite-shm"),
            appSupportURL.appendingPathComponent("\(databaseName).sqlite-wal")
        ]
        
        for fileURL in possibleFiles {
            if fileManager.fileExists(atPath: fileURL.path) {
                do {
                    try fileManager.removeItem(at: fileURL)
                    print("✅ 删除数据库文件: \(fileURL.lastPathComponent)")
                } catch {
                    print("❌ 删除数据库文件失败: \(error)")
                }
            }
        }
        
        // 也检查文档目录
        guard let documentsURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first else {
            return
        }
        
        let documentFiles = [
            documentsURL.appendingPathComponent("\(databaseName).sqlite"),
            documentsURL.appendingPathComponent("\(databaseName).sqlite-shm"),
            documentsURL.appendingPathComponent("\(databaseName).sqlite-wal")
        ]
        
        for fileURL in documentFiles {
            if fileManager.fileExists(atPath: fileURL.path) {
                do {
                    try fileManager.removeItem(at: fileURL)
                    print("✅ 删除数据库文件: \(fileURL.lastPathComponent)")
                } catch {
                    print("❌ 删除数据库文件失败: \(error)")
                }
            }
        }
    }
    
    // 搜索历史记录
    func searchHistoryItems(query: String) -> [HistoryItem] {
        let request: NSFetchRequest<HistoryItem> = HistoryItem.fetchRequest()
        
        if !query.isEmpty {
            let contentPredicate = NSPredicate(format: "content CONTAINS[cd] %@", query)
            let barcodeTypePredicate = NSPredicate(format: "barcodeType CONTAINS[cd] %@", query)
            let qrCodeTypePredicate = NSPredicate(format: "qrCodeType CONTAINS[cd] %@", query)
            
            let compoundPredicate = NSCompoundPredicate(
                orPredicateWithSubpredicates: [
                    contentPredicate,
                    barcodeTypePredicate,
                    qrCodeTypePredicate
                ]
            )
            
            request.predicate = compoundPredicate
        }
        
        request.sortDescriptors = [NSSortDescriptor(keyPath: \HistoryItem.createdAt, ascending: false)]
        
        do {
            return try container.viewContext.fetch(request)
        } catch {
            print("搜索历史记录失败: \(error.localizedDescription)")
            return []
        }
    }
    
    // 按类型过滤
    func filterByType(_ type: DataType) -> [HistoryItem] {
        let request: NSFetchRequest<HistoryItem> = HistoryItem.fetchRequest()
        request.predicate = NSPredicate(format: "dataType == %@", type.rawValue)
        request.sortDescriptors = [NSSortDescriptor(keyPath: \HistoryItem.createdAt, ascending: false)]
        
        do {
            return try container.viewContext.fetch(request)
        } catch {
            print("按类型过滤失败: \(error.localizedDescription)")
            return []
        }
    }
    
    // 按来源过滤
    func filterBySource(_ source: DataSource) -> [HistoryItem] {
        let request: NSFetchRequest<HistoryItem> = HistoryItem.fetchRequest()
        request.predicate = NSPredicate(format: "dataSource == %@", source.rawValue)
        request.sortDescriptors = [NSSortDescriptor(keyPath: \HistoryItem.createdAt, ascending: false)]
        
        do {
            return try container.viewContext.fetch(request)
        } catch {
            print("按来源过滤失败: \(error.localizedDescription)")
            return []
        }
    }
    
    // 获取收藏项目
    func getFavoriteItems() -> [HistoryItem] {
        let request: NSFetchRequest<HistoryItem> = HistoryItem.fetchRequest()
        request.predicate = NSPredicate(format: "isFavorite == YES")
        request.sortDescriptors = [NSSortDescriptor(keyPath: \HistoryItem.createdAt, ascending: false)]
        
        do {
            return try container.viewContext.fetch(request)
        } catch {
            print("获取收藏项目失败: \(error.localizedDescription)")
            return []
        }
    }
}