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("Core Data 加载失败: \(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("🔄 检测到架构不匹配，删除现有数据库文件")
                    self.deleteDatabaseFiles()
                    
                    // 重新加载持久化存储
                    self.container.loadPersistentStores { _, reloadError in
                        if let reloadError = reloadError {
                            print("❌ 重新加载Core Data失败: \(reloadError.localizedDescription)")
                        } else {
                            print("✅ Core Data重新加载成功")
                        }
                    }
                }
            }
        }
        
        // 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保存成功")
            } catch {
                print("❌ Core Data保存失败: \(error.localizedDescription)")
                print("❌ 错误详情: \(error)")
                
                // 如果是NSError，打印更多信息
                if let nsError = error as NSError? {
                    print("❌ 错误域: \(nsError.domain)")
                    print("❌ 错误代码: \(nsError.code)")
                    print("❌ 用户信息: \(nsError.userInfo)")
                    
                    // 检查是否是Transformable属性错误
                    if nsError.domain == NSCocoaErrorDomain && nsError.code == 134030 {
                        print("❌ 可能是Transformable属性编码错误")
                    }
                }
            }
        } else {
            print("ℹ️ 没有更改需要保存")
        }
    }
    
    // 获取历史记录
    func fetchHistoryItems() -> [HistoryItem] {
        let request: NSFetchRequest<HistoryItem> = HistoryItem.fetchRequest()
        request.sortDescriptors = [NSSortDescriptor(keyPath: \HistoryItem.createdAt, ascending: false)]
        
        do {
            return try container.viewContext.fetch(request)
        } catch {
            print("获取历史记录失败: \(error.localizedDescription)")
            return []
        }
    }
    
    // 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("清空历史记录失败: \(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 []
        }
    }
}