import Foundation
import os.log

/**
 * 文件日志工具
 * 将日志同时输出到控制台和文件系统
 */
@objc public class FileLogger: NSObject {
    
    private static let TAG = "FileLogger"
    private static var instance: FileLogger?
    
    private let logDir: URL
    private var currentLogFile: URL?
    private let logQueue = DispatchQueue(label: "com.yunqiinnovation.deepvoice_utils.logger", qos: .utility)
    
    private let dateFormatter: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy-MM-dd"
        return formatter
    }()
    
    private let timeFormatter: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "HH:mm:ss.SSS"
        return formatter
    }()
    
    /**
     * 初始化日志系统
     */
    private init(directory: URL) {
        self.logDir = directory.appendingPathComponent("logs", isDirectory: true)
        super.init()
        
        // 创建日志目录
        try? FileManager.default.createDirectory(at: logDir, withIntermediateDirectories: true)
        
        // 创建当天日志文件
        updateLogFile()
        
        // 记录初始化完成
        self.d(FileLogger.TAG, "文件日志系统已初始化")
    }
    
    /**
     * 更新日志文件为当天日期
     */
    private func updateLogFile() {
        let today = dateFormatter.string(from: Date())
        let logFile = logDir.appendingPathComponent("log_\(today).txt")
        
        if currentLogFile == nil || currentLogFile?.path != logFile.path {
            currentLogFile = logFile
            
            // 如果是新文件，添加文件头
            if !FileManager.default.fileExists(atPath: logFile.path) {
                let headerDate = DateFormatter()
                headerDate.dateFormat = "yyyy-MM-dd HH:mm:ss"
                let headerLine = "===== 日志开始: \(headerDate.string(from: Date())) =====\n"
                
                try? headerLine.write(to: logFile, atomically: true, encoding: .utf8)
            }
        }
    }
    
    /**
     * 将日志写入文件
     */
    private func logToFile(level: String, tag: String, message: String) {
        logQueue.async { [weak self] in
            guard let self = self else { return }
            
            do {
                // 检查是否需要更新日志文件
                self.updateLogFile()
                
                guard let logFile = self.currentLogFile, 
                      FileManager.default.fileExists(atPath: logFile.path) else {
                    return
                }
                
                // 格式化日志内容
                let timestamp = self.timeFormatter.string(from: Date())
                let logLine = "\(timestamp) \(level)/\(tag): \(message)\n"
                
                // 获取文件句柄并追加内容
                if let fileHandle = try? FileHandle(forWritingTo: logFile) {
                    fileHandle.seekToEndOfFile()
                    if let data = logLine.data(using: .utf8) {
                        fileHandle.write(data)
                    }
                    fileHandle.closeFile()
                } else {
                    // 如果无法获取文件句柄，尝试直接写入
                    let existingContent = try? String(contentsOf: logFile, encoding: .utf8)
                    let newContent = (existingContent ?? "") + logLine
                    try newContent.write(to: logFile, atomically: true, encoding: .utf8)
                }
            } catch {
                print("写入日志文件失败: \(error.localizedDescription)")
            }
        }
    }
    
    /**
     * 调试级别日志
     */
    private func d(_ tag: String, _ message: String) {
        // 输出到控制台
        print("D/\(tag): \(message)")
        
        // 写入文件
        logToFile(level: "D", tag: tag, message: message)
    }
    
    /**
     * 信息级别日志
     */
    private func i(_ tag: String, _ message: String) {
        // 输出到控制台
        print("I/\(tag): \(message)")
        
        // 写入文件
        logToFile(level: "I", tag: tag, message: message)
    }
    
    /**
     * 警告级别日志
     */
    private func w(_ tag: String, _ message: String) {
        // 输出到控制台
        print("W/\(tag): \(message)")
        
        // 写入文件
        logToFile(level: "W", tag: tag, message: message)
    }
    
    /**
     * 错误级别日志
     */
    private func e(_ tag: String, _ message: String, _ error: Error? = nil) {
        var fullMessage = message
        
        // 如果有错误，添加错误信息
        if let error = error {
            fullMessage += "\n\(error.localizedDescription)"
        }
        
        // 输出到控制台
        print("E/\(tag): \(fullMessage)")
        
        // 写入文件
        logToFile(level: "E", tag: tag, message: fullMessage)
    }
    
    /**
     * 清理旧日志文件
     */
    private func cleanOldLogs(daysToKeep: Int = 7) {
        logQueue.async {
            do {
                let currentDate = Date()
                let fileManager = FileManager.default
                
                let logFiles = try fileManager.contentsOfDirectory(at: self.logDir, includingPropertiesForKeys: [.creationDateKey], options: [])
                
                for fileURL in logFiles where fileURL.pathExtension == "txt" {
                    if let fileAttributes = try? fileManager.attributesOfItem(atPath: fileURL.path),
                       let creationDate = fileAttributes[.creationDate] as? Date {
                        
                        let age = Calendar.current.dateComponents([.day], from: creationDate, to: currentDate)
                        
                        if let days = age.day, days > daysToKeep {
                            try? fileManager.removeItem(at: fileURL)
                            print("D/\(FileLogger.TAG): 已删除旧日志文件: \(fileURL.lastPathComponent)")
                        }
                    }
                }
            } catch {
                print("E/\(FileLogger.TAG): 清理旧日志失败: \(error.localizedDescription)")
            }
        }
    }
    
    // MARK: - 公共静态方法
    
    /**
     * 初始化日志系统
     */
    @objc public static func initialize() {
        if instance == nil {
            let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
            instance = FileLogger(directory: documentsDirectory)
        }
    }
    
    /**
     * 初始化日志系统（使用自定义目录）
     */
    @objc public static func initialize(withDirectory directory: URL) {
        if instance == nil {
            instance = FileLogger(directory: directory)
        }
    }
    
    /**
     * 调试日志
     */
    @objc public static func d(_ tag: String, _ message: String) {
        // 如果实例不存在，先使用默认目录初始化
        if instance == nil {
            initialize()
        }
        
        instance?.d(tag, message)
        
        // 使用系统日志
        if #available(iOS 10.0, *) {
            os_log("%{public}@", log: OSLog(subsystem: "com.yunqiinnovation.deepvoice_utils", category: tag), type: .debug, message)
        }
    }
    
    /**
     * 信息日志
     */
    @objc public static func i(_ tag: String, _ message: String) {
        if instance == nil {
            initialize()
        }
        
        instance?.i(tag, message)
        
        // 使用系统日志
        if #available(iOS 10.0, *) {
            os_log("%{public}@", log: OSLog(subsystem: "com.yunqiinnovation.deepvoice_utils", category: tag), type: .info, message)
        }
    }
    
    /**
     * 警告日志
     */
    @objc public static func w(_ tag: String, _ message: String) {
        if instance == nil {
            initialize()
        }
        
        instance?.w(tag, message)
        
        // 使用系统日志
        if #available(iOS 10.0, *) {
            os_log("%{public}@", log: OSLog(subsystem: "com.yunqiinnovation.deepvoice_utils", category: tag), type: .default, message)
        }
    }
    
    /**
     * 错误日志
     */
    @objc public static func e(_ tag: String, _ message: String, _ error: Error? = nil) {
        if instance == nil {
            initialize()
        }
        
        instance?.e(tag, message, error)
        
        // 使用系统日志
        if #available(iOS 10.0, *) {
            let errorMessage = error != nil ? "\(message): \(error!.localizedDescription)" : message
            os_log("%{public}@", log: OSLog(subsystem: "com.yunqiinnovation.deepvoice_utils", category: tag), type: .error, errorMessage)
        }
    }
    
    /**
     * 清理旧日志
     */
    @objc public static func cleanOldLogs(daysToKeep: Int = 7) {
        instance?.cleanOldLogs(daysToKeep: daysToKeep)
    }
    
    /**
     * 关闭日志系统
     */
    @objc public static func shutdown() {
        instance = nil
    }
}