using System.Text.Json;

namespace SHH.CameraSdk;

public class FileStorageService : IStorageService
{
    public int ProcessId { get; }
    private readonly string _baseDir;
    private readonly string _devicesPath;
    private readonly string _systemLogPath; // 系统日志路径
    private readonly string _logsDir;       // 设备日志文件夹

    // 【关键优化】双锁分离：配置读写和日志读写互不干扰
    private readonly SemaphoreSlim _configLock = new SemaphoreSlim(1, 1);
    private readonly SemaphoreSlim _logLock = new SemaphoreSlim(1, 1);

    // JSON 配置 (保持不变)
    private readonly JsonSerializerOptions _jsonOptions = new JsonSerializerOptions
    {
        WriteIndented = true,
        IncludeFields = true,
        PropertyNameCaseInsensitive = true,
        NumberHandling = JsonNumberHandling.AllowReadingFromString
    };

    public FileStorageService(int processId)
    {
        ProcessId = processId;

        // 目录结构：
        // App_Data/Process_1/
        //   ├── devices.json
        //   ├── system.log
        //   └── logs/
        //       ├── device_101.log
        //       └── device_102.log

        _baseDir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "App_Data", $"Process_{processId}");
        _devicesPath = Path.Combine(_baseDir, "devices.json");
        _systemLogPath = Path.Combine(_baseDir, "system.log");
        _logsDir = Path.Combine(_baseDir, "logs");

        if (!Directory.Exists(_baseDir)) Directory.CreateDirectory(_baseDir);
        if (!Directory.Exists(_logsDir)) Directory.CreateDirectory(_logsDir);

        Console.WriteLine($"[Storage] 服务就绪 | 日志路径: {_systemLogPath}");
    }

    // ==================================================================
    // 1. 设备配置管理 (使用 _configLock)
    // ==================================================================

    public async Task SaveDevicesAsync(IEnumerable<VideoSourceConfig> configs)
    {
        await _configLock.WaitAsync();
        try
        {
            var json = JsonSerializer.Serialize(configs, _jsonOptions);
            await File.WriteAllTextAsync(_devicesPath, json);
        }
        catch (Exception ex)
        {
            Console.WriteLine($"[Storage] ❌ 保存配置失败: {ex.Message}");
        }
        finally { _configLock.Release(); }
    }

    public async Task<List<VideoSourceConfig>> LoadDevicesAsync()
    {
        if (!File.Exists(_devicesPath)) return new List<VideoSourceConfig>();

        await _configLock.WaitAsync();
        try
        {
            var json = await File.ReadAllTextAsync(_devicesPath);
            if (string.IsNullOrWhiteSpace(json)) return new List<VideoSourceConfig>();

            var list = JsonSerializer.Deserialize<List<VideoSourceConfig>>(json, _jsonOptions);
            return list ?? new List<VideoSourceConfig>();
            //return new List<VideoSourceConfig>();
        }
        catch (Exception ex)
        {
            Console.WriteLine($"[Storage] ❌ 读取配置失败: {ex.Message}");
            return new List<VideoSourceConfig>();
        }
        finally { _configLock.Release(); }
    }

    // ==================================================================
    // 2. 系统操作日志 (使用 _logLock)
    // ==================================================================

    public async Task AppendSystemLogAsync(string action, string ip, string path)
    {
        // 格式: [时间] | IP | 动作 路径
        var time = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
        var line = $"[{time}] | {ip} | {action} {path}";

        await _logLock.WaitAsync(); // 等待日志锁
        try
        {
            // 追加写入 (Async)
            await File.AppendAllTextAsync(_systemLogPath, line + Environment.NewLine);
        }
        catch { /* 忽略日志写入错误，别崩了主程序 */ }
        finally { _logLock.Release(); }
    }

    public async Task<List<string>> GetSystemLogsAsync(int count)
    {
        if (!File.Exists(_systemLogPath)) return new List<string> { "暂无日志" };

        await _logLock.WaitAsync();
        try
        {
            // 读取所有行 (如果日志文件非常大，这里建议优化为倒序读取，但几MB以内没问题)
            var lines = await File.ReadAllLinesAsync(_systemLogPath);

            // 取最后 N 行，并反转（让最新的显示在最上面）
            return lines.TakeLast(count).Reverse().ToList();
        }
        catch (Exception ex)
        {
            return new List<string> { $"读取失败: {ex.Message}" };
        }
        finally { _logLock.Release(); }
    }

    // ==================================================================
    // 3. 设备审计日志 (使用 _logLock)
    // ==================================================================

    public async Task AppendDeviceLogAsync(int deviceId, string message)
    {
        var path = Path.Combine(_logsDir, $"device_{deviceId}.log");
        var time = DateTime.Now.ToString("MM-dd HH:mm:ss");
        var line = $"{time} > {message}";

        await _logLock.WaitAsync(); // 复用日志锁，防止多文件同时IO导致磁盘抖动
        try
        {
            await File.AppendAllTextAsync(path, line + Environment.NewLine);
        }
        catch { }
        finally { _logLock.Release(); }
    }

    public async Task<List<string>> GetDeviceLogsAsync(int deviceId, int count)
    {
        var path = Path.Combine(_logsDir, $"device_{deviceId}.log");
        if (!File.Exists(path)) return new List<string>();

        await _logLock.WaitAsync();
        try
        {
            var lines = await File.ReadAllLinesAsync(path);
            return lines.TakeLast(count).Reverse().ToList();
        }
        catch
        {
            return new List<string>();
        }
        finally { _logLock.Release(); }
    }
}