using System.Text;
using MigrationTool;
using MigrationTool.Models;

// 设置控制台输出编码
Console.OutputEncoding = Encoding.UTF8;

PrintBanner();

// 解析命令行参数
var options = ParseArguments(args);

if (options == null)
{
    PrintHelp();
    return 1;
}

PrintOptions(options);

// 确认执行
if (!options.DryRun)
{
    Console.WriteLine();
    Console.Write("确认开始迁移? (y/N): ");
    var confirm = Console.ReadLine()?.Trim().ToLowerInvariant();
    if (confirm != "y" && confirm != "yes")
    {
        Console.WriteLine("已取消");
        return 0;
    }
}

Console.WriteLine();

// 创建日志记录器
var logger = new ConsoleLogger(options.LogLevel);

// 执行迁移
try
{
    var service = new MigrationService(options, logger);
    var report = await service.MigrateAsync();

    // 打印报告
    report.PrintSummary();

    return report.FailedCount > 0 ? 1 : 0;
}
catch (Exception ex)
{
    logger.LogError($"迁移失败: {ex.Message}");
    logger.LogDebug(ex.StackTrace ?? "");
    return 2;
}

/// <summary>
/// 解析命令行参数
/// </summary>
static MigrationOptions? ParseArguments(string[] args)
{
    var options = new MigrationOptions
    {
        ConnectionString = GetDefaultConnectionString()
    };

    for (int i = 0; i < args.Length; i++)
    {
        var arg = args[i];
        switch (arg.ToLowerInvariant())
        {
            case "--help":
            case "-h":
            case "-?":
                return null;

            case "--connection-string":
            case "-c":
                if (i + 1 < args.Length)
                    options.ConnectionString = args[++i];
                break;

            case "--output-dir":
            case "-o":
                if (i + 1 < args.Length)
                    options.OutputDir = args[++i];
                break;

            case "--dry-run":
            case "-d":
                options.DryRun = true;
                break;

            case "--default-host":
                if (i + 1 < args.Length)
                    options.DefaultHost = args[++i];
                break;

            case "--service-port":
                if (i + 1 < args.Length && int.TryParse(args[++i], out var svcPort))
                    options.ServicePort = svcPort;
                break;

            case "--target-port":
                if (i + 1 < args.Length && int.TryParse(args[++i], out var tgtPort))
                    options.TargetPort = tgtPort;
                break;

            case "--no-validate":
                options.Validate = false;
                break;

            case "--tenant":
            case "-t":
                if (i + 1 < args.Length)
                    options.TenantCode = args[++i];
                break;

            case "--log-level":
            case "-l":
                if (i + 1 < args.Length && Enum.TryParse<LogLevel>(args[++i], true, out var level))
                    options.LogLevel = level;
                break;

            case "--no-report":
                options.GenerateReport = false;
                break;

            case "--report-path":
                if (i + 1 < args.Length)
                    options.ReportPath = args[++i];
                break;

            default:
                Console.WriteLine($"未知参数: {arg}");
                break;
        }
    }

    return options;
}

/// <summary>
/// 获取默认连接字符串（从环境变量）
/// </summary>
static string GetDefaultConnectionString()
{
    var envConnectionString = Environment.GetEnvironmentVariable("GATEWAY_CONNECTION_STRING");
    if (!string.IsNullOrEmpty(envConnectionString))
    {
        return envConnectionString;
    }

    return "Host=localhost;Database=fengling_gateway;Username=postgres;Password=postgres";
}

/// <summary>
/// 打印 Banner
/// </summary>
static void PrintBanner()
{
    Console.WriteLine();
    Console.WriteLine(@"  __  __ _ _            _   _             _         _   ");
    Console.WriteLine(@" |  \/  (_) | ___ _ __ | |_(_)_ __   __ _| |_ ___  | |_ ");
    Console.WriteLine(@" | |\/| | | |/ _ \ '_ \| __| | '_ \ / _` | __/ _ \ | __|");
    Console.WriteLine(@" | |  | | | |  __/ | | | |_| | | | | (_| | ||  __/ | |_ ");
    Console.WriteLine(@" |_|  |_|_|_|\___|_| |_|\__|_|_| |_|\__,_|\__\___|  \__|");
    Console.WriteLine(@"                                                        ");
    Console.WriteLine(@"  Fengling Gateway Migration Tool v1.0.0");
    Console.WriteLine();
}

/// <summary>
/// 打印帮助信息
/// </summary>
static void PrintHelp()
{
    Console.WriteLine("用法: MigrationTool [选项]");
    Console.WriteLine();
    Console.WriteLine("选项:");
    Console.WriteLine("  -h, --help                 显示帮助信息");
    Console.WriteLine("  -c, --connection-string    数据库连接字符串 (默认: 从 GATEWAY_CONNECTION_STRING 环境变量读取)");
    Console.WriteLine("  -o, --output-dir           YAML 文件输出目录 (默认: ./output)");
    Console.WriteLine("  -d, --dry-run              干运行模式，只输出不写入文件");
    Console.WriteLine("  --default-host             默认路由 Host (默认: api.fengling.com)");
    Console.WriteLine("  --service-port             Service 端口 (默认: 80)");
    Console.WriteLine("  --target-port              目标端口 (默认: 8080)");
    Console.WriteLine("  --no-validate              跳过数据验证");
    Console.WriteLine("  -t, --tenant               仅处理指定租户");
    Console.WriteLine("  -l, --log-level            日志级别 (Trace/Debug/Information/Warning/Error)");
    Console.WriteLine("  --no-report                不生成报告文件");
    Console.WriteLine("  --report-path              指定报告文件路径");
    Console.WriteLine();
    Console.WriteLine("示例:");
    Console.WriteLine("  MigrationTool --dry-run");
    Console.WriteLine("  MigrationTool -c \"Host=db;Database=gateway;Username=postgres;Password=secret\" -o ./yaml");
    Console.WriteLine("  MigrationTool --tenant tenant1 --dry-run");
    Console.WriteLine();
}

/// <summary>
/// 打印选项
/// </summary>
static void PrintOptions(MigrationOptions options)
{
    Console.WriteLine("配置选项:");
    Console.WriteLine($"  连接字符串: {MaskConnectionString(options.ConnectionString)}");
    Console.WriteLine($"  输出目录: {Path.GetFullPath(options.OutputDir)}");
    Console.WriteLine($"  Dry-Run: {(options.DryRun ? "是" : "否")}");
    Console.WriteLine($"  默认 Host: {options.DefaultHost}");
    Console.WriteLine($"  Service 端口: {options.ServicePort}");
    Console.WriteLine($"  Target 端口: {options.TargetPort}");
    Console.WriteLine($"  验证数据: {(options.Validate ? "是" : "否")}");
    Console.WriteLine($"  日志级别: {options.LogLevel}");
    if (!string.IsNullOrEmpty(options.TenantCode))
    {
        Console.WriteLine($"  指定租户: {options.TenantCode}");
    }
}

/// <summary>
/// 掩盖连接字符串中的敏感信息
/// </summary>
static string MaskConnectionString(string connectionString)
{
    if (string.IsNullOrEmpty(connectionString))
        return "[empty]";

    try
    {
        var builder = new Npgsql.NpgsqlConnectionStringBuilder(connectionString);
        if (!string.IsNullOrEmpty(builder.Password))
        {
            builder.Password = "***";
        }
        return builder.ToString();
    }
    catch
    {
        return "[invalid]";
    }
}

/// <summary>
/// 简单的控制台日志记录器
/// </summary>
public class ConsoleLogger : ILogger
{
    private readonly LogLevel _minLevel;

    public ConsoleLogger(LogLevel minLevel)
    {
        _minLevel = minLevel;
    }

    public void LogTrace(string message)
    {
        if (_minLevel <= LogLevel.Trace)
            WriteLog("TRC", ConsoleColor.Gray, message);
    }

    public void LogDebug(string message)
    {
        if (_minLevel <= LogLevel.Debug)
            WriteLog("DBG", ConsoleColor.DarkGray, message);
    }

    public void LogInformation(string message)
    {
        if (_minLevel <= LogLevel.Information)
            WriteLog("INF", ConsoleColor.White, message);
    }

    public void LogWarning(string message)
    {
        if (_minLevel <= LogLevel.Warning)
            WriteLog("WRN", ConsoleColor.Yellow, message);
    }

    public void LogError(string message)
    {
        if (_minLevel <= LogLevel.Error)
            WriteLog("ERR", ConsoleColor.Red, message);
    }

    private static void WriteLog(string level, ConsoleColor color, string message)
    {
        var timestamp = DateTime.Now.ToString("HH:mm:ss");
        var originalColor = Console.ForegroundColor;
        Console.ForegroundColor = color;
        Console.WriteLine($"[{timestamp}] [{level}] {message}");
        Console.ForegroundColor = originalColor;
    }
}

/// <summary>
/// 日志记录器接口
/// </summary>
public interface ILogger
{
    void LogTrace(string message);
    void LogDebug(string message);
    void LogInformation(string message);
    void LogWarning(string message);
    void LogError(string message);
}

/// <summary>
/// 日志级别
/// </summary>
public enum LogLevel
{
    Trace,
    Debug,
    Information,
    Warning,
    Error
}