using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using OrpaonVision.Core.Results;
using OrpaonVision.Core.Training;
using OrpaonVision.Core.Training.Contracts;
using OrpaonVision.Core.Training.Contracts.Commands;
using System.IO;
using System.Text.Json;

namespace OrpaonVision.ConfigApp.Infrastructure.Services;

/// <summary>
/// 运行时部署快照配置选项。
/// </summary>
public class RuntimeDeploymentSnapshotOptions
{
    /// <summary>
    /// 快照基础路径。
    /// </summary>
    public string BasePath { get; set; } = "RuntimeDeploymentSnapshots";
}

/// <summary>
/// 运行时部署快照应用服务实现。
/// </summary>
public class RuntimeDeploymentSnapshotAppService : IRuntimeDeploymentSnapshotAppService
{
    private readonly ILogger<RuntimeDeploymentSnapshotAppService> _logger;
    private readonly RuntimeDeploymentSnapshotOptions _options;
    private readonly string _basePath;

    /// <summary>
    /// 初始化运行时部署快照应用服务。
    /// </summary>
    /// <param name="logger">日志记录器。</param>
    /// <param name="options">配置选项。</param>
    public RuntimeDeploymentSnapshotAppService(
        ILogger<RuntimeDeploymentSnapshotAppService> logger,
        IOptions<RuntimeDeploymentSnapshotOptions> options)
    {
        _logger = logger;
        _options = options.Value;
        _basePath = _options.BasePath ?? "RuntimeDeploymentSnapshots";
        
        // 确保基础目录存在
        if (!Directory.Exists(_basePath))
        {
            Directory.CreateDirectory(_basePath);
        }
    }

    /// <summary>
    /// 创建运行时部署快照。
    /// </summary>
    public async Task<Result<CreateRuntimeDeploymentSnapshotResultDto>> CreateSnapshotAsync(
        CreateRuntimeDeploymentSnapshotCommand command,
        CancellationToken cancellationToken = default)
    {
        try
        {
            _logger.LogInformation("开始创建运行时部署快照: {Name}", command.Name);

            var snapshotId = Guid.NewGuid();
            var snapshotDir = Path.Combine(_basePath, snapshotId.ToString("N"));
            
            // 创建快照目录
            Directory.CreateDirectory(snapshotDir);

            // 创建快照对象
            var snapshot = new RuntimeDeploymentSnapshot
            {
                Id = snapshotId,
                Name = command.Name,
                Description = command.Description,
                ProductTypeId = command.ProductTypeId,
                RuleVersionId = command.RuleVersionId,
                ModelPackageVersionId = command.ModelPackageVersionId,
                RuntimeParameterVersionId = command.RuntimeParameterVersionId,
                Status = RuntimeDeploymentSnapshotStatus.Draft,
                CreatedBy = command.CreatedBy,
                MetadataJson = command.MetadataJson
            };

            // 保存快照文件
            var snapshotFile = Path.Combine(snapshotDir, "snapshot.json");
            var snapshotJson = JsonSerializer.Serialize(snapshot, new JsonSerializerOptions { WriteIndented = true });
            await File.WriteAllTextAsync(snapshotFile, snapshotJson, cancellationToken);

            var result = new CreateRuntimeDeploymentSnapshotResultDto
            {
                SnapshotId = snapshotId,
                Name = command.Name,
                Status = RuntimeDeploymentSnapshotOperationStatus.Succeeded,
                Message = "快照创建成功",
                CreatedAtUtc = DateTime.UtcNow,
                CreatedBy = command.CreatedBy
            };

            _logger.LogInformation("成功创建运行时部署快照: {SnapshotId}", snapshotId);
            return Result<CreateRuntimeDeploymentSnapshotResultDto>.Success(result);
        }
        catch (Exception ex)
        {
            var traceId = Guid.NewGuid().ToString("N");
            _logger.LogError(ex, "创建运行时部署快照失败。TraceId: {TraceId}", traceId);
            return Result<CreateRuntimeDeploymentSnapshotResultDto>.FailWithTrace(
                "CREATE_SNAPSHOT_FAILED", "创建运行时部署快照失败。", traceId, ex.Message);
        }
    }

    /// <summary>
    /// 获取运行时部署快照详情。
    /// </summary>
    public async Task<Result<RuntimeDeploymentSnapshotDetailDto>> GetSnapshotAsync(
        Guid snapshotId,
        CancellationToken cancellationToken = default)
    {
        try
        {
            var snapshotDir = Path.Combine(_basePath, snapshotId.ToString("N"));
            var snapshotFile = Path.Combine(snapshotDir, "snapshot.json");

            if (!File.Exists(snapshotFile))
            {
                return Result<RuntimeDeploymentSnapshotDetailDto>.Fail("SNAPSHOT_NOT_FOUND", "快照不存在。");
            }

            var snapshotJson = await File.ReadAllTextAsync(snapshotFile, cancellationToken);
            var snapshot = JsonSerializer.Deserialize<RuntimeDeploymentSnapshot>(snapshotJson);

            if (snapshot == null)
            {
                return Result<RuntimeDeploymentSnapshotDetailDto>.Fail("INVALID_SNAPSHOT", "快照数据无效。");
            }

            var detailDto = new RuntimeDeploymentSnapshotDetailDto
            {
                Id = snapshot.Id,
                Name = snapshot.Name,
                Description = snapshot.Description,
                ProductTypeId = snapshot.ProductTypeId,
                ProductTypeCode = snapshot.ProductTypeCode,
                RuleVersionId = snapshot.RuleVersionId,
                RuleVersionNo = snapshot.RuleVersionNo,
                ModelPackageVersionId = snapshot.ModelPackageVersionId,
                ModelPackageVersionNo = snapshot.ModelPackageVersionNo,
                RuntimeParameterVersionId = snapshot.RuntimeParameterVersionId,
                RuntimeParameterVersionNo = snapshot.RuntimeParameterVersionNo,
                Status = snapshot.Status,
                CreatedAtUtc = snapshot.CreatedAtUtc,
                CreatedBy = snapshot.CreatedBy,
                ActivatedAtUtc = snapshot.ActivatedAtUtc,
                ActivatedBy = snapshot.ActivatedBy,
                RolledBackAtUtc = snapshot.RolledBackAtUtc,
                RolledBackBy = snapshot.RolledBackBy,
                MetadataJson = snapshot.MetadataJson
            };

            return Result<RuntimeDeploymentSnapshotDetailDto>.Success(detailDto);
        }
        catch (Exception ex)
        {
            var traceId = Guid.NewGuid().ToString("N");
            _logger.LogError(ex, "获取运行时部署快照详情失败。TraceId: {TraceId}", traceId);
            return Result<RuntimeDeploymentSnapshotDetailDto>.FailWithTrace(
                "GET_SNAPSHOT_FAILED", "获取运行时部署快照详情失败。", traceId, ex.Message);
        }
    }

    /// <summary>
    /// 获取运行时部署快照列表。
    /// </summary>
    public async Task<Result<IReadOnlyList<RuntimeDeploymentSnapshotSummaryDto>>> GetSnapshotsAsync(
        Guid? productTypeId = null,
        RuntimeDeploymentSnapshotStatus? status = null,
        CancellationToken cancellationToken = default)
    {
        try
        {
            var snapshots = new List<RuntimeDeploymentSnapshotSummaryDto>();

            foreach (var snapshotDir in Directory.GetDirectories(_basePath))
            {
                var snapshotFile = Path.Combine(snapshotDir, "snapshot.json");
                if (!File.Exists(snapshotFile)) continue;

                try
                {
                    var snapshotJson = await File.ReadAllTextAsync(snapshotFile, cancellationToken);
                    var snapshot = JsonSerializer.Deserialize<RuntimeDeploymentSnapshot>(snapshotJson);
                    
                    if (snapshot == null) continue;

                    // 应用筛选条件
                    if (productTypeId.HasValue && snapshot.ProductTypeId != productTypeId.Value) continue;
                    if (status.HasValue && snapshot.Status != status.Value) continue;

                    var summaryDto = new RuntimeDeploymentSnapshotSummaryDto
                    {
                        Id = snapshot.Id,
                        Name = snapshot.Name,
                        Description = snapshot.Description,
                        ProductTypeCode = snapshot.ProductTypeCode,
                        RuleVersionNo = snapshot.RuleVersionNo,
                        ModelPackageVersionNo = snapshot.ModelPackageVersionNo,
                        RuntimeParameterVersionNo = snapshot.RuntimeParameterVersionNo,
                        Status = snapshot.Status,
                        CreatedAtUtc = snapshot.CreatedAtUtc,
                        CreatedBy = snapshot.CreatedBy,
                        ActivatedAtUtc = snapshot.ActivatedAtUtc,
                        ActivatedBy = snapshot.ActivatedBy
                    };

                    snapshots.Add(summaryDto);
                }
                catch (Exception ex)
                {
                    _logger.LogWarning(ex, "读取快照文件失败: {SnapshotFile}", snapshotFile);
                }
            }

            // 按创建时间降序排序
            snapshots = snapshots.OrderByDescending(s => s.CreatedAtUtc).ToList();

            return Result<IReadOnlyList<RuntimeDeploymentSnapshotSummaryDto>>.Success(snapshots);
        }
        catch (Exception ex)
        {
            var traceId = Guid.NewGuid().ToString("N");
            _logger.LogError(ex, "获取运行时部署快照列表失败。TraceId: {TraceId}", traceId);
            return Result<IReadOnlyList<RuntimeDeploymentSnapshotSummaryDto>>.FailWithTrace(
                "GET_SNAPSHOTS_FAILED", "获取运行时部署快照列表失败。", traceId, ex.Message);
        }
    }

    /// <summary>
    /// 激活运行时部署快照。
    /// </summary>
    public async Task<Result<ActivateRuntimeDeploymentSnapshotResultDto>> ActivateSnapshotAsync(
        ActivateRuntimeDeploymentSnapshotCommand command,
        CancellationToken cancellationToken = default)
    {
        try
        {
            _logger.LogInformation("开始激活运行时部署快照: {SnapshotId}", command.SnapshotId);

            // 获取目标快照
            var snapshotResult = await GetSnapshotAsync(command.SnapshotId, cancellationToken);
            if (!snapshotResult.Succeeded)
            {
                return Result<ActivateRuntimeDeploymentSnapshotResultDto>.Fail(snapshotResult.Code, snapshotResult.Message);
            }

            var snapshot = snapshotResult.Data!;

            // 停用当前激活的快照（同一机种）
            var previousSnapshotId = await DeactivateCurrentSnapshotAsync(snapshot.ProductTypeId, cancellationToken);

            // 创建新的快照对象用于更新
            var updatedSnapshot = new RuntimeDeploymentSnapshot
            {
                Id = snapshot.Id,
                Name = snapshot.Name,
                Description = snapshot.Description,
                ProductTypeId = snapshot.ProductTypeId,
                ProductTypeCode = snapshot.ProductTypeCode,
                RuleVersionId = snapshot.RuleVersionId,
                RuleVersionNo = snapshot.RuleVersionNo,
                ModelPackageVersionId = snapshot.ModelPackageVersionId,
                ModelPackageVersionNo = snapshot.ModelPackageVersionNo,
                RuntimeParameterVersionId = snapshot.RuntimeParameterVersionId,
                RuntimeParameterVersionNo = snapshot.RuntimeParameterVersionNo,
                Status = RuntimeDeploymentSnapshotStatus.Activated,
                CreatedAtUtc = snapshot.CreatedAtUtc,
                CreatedBy = snapshot.CreatedBy,
                ActivatedAtUtc = DateTime.UtcNow,
                ActivatedBy = command.ActivatedBy,
                RolledBackAtUtc = snapshot.RolledBackAtUtc,
                RolledBackBy = snapshot.RolledBackBy,
                MetadataJson = snapshot.MetadataJson
            };

            // 保存更新后的快照
            await SaveSnapshotAsync(updatedSnapshot, cancellationToken);

            var result = new ActivateRuntimeDeploymentSnapshotResultDto
            {
                SnapshotId = command.SnapshotId,
                Status = RuntimeDeploymentSnapshotOperationStatus.Succeeded,
                Message = "快照激活成功",
                PreviousSnapshotId = previousSnapshotId,
                ActivatedAtUtc = DateTime.UtcNow,
                ActivatedBy = command.ActivatedBy
            };

            _logger.LogInformation("成功激活运行时部署快照: {SnapshotId}", command.SnapshotId);
            return Result<ActivateRuntimeDeploymentSnapshotResultDto>.Success(result);
        }
        catch (Exception ex)
        {
            var traceId = Guid.NewGuid().ToString("N");
            _logger.LogError(ex, "激活运行时部署快照失败。TraceId: {TraceId}", traceId);
            return Result<ActivateRuntimeDeploymentSnapshotResultDto>.FailWithTrace(
                "ACTIVATE_SNAPSHOT_FAILED", "激活运行时部署快照失败。", traceId, ex.Message);
        }
    }

    /// <summary>
    /// 回滚到运行时部署快照。
    /// </summary>
    public async Task<Result<RollbackToRuntimeDeploymentSnapshotResultDto>> RollbackToSnapshotAsync(
        RollbackToRuntimeDeploymentSnapshotCommand command,
        CancellationToken cancellationToken = default)
    {
        try
        {
            _logger.LogInformation("开始回滚到运行时部署快照: {TargetSnapshotId}", command.TargetSnapshotId);

            // 获取目标快照
            var targetSnapshotResult = await GetSnapshotAsync(command.TargetSnapshotId, cancellationToken);
            if (!targetSnapshotResult.Succeeded)
            {
                return Result<RollbackToRuntimeDeploymentSnapshotResultDto>.Fail(targetSnapshotResult.Code, targetSnapshotResult.Message);
            }

            var targetSnapshot = targetSnapshotResult.Data!;

            // 获取当前激活的快照
            var currentSnapshotId = await GetCurrentActivatedSnapshotIdAsync(targetSnapshot.ProductTypeId, cancellationToken);

            // 停用当前激活的快照
            if (currentSnapshotId.HasValue)
            {
                await DeactivateSnapshotAsync(currentSnapshotId.Value, cancellationToken);
            }

            // 激活目标快照
            var activateCommand = new ActivateRuntimeDeploymentSnapshotCommand
            {
                SnapshotId = command.TargetSnapshotId,
                ActivatedBy = command.RolledBackBy,
                Reason = command.Reason
            };

            var activateResult = await ActivateSnapshotAsync(activateCommand, cancellationToken);
            if (!activateResult.Succeeded)
            {
                return Result<RollbackToRuntimeDeploymentSnapshotResultDto>.Fail(activateResult.Code, activateResult.Message);
            }

            var result = new RollbackToRuntimeDeploymentSnapshotResultDto
            {
                TargetSnapshotId = command.TargetSnapshotId,
                PreviousSnapshotId = currentSnapshotId,
                Status = RuntimeDeploymentSnapshotOperationStatus.Succeeded,
                Message = "回滚成功",
                RolledBackAtUtc = DateTime.UtcNow,
                RolledBackBy = command.RolledBackBy
            };

            _logger.LogInformation("成功回滚到运行时部署快照: {TargetSnapshotId}", command.TargetSnapshotId);
            return Result<RollbackToRuntimeDeploymentSnapshotResultDto>.Success(result);
        }
        catch (Exception ex)
        {
            var traceId = Guid.NewGuid().ToString("N");
            _logger.LogError(ex, "回滚到运行时部署快照失败。TraceId: {TraceId}", traceId);
            return Result<RollbackToRuntimeDeploymentSnapshotResultDto>.FailWithTrace(
                "ROLLBACK_SNAPSHOT_FAILED", "回滚到运行时部署快照失败。", traceId, ex.Message);
        }
    }

    /// <summary>
    /// 获取当前激活的快照。
    /// </summary>
    public async Task<Result<RuntimeDeploymentSnapshotDetailDto>> GetCurrentActivatedSnapshotAsync(
        Guid productTypeId,
        CancellationToken cancellationToken = default)
    {
        try
        {
            var snapshotsResult = await GetSnapshotsAsync(productTypeId, RuntimeDeploymentSnapshotStatus.Activated, cancellationToken);
            if (!snapshotsResult.Succeeded)
            {
                return Result<RuntimeDeploymentSnapshotDetailDto>.Fail(snapshotsResult.Code, snapshotsResult.Message);
            }

            var activatedSnapshots = snapshotsResult.Data!;
            if (!activatedSnapshots.Any())
            {
                return Result<RuntimeDeploymentSnapshotDetailDto>.Fail("NO_ACTIVATED_SNAPSHOT", "没有找到激活的快照。");
            }

            // 获取最新的激活快照
            var latestSnapshot = activatedSnapshots.OrderByDescending(s => s.ActivatedAtUtc).First();
            var snapshotDetailResult = await GetSnapshotAsync(latestSnapshot.Id, cancellationToken);

            return snapshotDetailResult;
        }
        catch (Exception ex)
        {
            var traceId = Guid.NewGuid().ToString("N");
            _logger.LogError(ex, "获取当前激活的快照失败。TraceId: {TraceId}", traceId);
            return Result<RuntimeDeploymentSnapshotDetailDto>.FailWithTrace(
                "GET_CURRENT_SNAPSHOT_FAILED", "获取当前激活的快照失败。", traceId, ex.Message);
        }
    }

    /// <summary>
    /// 获取快照历史记录。
    /// </summary>
    public async Task<Result<IReadOnlyList<RuntimeDeploymentSnapshotSummaryDto>>> GetSnapshotHistoryAsync(
        Guid productTypeId,
        CancellationToken cancellationToken = default)
    {
        return await GetSnapshotsAsync(productTypeId, null, cancellationToken);
    }

    #region 辅助方法

    /// <summary>
    /// 停用当前激活的快照。
    /// </summary>
    private async Task<Guid?> DeactivateCurrentSnapshotAsync(Guid productTypeId, CancellationToken cancellationToken)
    {
        var currentSnapshotResult = await GetCurrentActivatedSnapshotAsync(productTypeId, cancellationToken);
        if (currentSnapshotResult.Succeeded)
        {
            var currentSnapshotId = currentSnapshotResult.Data!.Id;
            await DeactivateSnapshotAsync(currentSnapshotId, cancellationToken);
            return currentSnapshotId;
        }
        return null;
    }

    /// <summary>
    /// 停用指定快照。
    /// </summary>
    private async Task DeactivateSnapshotAsync(Guid snapshotId, CancellationToken cancellationToken)
    {
        var snapshotDir = Path.Combine(_basePath, snapshotId.ToString("N"));
        var snapshotFile = Path.Combine(snapshotDir, "snapshot.json");

        if (File.Exists(snapshotFile))
        {
            var snapshotJson = await File.ReadAllTextAsync(snapshotFile, cancellationToken);
            var snapshot = JsonSerializer.Deserialize<RuntimeDeploymentSnapshot>(snapshotJson);
            
            if (snapshot != null)
            {
                snapshot.Status = RuntimeDeploymentSnapshotStatus.RolledBack;
                snapshot.RolledBackAtUtc = DateTime.UtcNow;
                snapshot.RolledBackBy = "System"; // 系统自动回滚

                await SaveSnapshotAsync(snapshot, cancellationToken);
            }
        }
    }

    /// <summary>
    /// 获取当前激活的快照ID。
    /// </summary>
    private async Task<Guid?> GetCurrentActivatedSnapshotIdAsync(Guid productTypeId, CancellationToken cancellationToken)
    {
        var snapshotsResult = await GetSnapshotsAsync(productTypeId, RuntimeDeploymentSnapshotStatus.Activated, cancellationToken);
        if (snapshotsResult.Succeeded)
        {
            var activatedSnapshots = snapshotsResult.Data!;
            if (activatedSnapshots.Any())
            {
                return activatedSnapshots.OrderByDescending(s => s.ActivatedAtUtc).First().Id;
            }
        }
        return null;
    }

    /// <summary>
    /// 保存快照。
    /// </summary>
    private async Task SaveSnapshotAsync(RuntimeDeploymentSnapshot snapshot, CancellationToken cancellationToken)
    {
        var snapshotDir = Path.Combine(_basePath, snapshot.Id.ToString("N"));
        var snapshotFile = Path.Combine(snapshotDir, "snapshot.json");

        var snapshotJson = JsonSerializer.Serialize(snapshot, new JsonSerializerOptions { WriteIndented = true });
        await File.WriteAllTextAsync(snapshotFile, snapshotJson, cancellationToken);
    }

    #endregion
}