namespace Admin.NET.Plugin.AiDOP.Service.S8.Rules.DataAccess;

/// <summary>
/// 数据集可用性诊断项。回答"这个数据集当前能不能用、能用于哪类规则"，
/// 不预览任何业务数据。
/// </summary>
public sealed class S8DatasetDiagnosticDto
{
    public string DatasetCode { get; init; } = string.Empty;
    public string DisplayName { get; init; } = string.Empty;
    public string Kind { get; init; } = string.Empty;
    public string? Description { get; init; }

    /// <summary>声明状态：DEFINED / DISABLED。</summary>
    public string DeclaredStatus { get; init; } = string.Empty;

    /// <summary>有效状态：READY / PROVIDER_MISSING / DISABLED。</summary>
    public string EffectiveStatus { get; init; } = string.Empty;

    public bool ProviderRegistered { get; init; }
    public string? ProviderType { get; init; }

    /// <summary>目录声明支持的规则类型（仅机制层）。</summary>
    public IReadOnlyList<string> DeclaredRuleTypes { get; init; } = Array.Empty<string>();

    /// <summary>真正可用的规则类型：机制支持 + canonical 字段齐备 + Provider 已注册且能力一致。</summary>
    public IReadOnlyList<string> UsableRuleTypes { get; init; } = Array.Empty<string>();

    /// <summary>各规则类型缺失的 canonical 字段，供配置界面提示。</summary>
    public IReadOnlyDictionary<string, IReadOnlyList<string>> MissingFieldsByRuleType { get; init; }
        = new Dictionary<string, IReadOnlyList<string>>();
}

/// <summary>
/// 数据集诊断服务。为后续规则配置界面提供"哪些数据集当前可用于哪类规则"的依据，
/// 使配置方不必先建规则再靠报错试探。
/// </summary>
public class S8DatasetDiagnosticsService : ITransient
{
    private readonly IS8DatasetCatalog _catalog;
    private readonly S8MonitoringDataProviderRegistry _registry;

    public S8DatasetDiagnosticsService(IS8DatasetCatalog catalog, S8MonitoringDataProviderRegistry registry)
    {
        _catalog = catalog;
        _registry = registry;
    }

    /// <summary>列出全部已定义数据集（含尚无 Provider 的）。</summary>
    public IReadOnlyList<S8DatasetDiagnosticDto> List() =>
        _catalog.All.Select(Describe).OrderBy(x => x.DatasetCode, StringComparer.OrdinalIgnoreCase).ToList();

    /// <summary>描述单个数据集；未定义返回 null（与"已定义但无 Provider"区分）。</summary>
    public S8DatasetDiagnosticDto? Describe(string? datasetCode)
    {
        var definition = _catalog.Find(datasetCode);
        return definition == null ? null : Describe(definition);
    }

    private S8DatasetDiagnosticDto Describe(S8DatasetDefinition definition)
    {
        var registered = _registry.IsRegistered(definition.DatasetCode);
        var provider = registered ? _registry.Resolve(definition.DatasetCode) : null;

        var effectiveStatus = !definition.IsActive
            ? S8DatasetStatus.Disabled
            : registered
                ? S8DatasetStatus.Ready
                : S8DatasetStatus.ProviderMissing;

        var declared = S8RuleTypeFieldRequirements.KnownRuleTypes
            .Where(rt => definition.Capabilities.Supports(rt))
            .ToList();

        // 可用 = 目录能力齐备 && （若已注册）Provider 能力也齐备。
        var usable = declared
            .Where(rt => definition.Capabilities.CanServe(rt))
            .Where(rt => provider == null || provider.Capabilities.CanServe(rt))
            .ToList();

        var missing = new Dictionary<string, IReadOnlyList<string>>(StringComparer.OrdinalIgnoreCase);
        foreach (var ruleType in declared)
        {
            var gaps = definition.Capabilities.MissingFieldsFor(ruleType);
            if (gaps is { Count: > 0 }) missing[ruleType] = gaps;
        }

        return new S8DatasetDiagnosticDto
        {
            DatasetCode = definition.DatasetCode,
            DisplayName = definition.DisplayName,
            Kind = definition.Kind,
            Description = definition.Description,
            DeclaredStatus = definition.Status,
            EffectiveStatus = effectiveStatus,
            ProviderRegistered = registered,
            ProviderType = provider?.GetType().Name,
            DeclaredRuleTypes = declared,
            UsableRuleTypes = usable,
            MissingFieldsByRuleType = missing
        };
    }
}