using System.Text.Json;
using Microsoft.EntityFrameworkCore;
using Tiku.Application.Assets;
using Tiku.Application.Content;
using Tiku.Application.Security;
using Tiku.Domain.Common;
using Tiku.Domain.Content;
using Tiku.Domain.Learning;
using Tiku.Domain.Operations;

namespace Tiku.Infrastructure.Content;

internal abstract partial class DirectContentServiceBase
{
    protected static VideoManagementItem ToVideoItem(VideoExplanation item)
    {
        return new VideoManagementItem(
            item.Id,
            item.SubjectId,
            item.LegacyId,
            item.Title,
            item.Description,
            item.VideoUrl,
            item.ThumbnailUrl,
            item.DurationSeconds,
            item.KnowledgeTags,
            item.IsGeneral,
            item.Difficulty,
            item.SortOrder,
            item.IsActive,
            item.Metadata);
    }

    protected static QuestionVideoManagementItem ToQuestionVideoItem(QuestionVideo item)
    {
        return new QuestionVideoManagementItem(
            item.Id,
            item.QuestionPlacementId,
            item.VideoId,
            item.LegacyId,
            item.VideoType,
            item.SortOrder,
            item.Metadata);
    }

    protected static OperationContentItem ToOperationItem(Banner item)
    {
        return new OperationContentItem(
            item.Id,
            "banners",
            item.RegionId,
            null,
            item.LegacyId,
            item.Title,
            item.Content,
            null,
            null,
            null,
            null,
            item.SortOrder,
            item.IsActive,
            JsonSerializer.SerializeToElement(new
            {
                item.Subtitle,
                item.ButtonText,
                item.ButtonLink,
                item.BackgroundColor,
                item.BorderColor
            }));
    }

    protected static OperationContentItem ToOperationItem(Faq item)
    {
        return new OperationContentItem(
            item.Id,
            "faqs",
            item.RegionId,
            null,
            item.LegacyId,
            null,
            null,
            item.Question,
            item.Answer,
            null,
            null,
            item.SortOrder,
            item.IsActive,
            JsonDefaults.Object());
    }

    protected static OperationContentItem ToOperationItem(Announcement item)
    {
        return new OperationContentItem(
            item.Id,
            "announcements",
            null,
            null,
            item.LegacyId,
            null,
            item.Content,
            null,
            null,
            null,
            null,
            item.SortOrder,
            item.IsActive,
            JsonSerializer.SerializeToElement(new
            {
                item.Link,
                item.BackgroundColor
            }));
    }

    protected static OperationContentItem ToOperationItem(ExamDate item)
    {
        return new OperationContentItem(
            item.Id,
            "exam-dates",
            item.RegionId,
            item.SchoolId,
            item.LegacyId,
            item.ExamName,
            item.Description,
            null,
            null,
            item.ExamAt,
            item.ExamType,
            item.SortOrder,
            item.IsActive,
            item.Metadata);
    }

    protected static ContentImportJobItem ToJobItem(ContentImportJob job)
    {
        return new ContentImportJobItem(
            job.Id,
            job.TargetRegionId,
            job.TargetSubjectId,
            job.TargetCategoryId,
            job.TargetContentNodeId,
            job.TargetQuestionBankId,
            job.ImportType,
            job.SourceFormat,
            job.Status,
            job.SourceName,
            job.SourceHash,
            job.DryRun,
            job.TotalCount,
            job.ValidCount,
            job.ErrorCount,
            job.WarningCount,
            job.InsertedCount,
            job.UpdatedCount,
            job.SkippedCount,
            job.Summary,
            job.ErrorMessage,
            job.StartedAt,
            job.FinishedAt,
            job.CreatedAt,
            job.UpdatedAt);
    }

    protected static ContentImportItemModel ToImportItem(ContentImportItem item)
    {
        return new ContentImportItemModel(
            item.Id,
            item.JobId,
            item.RowNo,
            item.ExternalId,
            item.Status,
            item.TargetType,
            item.TargetId,
            item.SourcePayload,
            item.NormalizedPayload,
            item.ContentHash,
            item.IssuesCount);
    }

    protected async Task<CurrentDataScope> RequireDataScopeAsync(
        DirectContentActor actor,
        CancellationToken cancellationToken)
    {
        var access = await currentAccessContext.GetAsync(cancellationToken);
        if (!access.IsCurrentTenantMember ||
            access.UserId != actor.UserId ||
            access.TenantId != actor.TenantId ||
            !ContentPermissions.Any(access.HasTenantPermission))
            throw new ContentManagementException("Tenant content access was denied.", "content_access_denied");

        return access.DataScope;
    }

    protected static void EnsureRegionWriteAllowed(
        CurrentDataScope scope,
        DirectContentActor actor,
        Guid? currentRegionId,
        Guid? targetRegionId,
        bool isNew,
        string notFoundCode)
    {
        var canAccessCurrent = isNew || scope.AllowsResource(actor.UserId, regionId: currentRegionId);
        var canAccessTarget = scope.AllowsResource(actor.UserId, regionId: targetRegionId);
        if (!canAccessCurrent || !canAccessTarget)
            throw new ContentManagementException("Content resource was not found.", notFoundCode);
    }

    protected async Task<TEntity?> ResolveByIdOrLegacyAsync<TEntity>(
        DbSet<TEntity> set,
        Guid tenantId,
        Guid? id,
        string? legacyId,
        CancellationToken cancellationToken)
        where TEntity : AuditableTenantEntity
    {
        if (id.HasValue)
            return await set.SingleOrDefaultAsync(item => item.TenantId == tenantId && item.Id == id.Value,
                cancellationToken);

        var normalizedLegacyId = Normalize(legacyId);
        return normalizedLegacyId is null
            ? null
            : await set.SingleOrDefaultAsync(
                item => item.TenantId == tenantId && EF.Property<string?>(item, "LegacyId") == normalizedLegacyId,
                cancellationToken);
    }

    protected async Task AssertReferenceAsync<TEntity>(
        Guid tenantId,
        Guid? id,
        string code,
        CancellationToken cancellationToken)
        where TEntity : class
    {
        if (!id.HasValue) return;

        var exists = await unitOfWork.Set<TEntity>()
            .AnyAsync(
                item => EF.Property<Guid>(item, "TenantId") == tenantId && EF.Property<Guid>(item, "Id") == id.Value,
                cancellationToken);
        if (!exists) throw new ContentManagementException("Referenced entity was not found.", code);
    }

    protected async Task AssertImportJobAsync(Guid tenantId, Guid jobId, CancellationToken cancellationToken)
    {
        var exists = await questionBankPersistence.ContentImportJobs.AnyAsync(
            item => item.TenantId == tenantId && item.Id == jobId,
            cancellationToken);
        if (!exists) throw new ContentManagementException("Import job was not found.", "import_job_not_found");
    }

    protected static string NormalizeOperationKind(string kind)
    {
        var normalized = Normalize(kind)?.ToLowerInvariant();
        return normalized switch
        {
            "banner" or "banners" => "banners",
            "faq" or "faqs" => "faqs",
            "announcement" or "announcements" => "announcements",
            "exam-date" or "exam-dates" or "examdates" => "exam-dates",
            _ => normalized ?? string.Empty
        };
    }

    protected static ContentImportType ParseImportType(string value)
    {
        return value.ToLowerInvariant() switch
        {
            "questions" => ContentImportType.Questions,
            "vocabulary" => ContentImportType.Vocabulary,
            "handbook" => ContentImportType.Handbook,
            "scoreline" => ContentImportType.Scoreline,
            "videos" => ContentImportType.Videos,
            _ => throw new ContentManagementException("Import type is invalid.", "import_type_invalid")
        };
    }

    protected static TEnum Parse<TEnum>(string? value, TEnum fallback, string code)
        where TEnum : struct
    {
        if (string.IsNullOrWhiteSpace(value)) return fallback;

        if (Enum.TryParse<TEnum>(value.Trim(), true, out var parsed)) return parsed;

        throw new ContentManagementException("Enum value is invalid.", code);
    }

    protected static TEnum? ParseNullable<TEnum>(string? value, string code)
        where TEnum : struct
    {
        if (string.IsNullOrWhiteSpace(value)) return null;

        if (Enum.TryParse<TEnum>(value.Trim(), true, out var parsed)) return parsed;

        throw new ContentManagementException("Enum value is invalid.", code);
    }

    protected static string? Normalize(string? value)
    {
        return string.IsNullOrWhiteSpace(value) ? null : value.Trim();
    }

    protected static int ResolveLimit(int? limit)
    {
        return !limit.HasValue || limit <= 0 ? DefaultLimit : Math.Min(limit.Value, MaxLimit);
    }

    protected static JsonElement JsonObjectOrDefault(JsonElement value)
    {
        return value.ValueKind is JsonValueKind.Object ? value : JsonDefaults.Object();
    }

    protected static JsonElement JsonArrayOrDefault(JsonElement value)
    {
        return value.ValueKind is JsonValueKind.Array ? value : JsonDefaults.Array();
    }

    protected static JsonElement GetElement(JsonElement payload, string name, JsonElement fallback)
    {
        return payload.ValueKind == JsonValueKind.Object && payload.TryGetProperty(name, out var value)
            ? value
            : fallback;
    }

    protected static string? GetString(JsonElement payload, string name)
    {
        if (payload.ValueKind != JsonValueKind.Object || !payload.TryGetProperty(name, out var value)) return null;

        return value.ValueKind == JsonValueKind.String ? Normalize(value.GetString()) : value.ToString();
    }

    protected static int? GetInt(JsonElement payload, string name)
    {
        if (payload.ValueKind != JsonValueKind.Object || !payload.TryGetProperty(name, out var value)) return null;

        return value.ValueKind == JsonValueKind.Number && value.TryGetInt32(out var number)
            ? number
            : int.TryParse(value.ToString(), out number)
                ? number
                : null;
    }

    protected static Guid? GetGuid(JsonElement payload, string name)
    {
        if (payload.ValueKind != JsonValueKind.Object || !payload.TryGetProperty(name, out var value)) return null;

        return value.ValueKind == JsonValueKind.String &&
               Guid.TryParse(value.GetString(), out var guid)
            ? guid
            : null;
    }

    protected static bool? GetBool(JsonElement payload, string name)
    {
        if (payload.ValueKind != JsonValueKind.Object || !payload.TryGetProperty(name, out var value)) return null;

        return value.ValueKind switch
        {
            JsonValueKind.True => true,
            JsonValueKind.False => false,
            JsonValueKind.String when bool.TryParse(value.GetString(), out var parsed) => parsed,
            _ => null
        };
    }
}