using System.Diagnostics;
using Umbraco.Cms.Core.Models.PublishedContent;
using Umbraco.Cms.Core.PublishedCache;
using Umbraco.Cms.Infrastructure.PublishedCache.DataSource;
using Umbraco.Extensions;

namespace Umbraco.Cms.Infrastructure.PublishedCache;

// represents a content "node" ie a pair of draft + published versions
// internal, never exposed, to be accessed from ContentStore (only!)
[DebuggerDisplay("Id: {Id}, Path: {Path}")]
public class ContentNode
{
    // everything that is common to both draft and published versions
    // keep this as small as possible
#pragma warning disable IDE1006 // Naming Styles
    public readonly int Id;

    private ContentData? _draftData;

    // draft and published version (either can be null, but not both)
    // are models not direct PublishedContent instances
    private IPublishedContent? _draftModel;
    private ContentData? _publishedData;
    private IPublishedContent? _publishedModel;
    private IPublishedModelFactory? _publishedModelFactory;
    private IPublishedSnapshotAccessor? _publishedSnapshotAccessor;

    private IVariationContextAccessor? _variationContextAccessor;

    // special ctor for root pseudo node
    public ContentNode()
    {
        FirstChildContentId = -1;
        LastChildContentId = -1;
        NextSiblingContentId = -1;
        PreviousSiblingContentId = -1;
        Path = string.Empty;
    }

    // special ctor with no content data - for members
    public ContentNode(
        int id,
        Guid uid,
        IPublishedContentType contentType,
        int level,
        string path,
        int sortOrder,
        int parentContentId,
        DateTime createDate,
        int creatorId)
        : this()
    {
        Id = id;
        Uid = uid;
        ContentType = contentType;
        Level = level;
        Path = path;
        SortOrder = sortOrder;
        ParentContentId = parentContentId;
        CreateDate = createDate;
        CreatorId = creatorId;
    }

    public ContentNode(
        int id,
        Guid uid,
        IPublishedContentType contentType,
        int level,
        string path,
        int sortOrder,
        int parentContentId,
        DateTime createDate,
        int creatorId,
        ContentData draftData,
        ContentData publishedData,
        IPublishedSnapshotAccessor publishedSnapshotAccessor,
        IVariationContextAccessor variationContextAccessor,
        IPublishedModelFactory publishedModelFactory)
        : this(id, uid, level, path, sortOrder, parentContentId, createDate, creatorId) =>
        SetContentTypeAndData(contentType, draftData, publishedData, publishedSnapshotAccessor, variationContextAccessor, publishedModelFactory);

    // 2-phases ctor, phase 1
    public ContentNode(
        int id,
        Guid uid,
        int level,
        string path,
        int sortOrder,
        int parentContentId,
        DateTime createDate,
        int creatorId)
    {
        Id = id;
        Uid = uid;
        Level = level;
        Path = path;
        SortOrder = sortOrder;
        ParentContentId = parentContentId;
        FirstChildContentId = -1;
        LastChildContentId = -1;
        NextSiblingContentId = -1;
        PreviousSiblingContentId = -1;
        CreateDate = createDate;
        CreatorId = creatorId;
    }

    // clone
    public ContentNode(ContentNode origin, IPublishedModelFactory publishedModelFactory, IPublishedContentType? contentType = null)
    {
        _publishedModelFactory = publishedModelFactory;
        Id = origin.Id;
        Uid = origin.Uid;
        ContentType = contentType ?? origin.ContentType;
        Level = origin.Level;
        Path = origin.Path;
        SortOrder = origin.SortOrder;
        ParentContentId = origin.ParentContentId;
        FirstChildContentId = origin.FirstChildContentId;
        LastChildContentId = origin.LastChildContentId;
        NextSiblingContentId = origin.NextSiblingContentId;
        PreviousSiblingContentId = origin.PreviousSiblingContentId;
        CreateDate = origin.CreateDate;
        CreatorId = origin.CreatorId;

        _draftData = origin._draftData;
        _publishedData = origin._publishedData;
        _publishedSnapshotAccessor = origin._publishedSnapshotAccessor;
        _variationContextAccessor = origin._variationContextAccessor;
    }

    public bool HasPublished => _publishedData != null;

    public IPublishedContent? DraftModel => GetModel(ref _draftModel, _draftData);

    public IPublishedContent? PublishedModel => GetModel(ref _publishedModel, _publishedData);

    // two-phase ctor, phase 2
    public void SetContentTypeAndData(
        IPublishedContentType contentType,
        ContentData? draftData,
        ContentData? publishedData,
        IPublishedSnapshotAccessor publishedSnapshotAccessor,
        IVariationContextAccessor variationContextAccessor,
        IPublishedModelFactory publishedModelFactory)
    {
        ContentType = contentType;

        if (draftData == null && publishedData == null)
        {
            throw new ArgumentException("Both draftData and publishedData cannot be null at the same time.");
        }

        _publishedSnapshotAccessor = publishedSnapshotAccessor;
        _variationContextAccessor = variationContextAccessor;
        _publishedModelFactory = publishedModelFactory;

        _draftData = draftData;
        _publishedData = publishedData;
    }

    public bool HasPublishedCulture(string culture) =>
        _publishedData != null && (_publishedData.CultureInfos?.ContainsKey(culture) ?? false);

    public ContentNodeKit ToKit() => new(this, ContentType.Id, _draftData, _publishedData);

    private IPublishedContent? GetModel(ref IPublishedContent? model, ContentData? contentData)
    {
        if (model != null)
        {
            return model;
        }

        if (contentData == null)
        {
            return null;
        }

        // create the model - we want to be fast, so no lock here: we may create
        // more than 1 instance, but the lock below ensures we only ever return
        // 1 unique instance - and locking is a nice explicit way to ensure this
        IPublishedContent? m =
            new PublishedContent(this, contentData, _publishedSnapshotAccessor, _variationContextAccessor, _publishedModelFactory).CreateModel(_publishedModelFactory);

        // locking 'this' is not a best-practice but ContentNode is internal and
        // we know what we do, so it is fine here and avoids allocating an object
        lock (this)
        {
            return model ??= m;
        }
    }

    public readonly Guid Uid;
    public readonly int Level;
    public IPublishedContentType ContentType = null!;
    public readonly string Path;
    public readonly int SortOrder;
    public readonly int ParentContentId;
    public readonly DateTime CreateDate;

#pragma warning restore IDE1006 // Naming Styles

    // TODO: Can we make everything readonly?? This would make it easier to debug and be less error prone especially for new developers.
    // Once a Node is created and exists in the cache it is readonly so we should be able to make that happen at the API level too.
#pragma warning disable IDE1006 // Naming Styles
    public int FirstChildContentId;
    public int LastChildContentId;
    public int NextSiblingContentId;
    public int PreviousSiblingContentId;
    public readonly int CreatorId;
#pragma warning restore IDE1006 // Naming Styles
}