using System.Xml.Serialization;
using Umbraco.Cms.Core.Cache;
using Umbraco.Cms.Core.Collections;
using Umbraco.Cms.Core.Models;
using Umbraco.Cms.Core.Models.PublishedContent;
using Umbraco.Cms.Core.PropertyEditors;
using Umbraco.Cms.Core.PublishedCache;
using Umbraco.Cms.Infrastructure.PublishedCache.DataSource;
using Umbraco.Extensions;

namespace Umbraco.Cms.Infrastructure.PublishedCache;

[Serializable]
[XmlType(Namespace = "http://umbraco.org/webservices/")]
internal class Property : PublishedPropertyBase
{
    private readonly PublishedContent _content;
    private readonly Guid _contentUid;
    private readonly bool _isMember;
    private readonly bool _isPreviewing;

    private readonly object _locko = new();
    private readonly IPublishedSnapshotAccessor _publishedSnapshotAccessor;

    // the invariant-neutral source and inter values
    private readonly object? _sourceValue;
    private readonly ContentVariation _variations;

    // the variant and non-variant object values
    private CacheValues? _cacheValues;
    private bool _interInitialized;
    private object? _interValue;

    // the variant source and inter values
    private Dictionary<CompositeStringStringKey, SourceInterValue>? _sourceValues;

    private string? _valuesCacheKey;

    // initializes a published content property with no value
    public Property(
        IPublishedPropertyType propertyType,
        PublishedContent content,
        IPublishedSnapshotAccessor publishedSnapshotAccessor,
        PropertyCacheLevel referenceCacheLevel = PropertyCacheLevel.Element)
        : this(propertyType, content, null, publishedSnapshotAccessor, referenceCacheLevel)
    {
    }

    // initializes a published content property with a value
    public Property(
        IPublishedPropertyType propertyType,
        PublishedContent content,
        PropertyData[]? sourceValues,
        IPublishedSnapshotAccessor publishedSnapshotAccessor,
        PropertyCacheLevel referenceCacheLevel = PropertyCacheLevel.Element)
        : base(propertyType, referenceCacheLevel)
    {
        if (sourceValues != null)
        {
            foreach (PropertyData sourceValue in sourceValues)
            {
                if (sourceValue.Culture == string.Empty && sourceValue.Segment == string.Empty)
                {
                    _sourceValue = sourceValue.Value;
                }
                else
                {
                    if (_sourceValues == null)
                    {
                        _sourceValues = new Dictionary<CompositeStringStringKey, SourceInterValue>();
                    }

                    _sourceValues[new CompositeStringStringKey(sourceValue.Culture, sourceValue.Segment)]
                        = new SourceInterValue
                        {
                            Culture = sourceValue.Culture,
                            Segment = sourceValue.Segment,
                            SourceValue = sourceValue.Value,
                        };
                }
            }
        }

        _contentUid = content.Key;
        _content = content;
        _isPreviewing = content.IsPreviewing;
        _isMember = content.ContentType.ItemType == PublishedItemType.Member;
        _publishedSnapshotAccessor = publishedSnapshotAccessor;
        _variations = propertyType.Variations;
    }

    // clone for previewing as draft a published content that is published and has no draft
    public Property(Property origin, PublishedContent content)
        : base(origin.PropertyType, origin.ReferenceCacheLevel)
    {
        _sourceValue = origin._sourceValue;
        _sourceValues = origin._sourceValues;

        _contentUid = origin._contentUid;
        _content = content;
        _isPreviewing = true;
        _isMember = origin._isMember;
        _publishedSnapshotAccessor = origin._publishedSnapshotAccessor;
        _variations = origin._variations;
    }

    // used to cache the CacheValues of this property
    internal string ValuesCacheKey => _valuesCacheKey ??=
                                          CacheKeys.PropertyCacheValues(_contentUid, Alias, _isPreviewing);

    // determines whether a property has value
    public override bool HasValue(string? culture = null, string? segment = null)
    {
        _content.VariationContextAccessor.ContextualizeVariation(_variations, _content.Id, ref culture, ref segment);

        var value = GetSourceValue(culture, segment);
        var hasValue = PropertyType.IsValue(value, PropertyValueLevel.Source);
        if (hasValue.HasValue)
        {
            return hasValue.Value;
        }

        lock (_locko)
        {
            value = GetInterValue(culture, segment);
            hasValue = PropertyType.IsValue(value, PropertyValueLevel.Inter);
            if (hasValue.HasValue)
            {
                return hasValue.Value;
            }

            CacheValue cacheValues = GetCacheValues(PropertyType.CacheLevel).For(culture, segment);

            // initial reference cache level always is .Content
            const PropertyCacheLevel initialCacheLevel = PropertyCacheLevel.Element;

            if (!cacheValues.ObjectInitialized)
            {
                cacheValues.ObjectValue =
                    PropertyType.ConvertInterToObject(_content, initialCacheLevel, value, _isPreviewing);
                cacheValues.ObjectInitialized = true;
            }

            value = cacheValues.ObjectValue;
            return PropertyType.IsValue(value, PropertyValueLevel.Object) ?? false;
        }
    }

    public override object? GetSourceValue(string? culture = null, string? segment = null)
    {
        _content.VariationContextAccessor.ContextualizeVariation(_variations, _content.Id, ref culture, ref segment);

        if (culture == string.Empty && segment == string.Empty)
        {
            return _sourceValue;
        }

        lock (_locko)
        {
            if (_sourceValues == null)
            {
                return null;
            }

            return _sourceValues.TryGetValue(
                new CompositeStringStringKey(culture, segment),
                out SourceInterValue? sourceValue)
                ? sourceValue.SourceValue
                : null;
        }
    }

    private CacheValues GetCacheValues(PropertyCacheLevel cacheLevel)
    {
        CacheValues cacheValues;
        IPublishedSnapshot publishedSnapshot;
        IAppCache? cache;
        switch (cacheLevel)
        {
            case PropertyCacheLevel.None:
                // never cache anything
                cacheValues = new CacheValues();
                break;
            case PropertyCacheLevel.Element:
                // cache within the property object itself, ie within the content object
                cacheValues = _cacheValues ??= new CacheValues();
                break;
            case PropertyCacheLevel.Elements:
                // cache within the elements cache, unless previewing, then use the snapshot or
                // elements cache (if we don't want to pollute the elements cache with short-lived
                // data) depending on settings
                // for members, always cache in the snapshot cache - never pollute elements cache
                publishedSnapshot = _publishedSnapshotAccessor.GetRequiredPublishedSnapshot();
                cache = publishedSnapshot == null
                    ? null
                    : (_isPreviewing == false || PublishedSnapshotService.FullCacheWhenPreviewing) && _isMember == false
                        ? publishedSnapshot.ElementsCache
                        : publishedSnapshot.SnapshotCache;
                cacheValues = GetCacheValues(cache);
                break;
            case PropertyCacheLevel.Snapshot:
                // cache within the snapshot cache
                publishedSnapshot = _publishedSnapshotAccessor.GetRequiredPublishedSnapshot();
                cache = publishedSnapshot?.SnapshotCache;
                cacheValues = GetCacheValues(cache);
                break;
            default:
                throw new InvalidOperationException("Invalid cache level.");
        }

        return cacheValues;
    }

    private CacheValues GetCacheValues(IAppCache? cache)
    {
        // no cache, don't cache
        if (cache == null)
        {
            return new CacheValues();
        }

        return (CacheValues)cache.Get(ValuesCacheKey, () => new CacheValues())!;
    }

    // this is always invoked from within a lock, so does not require its own lock
    private object? GetInterValue(string? culture, string? segment)
    {
        if (culture == string.Empty && segment == string.Empty)
        {
            if (_interInitialized)
            {
                return _interValue;
            }

            _interValue = PropertyType.ConvertSourceToInter(_content, _sourceValue, _isPreviewing);
            _interInitialized = true;
            return _interValue;
        }

        if (_sourceValues == null)
        {
            _sourceValues = new Dictionary<CompositeStringStringKey, SourceInterValue>();
        }

        var k = new CompositeStringStringKey(culture, segment);
        if (!_sourceValues.TryGetValue(k, out SourceInterValue? vvalue))
        {
            _sourceValues[k] = vvalue = new SourceInterValue
            {
                Culture = culture,
                Segment = segment,
                SourceValue = GetSourceValue(culture, segment),
            };
        }

        if (vvalue.InterInitialized)
        {
            return vvalue.InterValue;
        }

        vvalue.InterValue = PropertyType.ConvertSourceToInter(_content, vvalue.SourceValue, _isPreviewing);
        vvalue.InterInitialized = true;
        return vvalue.InterValue;
    }

    public override object? GetValue(string? culture = null, string? segment = null)
    {
        _content.VariationContextAccessor.ContextualizeVariation(_variations, _content.Id, ref culture, ref segment);

        object? value;
        lock (_locko)
        {
            CacheValue cacheValues = GetCacheValues(PropertyType.CacheLevel).For(culture, segment);

            // initial reference cache level always is .Content
            const PropertyCacheLevel initialCacheLevel = PropertyCacheLevel.Element;

            if (cacheValues.ObjectInitialized)
            {
                return cacheValues.ObjectValue;
            }

            cacheValues.ObjectValue = PropertyType.ConvertInterToObject(_content, initialCacheLevel, GetInterValue(culture, segment), _isPreviewing);
            cacheValues.ObjectInitialized = true;
            value = cacheValues.ObjectValue;
        }

        return value;
    }

    public override object? GetXPathValue(string? culture = null, string? segment = null)
    {
        _content.VariationContextAccessor.ContextualizeVariation(_variations, _content.Id, ref culture, ref segment);

        lock (_locko)
        {
            CacheValue cacheValues = GetCacheValues(PropertyType.CacheLevel).For(culture, segment);

            // initial reference cache level always is .Content
            const PropertyCacheLevel initialCacheLevel = PropertyCacheLevel.Element;

            if (cacheValues.XPathInitialized)
            {
                return cacheValues.XPathValue;
            }

            cacheValues.XPathValue = PropertyType.ConvertInterToXPath(_content, initialCacheLevel, GetInterValue(culture, segment), _isPreviewing);
            cacheValues.XPathInitialized = true;
            return cacheValues.XPathValue;
        }
    }

    #region Classes

    private class CacheValue
    {
        public bool ObjectInitialized { get; set; }

        public object? ObjectValue { get; set; }

        public bool XPathInitialized { get; set; }

        public object? XPathValue { get; set; }
    }

    private class CacheValues : CacheValue
    {
        private Dictionary<CompositeStringStringKey, CacheValue>? _values;

        // this is always invoked from within a lock, so does not require its own lock
        public CacheValue For(string? culture, string? segment)
        {
            if (culture == string.Empty && segment == string.Empty)
            {
                return this;
            }

            if (_values == null)
            {
                _values = new Dictionary<CompositeStringStringKey, CacheValue>();
            }

            var k = new CompositeStringStringKey(culture, segment);
            if (!_values.TryGetValue(k, out CacheValue? value))
            {
                _values[k] = value = new CacheValue();
            }

            return value;
        }
    }

    private class SourceInterValue
    {
        private string? _culture;
        private string? _segment;

        public string? Culture
        {
            get => _culture;
            internal set => _culture = value?.ToLowerInvariant();
        }

        public string? Segment
        {
            get => _segment;
            internal set => _segment = value?.ToLowerInvariant();
        }

        public object? SourceValue { get; set; }

        public bool InterInitialized { get; set; }

        public object? InterValue { get; set; }
    }

    #endregion
}