using System;
using System.Collections.Generic;
using System.Linq;
using Newtonsoft.Json.Linq;
using Umbraco.Core;
using Umbraco.Core.Composing;
using Umbraco.Core.Events;
using Umbraco.Core.Models;
using Umbraco.Core.PropertyEditors;
using Umbraco.Core.Services;
using Umbraco.Core.Services.Implement;
using Umbraco.Web.PropertyEditors;

namespace Umbraco.Web.Compose
{

    /// <summary>
    /// A component for NestedContent used to bind to events
    /// </summary>
    public class NestedContentPropertyComponent : IComponent
    {
        private ComplexPropertyEditorContentEventHandler _handler;

        public void Initialize()
        {
            _handler = new ComplexPropertyEditorContentEventHandler(
                Constants.PropertyEditors.Aliases.NestedContent,
                CreateNestedContentKeys);
        }

        public void Terminate() => _handler?.Dispose();

        private string CreateNestedContentKeys(string rawJson, bool onlyMissingKeys) => CreateNestedContentKeys(rawJson, onlyMissingKeys, null);

        // internal for tests
        internal string CreateNestedContentKeys(string rawJson, bool onlyMissingKeys, Func<Guid> createGuid = null)
        {
            // used so we can test nicely
            if (createGuid == null)
                createGuid = () => Guid.NewGuid();

            if (string.IsNullOrWhiteSpace(rawJson) || !rawJson.DetectIsJson())
                return rawJson;

            // Parse JSON            
            var complexEditorValue = JToken.Parse(rawJson);

            UpdateNestedContentKeysRecursively(complexEditorValue, onlyMissingKeys, createGuid);

            return complexEditorValue.ToString();
        }

        private void UpdateNestedContentKeysRecursively(JToken json, bool onlyMissingKeys, Func<Guid> createGuid)
        {
            // check if this is NC
            var isNestedContent = json.SelectTokens($"$..['{NestedContentPropertyEditor.ContentTypeAliasPropertyKey}']", false).Any();

            // select all values (flatten)
            var allProperties = json.SelectTokens("$..*").OfType<JValue>().Select(x => x.Parent as JProperty).WhereNotNull().ToList();
            foreach (var prop in allProperties)
            {
                if (prop.Name == NestedContentPropertyEditor.ContentTypeAliasPropertyKey)
                {
                    // get it's sibling 'key' property
                    var ncKeyVal = prop.Parent["key"] as JValue;
                    if ((onlyMissingKeys && ncKeyVal == null) || (!onlyMissingKeys && ncKeyVal != null))
                    {
                        // create or replace
                        prop.Parent["key"] = createGuid().ToString();
                    }                   
                }
                else if (!isNestedContent || prop.Name != "key")
                {
                    // this is an arbitrary property that could contain a nested complex editor
                    var propVal = prop.Value?.ToString();
                    // check if this might contain a nested NC
                    if (!propVal.IsNullOrWhiteSpace() && propVal.DetectIsJson() && propVal.InvariantContains(NestedContentPropertyEditor.ContentTypeAliasPropertyKey))
                    {
                        // recurse
                        var parsed = JToken.Parse(propVal);
                        UpdateNestedContentKeysRecursively(parsed, onlyMissingKeys, createGuid);
                        // set the value to the updated one
                        prop.Value = parsed.ToString();
                    }
                }
            }
        }

    }
}