using Microsoft.AspNetCore.Components;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Blog3000.Client.Shared
{
    public partial class TopicCloud: IDisposable
    {
        public class Topic
        {
            public string DispId;
            public int Count;
        }


        [Inject]
        private BlogDb BlogDb { get; set; }

        private List<Topic> topics = new List<Topic>();


        [Parameter]
        public EventCallback<string> OnTopicClick { get; set; }

        public void Dispose()
        {
            BlogDb.BlogPostsChanged -= BlogDb_BlogPostsChanged;
        }


        protected override async Task OnInitializedAsync()
        {
            topics = await UpdateTopicsAsync();
            BlogDb.BlogPostsChanged += BlogDb_BlogPostsChanged;
        }


        private async void BlogDb_BlogPostsChanged(object sender, EventArgs e)
        {
            topics = await UpdateTopicsAsync();
            StateHasChanged();
        }

        private void TopicClicked(string topic)
        {
            //System.Diagnostics.Debug.WriteLine(topic);
            OnTopicClick.InvokeAsync(topic);
        }


        private async Task<List<Topic>> UpdateTopicsAsync()
        {
            var dict = new Dictionary<string, Topic>();

            foreach (var bp in await BlogDb.GetHeadersAsync().ToListAsync())
            {
                if (bp != null && bp.Topics != null)
                {
                    foreach (var t in bp.Topics)
                    {
                        Topic tp;
                        if (!dict.TryGetValue(t, out tp))
                        {
                            tp = new Topic();
                            tp.DispId = t;
                            dict.Add(tp.DispId, tp);
                        }
                        tp.Count++;
                    }
                }
            }

            return new List<Topic>(dict.Values
                .OrderByDescending(t => t.Count)
                .OrderBy(t => t.DispId)
                );
        }
    }
}