using Microsoft.AspNetCore.Components;
using Blazored.LocalStorage;
using Blog3000.Shared;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Net.Http;
using System.Text.Json;

namespace Blog3000.Client
{
    
    public class Config: IDisposable    
    {
        public static string DBKEY_PREFIX="config-";

        public MainConfig Main { get; private set; }

        public event EventHandler ConfigChanged;
        
        private readonly NetworkStatus networkStatus;
        private readonly ILocalStorageService localStorage;
        private readonly HttpClient httpClient;

        private bool configLoadedOnce = false;

        public Config(ILocalStorageService ls, NetworkStatus networkStatus, HttpClient http)
        {
            this.localStorage = ls;
            this.networkStatus = networkStatus;
            this.httpClient = http;

         
        }


        public void Dispose()
        {
            networkStatus.StatusChanged -= NetworkStatus_StatusChanged;
        }


        public async Task FetchAsync()
        {
            var config = await localStorage.GetItemAsync<MainConfig>($"{DBKEY_PREFIX}main.json");
            if (config == null)
            {
                await ReloadConfigFromRemote();
            }
            else
            {
                System.Diagnostics.Debug.WriteLine("Using cached config");
                Main = config;                
                ConfigChanged?.Invoke(this, EventArgs.Empty);
                configLoadedOnce = false;
                _ = ReloadConfigFromRemote();                
            }

            if (Main == null) throw new Exception("Can't load config");            
        }



        private void NetworkStatus_StatusChanged(object sender, EventArgs e)
        {
            if (!configLoadedOnce && networkStatus.IsOnline)
            {
                // Ensure config will be reloaded event when started offline!
                _ = ReloadConfigFromRemote();
            }
        }


        private async Task ReloadConfigFromRemote()
        {
            if (networkStatus.IsOnline)
            {
                var json = await httpClient.GetStringAsync("config.json?" + DateTime.Now.Ticks);
                //Log += json;
                if (String.IsNullOrEmpty(json)) throw new Exception("Can't load config from server");
                
                var res = System.Text.Json.JsonSerializer.Deserialize<MainConfig>(json, new JsonSerializerOptions() { PropertyNameCaseInsensitive = true });
                await localStorage.SetItemAsync($"{DBKEY_PREFIX}main.json", res);
                Main = res;
                configLoadedOnce = true;
                ConfigChanged?.Invoke(this, EventArgs.Empty);
                System.Diagnostics.Debug.WriteLine($"Config reloaded from server");
                //System.Diagnostics.Debug.WriteLine(res.Title);
            }
            else
            {
                System.Diagnostics.Debug.WriteLine("Config not reloading, offline");
            }
        }

      
    }
}