using System;
using System.Linq;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Net;
using System.Windows;
using System.Windows.Media.Imaging;
using Juick.Classes;
using JuickApi;
using RestSharp;

namespace Juick.ViewModels
{
    public class ViewModelBase : INotifyPropertyChanged
    {
        static readonly string IsDataLoadingPropertyName = ExpressionHelper.GetPropertyName<ViewModelBase>(x => x.IsDataLoading);
        bool isDataLoading;

        public ViewModelBase()
        {
            Items = new ObservableCollection<PostItem>();
            LoadMessagesPageCommand = new DelegateCommand(LoadData, () => !IsDataLoading);
        }

        public string RestUri { get; set; }
        public virtual string Caption { get { return "juick"; } }

        /// <summary>
        /// A collection for MessageViewModel objects.
        /// </summary>
        public ObservableCollection<PostItem> Items { get; private set; }

        public DelegateCommand LoadMessagesPageCommand { get; private set; }

        public bool IsDataLoading
        {
            get { return isDataLoading; }
            set
            {
                isDataLoading = value;
                NotifyPropertyChanged(IsDataLoadingPropertyName);
                LoadMessagesPageCommand.NotifyCanExecuteChanged();
            }
        }

        /// <summary>
        /// Creates and adds a few MessageViewModel objects into the Items collection.
        /// </summary>
        public void LoadData()
        {
            if (IsDataLoading) {
                return;
            }

            const int PageSize = 1;

            if (string.IsNullOrEmpty(RestUri))
            {
                RestUri = "/home?1=1";
            }

            // super-костыли
            // todo: rewrite
            else if (RestUri.StartsWith("/home?", StringComparison.InvariantCulture) && Items.Count > 0)
            {
                var lastItem = Items[Items.Count - 1];
                RestUri = string.Format("/home?before_mid={0}&page={1}", lastItem.MID, PageSize);
            }
            else if (RestUri.StartsWith("/messages?", StringComparison.InvariantCulture) && Items.Count > 0)
            {
                var lastItem = Items[Items.Count - 1];
                RestUri = string.Format("/messages?before_mid={0}&page={1}", lastItem.MID, PageSize);
            }

            var request = new RestRequest(RestUri + "&rnd=" + Environment.TickCount);
            App.Client.Authenticator = new HttpBasicAuthenticator(App.Account.Credentials.UserName, App.Account.Credentials.Password);
            App.Client.ExecuteAsync<List<Message>>(request, ProcessResponse);
            IsDataLoading = true;
        }

        void ProcessResponse(IRestResponse<List<Message>> response)
        {
            IsDataLoading = false;
            if (response.StatusCode != HttpStatusCode.OK)
            {
                MessageBox.Show(response.StatusCode.ToString());
                return;
            }

            //Items.Clear();
            response.Data.Select(x => new PostItem(x)).ToList().ForEach(i => Items.Add(i));
            
        }


        public event PropertyChangedEventHandler PropertyChanged;

        public void NotifyPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}