namespace GDNXFD.Alert.Config.ViewModel
{
    using GalaSoft.MvvmLight.Command;
    using GalaSoft.MvvmLight.Messaging;
    using GDNXFD.Alert.Config.Model;
    using GDNXFD.Alert.Config.Services.Navigation;
    using GDNXFD.Alert.Config.ViewModel.Base;
    using System;
    using System.Collections.Generic;
    using System.Collections.ObjectModel;
    using System.Threading;
    using System.Threading.Tasks;
    using System.Windows;
    using System.Windows.Input;
    using System.Linq;
    using GDNXFD.Alert.Config.Resources.Strings;
    using Data;
    using Data.Repositories;

    /// <summary>
    /// Travel list ViewModel.
    /// </summary>
    public class RuleListViewModel : VMBase
    {
        private const int PAGESIZE = 25;
        private RelayCommand<AlertRule> editRuleCommand;
        private RelayCommand addRuleCommand;
        private RelayCommand refreshRuleListCommand;
        private RelayCommand<string> removeRuleCommand;
        private RelayCommand<AlertRule> viewRuleCommand;
        private RelayCommand nextPageCommand;
        private RelayCommand previousPageCommand;
        private ObservableCollection<AlertRule> ruleList;
        private ObservableCollection<PageItem> pagesList;
        private string filter;
        //private CancellationTokenSource searchCancellationTokenSource;

        private readonly INavigationService navService;
        private PaginationConfig pagConfig;
        private int rulesCount;

        #region 初始化

        public RuleListViewModel(INavigationService navService)
        {
            this.navService = navService;
            SubscribeCommands();
            //InitializeMockedData();
        }

        public void InitializeData()
        {
            try
            {
                Messenger.Default.Send(new LoadingMessage(true));
                RulesCount = AlertRuleRepository.GetAlertRuleTotals(filter);
                this.pagConfig = new PaginationConfig(this.rulesCount, PAGESIZE);
                NavigateToPage(this.pagConfig.NumberOfPageSelected);
                Messenger.Default.Send(new UserLoginMessage(true));
            }
            catch (Exception ex)
            {
                CustomDialogMessage message = new CustomDialogMessage(() => { }, StringResources.UnexpectedError, Visibility.Collapsed);
                Messenger.Default.Send<CustomDialogMessage>(message);
            }
        }

        private void InitializeMockedData()
        {
            var alertRules = AlertRuleRepository.GetAlertRules();
            //var travels =  this.sampleDataService.GetTravelRequests();
            RuleList = new ObservableCollection<AlertRule>(alertRules);

            var pages = GetPagesList();
            PagesList = new ObservableCollection<PageItem>(pages);
        }

        private void SubscribeCommands()
        {
            this.editRuleCommand = new RelayCommand<AlertRule>(EditRuleCommandExecute);
            this.addRuleCommand = new RelayCommand(AddRuleCommandExecute);
            this.viewRuleCommand = new RelayCommand<AlertRule>(ViewRuleCommandExecute);
            this.nextPageCommand = new RelayCommand(NextPageCommandExecute);
            this.previousPageCommand = new RelayCommand(PreviousPageCommandExecute);
            this.refreshRuleListCommand = new RelayCommand(RefreshRuleListCommandExecute);
            this.removeRuleCommand = new RelayCommand<string>(RemoveRuleCommandExecute);
        }


        #endregion


        #region 表头及操作

        public string Filter
        {
            get { return this.filter; }
            set
            {
                this.filter = value;
                SearchTravels();
                RaisePropertyChanged(() => Filter);
            }
        }

        public int RulesCount
        {
            get { return this.rulesCount; }
            set
            {
                this.rulesCount = value;
                RaisePropertyChanged(() => RulesCount);
            }
        }

        public ICommand AddRuleCommand
        {
            get { return addRuleCommand; }
        }

        public ICommand RefreshRuleListCommand
        {
            get { return refreshRuleListCommand; }
        }

        private void SearchTravels()
        {
           InitializeData();
        }

        private void AddRuleCommandExecute()
        {
            AlertRule ar = new AlertRule();
            ar.Category = "1";
            ar.Rank = "3";
            navService.NavigateToRuleForm(ar, FormMode.Create);
        }

        private void RefreshRuleListCommandExecute()
        {
            InitializeData();
        }
        #endregion

        #region 规则列表及操作

        public ObservableCollection<AlertRule> RuleList
        {
            get
            {
                return this.ruleList;
            }
            set
            {
                this.ruleList = value;
                base.RaisePropertyChanged(() => RuleList);
            }
        }

        public ICommand EditRuleCommand
        {
            get { return editRuleCommand; }
        }

        public ICommand ViewRuleCommand
        {
            get { return this.viewRuleCommand; }
        }

        public ICommand RemoveRuleCommand
        {
            get { return this.removeRuleCommand; }
        }

        private void EditRuleCommandExecute(AlertRule rule)
        {
            navService.NavigateToRuleForm(rule, FormMode.Update);
        }

        
        private void RemoveRuleCommandExecute(string id)
        {
            // Get the travel request to remove.
            AlertRule rule = this.ruleList.FirstOrDefault(t => t.Id == id);

            CustomDialogMessage message = new CustomDialogMessage( () =>
            {
                AlertRuleRepository.DeleteAlertRule(id);
                RemoveFromList(rule);
            }, String.Format(Resources.Strings.StringResources.ConfirmDeleteMessage, rule.Name), Visibility.Visible);

            Messenger.Default.Send<CustomDialogMessage>(message);
        }

        private void RemoveFromList(AlertRule rule)
        {
            this.pagConfig.ItemsCounted--;
            RulesCount--;

            this.ruleList.Remove(rule);

            if (this.ruleList.Count != 0)
            {
                RaisePropertyChanged(() => RuleList);
            }
            else
            {
                if (this.pagConfig.CanGoNext)
                {
                    NavigateToPage(this.pagConfig.NumberOfPageSelected);
                }
                else if (this.pagConfig.CanGoPrevious)
                {
                    this.pagConfig.NumberOfPageSelected--;
                    NavigateToPage(this.pagConfig.NumberOfPageSelected);
                }
            }
        }

        private void ViewRuleCommandExecute(AlertRule rule)
        {
            navService.NavigateToRuleForm(rule, FormMode.ReadOnly);
        }
        #endregion

        #region 分页操作

        public ObservableCollection<PageItem> PagesList
        {
            get { return this.pagesList; }
            set
            {
                this.pagesList = value;
                RaisePropertyChanged(() => PagesList);
            }
        }

        public ICommand NextPageCommand
        {
            get { return this.nextPageCommand; }
        }

        public ICommand PreviousPageCommand
        {
            get { return this.previousPageCommand; }
        }

        public List<PageItem> GetPagesList()
        {
            var pagesList = new List<PageItem>();
            pagesList.Add(new PageItem((1).ToString(), true, true));
            for (int i = 2; i <= 5; i++)
            {
                pagesList.Add(new PageItem((i).ToString(), false, true));
            }

            return pagesList;
        }
        private List<PageItem> CalculatePaginator()
        {
            var pages = new List<PageItem>();
            int firstPage = (int)Math.Floor((double)this.pagConfig.NumberOfPageSelected / 12) * 12;

            if (firstPage > 0)
                firstPage = firstPage - 2;

            for (int i = firstPage; i < (firstPage + Math.Min(12, this.pagConfig.NumberOfPages)) && (i < this.pagConfig.NumberOfPages); i++)
            {
                var isSelected = false;

                if (this.pagConfig.NumberOfPageSelected == i + 1)
                    isSelected = true;

                PageItem page = new PageItem((i + 1).ToString(), isSelected, true);
                page.PageSelected += PageSelectedChanged;
                pages.Add(page);
            }

            if (this.pagConfig.NumberOfPages > this.pagConfig.PageSize && int.Parse(pages[pages.Count - 1].Page) != this.pagConfig.NumberOfPages)
            {
                pages.Add(new PageItem("...", false, false));
                var lastPage = new PageItem(this.pagConfig.NumberOfPages.ToString(), false, true);
                pages.Add(lastPage);
                lastPage.PageSelected += PageSelectedChanged;
            }
            return pages;
        }
        private void PageSelectedChanged(object sender, EventArgs args)
        {
            this.pagConfig.PageSelected = (PageItem)sender;
            NavigateToPage(this.pagConfig.NumberOfPageSelected);
        }
        private void ResetPaginator()
        {
            if (this.pagesList != null)
            {
                foreach (var page in this.pagesList)
                {
                    page.PageSelected -= PageSelectedChanged;
                }
            }
        }

        private void NextPageCommandExecute()
        {
            if (this.pagConfig.CanGoNext)
            {
                this.pagConfig.NumberOfPageSelected = this.pagConfig.NumberOfPageSelected + 1;
                NavigateToPage(this.pagConfig.NumberOfPageSelected);
            }
        }
        private void PreviousPageCommandExecute()
        {
            if (this.pagConfig.CanGoPrevious)
            {
                this.pagConfig.NumberOfPageSelected = this.pagConfig.NumberOfPageSelected - 1;
                NavigateToPage(this.pagConfig.NumberOfPageSelected);
            }
        }

        private void NavigateToPage(int pageToNavigate)
        {
            try
            {
                Messenger.Default.Send(new LoadingMessage(true));

                ResetPaginator();
                var travels = AlertRuleRepository.GetAllAlertRules(filter, this.pagConfig.PageSize, pageToNavigate - 1);
                RuleList = new ObservableCollection<AlertRule>(travels);
                PagesList = new ObservableCollection<PageItem>(CalculatePaginator());
            }
            catch (Exception ex)
            {
                CustomDialogMessage message = new CustomDialogMessage(() => { }, StringResources.UnexpectedError, Visibility.Collapsed);
                Messenger.Default.Send<CustomDialogMessage>(message);
            }
            finally
            {
                Messenger.Default.Send(new LoadingMessage(false));
            }
        }

        #endregion


   }
}