using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using WguApp.Models;
using WguApp.Services;

namespace WguApp.Views;

public partial class AssessmentPage : ContentPage
{

    private Assessment _assessment;
    
    public AssessmentPage(Assessment assessment)
    {
        InitializeComponent();
        
        _assessment = assessment;

        Title = assessment.Name;
        
        TitleEntry.Text = _assessment.Name;
        StartDatePicker.Date =  _assessment.StartDate;
        EndDatePicker.Date = _assessment.EndDate;
        StartNotifCheck.IsChecked = _assessment.StartNotifCheck;
        EndNotifCheck.IsChecked = _assessment.EndNotifCheck;
        
        StartNotifCheck.CheckedChanged += async (sender, e) => { await ToggleStartNotification(); };
        EndNotifCheck.CheckedChanged += async (sender, e) => { await ToggleEndNotification(); };
    }
    
    private async Task ToggleStartNotification()
    {
        if (StartNotifCheck.IsChecked)
        {
            var id = await LocalNotificationService.ScheduleNotification($"{_assessment.Name} Start Reminder", $"Your assessment '{_assessment.Id} starts in 12 hours'", _assessment.StartDate.Subtract(TimeSpan.FromHours(12)));
            _assessment.StartNotifId = id ?? 0;
            LoggerService.LogToFile($"{_assessment.Id}:{_assessment.Name} set start notification {_assessment.StartNotifId}");
        }
        else
        {
            var res = await LocalNotificationService.CancelNotification(_assessment.StartNotifId);
            LoggerService.LogToFile($"{_assessment.Id}:{_assessment.Name} canceled start notification {_assessment.StartNotifId}");
            _assessment.StartNotifId = 0;
        }
        
        _assessment.StartNotifCheck = StartNotifCheck.IsChecked;
    }

    private async Task ToggleEndNotification()
    {
        if (EndNotifCheck.IsChecked)
        {
            var id = await LocalNotificationService.ScheduleNotification($"{_assessment.Name} End Reminder", $"Your assessment '{_assessment.Id} ends in 12 hours'", _assessment.EndDate.Subtract(TimeSpan.FromHours(12)));
            _assessment.EndNotifId = id ?? 0;
            LoggerService.LogToFile($"{_assessment.Id}:{_assessment.Name} set end notification {_assessment.EndNotifId}");
        }
        else
        {
            var res = await LocalNotificationService.CancelNotification(_assessment.EndNotifId);
            LoggerService.LogToFile($"{_assessment.Id}:{_assessment.Name} canceled end notification {_assessment.EndNotifId}");
            _assessment.EndNotifId = 0;
        }
        
        _assessment.EndNotifCheck = EndNotifCheck.IsChecked;
    }
    
    private (string msg, bool result) ValidateFields()
    {
        var message = string.Empty;
        
        if (string.IsNullOrWhiteSpace(TitleEntry.Text)) message += "Title cannot be blank\n";
        if (StartDatePicker.Date > EndDatePicker.Date) message += "Start Date cannot be after the End Date\n";

        return string.IsNullOrWhiteSpace(message) ? (message, true) : (message, false);
    }

    private async Task<bool> Save()
    {
        var validationResult = ValidateFields();

        if (!validationResult.result)
        {
            await DisplayAlert("Validation Error", validationResult.msg, "Ok");
            return false;
        }

        _assessment.Name = TitleEntry.Text;
        _assessment.StartDate = StartDatePicker.Date;
        _assessment.EndDate = EndDatePicker.Date;
        _assessment.StartNotifCheck = StartNotifCheck.IsChecked;
        _assessment.EndNotifCheck = EndNotifCheck.IsChecked;
        
        var updateResult = await DatabaseService.UpdateAssessment(_assessment);

        if (updateResult)
        {
            await DisplayAlert("Info", $"{_assessment.Name} Saved!", "Ok");
        }
        else
        {
            await DisplayAlert("Error", "Could not save term", "Ok");
        }
        
        Title = _assessment.Name;

        if (_assessment.StartNotifId != 0)
        {
            await LocalNotificationService.UpdateNotification(_assessment.StartNotifId, $"{_assessment.Name} Start Reminder",
                $"Your course '{_assessment.Id} starts in 12 hours'", _assessment.StartDate.Subtract(TimeSpan.FromHours(12)));
        }

        if (_assessment.EndNotifId != 0)
        {
            await LocalNotificationService.UpdateNotification(_assessment.EndNotifId, $"{_assessment.Name} End Reminder",
                $"Your course '{_assessment.Id} ends in 12 hours'", _assessment.EndDate.Subtract(TimeSpan.FromHours(12)));
        }

        return true;
    }

    private async void SaveButton_OnClicked(object? sender, EventArgs e)
    {
        await Save();
    }

    private async void DeleteButton_OnClicked(object? sender, EventArgs e)
    {
        var result = await DisplayAlert("Delete Course", $"Do you really want to delete '{_assessment.Name}'? This action cannot be undone.", "Delete", "Cancel");
        if (!result) return;
        
        await DatabaseService.DeleteAssessment(_assessment);
        await Navigation.PopAsync();
    }
}