using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using trakker.Models;

namespace trakker.Forms
{

    public partial class TaskForm : Form
    {
        /// <summary>
        /// The task instance being edited by this form.
        /// </summary>
        private readonly trakker.Models.Task _task;

        /// <summary>
        /// Binding source that connects the task status to the form controls.
        /// </summary>
        private BindingSource? _status;

        /// <summary>
        /// Binding source that connects the task priority to the form controls.
        /// </summary>
        private BindingSource? _priority;

        /// <summary>
        /// Binding source that connects the task model to the form controls.
        /// </summary>
        private BindingSource bindingSource = new BindingSource();

        /// <summary>
        /// Error provider used to display validation errors next to input controls.
        /// </summary>
        private ErrorProvider errorProvider = new ErrorProvider();

        /// <summary>
        /// Initializes a new instance of the <see cref="ProjectForm"/> class bound to
        /// the provided <paramref name="project"/>. Sets up data bindings for all
        /// visible input controls and configures dialog button behavior.
        /// </summary>
        /// <param name="task">The <see cref="Task"/> instance to edit. Must not be null.</param>
        /// <param name="status">The binding source for status values. Must not be null.</param>
        /// <param name="priority">The binding source for priority values. Must not be null.</param>
        public TaskForm(trakker.Models.Task task, BindingSource status, BindingSource priority)
        {
            InitializeComponent();
            _task = task ?? throw new ArgumentNullException(nameof(task));
            _status = status ?? throw new ArgumentNullException(nameof(status));
            _priority = priority ?? throw new ArgumentNullException(nameof(priority));

            Text = "Task Details";

            comboBoxStatus.DataSource = _status;
            comboBoxStatus.DisplayMember = "Display";
            comboBoxStatus.ValueMember = "Value";

            comboBoxPriority.DataSource = _priority;
            comboBoxPriority.DisplayMember = "Display";
            comboBoxPriority.ValueMember = "Value";

            dateTimePickerDueDate.Format = DateTimePickerFormat.Custom;
            dateTimePickerDueDate.CustomFormat = "yyyy-MM-dd";

            // // Bind model properties to controls so the UI reflects and updates the model.
            bindingSource.DataSource = _task;
            textBoxTitle.DataBindings.Add("Text", bindingSource, "Title", true);
            richTextBoxDescription.DataBindings.Add("Text", bindingSource, "Description", true);
            dateTimePickerDueDate.DataBindings.Add("Value", bindingSource, "DueDate", true);
            textBoxHoursEst.DataBindings.Add("Text", bindingSource, "EstimatedHours", true);
            textBoxHoursActual.DataBindings.Add("Text", bindingSource, "ActualHours", true);
            textBoxRate.DataBindings.Add("Text", bindingSource, "HourlyRate", true);
            comboBoxStatus.DataBindings.Add("SelectedValue", bindingSource, "Status", true);
            comboBoxPriority.DataBindings.Add("SelectedValue", bindingSource, "Priority", true);

            // Configure dialog buttons and window behavior.
            buttonOkay.DialogResult = DialogResult.OK;
            buttonCancel.DialogResult = DialogResult.Cancel;
            this.CancelButton = buttonCancel;
            this.StartPosition = FormStartPosition.CenterParent;
        }

        /// <summary>
        /// Gets the <see cref="Task"/> instance edited by the form.
        /// </summary>
        public trakker.Models.Task Task { get => _task; private set { } }

        /// <summary>
        /// Validates the Name field. If the name is empty or whitespace, an error is set
        /// on the <see cref="errorProvider"/> and the event is canceled to prevent the
        /// form from closing.
        /// </summary>
        private void textBoxTitle_Validating(object sender, System.ComponentModel.CancelEventArgs e)
        {
            if (string.IsNullOrWhiteSpace(textBoxTitle.Text))
            {
                errorProvider.SetError(textBoxTitle, "Title is required.");
                errorProvider.SetIconAlignment(textBoxTitle, ErrorIconAlignment.MiddleRight);
                errorProvider.SetIconPadding(textBoxTitle, 2);
                e.Cancel = true;
            }
            else
            {
                errorProvider.SetError(textBoxTitle, "");
            }
        }

    }
}