/*
    Copyright (C) 2014-2019 de4dot@gmail.com

    This file is part of dnSpy

    dnSpy is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    dnSpy is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with dnSpy.  If not, see <http://www.gnu.org/licenses/>.
*/

using System;
using System.Collections.Generic;
using dnSpy.Contracts.Images;
using Microsoft.VisualStudio.Language.Intellisense;
using Microsoft.VisualStudio.Text;

namespace dnSpy.Contracts.Language.Intellisense {
	/// <summary>
	/// A completion item
	/// </summary>
	public class DsCompletion : Completion2 {
		/// <summary>
		/// Gets the suffix or null
		/// </summary>
		public string? Suffix { get; }

		/// <summary>
		/// Gets the text that is used to filter this item
		/// </summary>
		public string FilterText { get; }

		/// <summary>
		/// Gets the icon
		/// </summary>
		public virtual ImageReference ImageReference => imageReference ??= GetImageReference();
		ImageReference? imageReference;

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="displayText">Text shown in the UI</param>
		/// <param name="filterText">Text used to filter out items or null to use <paramref name="displayText"/></param>
		/// <param name="insertionText">Text that gets inserted in the text buffer or null to use <paramref name="displayText"/></param>
		/// <param name="description">Description or null</param>
		/// <param name="imageReference">Icon moniker or null</param>
		/// <param name="iconAutomationText">Icon automation text or null</param>
		/// <param name="attributeIcons">Attribute icons shown on the right side</param>
		/// <param name="suffix">Text shown after the normal completion text</param>
		public DsCompletion(string displayText, string? filterText = null, string? insertionText = null, string? description = null, ImageReference imageReference = default, string? iconAutomationText = null, IEnumerable<DsCompletionIcon>? attributeIcons = null, string? suffix = null)
			: base(displayText, insertionText, description, default, iconAutomationText, attributeIcons) {
			if (displayText is null)
				throw new ArgumentNullException(nameof(displayText));
			FilterText = filterText ?? displayText;
			InsertionText = insertionText ?? displayText;
			Suffix = suffix;
			this.imageReference = imageReference.IsDefault ? (ImageReference?)null : imageReference;
		}

		/// <summary>
		/// Gets the image reference. Only called if <see cref="ImageReference"/> hasn't been initialized.
		/// </summary>
		/// <returns></returns>
		protected virtual ImageReference GetImageReference() => default;

		/// <summary>
		/// Adds the new text to the text buffer
		/// </summary>
		/// <param name="replaceSpan">Span to replace with new content</param>
		public virtual void Commit(ITrackingSpan replaceSpan) {
			var buffer = replaceSpan.TextBuffer;
			var span = replaceSpan.GetSpan(buffer.CurrentSnapshot);
			buffer.Replace(span.Span, InsertionText);
		}
	}
}