#nullable enable
using System;
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Diagnostics;
using System.Globalization;
using System.Runtime.InteropServices;
using System.Text;
using Vanara.PInvoke;

namespace Vanara.Windows.Shell
{
	/// <summary>Wraps a string resource reference used by some Shell classes.</summary>
	[TypeConverter(typeof(IndirectStringTypeConverter))]
	[DebuggerDisplay("{RawValue} => {Value}")]
	public class IndirectString : IndirectResource
	{
		/// <summary>Initializes a new instance of the <see cref="IndirectString"/> class.</summary>
		public IndirectString() { }

		/// <summary>Initializes a new instance of the <see cref="IndirectString"/> class.</summary>
		public IndirectString(string? value) : base(value) { }

		/// <summary>Initializes a new instance of the <see cref="IndirectString"/> class.</summary>
		/// <param name="module">The module file name.</param>
		/// <param name="resourceIdOrIndex">
		/// If this number is positive, this is the index of the resource in the module file. If negative, the absolute value of the number
		/// is the resource ID of the string in the module file.
		/// </param>
		public IndirectString(string module, int resourceIdOrIndex) : base(module, resourceIdOrIndex) { }

		/// <summary>Gets the localized string referred to by this instance.</summary>
		/// <value>The referenced localized string.</value>
		[Browsable(false)]
		public string? Value
		{
			get
			{
				if (RawValue is null) return null;
				if (!IsValid) return RawValue;
				var sb = new StringBuilder(4096);
				SHLoadIndirectString(RawValue, sb, (uint)sb.Capacity).ThrowIfFailed();
				return sb.ToString();
			}
		}

		/// <summary>Performs an implicit conversion from <see cref="IndirectString"/> to <see cref="string"/>.</summary>
		/// <param name="ind">The ind.</param>
		/// <returns>The result of the conversion.</returns>
		public static implicit operator string?(IndirectString? ind) => ind?.RawValue;

		/// <summary>Performs an implicit conversion from <see cref="string"/> to <see cref="IndirectString"/>.</summary>
		/// <param name="s">The s.</param>
		/// <returns>The result of the conversion.</returns>
		public static implicit operator IndirectString(string? s) => new(s);

		/// <summary>Tries to parse the specified string to create a <see cref="IndirectString"/> instance.</summary>
		/// <param name="value">The string representation in the format of either "ModuleFileName,ResourceIndex" or "ModuleFileName,-ResourceID".</param>
		/// <param name="loc">The resulting <see cref="IndirectString"/> instance on success.</param>
		/// <returns><c>true</c> if successfully parsed.</returns>
		public static bool TryParse(string? value, out IndirectString loc)
		{
			loc = new IndirectString(value);
			return loc.IsValid || value != null;
		}

		[DllImport("shlwapi.dll", SetLastError = false, ExactSpelling = true)]
		private static extern HRESULT SHLoadIndirectString([MarshalAs(UnmanagedType.LPWStr)] string pszSource,
			[Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder pszOutBuf, uint cchOutBuf, IntPtr ppvReserved = default);
	}

	internal class IndirectStringTypeConverter : ExpandableObjectConverter
	{
		public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType) =>
			sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);

		public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destType) =>
			destType == typeof(InstanceDescriptor) || destType == typeof(string) || base.CanConvertTo(context, destType);

		public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value) =>
			value is string s ? IndirectString.TryParse(s, out var loc) ? loc : null : base.ConvertFrom(context, culture, value);

		public override object? ConvertTo(ITypeDescriptorContext? context, CultureInfo? info, object? value, Type destType)
		{
			if (destType == typeof(string) && value is IndirectString s)
				return s.RawValue;
			return destType == typeof(InstanceDescriptor)
				? new InstanceDescriptor(typeof(IndirectString).GetConstructor(new Type[0]), null, false)
				: base.ConvertTo(context, info, value, destType);
		}
	}
}