#region Copyright & License Information
/*
 * Copyright (c) The OpenRA Developers and Contributors
 * This file is part of OpenRA, which is free software. It is made
 * available to you 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. For more
 * information, see COPYING.
 */
#endregion

using System;
using System.Linq;
using System.Reflection;

namespace OpenRA.Mods.Common.UtilityCommands.Documentation
{
	sealed class ExtractSettingsDocsCommand : IUtilityCommand
	{
		string IUtilityCommand.Name => "--settings-docs";

		bool IUtilityCommand.ValidateArguments(string[] args)
		{
			return true;
		}

		static void WriteFields(string key, object value)
		{
			var fields = Utility.GetFields(value.GetType());
			var writeHeader = true;

			foreach (var field in fields)
			{
				if (!Utility.HasAttribute<DescAttribute>(field))
					continue;

				if (writeHeader)
				{
					Console.WriteLine($"## {key}");
					if (key == "Launch")
						Console.WriteLine("These are runtime parameters which can't be defined in `settings.yaml`.");
					writeHeader = false;
				}

				Console.WriteLine($"### {field.Name}");
				var lines = Utility.GetCustomAttributes<DescAttribute>(field, false).SelectMany(d => d.Lines);
				foreach (var line in lines)
				{
					Console.WriteLine(line);
					Console.WriteLine();
				}

				var fieldValue = field.GetValue(value)?.ToString();
				if (fieldValue != null && !fieldValue.StartsWith("System.", StringComparison.Ordinal))
				{
					Console.WriteLine($"**Default Value:** {value}");
					Console.WriteLine();
					Console.WriteLine("```miniyaml");
					Console.WriteLine($"{key}: ");
					Console.WriteLine($"\t{field.Name}: {fieldValue}");
					Console.WriteLine("```");
				}
			}
		}

		[Desc("[VERSION]", "Generate settings documentation in markdown format.")]
		void IUtilityCommand.Run(Utility utility, string[] args)
		{
			Game.ModData = utility.ModData;

			var version = utility.ModData.Manifest.Metadata.Version;
			if (args.Length > 1)
				version = args[1];

			Console.WriteLine(
				"This documentation displays annotated settings with default values and description. " +
				"Please do not edit it directly, but add new `[Desc(\"String\")]` tags to the source code. This file has been " +
				$"automatically generated for version {version} of OpenRA.");
			Console.WriteLine();
			Console.WriteLine("All settings can be changed by starting the game via a command-line parameter like `Game.Mod=ra`.");
			Console.WriteLine();
			Console.WriteLine("## Location");
			Console.WriteLine("* Windows: `%APPDATA%\\OpenRA\\settings.yaml`");
			Console.WriteLine("* Mac OS X: `~/Library/Application Support/OpenRA/settings.yaml`");
			Console.WriteLine("* Linux `~/.config/openra/settings.yaml`");
			Console.WriteLine();
			Console.WriteLine(
				"Older releases (before playtest-20190825) used different locations, " +
				"which newer versions may continue to use in some circumstances:");
			Console.WriteLine("* Windows: `%USERPROFILE%\\Documents\\OpenRA\\settings.yaml`");
			Console.WriteLine("* Linux `~/.openra/settings.yaml`");
			Console.WriteLine();
			Console.WriteLine(
				"If you create the folder `Support` relative to the OpenRA main directory, everything " +
				"including settings gets stored there to aid portable installations.");
			Console.WriteLine();

			var sections = utility.ModData.ObjectCreator.GetTypesImplementing<SettingsModule>();
			foreach (var type in sections.OrderBy(s => s.Name))
			{
				var attribute = type.GetCustomAttribute<SettingsModule.YamlNodeAttribute>();
				if (attribute == null)
					continue;

				var defaults = (SettingsModule)utility.ModData.ObjectCreator.CreateBasic(type);
				WriteFields(attribute.Key, defaults);
			}

			WriteFields("Launch", new LaunchArguments(new Arguments()));
		}
	}
}