using System;
using System.IO;
using System.Text;
using BepInEx.Configuration;
using BepInEx.Unix;
using MonoMod.Utils;

namespace BepInEx
{
	internal static class ConsoleManager
	{
		private const uint SHIFT_JIS_CP = 932;
		
		internal static IConsoleDriver Driver { get; set; }

		/// <summary>
		/// True if an external console has been started, false otherwise.
		/// </summary>
		public static bool ConsoleActive => Driver?.ConsoleActive ?? false;

		/// <summary>
		/// The stream that writes to the standard out stream of the process. Should never be null.
		/// </summary>
		public static TextWriter StandardOutStream => Driver?.StandardOut;

		/// <summary>
		/// The stream that writes to an external console. Null if no such console exists
		/// </summary>
		public static TextWriter ConsoleStream => Driver?.ConsoleOut;


		public static void Initialize(bool alreadyActive)
		{
			switch (Utility.CurrentOs)
			{
				case Platform.MacOS:
				case Platform.Linux:
				{
					Driver = new LinuxConsoleDriver();
					break;
				}

				case Platform.Windows:
				{
					Driver = new WindowsConsoleDriver();
					break;
				}
			}

			Driver.Initialize(alreadyActive);
		}

		private static void DriverCheck()
		{
			if (Driver == null)
				throw new InvalidOperationException("Driver has not been initialized");
		}

		public static void CreateConsole()
		{
			if (ConsoleActive)
				return;

			DriverCheck();
			
			// Apparently some versions of Mono throw a "Encoding name 'xxx' not supported"
			// if you use Encoding.GetEncoding
			// That's why we use of codepages directly and handle then in console drivers separately
			var codepage = ConfigConsoleShiftJis.Value ? SHIFT_JIS_CP: (uint)Encoding.UTF8.CodePage;
			
			Driver.CreateConsole(codepage);
		}

		public static void DetachConsole()
		{
			if (!ConsoleActive)
				return;

			DriverCheck();

			Driver.DetachConsole();
		}

		public static void SetConsoleTitle(string title)
		{
			DriverCheck();

			Driver.SetConsoleTitle(title);
		}

		public static void SetConsoleColor(ConsoleColor color)
		{
			DriverCheck();

			Driver.SetConsoleColor(color);
		}

		public static readonly ConfigEntry<bool> ConfigConsoleEnabled = ConfigFile.CoreConfig.Bind(
			"Logging.Console", "Enabled",
			false,
			"Enables showing a console for log output.");

		public static readonly ConfigEntry<bool> ConfigConsoleShiftJis = ConfigFile.CoreConfig.Bind(
			"Logging.Console", "ShiftJisEncoding",
			false,
			"If true, console is set to the Shift-JIS encoding, otherwise UTF-8 encoding.");
	}
}