using System;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using Robust.Shared.Console;
using Robust.Shared.IoC;
using Robust.Shared.Localization;
using Robust.Shared.Utility;

namespace Robust.Shared.Configuration
{
    public static class CVarCommandUtil
    {
        /// <summary>
        /// Parses a string into an object of the given type.
        /// </summary>
        /// <exception cref="FormatException">Thrown if the string could not be parsed into the given type.</exception>
        /// <exception cref="NotSupportedException">Thrown if the type is not supported.</exception>
        public static object ParseObject(Type type, string input)
        {
            if (type == typeof(bool))
            {
                if (bool.TryParse(input, out var val))
                    return val;

                if (Parse.TryInt32(input, out var intVal))
                {
                    if (intVal == 0) return false;
                    if (intVal == 1) return true;
                }

                throw new FormatException($"Could not parse bool value: {input}");
            }

            if (type == typeof(string))
            {
                return input;
            }

            if (type == typeof(int))
            {
                return Parse.Int32(input);
            }

            if (type == typeof(float))
            {
                return Parse.Float(input);
            }

            if (type == typeof(long))
            {
                return long.Parse(input);
            }

            if (type == typeof(ushort))
            {
                return ushort.Parse(input);
            }

            throw new NotSupportedException();
        }
    }

    [SuppressMessage("ReSharper", "StringLiteralTypo")]
    internal sealed class CVarCommand : LocalizedCommands
    {
        [Dependency] private readonly IConfigurationManager _cfg = default!;

        public override string Command => "cvar";

        public override void Execute(IConsoleShell shell, string argStr, string[] args)
        {
            if (args.Length is < 1 or > 2)
            {
                shell.WriteError(Loc.GetString("cmd-cvar-invalid-args"));
                return;
            }

            var name = args[0];

            if (name == "?")
            {
                var cvars = _cfg.GetRegisteredCVars().OrderBy(c => c);
                shell.WriteLine(string.Join("\n", cvars));
                return;
            }

            if (!_cfg.IsCVarRegistered(name))
            {
                shell.WriteError(Loc.GetString("cmd-cvar-not-registered", ("cvar", name)));
                return;
            }

            if (args.Length == 1)
            {
                // Read CVar
                var value = _cfg.GetCVar<object>(name);
                shell.WriteLine(value.ToString()!);
            }
            else
            {
                // Write CVar
                var value = args[1];
                var type = _cfg.GetCVarType(name);
                try
                {
                    var parsed = CVarCommandUtil.ParseObject(type, value);
                    _cfg.SetCVar(name, parsed);
                }
                catch (FormatException)
                {
                    shell.WriteError(Loc.GetString("cmd-cvar-parse-error", ("type", type)));
                }
            }
        }

        public override CompletionResult GetCompletion(IConsoleShell shell, string[] args)
        {
            if (args.Length == 1)
            {
                var helpQuestion = Loc.GetString("cmd-cvar-compl-list");

                return CompletionResult.FromHintOptions(
                    _cfg.GetRegisteredCVars()
                        .Select(c => new CompletionOption(c, GetCVarValueHint(_cfg, c)))
                        .Union(new[] { new CompletionOption("?", helpQuestion) })
                        .OrderBy(c => c.Value),
                    Loc.GetString("cmd-cvar-arg-name"));
            }

            var cvar = args[0];
            if (!_cfg.IsCVarRegistered(cvar))
                return CompletionResult.Empty;

            var type = _cfg.GetCVarType(cvar);
            return CompletionResult.FromHint($"<{type.Name}>");
        }

        private static string GetCVarValueHint(IConfigurationManager cfg, string cVar)
        {
            var flags = cfg.GetCVarFlags(cVar);
            if ((flags & CVar.CONFIDENTIAL) != 0)
                return Loc.GetString("cmd-cvar-value-hidden");

            var value = cfg.GetCVar<object>(cVar).ToString() ?? "";
            if (value.Length > 50)
                value = $"{value[..51]}…";

            return value;
        }
    }

    internal sealed class CVarSubsCommand : LocalizedCommands
    {
        [Dependency] private readonly IConfigurationManager _cfg = default!;

        public override string Command => "cvar_subs";

        public override void Execute(IConsoleShell shell, string argStr, string[] args)
        {
            if (args.Length < 1)
            {
                shell.WriteError(Loc.GetString("cmd-cvar_subs-invalid-args"));
                return;
            }

            var name = args[0];
            var subs = ((ConfigurationManager)_cfg).GetSubs(name);

            foreach (var @delegate in subs)
            {
                shell.WriteLine(ShowDelegateInfo(@delegate));
            }
        }

        private static string ShowDelegateInfo(Delegate del)
        {
            return $"{del}: {del.Method} -> {del.Target}";
        }

        public override CompletionResult GetCompletion(IConsoleShell shell, string[] args)
        {
            if (args.Length == 1)
            {
                return CompletionResult.FromHintOptions(
                    _cfg.GetRegisteredCVars()
                        .Select(c => new CompletionOption(c))
                        .OrderBy(c => c.Value),
                    Loc.GetString("cmd-cvar_subs-arg-name"));
            }

            return CompletionResult.Empty;
        }
    }
}