34 help command

BusyList/Commands/Commands.cs

@@ -1,4 +1,6 @@
-namespace BusyList.Commands
+using System;
+
+namespace BusyList.Commands
 {
     public record Command;
 
@@ -7,4 +9,6 @@ public record NextCommand() : Command;
     public record AddCommand(string Description, PriorityEnum Priority = PriorityEnum.Normal) : Command;
     public record DeleteCommand(int Id) : Command;
     public record DoneCommand(int Id) : Command;
+    public record HelpCommand(string name = null) : Command;
 }
+

BusyList/Handlers/AddHandler.cs

@@ -1,9 +1,11 @@
 using BusyList.Commands;
+using BusyList.HelpSystem;
 using System;
 
 
 namespace BusyList.Handlers
 {
+    [HelpAttribute("add", "Add a new task with the passed description", "add [Description]")]
     public class AddHandler : IHandler<AddCommand>
     {
         private readonly ITaskRepository _taskRepository;
@@ -12,6 +14,7 @@ public AddHandler(ITaskRepository taskRepository)
         {
             _taskRepository = taskRepository;
         }
+
         public void Run(AddCommand command)
         {
             var item = new AddTaskData(command.Description, command.Priority);
@@ -20,6 +23,5 @@ public void Run(AddCommand command)
 
             Console.WriteLine($"Added {currentTask.Print()}");
         }
-
     }
 }

BusyList/Handlers/DeleteHandler.cs

@@ -1,8 +1,10 @@
 using BusyList.Commands;
+using BusyList.HelpSystem;
 using System;
 
 namespace BusyList.Handlers
 {
+    [HelpAttribute("delete", "Delete the task with the passed id", "[Id] delete")]
     public class DeleteHandler : IHandler<DeleteCommand>
     {
         private readonly ITaskRepository _taskRepository;
@@ -11,12 +13,12 @@ public DeleteHandler(ITaskRepository taskRepository)
         {
             _taskRepository = taskRepository;
         }
-        
+
         public void Run(DeleteCommand command)
         {
             var selectedTask = _taskRepository.GetTaskById(command.Id);
             _taskRepository.DeleteTask(selectedTask);
             Console.WriteLine($"Task with id {command.Id} has been deleted.");
         }
     }
-}
+}

BusyList/Handlers/DoneHandler.cs

@@ -1,8 +1,10 @@
 using BusyList.Commands;
+using BusyList.HelpSystem;
 using System;
 
 namespace BusyList.Handlers
 {
+    [HelpAttribute("done", "Mark the task with the given id as done", "[Id] done")]
     public class DoneHandler : IHandler<DoneCommand>
     {
         private readonly ITaskRepository _taskRepository;

BusyList/Handlers/HelpHandler.cs

@@ -0,0 +1,51 @@
+using BusyList.Commands;
+using BusyList.HelpSystem;
+using System;
+
+namespace BusyList.Handlers
+{
+    public class HelpHandler : IHandler<HelpCommand>
+    {
+        private readonly HelpProvider _helpProvider;
+
+        public HelpHandler(HelpProvider helpProvider)
+        {
+            _helpProvider = helpProvider;
+        }
+
+        public void Help()
+        {
+            var helpTexts = _helpProvider.GetAllHelpText();
+
+            foreach (var (name, description) in helpTexts)
+            {
+                Console.WriteLine($"{name}: {description}");
+            }
+
+            Console.WriteLine("For further information type help [keyword] e.g help add");
+        }
+
+        public void Run(HelpCommand command)
+        {
+            if (command.name == null)
+            {
+                Help();
+
+                return;
+            }
+
+            var (description, syntax) = _helpProvider.GetHelpText(command.name);
+
+            if (description != null && syntax != null)
+            {
+                Console.WriteLine($"Command: {command.name.ToLowerInvariant()}");
+                Console.WriteLine($"Description: {description}");
+                Console.WriteLine($"Syntax: {syntax}");
+            }
+            else
+            {
+                Console.WriteLine($"Help for the command '{command.name.ToLowerInvariant()}' does not exists");
+            }
+        }
+    }
+}

BusyList/Handlers/IHandler.cs

@@ -2,8 +2,8 @@
 
 namespace BusyList.Handlers
 {
-    internal interface IHandler<in TCommand> where TCommand : Command
+    public interface IHandler<in TCommand> where TCommand : Command
     {
         void Run(TCommand command);
     }
-}
+}

BusyList/Handlers/NextHandler.cs

@@ -1,8 +1,11 @@
 using BusyList.Commands;
+using BusyList.HelpSystem;
 using System;
 
 namespace BusyList.Handlers
 {
+
+    [HelpAttribute("next", "Lists all tasks", "next")] 
     public class NextHandler : IHandler<NextCommand>
     {
         private readonly ITaskRepository _taskRepository;

BusyList/Handlers/ReadHandler.cs

@@ -1,8 +1,10 @@
 using BusyList.Commands;
+using BusyList.HelpSystem;
 using System;
 
 namespace BusyList.Handlers
 {
+    [HelpAttribute("read", "Print the id, description and status of the task with the passed id", "[Id]")]
     public class ReadHandler : IHandler<ReadCommand>
     {
         private readonly ITaskRepository _taskRepository;
@@ -25,4 +27,4 @@ public void Run(ReadCommand command)
             Console.WriteLine(task.Print());
         }
     }
-}
+}

BusyList/HelpSystem/HelpAttribute.cs

@@ -0,0 +1,19 @@
+using System;
+
+namespace BusyList.HelpSystem
+{
+    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
+    public class HelpAttribute : Attribute
+    {
+        public string Name { get; }
+        public string Description { get; }
+        public string Syntax { get; }
+
+        public HelpAttribute(string name, string description, string syntax)
+        {
+            Name = name;
+            Description = description;
+            Syntax = syntax;
+        }
+    }
+}

BusyList/HelpSystem/HelpProvider.cs

@@ -0,0 +1,31 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+
+namespace BusyList.HelpSystem
+{
+    public class HelpProvider
+    {
+        private readonly Dictionary<string, (string, string)> _helpText = new();
+
+        public HelpProvider()
+        {
+            _helpText = Assembly.GetExecutingAssembly().GetExportedTypes()
+                .Where(x => x.IsDefined(typeof(HelpAttribute)))
+                .Select(x => x.GetCustomAttribute<HelpAttribute>())
+                .ToDictionary(x => x.Name.ToLowerInvariant(), x => (x.Description, x.Syntax));
+        }
+
+        public (string, string)[] GetAllHelpText() => _helpText.Select(x => (x.Key.ToLowerInvariant(), x.Value.Item1)).ToArray();
+
+        public (string, string) GetHelpText(string key)
+        {
+            if(_helpText.TryGetValue(key.ToLowerInvariant(), out var value))
+            {
+                return value;
+            }
+
+            return (null, null);
+        }
+    }
+}

BusyList/Parsing/CommandGrammar.cs

@@ -1,5 +1,8 @@
-using BusyList.Commands;
+using BusyList.Commands;
 using Sprache;
+using System;
+using System.Linq;
+
 
 namespace BusyList.Parsing
 {
@@ -8,6 +11,9 @@ public static class CommandGrammar
         private static readonly Parser<string> _keywordAdd =
             Parse.IgnoreCase("add").Text();
 
+        private static readonly Parser<string> _keywordHelp =
+            Parse.IgnoreCase("help").Text();
+
         private static readonly Parser<string> _keywordDelete =
             Parse.IgnoreCase("delete")
             .Or(Parse.IgnoreCase("del"))
@@ -78,13 +84,25 @@ from _ in Parse.WhiteSpace
             from keyword in _keywordDone
             select new DoneCommand(id);
 
+        private static readonly Parser<Command> _helpCommand =
+           from keyword in _keywordHelp
+           select new HelpCommand();
+
+        private static readonly Parser<Command> _helpCommandSpecific =
+            from keyword in _keywordHelp
+            from _ in Parse.WhiteSpace
+            from name in Parse.AnyChar.AtLeastOnce().Text()
+            select new HelpCommand(name);
+
         public static readonly Parser<Command> Source =
             _deleteCommand
             .Or(_nextCommand)
             .Or(_doneCommand)
             .Or(_readCommand)
             .Or(_addCommandWithPriority)
             .Or(_addCommand)
+            .Or(_helpCommandSpecific)
+            .Or(_helpCommand)
             .End();
     }
 }

BusyList/Program.cs

@@ -1,9 +1,11 @@
 using BusyList.Commands;
 using BusyList.Handlers;
+using BusyList.HelpSystem;
 using BusyList.Parsing;
 using Microsoft.Extensions.DependencyInjection;
 using Sprache;
 using System;
+using System.Reflection;
 
 namespace BusyList
 {
@@ -65,6 +67,8 @@ private static IServiceCollection ConfigureServices()
             services.AddTransient<IHandler<DoneCommand>, DoneHandler>();
             services.AddTransient<IHandler<NextCommand>, NextHandler>();
             services.AddTransient<IHandler<ReadCommand>, ReadHandler>();
+            services.AddTransient<IHandler<HelpCommand>, HelpHandler>();
+            services.AddSingleton<HelpProvider>();
 
             return services;
         }
@@ -88,6 +92,9 @@ private static void HandleCommand(ServiceProvider provider, Command command)
                 case ReadCommand read:
                     provider.GetRequiredService<IHandler<ReadCommand>>().Run(read);
                     break;
+                case HelpCommand help:
+                    provider.GetRequiredService<IHandler<HelpCommand>>().Run(help);
+                    break;
                 default:
                     throw new Exception($"Unknown command type {command.GetType().FullName} sent to HandleCommand!");
             }