From ddc1ae8537078c5d4259d9b5e201bc9aa66715aa Mon Sep 17 00:00:00 2001
From: Alexey Golub <Tyrrrrrr@gmail.com>
Date: Fri, 16 Aug 2019 17:43:50 +0300
Subject: [PATCH] Add application description to metadata

---
 CliFx.Tests.Dummy/Program.cs              |  1 +
 CliFx/CliApplicationBuilder.cs            | 10 +++++++++-
 CliFx/ICliApplicationBuilder.cs           |  5 +++++
 CliFx/Models/ApplicationMetadata.cs       |  8 +++++++-
 CliFx/Services/CommandHelpTextRenderer.cs |  7 +++++++
 5 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/CliFx.Tests.Dummy/Program.cs b/CliFx.Tests.Dummy/Program.cs
index 24b79cb..f40bd6d 100644
--- a/CliFx.Tests.Dummy/Program.cs
+++ b/CliFx.Tests.Dummy/Program.cs
@@ -7,6 +7,7 @@ namespace CliFx.Tests.Dummy
         public static Task<int> Main(string[] args) =>
             new CliApplicationBuilder()
                 .WithCommandsFromThisAssembly()
+                .UseDescription("Dummy program used for E2E tests.")
                 .Build()
                 .RunAsync(args);
     }
diff --git a/CliFx/CliApplicationBuilder.cs b/CliFx/CliApplicationBuilder.cs
index e73874c..57c2ac7 100644
--- a/CliFx/CliApplicationBuilder.cs
+++ b/CliFx/CliApplicationBuilder.cs
@@ -19,6 +19,7 @@ namespace CliFx
         private string _title;
         private string _executableName;
         private string _versionText;
+        private string _description;
         private IConsole _console;
         private ICommandFactory _commandFactory;
 
@@ -66,6 +67,13 @@ namespace CliFx
             return this;
         }
 
+        /// <inheritdoc />
+        public ICliApplicationBuilder UseDescription(string description)
+        {
+            _description = description; // can be null
+            return this;
+        }
+
         /// <inheritdoc />
         public ICliApplicationBuilder UseConsole(IConsole console)
         {
@@ -108,7 +116,7 @@ namespace CliFx
             SetFallbackValues();
 
             // Project parameters to expected types
-            var metadata = new ApplicationMetadata(_title, _executableName, _versionText);
+            var metadata = new ApplicationMetadata(_title, _executableName, _versionText, _description);
             var commandTypes = _commandTypes.ToArray();
 
             return new CliApplication(metadata, commandTypes,
diff --git a/CliFx/ICliApplicationBuilder.cs b/CliFx/ICliApplicationBuilder.cs
index 5bdbac5..93b05a3 100644
--- a/CliFx/ICliApplicationBuilder.cs
+++ b/CliFx/ICliApplicationBuilder.cs
@@ -34,6 +34,11 @@ namespace CliFx
         /// </summary>
         ICliApplicationBuilder UseVersionText(string versionText);
 
+        /// <summary>
+        /// Sets application description, which appears in the help text.
+        /// </summary>
+        ICliApplicationBuilder UseDescription(string description);
+
         /// <summary>
         /// Configures application to use specified implementation of <see cref="IConsole"/>.
         /// </summary>
diff --git a/CliFx/Models/ApplicationMetadata.cs b/CliFx/Models/ApplicationMetadata.cs
index e7bd062..5003e95 100644
--- a/CliFx/Models/ApplicationMetadata.cs
+++ b/CliFx/Models/ApplicationMetadata.cs
@@ -22,14 +22,20 @@ namespace CliFx.Models
         /// </summary>
         public string VersionText { get; }
 
+        /// <summary>
+        /// Application description.
+        /// </summary>
+        public string Description { get; }
+
         /// <summary>
         /// Initializes an instance of <see cref="ApplicationMetadata"/>.
         /// </summary>
-        public ApplicationMetadata(string title, string executableName, string versionText)
+        public ApplicationMetadata(string title, string executableName, string versionText, string description)
         {
             Title = title.GuardNotNull(nameof(title));
             ExecutableName = executableName.GuardNotNull(nameof(executableName));
             VersionText = versionText.GuardNotNull(nameof(versionText));
+            Description = description; // can be null
         }
     }
 }
\ No newline at end of file
diff --git a/CliFx/Services/CommandHelpTextRenderer.cs b/CliFx/Services/CommandHelpTextRenderer.cs
index 143e97e..1888668 100644
--- a/CliFx/Services/CommandHelpTextRenderer.cs
+++ b/CliFx/Services/CommandHelpTextRenderer.cs
@@ -89,6 +89,13 @@ namespace CliFx.Services
                 Render(" ");
                 RenderWithColor(source.ApplicationMetadata.VersionText, ConsoleColor.Yellow);
                 RenderNewLine();
+
+                // Description
+                if (!source.ApplicationMetadata.Description.IsNullOrWhiteSpace())
+                {
+                    Render(source.ApplicationMetadata.Description);
+                    RenderNewLine();
+                }
             }
 
             void RenderDescription()