Add support for indeterminate progress

This commit also changes the behavior of ProgressContext.IsFinished.
Only tasks that have been started will be taken into consideration,
and not indeterminate tasks.

Closes #329
Closes #331

src/Spectre.Console/Widgets/Progress/Columns/ProgressBarColumn.cs

@@ -28,6 +28,11 @@ namespace Spectre.Console
         /// </summary>
         public Style RemainingStyle { get; set; } = new Style(foreground: Color.Grey);
 
+        /// <summary>
+        /// Gets or sets the style of an indeterminate progress bar.
+        /// </summary>
+        public Style IndeterminateStyle { get; set; } = ProgressBar.DefaultPulseStyle;
+
         /// <inheritdoc/>
         public override IRenderable Render(RenderContext context, ProgressTask task, TimeSpan deltaTime)
         {
@@ -39,6 +44,8 @@ namespace Spectre.Console
                 CompletedStyle = CompletedStyle,
                 FinishedStyle = FinishedStyle,
                 RemainingStyle = RemainingStyle,
+                IndeterminateStyle = IndeterminateStyle,
+                IsIndeterminate = task.IsIndeterminate,
             };
         }
     }

src/Spectre.Console/Widgets/Progress/ProgressContext.cs

@@ -16,9 +16,9 @@ namespace Spectre.Console
         private int _taskId;
 
         /// <summary>
-        /// Gets a value indicating whether or not all tasks have completed.
+        /// Gets a value indicating whether or not all started tasks have completed.
         /// </summary>
-        public bool IsFinished => _tasks.All(task => task.IsFinished);
+        public bool IsFinished => _tasks.Where(x => x.IsStarted).All(task => task.IsFinished);
 
         internal ProgressContext(IAnsiConsole console, ProgressRenderer renderer)
         {
@@ -28,20 +28,41 @@ namespace Spectre.Console
             _renderer = renderer ?? throw new ArgumentNullException(nameof(renderer));
         }
 
+        /// <summary>
+        /// Adds a task.
+        /// </summary>
+        /// <param name="description">The task description.</param>
+        /// <param name="autoStart">Whether or not the task should start immediately.</param>
+        /// <param name="maxValue">The task's max value.</param>
+        /// <returns>The newly created task.</returns>
+        public ProgressTask AddTask(string description, bool autoStart = true, double maxValue = 100)
+        {
+            return AddTask(description, new ProgressTaskSettings
+            {
+                AutoStart = autoStart,
+                MaxValue = maxValue,
+            });
+        }
+
         /// <summary>
         /// Adds a task.
         /// </summary>
         /// <param name="description">The task description.</param>
         /// <param name="settings">The task settings.</param>
         /// <returns>The newly created task.</returns>
-        public ProgressTask AddTask(string description, ProgressTaskSettings? settings = null)
+        public ProgressTask AddTask(string description, ProgressTaskSettings settings)
         {
+            if (settings is null)
+            {
+                throw new ArgumentNullException(nameof(settings));
+            }
+
             lock (_taskLock)
             {
-                settings ??= new ProgressTaskSettings();
                 var task = new ProgressTask(_taskId++, description, settings.MaxValue, settings.AutoStart);
 
                 _tasks.Add(task);
+
                 return task;
             }
         }

src/Spectre.Console/Widgets/Progress/ProgressTask.cs

@@ -93,6 +93,12 @@ namespace Spectre.Console
         /// </summary>
         public TimeSpan? RemainingTime => GetRemainingTime();
 
+        /// <summary>
+        /// Gets or sets a value indicating whether the ProgressBar shows
+        /// actual values or generic, continuous progress feedback.
+        /// </summary>
+        public bool IsIndeterminate { get; set; }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="ProgressTask"/> class.
         /// </summary>

src/Spectre.Console/Widgets/Progress/ProgressTaskSettings.cs

@@ -16,5 +16,10 @@ namespace Spectre.Console
         /// will be auto started. Defaults to <c>true</c>.
         /// </summary>
         public bool AutoStart { get; set; } = true;
+
+        /// <summary>
+        /// Gets the default progress task settings.
+        /// </summary>
+        internal static ProgressTaskSettings Default { get; } = new ProgressTaskSettings();
     }
 }

src/Spectre.Console/Widgets/Progress/Renderers/DefaultProgressRenderer.cs

@@ -62,7 +62,7 @@ namespace Spectre.Console
                     _stopwatch.Start();
                 }
 
-                var renderContext = new RenderContext(_console.Profile.Capabilities);
+                var renderContext = new RenderContext(_console.Profile.ColorSystem, _console.Profile.Capabilities);
 
                 var delta = _stopwatch.Elapsed - _lastUpdate;
                 _lastUpdate = _stopwatch.Elapsed;