Add split-second-stopwatch exercise

config.json

@@ -2713,6 +2713,20 @@
           "for-loops"
         ],
         "difficulty": 7
+      },
+      {
+        "slug": "split-second-stopwatch",
+        "name": "Split-Second Stopwatch",
+        "uuid": "1d95976d-b3db-4705-b345-0832f226620f",
+        "practices": [
+          "datetimes",
+          "classes"
+        ],
+        "prerequisites": [
+          "datetimes",
+          "classes"
+        ],
+        "difficulty": 5
       }
     ],
     "foregone": [

exercises/practice/split-second-stopwatch/.docs/instructions.md

@@ -0,0 +1,22 @@
+# Instructions
+
+Your task is to build a stopwatch to keep precise track of lap times.
+
+The stopwatch uses four commands (start, stop, lap, and reset) to keep track of:
+
+1. The current lap's tracked time
+2. Previously recorded lap times
+
+What commands can be used depends on which state the stopwatch is in:
+
+1. Ready: initial state
+2. Running: tracking time
+3. Stopped: not tracking time
+
+| Command | Begin state | End state | Effect                                                   |
+| ------- | ----------- | --------- | -------------------------------------------------------- |
+| Start   | Ready       | Running   | Start tracking time                                      |
+| Start   | Stopped     | Running   | Resume tracking time                                     |
+| Stop    | Running     | Stopped   | Stop tracking time                                       |
+| Lap     | Running     | Running   | Add current lap to previous laps, then reset current lap |
+| Reset   | Stopped     | Ready     | Reset current lap and clear previous laps                |

exercises/practice/split-second-stopwatch/.docs/introduction.md

@@ -0,0 +1,6 @@
+# Introduction
+
+You've always run for the thrill of it — no schedules, no timers, just the sound of your feet on the pavement.
+But now that you've joined a competitive running crew, things are getting serious.
+Training sessions are timed to the second, and every split second counts.
+To keep pace, you've picked up the _Split-Second Stopwatch_ — a sleek, high-tech gadget that's about to become your new best friend.

exercises/practice/split-second-stopwatch/.editorconfig

@@ -0,0 +1,141 @@
+###############################
+# Core EditorConfig Options   #
+###############################
+
+; This file is for unifying the coding style for different editors and IDEs.
+; More information at:
+; https://docs.microsoft.com/en-us/visualstudio/ide/editorconfig-code-style-settings-reference?view=vs-2017
+; https://docs.microsoft.com/en-us/visualstudio/ide/create-portable-custom-editor-options?view=vs-2017
+
+root = true
+
+[*]
+indent_style = space
+
+[SplitSecondStopwatch.cs]
+indent_size = 4
+
+###############################
+# .NET Coding Conventions     #
+###############################
+
+# Organize usings
+dotnet_sort_system_directives_first = true
+dotnet_separate_import_directive_groups = true
+
+# this. preferences
+dotnet_style_qualification_for_field = false:suggestion
+dotnet_style_qualification_for_property = false:suggestion
+dotnet_style_qualification_for_method = false:suggestion
+dotnet_style_qualification_for_event = false:suggestion
+
+# Language keywords vs BCL types preferences
+dotnet_style_predefined_type_for_locals_parameters_members = true:suggestion
+dotnet_style_predefined_type_for_member_access = true:suggestion
+
+# Parentheses preferences
+dotnet_style_parentheses_in_arithmetic_binary_operators = never_if_unnecessary:none
+dotnet_style_parentheses_in_relational_binary_operators = never_if_unnecessary:none
+dotnet_style_parentheses_in_other_binary_operators = never_if_unnecessary:none
+dotnet_style_parentheses_in_other_operators = never_if_unnecessary:suggestion
+
+# Modifier preferences
+dotnet_style_require_accessibility_modifiers = always:suggestion
+dotnet_style_readonly_field = true:suggestion
+
+# Expression-level preferences
+dotnet_style_object_initializer = true:suggestion
+dotnet_style_collection_initializer = true:suggestion
+dotnet_style_explicit_tuple_names = true:suggestion
+dotnet_style_prefer_inferred_tuple_names = true:suggestion
+dotnet_style_prefer_inferred_anonymous_type_member_names = true:suggestion
+dotnet_style_prefer_auto_properties = true:suggestion
+dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion
+dotnet_style_prefer_conditional_expression_over_assignment = true:suggestion
+dotnet_style_prefer_conditional_expression_over_return = true:suggestion
+dotnet_style_coalesce_expression = true:suggestion
+dotnet_style_null_propagation = true:suggestion
+
+###############################
+# Naming Conventions          #
+###############################
+
+# Style Definitions
+dotnet_naming_style.pascal_case_style.capitalization = pascal_case
+
+# Use PascalCase for constant fields
+dotnet_naming_rule.constant_fields_should_be_pascal_case.severity = suggestion
+dotnet_naming_rule.constant_fields_should_be_pascal_case.symbols = constant_fields
+dotnet_naming_rule.constant_fields_should_be_pascal_case.style = pascal_case_style
+dotnet_naming_symbols.constant_fields.applicable_kinds = field
+dotnet_naming_symbols.constant_fields.applicable_accessibilities = *
+dotnet_naming_symbols.constant_fields.required_modifiers = const
+
+###############################
+# C# Code Style Rules         #
+###############################
+
+# var preferences
+csharp_style_var_for_built_in_types = true:none
+csharp_style_var_when_type_is_apparent = true:none
+csharp_style_var_elsewhere = true:none
+
+# Expression-bodied members
+csharp_style_expression_bodied_methods = true:suggestion
+csharp_style_expression_bodied_constructors = true:suggestion
+csharp_style_expression_bodied_operators = true:suggestion
+csharp_style_expression_bodied_properties = true:suggestion
+csharp_style_expression_bodied_indexers = true:suggestion
+csharp_style_expression_bodied_accessors = true:suggestion
+
+# Pattern-matching preferences
+csharp_style_pattern_matching_over_is_with_cast_check = true:suggestion
+csharp_style_pattern_matching_over_as_with_null_check = true:suggestion
+
+# Null-checking preferences
+csharp_style_throw_expression = true:suggestion
+csharp_style_conditional_delegate_call = true:suggestion
+
+# Modifier preferences
+csharp_preferred_modifier_order = public,private,protected,internal,static,extern,new,virtual,abstract,sealed,override,readonly,unsafe,volatile,async:suggestion
+
+# Expression-level preferences
+csharp_prefer_braces = true:none
+csharp_prefer_simple_default_expression = true:suggestion
+csharp_style_deconstructed_variable_declaration = true:suggestion
+csharp_style_pattern_local_over_anonymous_function = true:suggestion
+csharp_style_inlined_variable_declaration = true:suggestion
+
+###############################
+# C# Formatting Rules         #
+###############################
+
+# New line preferences
+csharp_new_line_before_open_brace = all
+csharp_new_line_before_else = true
+csharp_new_line_before_catch = true
+csharp_new_line_before_finally = true
+csharp_new_line_before_members_in_object_initializers = false
+csharp_new_line_before_members_in_anonymous_types = false
+csharp_new_line_between_query_expression_clauses = true
+
+# Indentation preferences
+csharp_indent_case_contents = true
+csharp_indent_switch_labels = true
+csharp_indent_labels = flush_left
+
+# Space preferences
+csharp_space_after_cast = false
+csharp_space_after_keywords_in_control_flow_statements = true
+csharp_space_between_method_declaration_parameter_list_parentheses = false
+csharp_space_between_method_call_parameter_list_parentheses = false
+csharp_space_before_colon_in_inheritance_clause = true
+csharp_space_after_colon_in_inheritance_clause = true
+csharp_space_around_binary_operators = before_and_after
+csharp_space_between_method_declaration_empty_parameter_list_parentheses = false
+csharp_space_between_method_call_name_and_opening_parenthesis = false
+csharp_space_between_method_call_empty_parameter_list_parentheses = false
+
+# Wrapping preferences
+csharp_preserve_single_line_blocks = true
+csharp_preserve_single_line_statements = true

exercises/practice/split-second-stopwatch/.meta/Example.cs

@@ -0,0 +1,65 @@
+public enum StopwatchState
+{
+    Ready,
+    Running,
+    Stopped
+}
+
+public class SplitSecondStopwatch(TimeProvider time)
+{
+    private List<TimeSpan> _previousLaps = [];
+    private TimeSpan _currentLapTrackedTime = TimeSpan.Zero;
+    private DateTimeOffset? _currentLapTrackingTimeSince; 
+
+    private TimeSpan PreviousLapsTotal => _previousLaps.Aggregate(TimeSpan.Zero, (total, lap) => total + lap);
+    private TimeSpan CurrentLapTrackingTime =>
+        _currentLapTrackingTimeSince is null ? TimeSpan.Zero : time.GetUtcNow() - _currentLapTrackingTimeSince.Value;
+
+    public StopwatchState State { get; private set; } = StopwatchState.Ready;
+    public TimeSpan CurrentLap => _currentLapTrackedTime + CurrentLapTrackingTime;
+    public TimeSpan Total => CurrentLap + PreviousLapsTotal;
+    public IReadOnlyCollection<TimeSpan> PreviousLaps => _previousLaps.AsReadOnly();
+
+    public void Start()
+    {
+        if (State == StopwatchState.Running)
+            throw new InvalidOperationException();
+
+        _currentLapTrackingTimeSince = time.GetUtcNow();
+
+        State = StopwatchState.Running;
+    }
+
+    public void Stop()
+    {
+        if (State != StopwatchState.Running)
+            throw new InvalidOperationException();
+
+        _currentLapTrackedTime += CurrentLap;
+        _currentLapTrackingTimeSince = null;
+
+        State = StopwatchState.Stopped;
+    }
+
+    public void Reset()
+    {
+        if (State != StopwatchState.Stopped)
+            throw new InvalidOperationException();
+
+        _previousLaps.Clear();
+        _currentLapTrackingTimeSince = null;
+        _currentLapTrackedTime = TimeSpan.Zero;
+
+        State = StopwatchState.Ready;
+    }
+
+    public void Lap()
+    {
+        if (State != StopwatchState.Running)
+            throw new InvalidOperationException();
+
+        _previousLaps.Add(CurrentLap);
+        _currentLapTrackedTime = TimeSpan.Zero;
+        _currentLapTrackingTimeSince = time.GetUtcNow();
+    }
+}

exercises/practice/split-second-stopwatch/.meta/Generator.tpl

@@ -0,0 +1,49 @@
+{{ func to_timespan
+    if $0 == "00:00:00"
+        ret "TimeSpan.Zero"
+    end
+
+    parts = string.split $0 ":"
+    hours = parts[0] | string.to_int
+    minutes = parts[1] | string.to_int
+    seconds = parts[2] | string.to_int        
+    $"new TimeSpan({hours},{minutes},{seconds})"
+end }}
+
+using Microsoft.Extensions.Time.Testing;
+
+public class {{ testClass }}
+{
+    {{- for test in tests }}
+    [Fact{{ if !for.first }}(Skip = "Remove this Skip property to run this test"){{ end }}]
+    public void {{ test.testMethod }}()
+    {
+        {{- for command in test.input.commands }}
+        {{- if command.command == "new" }}
+        var timeProvider = new FakeTimeProvider();
+        var stopwatch = new {{ testedClass }}(timeProvider);
+        {{- else if command.command == "state" }}
+        Assert.Equal({{ command.expected | enum "StopwatchState" }}, stopwatch.State);
+        {{- else if command.command == "currentLap" }}
+        Assert.Equal({{ command.expected | to_timespan }}, stopwatch.CurrentLap);
+        {{- else if command.command == "total" }}
+        Assert.Equal({{ command.expected | to_timespan }}, stopwatch.Total);
+        {{- else if command.command == "previousLaps" }}
+        {{- if command.expected.empty? }}
+        Assert.Empty(stopwatch.PreviousLaps);
+        {{ else }}
+        Assert.Equal([{{- for previousLap in command.expected }}{{ previousLap | to_timespan }}{{ if !for.last }}, {{ end }}{{ end -}}], stopwatch.PreviousLaps);
+        {{ end -}}
+        {{- else if command.command == "advanceTime" }}
+        timeProvider.Advance({{ command.by | to_timespan }});
+        {{- else }}
+        {{- if command.expected && command.expected.error }}
+        Assert.Throws<InvalidOperationException>(() => stopwatch.{{ command.command | pascalize }}());
+        {{ else }}
+        stopwatch.{{ command.command | pascalize }}();
+        {{ end -}}
+        {{ end -}}
+        {{ end -}}
+    }
+    {{ end -}}
+}

exercises/practice/split-second-stopwatch/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "erikschierboom"
+  ],
+  "files": {
+    "solution": [
+      "SplitSecondStopwatch.cs"
+    ],
+    "test": [
+      "SplitSecondStopwatchTests.cs"
+    ],
+    "example": [
+      ".meta/Example.cs"
+    ]
+  },
+  "blurb": "Keep track of time through a digital stopwatch.",
+  "source": "Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/pull/2547"
+}