Add split second stopwatch exercise

config.json

@@ -1257,6 +1257,14 @@
           "text_formatting"
         ]
       },
+      {
+        "slug": "split-second-stopwatch",
+        "name": "Split-Second Stopwatch",
+        "uuid": "25befc0a-cd5b-44d6-9f5f-647e12208381",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "state-of-tic-tac-toe",
         "name": "State of Tic-Tac-Toe",

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/.meta/config.json

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

exercises/practice/split-second-stopwatch/.meta/example.php

@@ -0,0 +1,88 @@
+<?php
+
+declare(strict_types=1);
+
+class SplitSecondStopwatch
+{
+    public function __construct(
+        public string $state = "ready",
+        public int $total = 0,
+        public int $currentLap = 0,
+        public array $previousLaps = []
+    ) {
+    }
+
+    public function advanceTime(string $duration): void
+    {
+        if ($this->state === 'running') {
+            $seconds = $this->formatSeconds($duration);
+            $this->currentLap += $seconds;
+            $this->total += $seconds;
+        }
+    }
+
+    private function formatTime(int $seconds): string
+    {
+        $hours = $seconds / 3600;
+        $minutes = ($seconds % 3600) / 60;
+        $seconds = $seconds % 60;
+
+        return sprintf("%02d:%02d:%02d", $hours, $minutes, $seconds);
+    }
+
+    private function formatSeconds(string $duration): int
+    {
+        [$hours, $minutes, $seconds] = explode(':', $duration);
+
+        return $hours * 3600 + $minutes * 60 + $seconds;
+    }
+
+    public function getCurrentLap(): string
+    {
+        return $this->formatTime($this->currentLap);
+    }
+
+    public function getTotal(): string
+    {
+        return $this->formatTime($this->total);
+    }
+
+    public function start(): void
+    {
+        if ($this->state === "running") {
+            throw new Exception("Error: cannot start an already running stopwatch");
+        }
+
+        $this->state = "running";
+    }
+
+    public function stop(): void
+    {
+        if ($this->state !== "running") {
+            throw new Exception("Error: cannot stop a stopwatch that is not running");
+        }
+
+        $this->state = "stopped";
+    }
+
+    public function lap(): void
+    {
+        if ($this->state !== "running") {
+            throw new Exception("Error: cannot lap a stopwatch that is not running");
+        }
+
+        $this->previousLaps[] = $this->getCurrentLap();
+        $this->currentLap = 0;
+    }
+
+    public function reset(): void
+    {
+        if ($this->state !== "stopped") {
+            throw new Exception("Error: cannot reset a stopwatch that is not stopped");
+        }
+
+        $this->state = "ready";
+        $this->currentLap = 0;
+        $this->previousLaps = [];
+    }
+}

exercises/practice/split-second-stopwatch/.meta/tests.toml

@@ -0,0 +1,97 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[ddb238ea-99d4-4eaa-a81d-3c917a525a23]
+description = "new stopwatch starts in ready state"
+
+[b19635d4-08ad-4ac3-b87f-aca10e844071]
+description = "new stopwatch's current lap has no elapsed time"
+
+[492eb532-268d-43ea-8a19-2a032067d335]
+description = "new stopwatch's total has no elapsed time"
+
+[8a892c1e-9ef7-4690-894e-e155a1fe4484]
+description = "new stopwatch does not have previous laps"
+
+[5b2705b6-a584-4042-ba3a-4ab8d0ab0281]
+description = "start from ready state changes state to running"
+
+[748235ce-1109-440b-9898-0a431ea179b6]
+description = "start does not change previous laps"
+
+[491487b1-593d-423e-a075-aa78d449ff1f]
+description = "start initiates time tracking for current lap"
+
+[a0a7ba2c-8db6-412c-b1b6-cb890e9b72ed]
+description = "start initiates time tracking for total"
+
+[7f558a17-ef6d-4a5b-803a-f313af7c41d3]
+description = "start cannot be called from running state"
+
+[32466eef-b2be-4d60-a927-e24fce52dab9]
+description = "stop from running state changes state to stopped"
+
+[621eac4c-8f43-4d99-919c-4cad776d93df]
+description = "stop pauses time tracking for current lap"
+
+[465bcc82-7643-41f2-97ff-5e817cef8db4]
+description = "stop pauses time tracking for total"
+
+[b1ba7454-d627-41ee-a078-891b2ed266fc]
+description = "stop cannot be called from ready state"
+
+[5c041078-0898-44dc-9d5b-8ebb5352626c]
+description = "stop cannot be called from stopped state"
+
+[3f32171d-8fbf-46b6-bc2b-0810e1ec53b7]
+description = "start from stopped state changes state to running"
+
+[626997cb-78d5-4fe8-b501-29fdef804799]
+description = "start from stopped state resumes time tracking for current lap"
+
+[58487c53-ab26-471c-a171-807ef6363319]
+description = "start from stopped state resumes time tracking for total"
+
+[091966e3-ed25-4397-908b-8bb0330118f8]
+description = "lap adds current lap to previous laps"
+
+[1aa4c5ee-a7d5-4d59-9679-419deef3c88f]
+description = "lap resets current lap and resumes time tracking"
+
+[4b46b92e-1b3f-46f6-97d2-0082caf56e80]
+description = "lap continues time tracking for total"
+
+[ea75d36e-63eb-4f34-97ce-8c70e620bdba]
+description = "lap cannot be called from ready state"
+
+[63731154-a23a-412d-a13f-c562f208eb1e]
+description = "lap cannot be called from stopped state"
+
+[e585ee15-3b3f-4785-976b-dd96e7cc978b]
+description = "stop does not change previous laps"
+
+[fc3645e2-86cf-4d11-97c6-489f031103f6]
+description = "reset from stopped state changes state to ready"
+
+[20fbfbf7-68ad-4310-975a-f5f132886c4e]
+description = "reset resets current lap"
+
+[00a8f7bb-dd5c-43e5-8705-3ef124007662]
+description = "reset clears previous laps"
+
+[76cea936-6214-4e95-b6d1-4d4edcf90499]
+description = "reset cannot be called from ready state"
+
+[ba4d8e69-f200-4721-b59e-90d8cf615153]
+description = "reset cannot be called from running state"
+
+[0b01751a-cb57-493f-bb86-409de6e84306]
+description = "supports very long laps"

exercises/practice/split-second-stopwatch/SplitSecondStopwatch.php

@@ -0,0 +1,39 @@
+<?php
+
+/*
+ * By adding type hints and enabling strict type checking, code can become
+ * easier to read, self-documenting and reduce the number of potential bugs.
+ * By default, type declarations are non-strict, which means they will attempt
+ * to change the original type to match the type specified by the
+ * type-declaration.
+ *
+ * In other words, if you pass a string to a function requiring a float,
+ * it will attempt to convert the string value to a float.
+ *
+ * To enable strict mode, a single declare directive must be placed at the top
+ * of the file.
+ * This means that the strictness of typing is configured on a per-file basis.
+ * This directive not only affects the type declarations of parameters, but also
+ * a function's return type.
+ *
+ * For more info review the Concept on strict type checking in the PHP track
+ * <link>.
+ *
+ * To disable strict typing, comment out the directive below.
+ */
+
+declare(strict_types=1);
+
+class SplitSecondStopwatch
+{
+    /**
+     * In PHP 8.4 and newer you can use Asymmetric Property Visibility to enhance data encapsulation
+     * @see https://www.php.net/manual/en/language.oop5.visibility.php#language.oop5.visibility-members-aviz
+     */
+    public function __construct()
+    {
+        throw new \BadMethodCallException(sprintf("Please implement the SplitSecondStopwatch class!"));
+    }
+
+    // Add methods as expected by the tests!
+}