Sync atbash-cipher (exercism#847)

exercises/practice/atbash-cipher/.docs/instructions.md

@@ -2,10 +2,8 @@
 
 Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.
 
-The Atbash cipher is a simple substitution cipher that relies on
-transposing all the letters in the alphabet such that the resulting
-alphabet is backwards. The first letter is replaced with the last
-letter, the second with the second-last, and so on.
+The Atbash cipher is a simple substitution cipher that relies on transposing all the letters in the alphabet such that the resulting alphabet is backwards.
+The first letter is replaced with the last letter, the second with the second-last, and so on.
 
 An Atbash cipher for the Latin alphabet would be as follows:
 
@@ -14,16 +12,16 @@ Plain:  abcdefghijklmnopqrstuvwxyz
 Cipher: zyxwvutsrqponmlkjihgfedcba
 ```
 
-It is a very weak cipher because it only has one possible key, and it is
-a simple monoalphabetic substitution cipher. However, this may not have
-been an issue in the cipher's time.
+It is a very weak cipher because it only has one possible key, and it is a simple mono-alphabetic substitution cipher.
+However, this may not have been an issue in the cipher's time.
 
-Ciphertext is written out in groups of fixed length, the traditional group size
-being 5 letters, and punctuation is excluded. This is to make it harder to guess
-things based on word boundaries.
+Ciphertext is written out in groups of fixed length, the traditional group size being 5 letters, leaving numbers unchanged, and punctuation is excluded.
+This is to make it harder to guess things based on word boundaries.
+All text will be encoded as lowercase letters.
 
 ## Examples
 
 - Encoding `test` gives `gvhg`
+- Encoding `x123 yes` gives `c123b vh`
 - Decoding `gvhg` gives `test`
 - Decoding `gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt` gives `thequickbrownfoxjumpsoverthelazydog`

exercises/practice/atbash-cipher/.meta/example.php

@@ -1,27 +1,5 @@
 <?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);
 
 function encode($string)
@@ -48,3 +26,20 @@ function encode($string)
 
     return implode('', $encoded);
 }
+
+function decode($string)
+{
+    $decodeMap = array_combine(range('z', 'a'), range('a', 'z'));
+    $encodedString = str_replace(' ', '', $string);
+
+    $decoded = [];
+    foreach (str_split($encodedString) as $char) {
+        if (isset($decodeMap[$char])) {
+            $decoded[] = $decodeMap[$char];
+        } elseif ($char >= '0' && $char <= '9') {
+            $decoded[] = $char;
+        }
+    }
+
+    return implode('', $decoded);
+}

exercises/practice/atbash-cipher/AtbashCipher.php

@@ -28,3 +28,8 @@ function encode(string $text): string
 {
     throw new \BadFunctionCallException("Implement the encode function");
 }
+
+function decode(string $text): string
+{
+    throw new \BadFunctionCallException("Implement the decode function");
+}

exercises/practice/atbash-cipher/AtbashCipherTest.php

@@ -1,27 +1,5 @@
 <?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 AtbashCipherTest extends PHPUnit\Framework\TestCase
@@ -31,45 +9,154 @@ public static function setUpBeforeClass(): void
         require_once 'AtbashCipher.php';
     }
 
-    public function testEncodeNo(): void
-    {
-        $this->assertEquals('ml', encode('no'));
-    }
+    /**
+     * Encoding from English to atbash cipher
+     */
 
+    /**
+     * uuid 2f47ebe1-eab9-4d6b-b3c6-627562a31c77
+     * @testdox encode yes
+     */
     public function testEncodeYes(): void
     {
         $this->assertEquals('bvh', encode('yes'));
     }
 
+    /**
+     * uuid b4ffe781-ea81-4b74-b268-cc58ba21c739
+     * @testdox encode no
+     */
+    public function testEncodeNo(): void
+    {
+        $this->assertEquals('ml', encode('no'));
+    }
+
+    /**
+     * uuid 10e48927-24ab-4c4d-9d3f-3067724ace00
+     * @testdox encode OMG
+     */
     public function testEncodeOmg(): void
     {
         $this->assertEquals('lnt', encode('OMG'));
     }
 
+    /**
+     * uuid d59b8bc3-509a-4a9a-834c-6f501b98750b
+     * @testdox encode spaces
+     */
     public function testEncodeOmgWithSpaces(): void
     {
         $this->assertEquals('lnt', encode('O M G'));
     }
 
+    /**
+     * uuid 31d44b11-81b7-4a94-8b43-4af6a2449429
+     * @testdox encode mindblowingly
+     */
     public function testEncodeLongWord(): void
     {
         $this->assertEquals('nrmwy oldrm tob', encode('mindblowingly'));
     }
 
+    /**
+     * uuid d503361a-1433-48c0-aae0-d41b5baa33ff
+     * @testdox encode numbers
+     */
     public function testEncodeNumbers(): void
     {
         $this->assertEquals('gvhgr mt123 gvhgr mt', encode('Testing, 1 2 3, testing.'));
     }
 
+    /**
+     * uuid 79c8a2d5-0772-42d4-b41b-531d0b5da926
+     * @testdox encode deep thought
+     */
     public function testEncodeSentence(): void
     {
         $this->assertEquals('gifgs rhurx grlm', encode('Truth is fiction.'));
     }
 
+    /**
+     * uuid 9ca13d23-d32a-4967-a1fd-6100b8742bab
+     * @testdox encode all the letters
+     */
     public function testEncodeAllTheThings(): void
     {
         $plaintext = 'The quick brown fox jumps over the lazy dog.';
         $encoded = 'gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt';
         $this->assertEquals($encoded, encode($plaintext));
     }
+
+    /**
+     * Decoding from atbash cipher to all-lowercase-mashed-together English
+     */
+
+    /**
+     * uuid bb50e087-7fdf-48e7-9223-284fe7e69851
+     * @testdox decode exercism
+     */
+    public function testDecodeExercism(): void
+    {
+        $this->assertEquals('exercism', decode('vcvix rhn'));
+    }
+
+    /**
+     * uuid ac021097-cd5d-4717-8907-b0814b9e292c
+     * @testdox decode a sentence
+     */
+    public function testDecodeASentence(): void
+    {
+        $this->assertEquals(
+            'anobstacleisoftenasteppingstone',
+            decode('zmlyh gzxov rhlug vmzhg vkkrm thglm v')
+        );
+    }
+
+    /**
+     * uuid 18729de3-de74-49b8-b68c-025eaf77f851
+     * @testdox decode numbers
+     */
+    public function testDecodeNumbers(): void
+    {
+        $this->assertEquals(
+            "testing123testing",
+            decode('gvhgr mt123 gvhgr mt')
+        );
+    }
+
+    /**
+     * uuid 0f30325f-f53b-415d-ad3e-a7a4f63de034
+     * @testdox decode all the letters
+     */
+    public function testDecodeAllTheLetters(): void
+    {
+        $this->assertEquals(
+            "thequickbrownfoxjumpsoverthelazydog",
+            decode('gsvjf rxpyi ldmul cqfnk hlevi gsvoz abwlt')
+        );
+    }
+
+    /**
+     * uuid 39640287-30c6-4c8c-9bac-9d613d1a5674
+     * @testdox decode with too many spaces
+     */
+    public function testDecodeWithTooManySpaces(): void
+    {
+        $this->assertEquals(
+            'exercism',
+            decode('vc vix    r hn')
+        );
+    }
+
+    /**
+     * uuid b34edf13-34c0-49b5-aa21-0768928000d5
+     * @testdox decode with no spaces
+     */
+    public function testDecodeWithNoSpacesInInput(): void
+    {
+        $this->assertEquals(
+            'anobstacleisoftenasteppingstone',
+            decode('zmlyhgzxovrhlugvmzhgvkkrmthglmv')
+        );
+    }
 }