Feature: Divide message to parts

src/SmsLength.php

@@ -82,11 +82,22 @@ class SmsLength
      */
     private $messageCount;
 
+    /**
+     * @var string
+     */
+    private $messageContent;
+
+    /**
+     * @var null|array
+     */
+    private $messageParts;
+
     /**
      * @param string $messageContent SMS message content (UTF-8)
      */
     public function __construct(string $messageContent)
     {
+        $this->messageContent = $messageContent;
         $this->inspect($messageContent);
     }
 
@@ -199,4 +210,74 @@ private function inspect(string $messageContent): void
             $this->messageCount = (int)ceil($this->size / $concatSize);
         }
     }
+
+    /**
+     * Divide message to SMS parts indexed from 1
+     * @return array|string[]
+     */
+    public function getMessageParts(): array
+    {
+        if ($this->messageParts === null) {
+            if ($this->getMessageCount() === 1) {
+                $this->messageParts = [1 => $this->messageContent];
+            } elseif ($this->getEncoding() === '7-bit') {
+                $this->messageParts = $this->divide7bitMessage();
+            } else {
+                $this->messageParts = $this->divideUcs2Message();
+            }
+        }
+
+        return $this->messageParts;
+    }
+
+    private function divide7bitMessage(): array
+    {
+        $size = 0;
+        $actualPart = 1;
+        $parts[$actualPart] = ''; // Init first part
+
+        $mbLength = mb_strlen($this->messageContent, 'UTF-8');
+        for ($i = 0; $i < $mbLength; $i++) {
+            $char = mb_substr($this->messageContent, $i, 1, 'UTF-8');
+            if (in_array($char, self::GSM0338_BASIC, true)) {
+                $size++;
+            } else {
+                $size += 2;
+            }
+
+            // Init next part
+            if ($actualPart * self::MAXIMUM_CHARACTERS_7BIT_CONCATENATED < $size) {
+                $actualPart++;
+                $parts[$actualPart] = '';
+            }
+
+            $parts[$actualPart] .= $char;
+        }
+        return $parts;
+    }
+
+    private function divideUcs2Message(): array
+    {
+        $size = 0;
+        $actualPart = 1;
+        $parts[$actualPart] = ''; // Init first part
+
+        $mbLength = mb_strlen($this->messageContent, 'UTF-8');
+        for ($i = 0; $i < $mbLength; $i++) {
+            $char = mb_substr($this->messageContent, $i, 1, 'UTF-8');
+            $utf16Hex = bin2hex(mb_convert_encoding($char, 'UTF-16', 'UTF-8'));
+            $charSize = strlen($utf16Hex) / 4;
+            $size += $charSize;
+
+            // Init next part
+            if ($actualPart * self::MAXIMUM_CHARACTERS_UCS2_CONCATENATED < $size) {
+                $actualPart++;
+                $parts[$actualPart] = '';
+            }
+
+            $parts[$actualPart] .= $char;
+        }
+
+        return $parts;
+    }
 }

tests/SmsLengthTest.php

@@ -91,6 +91,58 @@ public function providerSize(): array
         ];
     }
 
+    /**
+     * @dataProvider providerMessageParts
+     */
+    public function testDivideMessage(array $parts, int $characters): void {
+        $message = implode('', $parts);
+
+        $size = new SmsLength($message);
+
+        static::assertSame($parts, $size->getMessageParts());
+        static::assertCount(count($parts), $size->getMessageParts());
+        static::assertSame($characters, $size->getSize());
+    }
+
+    public function providerMessageParts(): array
+    {
+       return [
+           // 7-bit
+           'one-part-basic' => [[
+               1 => $this->getChars(self::GSM0338_BASIC, 160)
+           ], 160],
+           'two-parts-basic' => [[
+               1 => $this->getChars(self::GSM0338_BASIC, 153),
+               2 => $this->getChars(self::GSM0338_BASIC, 153)
+           ], 306],
+
+           // 7-bit extended
+           'one-part-extended' => [[
+               1 => $this->getChars(self::GSM0338_EXTENDED, 80)
+           ], 160],
+           'two-part-extended' => [[
+               1 => $this->getChars(self::GSM0338_BASIC, 153),
+               2 => $this->getChars(self::GSM0338_EXTENDED, 76)
+           ], 305],
+
+           // ucs-2
+           'one-part-ucs' => [[
+               1 => $this->getChars('simple msg plus •', 70)
+           ], 70],
+           'two-part-ucs' => [[
+               1 => $this->getChars('simple msg plus •', 67),
+               2 => $this->getChars('simple msg plus •', 67),
+           ], 134],
+           'one-part-ucs-double' => [[
+               1 => $this->getChars('simple msg plus ', 68) . "\xf0\x9f\x93\xb1",
+           ], 70],
+           'two-part-ucs-double' => [[
+               1 => $this->getChars('simple msg plus ', 65) . "\xf0\x9f\x93\xb1",
+               2 => $this->getChars('simple msg plus ', 65) . "\xf0\x9f\x93\xb1",
+           ], 134],
+        ];
+    }
+
     /**
      * @dataProvider providerTooLarge
      * @medium Expect tests to take >1 but <10
@@ -133,4 +185,17 @@ public function providerTooLarge(): array
             'ucs-2' => [str_repeat("simple msg plus \xf0\x9f\x93\xb1", 950), 'ucs-2', 17100, 256, 17152],
         ];
     }
+
+    /**
+     * Trims or extends the character set to the exact length
+     */
+    private function getChars(string $charSet, int $size): string
+    {
+        $chars = $charSet;
+        while (mb_strlen($chars, 'UTF-8') < $size) {
+            $chars .= $charSet;
+        }
+
+        return mb_substr($chars, 0, $size);
+    }
 }