Remove extra empty lines when setting context to 0

Signed-off-by: Jack Cherng <jfcherng@gmail.com>

Author: jfcherng

src/Renderer/Html/AbstractHtml.php

@@ -77,10 +77,12 @@ public function getChanges(): array
                 $lastTag = $tag;
 
                 if ($tag === SequenceMatcher::OPCODE_EQUAL) {
-                    $lines = \array_slice($a, $i1, ($i2 - $i1));
-                    $blocks[$lastBlock]['base']['lines'] += $this->formatLines($lines);
-                    $lines = \array_slice($b, $j1, ($j2 - $j1));
-                    $blocks[$lastBlock]['changed']['lines'] += $this->formatLines($lines);
+                    if (!empty($lines = \array_slice($a, $i1, ($i2 - $i1)))) {
+                        $formattedLines = $this->formatLines($lines);
+
+                        $blocks[$lastBlock]['base']['lines'] += $formattedLines;
+                        $blocks[$lastBlock]['changed']['lines'] += $formattedLines;
+                    }
                 } else {
                     if (
                         $tag === SequenceMatcher::OPCODE_REPLACE ||

src/Renderer/Text/Context.php

@@ -80,7 +80,10 @@ protected function renderBlockFrom(array $opcodes): string
                 continue;
             }
 
-            $ret .= self::TAG_MAP[$tag] . ' ' . \implode("\n" . self::TAG_MAP[$tag] . ' ', $this->diff->getA($i1, $i2)) . "\n";
+            $ret .= $this->renderContext(
+                self::TAG_MAP[$tag],
+                $this->diff->getA($i1, $i2)
+            );
         }
 
         return $ret;
@@ -102,9 +105,27 @@ protected function renderBlockTo(array $opcodes): string
                 continue;
             }
 
-            $ret .= self::TAG_MAP[$tag] . ' ' . \implode("\n" . self::TAG_MAP[$tag] . ' ', $this->diff->getB($j1, $j2)) . "\n";
+            $ret .= $this->renderContext(
+                self::TAG_MAP[$tag],
+                $this->diff->getB($j1, $j2)
+            );
         }
 
         return $ret;
     }
+
+    /**
+     * Render the context array with the symbol.
+     *
+     * @param string $symbol  the symbol
+     * @param array  $context the context
+     *
+     * @return string
+     */
+    protected function renderContext(string $symbol, array $context): string
+    {
+        return empty($context)
+            ? ''
+            : "{$symbol} " . \implode("\n{$symbol} ", $context) . "\n";
+    }
 }

src/Renderer/Text/Unified.php

@@ -25,6 +25,7 @@ public function render(): string
     {
         $ret = '';
 
+        // var_dump($this->diff->getGroupedOpcodes());
         foreach ($this->diff->getGroupedOpcodes() as $opcodes) {
             $lastItem = \count($opcodes) - 1;
 
@@ -41,7 +42,7 @@ public function render(): string
 
             foreach ($opcodes as [$tag, $i1, $i2, $j1, $j2]) {
                 if ($tag === SequenceMatcher::OPCODE_EQUAL) {
-                    $ret .= ' ' . \implode("\n ", $this->diff->getA($i1, $i2)) . "\n";
+                    $ret .= $this->renderContext(' ', $this->diff->getA($i1, $i2));
 
                     continue;
                 }
@@ -50,18 +51,33 @@ public function render(): string
                     $tag === SequenceMatcher::OPCODE_REPLACE ||
                     $tag === SequenceMatcher::OPCODE_DELETE
                 ) {
-                    $ret .= '-' . \implode("\n-", $this->diff->getA($i1, $i2)) . "\n";
+                    $ret .= $this->renderContext('-', $this->diff->getA($i1, $i2));
                 }
 
                 if (
                     $tag === SequenceMatcher::OPCODE_REPLACE ||
                     $tag === SequenceMatcher::OPCODE_INSERT
                 ) {
-                    $ret .= '+' . \implode("\n+", $this->diff->getB($j1, $j2)) . "\n";
+                    $ret .= $this->renderContext('+', $this->diff->getB($j1, $j2));
                 }
             }
         }
 
         return $ret;
     }
+
+    /**
+     * Render the context array with the symbol.
+     *
+     * @param string $symbol  the symbol
+     * @param array  $context the context
+     *
+     * @return string
+     */
+    protected function renderContext(string $symbol, array $context): string
+    {
+        return empty($context)
+            ? ''
+            : $symbol . \implode("\n{$symbol}", $context) . "\n";
+    }
 }