Initial commit

vendor/laravel/prompts/src/Concerns/Scrolling.php

@@ -0,0 +1,115 @@
+<?php
+
+namespace Laravel\Prompts\Concerns;
+
+use Laravel\Prompts\Themes\Contracts\Scrolling as ScrollingRenderer;
+
+trait Scrolling
+{
+    /**
+     * The number of items to display before scrolling.
+     */
+    public int $scroll;
+
+    /**
+     * The index of the highlighted option.
+     */
+    public ?int $highlighted;
+
+    /**
+     * The index of the first visible option.
+     */
+    public int $firstVisible = 0;
+
+    /**
+     * Initialize scrolling.
+     */
+    protected function initializeScrolling(?int $highlighted = null): void
+    {
+        $this->highlighted = $highlighted;
+
+        $this->reduceScrollingToFitTerminal();
+    }
+
+    /**
+     * Reduce the scroll property to fit the terminal height.
+     */
+    protected function reduceScrollingToFitTerminal(): void
+    {
+        $reservedLines = ($renderer = $this->getRenderer()) instanceof ScrollingRenderer ? $renderer->reservedLines() : 0;
+
+        $this->scroll = max(1, min($this->scroll, $this->terminal()->lines() - $reservedLines));
+    }
+
+    /**
+     * Highlight the given index.
+     */
+    protected function highlight(?int $index): void
+    {
+        $this->highlighted = $index;
+
+        if ($this->highlighted === null) {
+            return;
+        }
+
+        if ($this->highlighted < $this->firstVisible) {
+            $this->firstVisible = $this->highlighted;
+        } elseif ($this->highlighted > $this->firstVisible + $this->scroll - 1) {
+            $this->firstVisible = $this->highlighted - $this->scroll + 1;
+        }
+    }
+
+    /**
+     * Highlight the previous entry, or wrap around to the last entry.
+     */
+    protected function highlightPrevious(int $total, bool $allowNull = false): void
+    {
+        if ($total === 0) {
+            return;
+        }
+
+        if ($this->highlighted === null) {
+            $this->highlight($total - 1);
+        } elseif ($this->highlighted === 0) {
+            $this->highlight($allowNull ? null : ($total - 1));
+        } else {
+            $this->highlight($this->highlighted - 1);
+        }
+    }
+
+    /**
+     * Highlight the next entry, or wrap around to the first entry.
+     */
+    protected function highlightNext(int $total, bool $allowNull = false): void
+    {
+        if ($total === 0) {
+            return;
+        }
+
+        if ($this->highlighted === $total - 1) {
+            $this->highlight($allowNull ? null : 0);
+        } else {
+            $this->highlight(($this->highlighted ?? -1) + 1);
+        }
+    }
+
+    /**
+     * Center the highlighted option.
+     */
+    protected function scrollToHighlighted(int $total): void
+    {
+        if ($this->highlighted < $this->scroll) {
+            return;
+        }
+
+        $remaining = $total - $this->highlighted - 1;
+        $halfScroll = (int) floor($this->scroll / 2);
+        $endOffset = max(0, $halfScroll - $remaining);
+
+        if ($this->scroll % 2 === 0) {
+            $endOffset--;
+        }
+
+        $this->firstVisible = $this->highlighted - $halfScroll - $endOffset;
+    }
+}