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src/Service/Builder.php

@@ -0,0 +1,90 @@
+<?php
+
+namespace Opdavies\GmailFilterBuilder;
+
+class Builder
+{
+    /**
+     * @var array
+     */
+    private $filters = [];
+
+    public function __construct(array $filters)
+    {
+        $this->filters = $filters;
+    }
+
+    public function __toString()
+    {
+        return $this->build();
+    }
+
+    /**
+     * Build XML for a set of filters.
+     *
+     * @return string
+     */
+    private function build()
+    {
+        $prefix = "<?xml version='1.0' encoding='UTF-8'?>" . PHP_EOL . "<feed xmlns='http://www.w3.org/2005/Atom' xmlns:apps='http://schemas.google.com/apps/2006'>";
+        $suffix = '</feed>';
+
+        $xml = collect($this->filters)->map(function ($items) {
+            return $this->buildEntry($items);
+        })->implode(PHP_EOL);
+
+        return collect([$prefix, $xml, $suffix])->implode(PHP_EOL);
+    }
+
+    /**
+     * Build XML for an filter.
+     *
+     * @param Filter $filter
+     *
+     * @return string
+     */
+    private function buildEntry(Filter $filter)
+    {
+        $entry = collect($filter->getProperties())->map(function ($value, $key) {
+            return $this->buildProperty($value, $key);
+        })->implode(PHP_EOL);
+
+        return collect(['<entry>', $entry, '</entry>'])->implode(PHP_EOL);
+    }
+
+    /**
+     * Build XML for a property.
+     *
+     * @param string $value
+     * @param string $key
+     *
+     * @return string
+     */
+    private function buildProperty($value, $key)
+    {
+        if (collect(['from', 'to'])->contains($key)) {
+            $value = $this->implode($value);
+        }
+
+        return vsprintf("<apps:property name='%s' value='%s'/>", [
+            $key,
+            htmlentities($this->implode($value)),
+        ]);
+    }
+
+    /**
+     * Implode values with the appropriate prefix, suffix and separator.
+     */
+    private function implode($value, $separator = '|')
+    {
+        if (is_string($value)) {
+            return $value;
+        }
+
+        if (is_array($value) && count($value) === 1) {
+            return reset($value);
+        }
+
+        return sprintf('(%s)', collect($value)->implode($separator));
+    }
+}