Implement JsonReader

src/DatasetManager.php

@@ -86,6 +86,7 @@ class DatasetManager
                 $this->loadDatasets($info, ltrim($prefix . "." . $name, "."), $package, $path);
                 return;
             }
+            $info['filename'] = $path . "/" . $info['filename'];
             $pn = sprintf("%s#%s", $package, ltrim($prefix.".".$name,"."));
             $ds = new Dataset($pn, $info);
             $this->registerDataset($ds);

src/Readers/JsonReader.php

@@ -2,12 +2,91 @@
 
 namespace NoccyLabs\Dataset\Readers;
 
+use Iterator;
 use NoccyLabs\Dataset\ReaderInterface;
 
-class JsonReader implements ReaderInterface
+class JsonReader implements ReaderInterface, Iterator
 {
+    private array $files = [];
+
+    private int $currentFile = 0;
+
+    private ?int $loadedFile = null;
+
+    private array $data = [];
+
+    private int $currentIndex = 0;
+
+    private int $counter = 0;
+
     public function __construct(string $filename, array $options)
     {
+        $this->files = glob($filename);
+    }
+
+    private function checkLoadedSlice()
+    {
+        // If the current file is the loaded file, we're already set
+        if ($this->currentFile === $this->loadedFile) return;
+
+        if ($this->currentFile >= count($this->files)) {
+            printf("Reached end of set at slice=%d\n", $this->currentFile);
+            return;
+        }
+        $file = $this->files[$this->currentFile]; 
+        $json = @json_decode(@file_get_contents($file), true);
+
+        $this->loadData($json);
+        $this->loadedFile = $this->currentFile;
+        printf("loaded slice %d: %s\n", $this->currentFile, $file);
+    }
+
+    private function loadData(array $data)
+    {
+        // FIXME parse data according to directives if present
+        $this->data = $data;
+        $this->currentIndex = 0;
+    }
+
+    public function rewind(): void
+    {
+        $this->currentFile = 0;
+        $this->currentIndex = 0;
+        $this->counter = 0;
+        printf("Rewinding to slice=%d index=%d\n", $this->currentFile, $this->currentIndex);
+        $this->checkLoadedSlice();
+    }
+
+    public function key(): mixed
+    {
+        //$this->checkLoadedSlice();
+        return $this->counter;
+    }
+
+    public function current(): mixed
+    {
+        //$this->checkLoadedSlice();   
+        return $this->data[$this->currentIndex];
+    }
+
+    public function next(): void
+    {
+        $this->counter++;        
+        $this->currentIndex++;
+        
+        if ($this->currentIndex >= count($this->data)) {
+            $this->currentFile++;
+            $this->currentIndex = 0;
+            printf("Rolling over to slice=%d index=%d counter=%d\n", $this->currentFile, $this->currentIndex, $this->counter);
+        }
+
+        //$this->checkLoadedSlice();   
+    }
+
+    public function valid(): bool
+    {
+        $this->checkLoadedSlice();
+        return ($this->currentFile < count($this->files) && ($this->currentIndex < count($this->data)));
         
     }
 }