diff --git a/app/Parser.php b/app/Parser.php
index b74cf7b9f7..eda04e6665 100644
--- a/app/Parser.php
+++ b/app/Parser.php
@@ -2,12 +2,82 @@
 
 namespace App;
 
-use Exception;
-
 final class Parser
 {
     public function parse(string $inputPath, string $outputPath): void
     {
-        throw new Exception('TODO');
+        gc_disable();
+
+        $handle = fopen($inputPath, 'r');
+
+        $urlIds = [];
+        $urls = [];
+        $nextId = 0;
+
+        $counts = [];
+
+        $buffer = '';
+        $chunkSize = 5 * 1024 * 1024;
+
+        while (!feof($handle)) {
+            $buffer .= fread($handle, $chunkSize);
+
+            $lines = explode("\n", $buffer);
+            $buffer = array_pop($lines);
+
+            foreach ($lines as $row) {
+                if ($row === '') {
+                    continue;
+                }
+
+                $comma = strpos($row, ',');
+
+                $url = substr($row, 19, $comma - 19);
+                $date = substr($row, $comma + 1, 10);
+
+                if (!isset($urlIds[$url])) {
+                    $urlIds[$url] = $nextId;
+                    $urls[$nextId] = $url;
+                    $nextId++;
+                }
+
+                $id = $urlIds[$url];
+
+                $counts[$id][$date] = ($counts[$id][$date] ?? 0) + 1;
+            }
+        }
+
+        fclose($handle);
+
+        $json = "{\n";
+        $firstUrl = true;
+
+        foreach ($counts as $id => $dates) {
+            if (! $firstUrl) {
+                $json .= ",\n";
+            }
+            $firstUrl = false;
+
+            ksort($dates);
+
+            $json .= "    " . json_encode($urls[$id]) . ": {\n";
+
+            $firstDate = true;
+
+            foreach ($dates as $date => $count) {
+                if (! $firstDate) {
+                    $json .= ",\n";
+                }
+                $firstDate = false;
+
+                $json .= "        \"$date\": $count";
+            }
+
+            $json .= "\n    }";
+        }
+
+        $json .= "\n}";
+
+        file_put_contents($outputPath, $json);
     }
 }
\ No newline at end of file