change user modify auth table to more understandable event names (#12)

supabase/functions/on_user_modify/index.ts

@@ -4,18 +4,31 @@ Deno.serve(async (req) => {
   let { record, old_record, type } = await req.json();
   record = record || old_record;
 
+  let event: string | undefined;
   // deno-lint-ignore no-explicit-any
   const properties: Record<string, any> = { type };
   properties["$set"] = properties["$set"] || {};
   properties["$set"].email = record.email || undefined;
   properties["$set"].created_at = record.created_at;
   properties["$set"].last_sign_in_at = record.last_sign_in_at;
 
-  posthog.capture({
-    distinctId: record.id,
-    event: "user modify auth table",
-    properties: properties,
-  });
+  if (type === "INSERT") {
+    event = "user signs up";
+  } else if (
+    type === "UPDATE" && record.last_sign_in_at !== old_record.last_sign_in_at
+  ) {
+    event = "user signs in";
+  } else if (type === "DELETE") {
+    event = "user deletes account";
+  }
+
+  if (event) {
+    posthog.capture({
+      distinctId: record.id,
+      event,
+      properties: properties,
+    });
+  }
 
   return new Response(null);
 });