From 56ca09692a308b22455420d11376ff8d41244c47 Mon Sep 17 00:00:00 2001
From: Maze Winther <mazewinther@gmail.com>
Date: Sun, 26 Apr 2026 17:31:28 +0200
Subject: refactor: thinner hooks

---
 apps/web/src/timeline/drag-source.ts | 40 ++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 apps/web/src/timeline/drag-source.ts

(limited to 'apps/web/src/timeline/drag-source.ts')

diff --git a/apps/web/src/timeline/drag-source.ts b/apps/web/src/timeline/drag-source.ts
new file mode 100644
index 00000000..503c547b
--- /dev/null
+++ b/apps/web/src/timeline/drag-source.ts
@@ -0,0 +1,40 @@
+import type { TimelineDragData } from "@/timeline/drag";
+
+const TIMELINE_DRAG_MIME = "application/x-timeline-drag";
+
+/**
+ * Owns the state of an in-progress timeline drag session.
+ *
+ * Exists because browsers restrict `DataTransfer.getData()` to the `drop`
+ * event for security — during `dragover`/`dragenter` only `types` is
+ * readable. The drop target needs the payload (element type, target
+ * element types, source duration) while the pointer is hovering, so we
+ * keep a live copy here and hand it out via {@link getActive}.
+ */
+export class TimelineDragSource {
+	private active: TimelineDragData | null = null;
+
+	begin({
+		dataTransfer,
+		dragData,
+	}: {
+		dataTransfer: DataTransfer;
+		dragData: TimelineDragData;
+	}): void {
+		dataTransfer.setData(TIMELINE_DRAG_MIME, JSON.stringify(dragData));
+		dataTransfer.effectAllowed = "copy";
+		this.active = dragData;
+	}
+
+	end(): void {
+		this.active = null;
+	}
+
+	getActive(): TimelineDragData | null {
+		return this.active;
+	}
+
+	isActive(): boolean {
+		return this.active !== null;
+	}
+}
-- 
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