/**
 * Shared drag-and-drop utilities for cross-module item dragging.
 *
 * Any module card/list-item can become draggable by calling
 * `makeDraggable(el, payload)` — the calendar and reminders widget
 * will accept the drop via `application/rspace-item`.
 */

export interface RSpaceItemPayload {
	title: string;
	module: string;       // e.g. "rnotes", "rtasks", "rfiles"
	entityId: string;
	label?: string;       // human-readable source, e.g. "Note", "Task"
	color?: string;       // module accent color
}

/** Module accent colors for drag ghost + calendar indicators */
export const MODULE_COLORS: Record<string, string> = {
	rnotes:  "#f59e0b",  // amber
	rtasks:  "#3b82f6",  // blue
	rfiles:  "#10b981",  // emerald
	rsplat:  "#818cf8",  // indigo
	rphotos: "#ec4899",  // pink
	rbooks:  "#f97316",  // orange
	rforum:  "#8b5cf6",  // violet
	rinbox:  "#06b6d4",  // cyan
	rvote:   "#ef4444",  // red
	rtube:   "#a855f7",  // purple
};

/**
 * Make an element draggable with the rspace-item protocol.
 * Adds draggable attribute and dragstart handler.
 */
export function makeDraggable(el: HTMLElement, payload: RSpaceItemPayload) {
	el.draggable = true;
	el.style.cursor = "grab";
	el.addEventListener("dragstart", (e) => {
		if (!e.dataTransfer) return;
		e.dataTransfer.setData("application/rspace-item", JSON.stringify(payload));
		e.dataTransfer.setData("text/plain", payload.title);
		e.dataTransfer.effectAllowed = "copyMove";
		el.style.opacity = "0.6";
	});
	el.addEventListener("dragend", () => {
		el.style.opacity = "";
	});
}

/**
 * Attach drag handlers to all matching elements within a root.
 * `selector` matches the card elements.
 * `payloadFn` extracts the payload from each matched element.
 */
export function makeDraggableAll(
	root: Element | ShadowRoot,
	selector: string,
	payloadFn: (el: HTMLElement) => RSpaceItemPayload | null,
) {
	root.querySelectorAll<HTMLElement>(selector).forEach((el) => {
		const payload = payloadFn(el);
		if (payload) makeDraggable(el, payload);
	});
}