/** The kind of an entrypoint in an extension manifest. */
enum ManifestEntrypointKind {
	/** Javascript run as part of a content script */
	CONTENT_SCRIPT_JS,
	/** CSS applied as part of a content script */
	CONTENT_SCRIPT_CSS,
	/** Javascript run in the background page of an MV2 extension */
	BACKGROUND_SCRIPT,
	/** Javascript run the service worker of an MV3 extension */
	BACKGROUND_SERVICE_WORKER,
	/** Image file loaded as the extension's icon at a particular size */
	ICON,
	/** Path listed in the `web_accessible_resources` of an MV2 extension */
	WEB_ACCESSIBLE_RESOURCE_V2,
	/** Path listed in the `web_accessible_resources` of an MV3 extension */
	WEB_ACCESSIBLE_RESOURCE_V3,
}

/**
 * A handle to a single entrypoint from a manifest, which allows for rewriting
 * the path of the asset in the manifest.
 */
interface ManifestEntrypoint {
	type: ManifestEntrypointKind;
	/** The full path to the entrypoint file. */
	path: string;
	/**
	 * Replaces this entry path with the given new path. This is an in-place
	 * operation and directly affects the original manifest object.
	 */
	replacePath: (path: string) => void;
}

/**
 * Gets all script entrypoints from a manifest, returning them as
 * {@link ManifestEntrypoint} objects which allow for rewriting the path of each
 * individual entrypoint in place.
 * @param manifest Parsed `manifest.json` data.
 */
export const getScriptEntrypoints = (manifest: chrome.runtime.Manifest): ManifestEntrypoint[] => [
	...(manifest.content_scripts ?? []).flatMap(script =>
		(script.js ?? []).map((path, i) => ({
			type: ManifestEntrypointKind.CONTENT_SCRIPT_JS,
			path,
			replacePath (newPath: string) {
				this.path = newPath;
				script.js!.splice(i, 1, newPath);
			},
		}))
	),
	...(manifest.manifest_version === 2
		? (manifest.background?.scripts || []).map((path, i) => ({
			type: ManifestEntrypointKind.BACKGROUND_SCRIPT,
			path,
			replacePath (newPath: string) {
				this.path = newPath;
				manifest.background!.scripts!.splice(i, 1, newPath);
			},
		}))
		: (manifest.background?.service_worker
			? [{
				type: ManifestEntrypointKind.BACKGROUND_SERVICE_WORKER,
				path: manifest.background.service_worker,
				replacePath (newPath: string) {
					this.path = newPath;
					manifest.background!.service_worker = newPath;
				},
			}]
			: [])),
];

/**
 * Gets all asset entrypoints from a manifest, returning them as
 * {@link ManifestEntrypoint} objects which allow for rewriting the path of each
 * individual entrypoint in place.
 * @param manifest Parsed `manifest.json` data.
 */
export const getAssetEntrypoints = (manifest: chrome.runtime.Manifest): ManifestEntrypoint[] => [
	...(manifest.content_scripts ?? []).flatMap(script =>
		(script.css ?? []).map((path, i) => ({
			type: ManifestEntrypointKind.CONTENT_SCRIPT_CSS,
			path,
			replacePath (newPath: string) {
				this.path = newPath;
				script.css!.splice(i, 1, newPath);
			},
		}))
	),
	...Object.entries(manifest.icons || {}).map(([iconSize, path]) => ({
		type: ManifestEntrypointKind.ICON,
		path,
		replacePath (newPath: string) {
			this.path = newPath;
			manifest.icons![iconSize as unknown as number] = newPath;
		},
	})),
	...(manifest.manifest_version === 2
		? (manifest.web_accessible_resources ?? []).map((path, i) => ({
			type: ManifestEntrypointKind.WEB_ACCESSIBLE_RESOURCE_V2,
			path,
			replacePath (newPath: string) {
				this.path = newPath;
				manifest.web_accessible_resources![i] = newPath;
			},
		}))
		: (manifest.web_accessible_resources ?? []).flatMap(entry =>
			entry.resources.map((path, i) => ({
				type: ManifestEntrypointKind.WEB_ACCESSIBLE_RESOURCE_V3,
				path,
				replacePath (newPath: string) {
					this.path = newPath;
					entry.resources.splice(i, 1, newPath);
				},
			}))
		)),
];