import { describe, it, expect } from "vitest";

import {
	getMediaThumbnailUrl,
	fallbackToOriginalThumbnail,
	MEDIA_THUMBNAIL_WIDTH,
} from "../../src/lib/media-utils";

const LOCAL_IMAGE = "/_emdash/api/media/file/01ABC.jpg";

describe("getMediaThumbnailUrl", () => {
	it("routes a local raster image through Astro's /_image endpoint", () => {
		const result = getMediaThumbnailUrl(LOCAL_IMAGE, "image/jpeg");
		expect(result.startsWith("/_image?")).toBe(true);

		const url = new URL(result, window.location.origin);
		expect(url.pathname).toBe("/_image");
		expect(url.searchParams.get("href")).toBe(`${window.location.origin}${LOCAL_IMAGE}`);
		expect(url.searchParams.get("w")).toBe(String(MEDIA_THUMBNAIL_WIDTH));
		expect(url.searchParams.get("f")).toBe("webp");
	});

	it("honors a custom width", () => {
		const result = getMediaThumbnailUrl(LOCAL_IMAGE, "image/png", 80);
		const url = new URL(result, window.location.origin);
		expect(url.searchParams.get("w")).toBe("80");
	});

	it("passes SVGs through unchanged (vector, nothing to downscale)", () => {
		const svg = "/_emdash/api/media/file/01ABC.svg";
		expect(getMediaThumbnailUrl(svg, "image/svg+xml")).toBe(svg);
	});

	it("passes non-image media through unchanged (an icon renders instead)", () => {
		const pdf = "/_emdash/api/media/file/01ABC.pdf";
		expect(getMediaThumbnailUrl(pdf, "application/pdf")).toBe(pdf);
	});

	it("passes external/provider URLs through unchanged (already a remote rendition)", () => {
		const external = "https://images.example.com/photo.jpg";
		expect(getMediaThumbnailUrl(external, "image/jpeg")).toBe(external);
	});
});

describe("fallbackToOriginalThumbnail", () => {
	it("swaps in the original URL on first error", () => {
		const img = { dataset: {} as DOMStringMap, src: "/_image?href=...&w=400&f=webp" };
		fallbackToOriginalThumbnail(img, LOCAL_IMAGE);
		expect(img.src).toBe(LOCAL_IMAGE);
		expect(img.dataset.thumbFallback).toBe("1");
	});

	it("does not loop if the original also fails", () => {
		const img = { dataset: { thumbFallback: "1" } as DOMStringMap, src: LOCAL_IMAGE };
		fallbackToOriginalThumbnail(img, "/some/other/url.jpg");
		// Guard short-circuits: src is left untouched.
		expect(img.src).toBe(LOCAL_IMAGE);
	});
});