// Cover art. Playnite stores art as local files on the host. Two delivery modes (see ArtMode):
//  - `host` (default): emit the local file PATH; the updated host serves the bytes via its art proxy
//    (`/library/art/…`), so the reconcile payload carries no image data and scales to any library size.
//  - `dataurl`: inline the cover as a size-capped `data:` URL (self-contained, but only fit for small
//    libraries — a big one blows past the host's reconcile body limit). `maxBytes` caps a single image.

import * as fs from "node:fs";
import * as path from "node:path";
import type { ArtOptions } from "./config.js";
import type { ExportedGame } from "./export-schema.js";
import type { Artwork } from "./wire.js";

const MIME: Record<string, string> = {
	".jpg": "image/jpeg",
	".jpeg": "image/jpeg",
	".png": "image/png",
	".webp": "image/webp",
	".gif": "image/gif",
	".bmp": "image/bmp",
	".ico": "image/x-icon",
	".tga": "image/x-tga",
};

const mimeFor = (file: string): string | null =>
	MIME[path.extname(file).toLowerCase()] ?? null;

/** Read a local image file into a `data:` URL, or null if missing, oversized, or an unknown type. */
export const fileToDataUrl = (
	file: string | null,
	maxBytes: number,
): string | null => {
	if (!file) return null;
	const mime = mimeFor(file);
	if (!mime) return null;
	try {
		const st = fs.statSync(file);
		if (!st.isFile() || st.size === 0 || st.size > maxBytes) return null;
		const b64 = fs.readFileSync(file).toString("base64");
		return `data:${mime};base64,${b64}`;
	} catch {
		return null;
	}
};

/** Build the artwork block for a game per the art config. Returns undefined when nothing was embedded. */
export const buildArtwork = (
	game: ExportedGame,
	art: ArtOptions,
): Artwork | undefined => {
	if (art.mode === "off") return undefined;
	// `host` mode: emit the local file paths verbatim (the exporter only sets a path when the file
	// exists). The host serves the bytes via its art proxy, so the reconcile payload carries no image
	// data and scales to any library size. The default.
	if (art.mode === "host") {
		const out: Artwork = {};
		if (game.cover) out.portrait = game.cover;
		if (art.includeBackground && game.background) out.hero = game.background;
		return out.portrait || out.hero ? out : undefined;
	}
	// `dataurl` mode: inline (size-capped) — self-contained but only fit for small libraries.
	const portrait = fileToDataUrl(game.cover, art.maxBytes);
	const hero = art.includeBackground
		? fileToDataUrl(game.background, art.maxBytes)
		: null;
	if (!portrait && !hero) return undefined;
	const out: Artwork = {};
	if (portrait) out.portrait = portrait;
	if (hero) out.hero = hero;
	return out;
};