import type { Kysely } from "kysely";

import type { Database } from "../../database/types.js";
import { parseAllowedMimeTypes } from "../../media/mime.js";

/**
 * MIME types allowed for upload by default (when no field-specific list
 * overrides this). Entries ending with "/" are prefix-matched (e.g.
 * "video/" matches "video/mp4", "video/webm", etc.).
 *
 * Image types are enumerated explicitly rather than using a bare "image/"
 * prefix so that "image/svg+xml" is excluded by default: there is no
 * upload-time content validation for SVG, so an unvalidated bare-prefix
 * allowlist would let a Contributor+ upload an SVG with an embedded
 * `<script>`. Fields that genuinely need SVG uploads can still opt in via
 * their own `allowedMimeTypes` (see `resolveFieldAllowlist` below), which is
 * unaffected by this default.
 */
export const GLOBAL_UPLOAD_ALLOWLIST: readonly string[] = [
	"image/png",
	"image/jpeg",
	"image/gif",
	"image/webp",
	"video/",
	"audio/",
	"application/pdf",
];

/**
 * Resolve the MIME allowlist for a specific field.
 *
 * Returns the field's `allowedMimeTypes` list when the field exists, is of
 * type "file" or "image", and has a non-empty list configured. Returns null
 * in all other cases — callers should fall back to GLOBAL_UPLOAD_ALLOWLIST.
 *
 * Authentication is the caller's responsibility (the upload routes already
 * gate on `media:upload`).
 */
export async function resolveFieldAllowlist(
	db: Kysely<Database>,
	fieldId: string,
): Promise<string[] | null> {
	const row = await db
		.selectFrom("_emdash_fields")
		.select(["type", "validation"])
		.where("id", "=", fieldId)
		.where("type", "in", ["file", "image"])
		.executeTakeFirst();

	return row ? parseAllowedMimeTypes(row.validation) : null;
}