import { DefaultTheme, SiteConfig } from 'vitepress';
import { Buffer } from 'node:buffer';

interface BuildEndGenerateOpenGraphImagesOptions {
    /**
     * The base URL to use for open graph image.
     *
     * Must be a full URL, e.g. `https://example.com` or `https://example.com/path/of/baseUrl`.
     *
     * This is because for platforms like Telegram, Twitter, and Facebook, they wouldn't accept
     * relative URLs for open graph image when dynamically fetching the image from the HTML meta tag.
     * Instead, they require a full URL to the image.
     *
     * If you would ever need to use a dynamic base URL (e.g. Cloudflare Pages, Vercel, Netlify staging
     * preview URL), you may need to create a separate stabled sub-domain or use a standalone services
     * S3 to host the generated open graph images to make sure the image URL is full with domain.
     */
    baseUrl: string;
    /**
     * The category options to use for open graph image.
     */
    category?: BuildEndGenerateOpenGraphImagesOptionsCategory;
    /**
     * This function will be called with each URL of the image hrefs in the SVG template.
     * You can return a Buffer of the image to use to avoid fetching the image from its URL.
     * If you return undefined, the image will be fetched from its URL.
     */
    svgImageUrlResolver?: (imageUrl: string) => Promise<Buffer> | Buffer | undefined;
    /**
     * Font buffers to load for rendering the template SVG
     */
    svgFontBuffers?: Buffer[];
    /**
     * Temaplte SVG file path.
     * If not supplied, will try to locate `og-template.svg` under `public` or `assets` directory,
     * and will fallback to a builtin template.
     */
    templateSvgPath?: string;
    /**
     * Width of the result image.
     *
     * @default 1200
     */
    resultImageWidth?: number;
    /**
     * Maximum characters per line.
     *
     * @default 17
     */
    maxCharactersPerLine?: number;
    /**
     * Whether to override existing meta tags.
     *
     * @default true
     */
    overrideExistingMetaTags?: boolean;
}
interface BuildEndGenerateOpenGraphImagesOptionsCategory {
    /**
     * Automatically extract category text from path with a specific level.
     *
     * For example, if you have a path like `/foo/bar/baz/index.md`, and you set `byLevel` to `1`,
     * the category text will be `bar`. This is extremely useful when you have a file based routing,
     * while having all the contents organized in a stable directory structure (e.g. knowledge base).
     *
     * As end user, either specify one of `byLevel`, `byPathPrefix`, or `byCustomGetter`, if multiple
     * options are provided, `byCustomGetter` would be used as the first priority. `byPathPrefix` secondary,
     * and `byLevel` as the last resort. If none of them are provided or produced undefined result for category
     * text, it will fallback to frontmatter category text.
     */
    byLevel?: number;
    /**
     * Automatically extract category text from path with a specific prefix.
     *
     * For example, if you have a path like `/foo/bar/baz/index.md`, and you set `byPathPrefix` to `[{ prefix: 'foo', text: 'Foo' }]`,
     * the category text will be `Foo`. This is extremely useful when you use file based routing, while organized the contents
     * inside a directory name that friendly to browsers.
     *
     * As end user, either specify one of `byLevel`, `byPathPrefix`, or `byCustomGetter`, if multiple
     * options are provided, `byCustomGetter` would be used as the first priority. `byPathPrefix` secondary,
     * and `byLevel` as the last resort. If none of them are provided or produced undefined result for category
     * text, it will fallback to frontmatter category text.
     */
    byPathPrefix?: {
        /**
         * The prefix to match.
         */
        prefix: string;
        /**
         * The text to use as category.
         */
        text: string;
    }[];
    /**
     * If `byLevel` or `byPathPrefix` is not enough, you can provide a custom getter to extract category text programmatically.
     *
     * For example you have a complex i18n system, or you want to extract category text from a specific field in frontmatter.
     *
     * As end user, either specify one of `byLevel`, `byPathPrefix`, or `byCustomGetter`, if multiple
     * options are provided, `byCustomGetter` would be used as the first priority. `byPathPrefix` secondary,
     * and `byLevel` as the last resort. If none of them are provided or produced undefined result for category
     * text, it will fallback to frontmatter category text.
     *
     * @param {PageItem} page - The page item to process
     * @returns {string} The category text
     */
    byCustomGetter?: (page: PageItem) => string | void | Promise<string | void>;
    /**
     * Fallback to frontmatter category text when no category text found.
     *
     * Only effective when no category text found from `byLevel`, `byPathPrefix`, or `byCustomGetter`, or none of them
     * were provided. If `true`, it will fallback to frontmatter category text when no category text found. Otherwise a 'Un-categorized'
     * will be used as category text.
     *
     * @default true
     */
    fallbackWithFrontmatter?: boolean;
}
interface PageItem extends DefaultTheme.SidebarItem {
    title: string;
    category: string;
    locale: string;
    sourceFilePath: string;
    normalizedSourceFilePath: string;
    frontmatter: Record<string, any>;
}

/**
 * Build end generate open graph images.
 * @param {BuildEndGenerateOpenGraphImagesOptions} options - Options used for generating open graph images.
 * @returns Build end hook for VitePress
 */
declare function buildEndGenerateOpenGraphImages(options: BuildEndGenerateOpenGraphImagesOptions): (siteConfig: SiteConfig) => Promise<void>;

export { buildEndGenerateOpenGraphImages };