/**
 * Languages bundled by default
 * @typedef {('asm'|'bash'|'bf'|'c'|'css'|'csv'|'diff'|'docker'|'git'|'go'|'html'|'http'|'ini'|'java'|'js'|'jsdoc'|'json'|'leanpub-md'|'log'|'lua'|'make'|'md'|'pl'|'plain'|'py'|'regex'|'rs'|'sql'|'todo'|'toml'|'ts'|'uri'|'xml'|'yaml')} ShjBuiltinLanguage
 */

/**
 * A bundled language or any name the loader can give
 * @typedef {ShjBuiltinLanguage | (string & {})} ShjLanguage
 */

/**
 * Republished from `tokenize.js` so writing a custom language only
 * takes the main entry, even for the types it never mentions itself
 *
 * @typedef {import('./tokenize.js').ShjToken} ShjToken
 * @typedef {import('./tokenize.js').ShjMatcher} ShjMatcher
 * @typedef {import('./tokenize.js').ShjLanguageData} ShjLanguageData
 * @typedef {import('./tokenize.js').ShjRule} ShjRule
 * @typedef {import('./tokenize.js').ShjGrammar} ShjGrammar
 * @typedef {import('./tokenize.js').ShjTokenCallback} ShjTokenCallback
 */

/**
 * Give a language for the asked name: the language, its module, or a promise of either
 * @typedef {(name: string) => ShjLanguageData | { default: ShjLanguageData } | Promise<ShjLanguageData | { default: ShjLanguageData }> | undefined} ShjLanguageLoader
 */

/**
 * Themes supported in the browser
 * @typedef {('atom-dark'|'github-dark'|'github-dim'|'dark'|'default'|'github-light'|'visual-studio-dark')} ShjBrowserTheme
 */

/**
 * A theme, mapping each token type to the ANSI escape printed before it
 * @typedef {Partial<Record<ShjToken, string>>} ShjTerminalTheme
 */

/**
 * @typedef {Object} ShjOptions
 * @property {boolean} [block=true] Render as a block, with the line numbering
 * and header wrapper, rather than inline. `highlightElement` defaults it from
 * the element instead: a `code` element is inline, anything else is a block
 * @property {boolean} [showLineNumbers=false] Indicates whether to number the
 * lines, in a gutter laid out inside the block
 */

import { tokenizer } from './tokenize.js';

/**
 * Loader of the bundled languages, can be called
 * by a custom loader as its fallback
 *
 * @type {ShjLanguageLoader}
 */
export const defaultLoader = name => import(`./languages/${name}.js`);

let loader = defaultLoader;

/**
 * Replace how language names are loaded, call it before highlighting
 *
 * @example
 * setLoader(name => customs[name] ?? defaultLoader(name));
 *
 * @param {ShjLanguageLoader} newLoader Given a name, returns the language, its module, or a promise of either
 */
export function setLoader(newLoader) {
	loader = newLoader;
}

const cache = /** @type {Object<string, ReturnType<ShjLanguageLoader>>} */ ({}),
	sanitize = (str = '') =>
		str.replaceAll('&', '&#38;').replaceAll('<', '&lt;').replaceAll('>', '&gt;'),
	/**
	 * Create a HTML element with the right token styling
	 *
	 * @param {string} str The content (need to be sanitized)
	 * @param {ShjToken} [token] The type of token
	 * @returns A HTML string
	 */
	toSpan = (str, token) => token ? `<span class="shj-syn-${token}">${str}</span>` : str;

/**
 * Find the tokens in the given code and call the given callback,
 * bundled languages are loaded on first use
 *
 * @param {string} src The code
 * @param {ShjLanguage|ShjLanguageData} lang The language of the code
 * @param {ShjTokenCallback} onToken Called with the text and type of each token
 * @returns {Promise<void>} Resolves once every token has been emitted
 */
export async function tokenize(src, lang, onToken) {
	let it = tokenizer(src, lang, onToken),
		res = it.next();

	while (!res.done) {
		let name = /** @type {string} */ (res.value),
			data;
		try {
			// the loader is only called on cache misses, import() can throw
			// synchronously when bundled so it cannot be a catch on the promise
			data = /** @type {{ default?: ShjLanguageData, sub?: ShjGrammar }|undefined} */ (await (cache[name] ??= loader(name)));
		}
		catch {}
		res = it.next(/** @type {ShjLanguageData|undefined} */ (data?.default ?? data));
	}
}

/**
 * Highlight a string passed as argument and return it
 * @example
 * elm.innerHTML = await highlightHTML(code, 'js');
 *
 * @param {string} src The code
 * @param {ShjLanguage|ShjLanguageData} lang The language of the code
 * @param {ShjOptions} [opt={}] Customization options
 * @returns {Promise<string>} The highlighted string
 */
export async function highlightHTML(src, lang, opt = {}) {
	let tmp = ''
	await tokenize(src, lang, (str, type) => tmp += toSpan(sanitize(str), type))

	return (opt.block ?? true)
		? `<div><div class="shj-numbers">${'<div></div>'.repeat(opt.showLineNumbers ? src.split('\n').length : 0)}</div><div>${tmp}</div></div>`
		: tmp;
}

/**
 * Highlight a DOM element by getting the new innerHTML with highlightHTML
 *
 * @param {Element} elm The DOM element
 * @param {ShjLanguage} [lang] The language of the code (searching by default on `elm` for a 'shj-lang-' class)
 * @param {ShjOptions} [opt={}] Customization options, `block` defaults to the element: a `code` element is inline
 * @returns {Promise<void>} Resolves once the element has been highlighted
 */
export async function highlightElement(elm, lang = /** @type {ShjLanguage} */ (elm.className.match(/shj-lang-([\w-]+)/)?.[1]), opt = {}) {
	let txt = elm.textContent;
	let block = opt.block ?? elm.tagName != 'CODE';
	/** @type {HTMLElement} */ (elm).dataset.lang = lang;
	elm.className = `${[...elm.classList].filter(className => !className.startsWith('shj-')).join(' ')} shj-lang-${lang} shj-${block ? 'block' : 'inline'}`;
	elm.innerHTML = await highlightHTML(txt, lang, { ...opt, block });
}

/**
 * Call highlightElement on element with a css class starting with `shj-lang-`
 *
 * @param {ShjOptions} [opt={}] Customization options
 * @returns {Promise<void[]>} Resolves once every element has been highlighted
 */
export async function highlightAll(opt) {
	return Promise.all(
		Array.from(document.querySelectorAll('[class*="shj-lang-"]'))
		.map(elm => highlightElement(elm, undefined, opt)));
}

/**
 * Highlight a string passed as argument and return a string that can directly
 * be printed in a terminal, bundled languages are loaded on first use
 *
 * @param {string} src The code
 * @param {ShjLanguage|ShjLanguageData} lang The language of the code
 * @param {ShjTerminalTheme} theme The theme to use, e.g. imported from `themes/atom-dark.js`
 * @returns {Promise<string>} The highlighted string
 */
export async function highlightANSI(src, lang, theme) {
	let res = '';

	await tokenize(src, lang, (str, token) => res += token ? `${theme[token] ?? ''}${str}\x1b[0m` : str);

	return res;
}