/**
 * @internal
 */
export type ValueFactoryApi = {
	preventCache() : void,
}


/**
 * @internal
 */
export type ValueFactory = (api : ValueFactoryApi) => Promise<any>;


export type Cache = {
	get(key : string) : Promise<string>,
	set(key : string, value : string) : Promise<void>,
}


/**
 * A PathContext represents a path (relPath) relative to an abolute path (refPath)
 * Note that relPath is not necessary relative, but it is, relPath is relative to refPath.
 */
export type PathContext = {
	/** reference path */
	refPath : string,
	/** relative to @refPath */
	relPath : string,
}


export type PathHandlers = {
	/** the extension name (or type) of a file (incluting the leading dot, eg. '.svg') */
	extname(filepath : string) : string,
	/** relative to absolute module path resolution */
	resolve(pathCx : PathContext) : string,
}



/**
 * Used by the library when it does not know how to handle a given file type (eg. `.json` files).
 * see [[moduleHandlers]]
 * @param source The content of the file
 * @param path The path of the file
 * @param options The options
 *
 *
 * **example:**
 *
 * ```javascript
 *	...
 *	moduleHandlers: {
 *		'.json': (source, path, options) => JSON.parse(source),
 *	}
 *	...
 * ```
 */
export type ModuleHandler = (extname : string, source : string, path : string, options : Options) => Promise<ModuleExport | null>;


/**
 * Represents a file content and the extension name.
 */
export type File = {
	/** The content data */
	content : string | ArrayBuffer,
	/** The content type (file extension name, eg. '.svg' ) */
	extname : string,
}


/**
 * Represents a resource.
 */
export type Resource = {
	/** 'abstract' unique id of the resource */
	id : string,
	/** file path of the resource */
	path : string,
	/** asynchronously get the content of the resource */
	getContent : () => Promise<File>,
}

/**
 * CustomBlockCallback function type
 */
export type CustomBlockCallback = ( component : ModuleExport ) => void;


/**
 * A custom block
 */
export type CustomBlock = {
	type: string,
	content: string,
	attrs: Record<string, string | true>,
//	loc: SourceLocation
//	map?: RawSourceMap
//	lang?: string
//	src?: string
}


/**
 * This just represents a loaded js module exports
 */
export type ModuleExport = {
}

/**
 * This just represents a loaded js module
 */
export type Module = {
	exports : ModuleExport,
}

/**
 * @internal
 */
 export type LoadingType<T> = {
	promise : Promise<T>,
}

export type Options = {

/**
 * Initial cache that will contain resolved dependencies. All new modules go here.
 * `vue` must initially be contained in this object.
 * [[moduleCache]] is mandatory for the lib. If you do not provide it, the library will create one.
 * It is recommended to provide a prototype-less object (`Object.create(null)`) to avoid potential conflict with `Object` properties (constructor, __proto__, hasOwnProperty, ...).
​ *
 * See also [[options.loadModule]].
 *
 * **example:**
 * ```javascript
 *	...
 *	moduleCache: Object.assign(Object.create(null), {
 *		vue: Vue,
 *	}),
 *	...
 * ```
 *
*/
	moduleCache?: Record<string, LoadingType<ModuleExport> | ModuleExport>,


/**
 * Called by the library when it needs a file.
 * @param path  The path of the file
 * @returns a Promise of the file content (UTF-8)
 *
 * **example:**
 * ```javascript
 *	...
 *	async getFile(url) {
 *	
 *		const res = await fetch(url);
 *		if ( !res.ok )
 *			throw Object.assign(new Error(url+' '+res.statusText), { res });
 *		return await res.text();
 *	},
 *	...
 * ```
*/
	getFile(path : string) : Promise<File>,


/**
 * Called by the library when CSS style must be added in the HTML document.
 * @param style The CSS style chunk
 * @param scopeId The scope ID of the CSS style chunk
 * @return
 *
 * **example:**
 * ```javascript
 *	...
 *	addStyle(styleStr) {
 *
 *		const style = document.createElement('style');
 *		style.textContent = styleStr;
 *		const ref = document.head.getElementsByTagName('style')[0] || null;
 *		document.head.insertBefore(style, ref);
 *	},
 *	...
 * ```
*/
	addStyle(style : string, scopeId : string | undefined) : void,

/**
 * Sets the delimiters used for text interpolation within the template.  
 * Typically this is used to avoid conflicting with server-side frameworks that also use mustache syntax.
 *
 *	```javascript
 *		...
 *		<script>
 *	
 *			// <!--
 *			const vueContent = `
 *				<template> Hello [[[[ who ]]]] !</template>
 *				<script>
 *				export default {
 *					data() {
 *						return {
 *							who: 'world'
 *						}
 *					}
 *				}
 *				</script>
 *			`;
 *			// -->
 *	
 *			const options = {
 *				moduleCache: { vue: Vue },
 *				getFile: () => vueContent,
 *				addStyle: () => {},
 *				delimiters: ['[[[[', ']]]]'],
 *			}
 *	
 *			const app = Vue.createApp(Vue.defineAsyncComponent(() => window['vue3-sfc-loader'].loadModule('file.vue', options)));
 *			app.mount(document.body);
 *	
 *		</script>
 *		...
 *	```
*/

	delimiters?: [string, string],


/**
 * Additional babel plugins. [TBD]
 *
 *	```javascript
 *		...
 *		...
 *	```
*/
	additionalBabelPlugins?: any[],


/**
 * Handle additional module types (eg. '.svg', '.json' ). see [[ModuleHandler]]
 *
*/
	handleModule?: ModuleHandler,


/**
 * [[get]]() and [[set]]() functions of this object are called when the lib needs to save or load already compiled code. get and set functions must return a `Promise` (or can be `async`).
 * Since compilation consume a lot of CPU, is is always a good idea to provide this object.
 *
 * **example:**
 *
 * In the following example, we cache the compiled code in the browser's local storage. Note that local storage is a limited place (usually 5MB).
 * Here we handle space limitation in a very basic way.
 * Maybe (not tested), the following libraries may help you to gain more space [pako](https://github.com/nodeca/pako), [lz-string](https://github.com/pieroxy/lz-string/)
 * ```javascript
 *	...
 *	compiledCache: {
 *		set(key, str) {
 *	
 *			// naive storage space management
 *			for (;;) {
 *	
 *				try {
 *	
 *					// doc: https://developer.mozilla.org/en-US/docs/Web/API/Storage
 *					window.localStorage.setItem(key, str);
 *					break;
 *				} catch(ex) {
 *					// here we handle DOMException: Failed to execute 'setItem' on 'Storage': Setting the value of 'XXX' exceeded the quota
 *	
 *					window.localStorage.removeItem(window.localStorage.key(0));
 *				}
 *			}
 *		},
 *		get(key) {
 *	
 *			return window.localStorage.getItem(key);
 *		},
 *	},
 *	...
 * ```
 */
	compiledCache?: Cache,


/**
 * Called by the library when there is somthing to log (eg. scripts compilation errors, template compilation errors, template compilation  tips, style compilation errors, ...)
 * @param type the type of the notification, it respects console property names (error, warn, info).
 * @param args the values to log
 * @return
 *
 * ```javascript
 *	...
 *	log(type, ...args) {
 *	
 *		console.log(type, ...args);
 *	},
 *	...
 * ```
 */
	log?(type : string, ...data : any[]) : void,


/**
 * Called when the lib requires a module. Do return `undefined` to let the library handle this.
 * @param path  The path of the module.
 * @param options  The options object.
 * @returns A Promise of the module or undefined
 *
 * [[moduleCache]] and [[Options.loadModule]] are strongly related, in the sense that the result of [[options.loadModule]] is stored in [[moduleCache]].
 * However, [[options.loadModule]] is asynchronous and may help you to handle modules or components that are conditionally required (optional features, current languages, plugins, ...).
 * ```javascript
 *	...
 *	loadModule(path, options) {
 *	
 *		if ( path === 'vue' )
 *			return Vue;
 *		},
 *	...
 * ```
 */
	loadModule?(path : string, options : Options) : Promise<ModuleExport | undefined>,


/**
 * Abstact path handling
 *
 */
 	pathHandlers : PathHandlers,


/**
 * Abstact resource handling
 *
 */
	getResource(pathCx : PathContext, options : Options) : Resource,



/**
 * Called for each custom block.
 * @returns A Promise of the module or undefined
 *
 * ```javascript
 *	...
 *	customBlockHandler(block, filename, options) {
 *	
 *		if ( block.type !== 'i18n' )
 *			 return;
 *	
 *		return (component) => {
 *	
 *			component.i18n = JSON.parse(block.content);
 *		}
 *	}
 *	...
 * ```
 */
 	customBlockHandler?(block : CustomBlock, filename : string, options : Options) : Promise<CustomBlockCallback | undefined>,

}


export type LangProcessor = (source: string, preprocessOptions?: any) => Promise<string> | string