import { TemplatePath } from "@11ty/eleventy-utils";

import eventBus from "./EventBus.js";

// Note: this is only used for TemplateLayout right now but could be used for more
// Just be careful because right now the TemplateLayout cache keys are not directly mapped to paths
// So you may get collisions if you use this for other things.
class TemplateCache {
	constructor() {
		this.cache = {};
		this.cacheByInputPath = {};
	}

	clear() {
		this.cache = {};
		this.cacheByInputPath = {};
	}

	// alias
	removeAll() {
		this.clear();
	}

	size() {
		return Object.keys(this.cacheByInputPath).length;
	}

	add(layoutTemplate) {
		let keys = new Set();

		if (typeof layoutTemplate === "string") {
			throw new Error(
				"Invalid argument type passed to TemplateCache->add(). Should be a TemplateLayout.",
			);
		}

		if ("getFullKey" in layoutTemplate) {
			keys.add(layoutTemplate.getFullKey());
		}

		if ("getKey" in layoutTemplate) {
			// if `key` was an alias, also set to the pathed layout value too
			// e.g. `layout: "default"` and `layout: "default.liquid"` will both map to the same template.
			keys.add(layoutTemplate.getKey());
		}

		for (let key of keys) {
			this.cache[key] = layoutTemplate;
		}

		// also the full template input path for use with eleventy --serve/--watch e.g. `_includes/default.liquid` (see `remove` below)
		let fullPath = TemplatePath.stripLeadingDotSlash(layoutTemplate.inputPath);
		this.cacheByInputPath[fullPath] = layoutTemplate;
	}

	has(key) {
		return key in this.cache;
	}

	get(key) {
		if (!this.has(key)) {
			throw new Error(`Could not find ${key} in TemplateCache.`);
		}

		return this.cache[key];
	}

	remove(layoutFilePath) {
		layoutFilePath = TemplatePath.stripLeadingDotSlash(layoutFilePath);
		if (!this.cacheByInputPath[layoutFilePath]) {
			// not a layout file
			return;
		}

		let layoutTemplate = this.cacheByInputPath[layoutFilePath];
		layoutTemplate.resetCaches();

		let keys = layoutTemplate.getCacheKeys();
		for (let key of keys) {
			delete this.cache[key];
		}

		delete this.cacheByInputPath[layoutFilePath];
	}
}

let layoutCache = new TemplateCache();

eventBus.on("eleventy.resourceModified", (path, usedBy, metadata = {}) => {
	// https://github.com/11ty/eleventy-plugin-bundle/issues/10
	if (metadata.viaConfigReset) {
		layoutCache.removeAll();
	} else if (metadata.relevantLayouts?.length) {
		// reset the appropriate layouts relevant to the file.
		for (let layoutPath of metadata.relevantLayouts || []) {
			layoutCache.remove(layoutPath);
		}
	} else {
		layoutCache.remove(path);
	}
});

// singleton
export default layoutCache;