/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/

"use strict";

/** @typedef {import("./Resolver")} Resolver */
/** @typedef {import("./Resolver").ResolveStepHook} ResolveStepHook */

module.exports = class FileExistsPlugin {
	/**
	 * @param {string | ResolveStepHook} source source
	 * @param {string | ResolveStepHook} target target
	 */
	constructor(source, target) {
		this.source = source;
		this.target = target;
	}

	/**
	 * @param {Resolver} resolver the resolver
	 * @returns {void}
	 */
	apply(resolver) {
		const target = resolver.ensureHook(this.target);
		const fs = resolver.fileSystem;
		resolver
			.getHook(this.source)
			.tapAsync("FileExistsPlugin", (request, resolveContext, callback) => {
				const file = request.path;
				if (!file) return callback();
				fs.stat(file, (err, stat) => {
					// Combine the two miss branches: a stat failure and a
					// "not a file" result share the same handling — record the
					// path on `missingDependencies`, log the right reason, then
					// bail. The error-message ternary picks the wording that
					// matched the failing condition.
					if (err || !stat || !stat.isFile()) {
						if (resolveContext.missingDependencies) {
							resolveContext.missingDependencies.add(file);
						}
						if (resolveContext.log) {
							resolveContext.log(
								err || !stat
									? `${file} doesn't exist`
									: `${file} is not a file`,
							);
						}
						return callback();
					}
					if (resolveContext.fileDependencies) {
						resolveContext.fileDependencies.add(file);
					}
					resolver.doResolve(
						target,
						request,
						`existing file: ${file}`,
						resolveContext,
						callback,
					);
				});
			});
	}
};