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

"use strict";

const {
	JAVASCRIPT_MODULE_TYPE_AUTO,
	JAVASCRIPT_MODULE_TYPE_DYNAMIC,
	JAVASCRIPT_MODULE_TYPE_ESM
} = require("./ModuleTypeConstants");
const RuntimeGlobals = require("./RuntimeGlobals");
const ConstDependency = require("./dependencies/ConstDependency");

/** @typedef {import("estree").CallExpression} CallExpression */
/** @typedef {import("./Compiler")} Compiler */
/** @typedef {import("./Dependency").DependencyLocation} DependencyLocation */
/** @typedef {import("./dependencies/ContextDependency")} ContextDependency */
/** @typedef {import("./javascript/JavascriptParser")} JavascriptParser */
/** @typedef {import("./javascript/JavascriptParser").Range} Range */

/**
 * Captures the source range of a renamed compatibility binding so it can be
 * rewritten exactly once.
 * @typedef {object} CompatibilitySettingsDeclaration
 * @property {boolean} updated
 * @property {DependencyLocation} loc
 * @property {Range} range
 */

/**
 * Stores the replacement variable name and the declaration metadata tracked
 * for a compatibility rewrite.
 * @typedef {object} CompatibilitySettings
 * @property {string} name
 * @property {CompatibilitySettingsDeclaration} declaration
 */

const nestedWebpackIdentifierTag = Symbol("nested webpack identifier");
const PLUGIN_NAME = "CompatibilityPlugin";

/**
 * Adds parser-time compatibility rewrites for legacy runtime patterns that
 * webpack still needs to recognize in user and generated code.
 */
class CompatibilityPlugin {
	/**
	 * Installs parser hooks that preserve compatibility with legacy patterns
	 * such as nested `__webpack_require__` bindings and hashbang handling.
	 * @param {Compiler} compiler the compiler instance
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.compilation.tap(
			PLUGIN_NAME,
			(compilation, { normalModuleFactory }) => {
				compilation.dependencyTemplates.set(
					ConstDependency,
					new ConstDependency.Template()
				);

				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_AUTO)
					.tap(PLUGIN_NAME, (parser, parserOptions) => {
						if (
							parserOptions.browserify !== undefined &&
							!parserOptions.browserify
						) {
							return;
						}

						parser.hooks.call.for("require").tap(
							PLUGIN_NAME,
							/**
							 * Rewrites browserify-style delegated `require` calls into a
							 * plain webpack require reference and removes the synthetic
							 * context dependency created for the delegator pattern.
							 * @param {CallExpression} expr call expression
							 * @returns {boolean | void} true when need to handle
							 */
							(expr) => {
								// support for browserify style require delegator: "require(o, !0)"
								if (expr.arguments.length !== 2) return;
								const second = parser.evaluateExpression(expr.arguments[1]);
								if (!second.isBoolean()) return;
								if (second.asBool() !== true) return;
								const dep = new ConstDependency(
									"require",
									/** @type {Range} */ (expr.callee.range)
								);
								dep.loc = /** @type {DependencyLocation} */ (expr.loc);
								if (parser.state.current.dependencies.length > 0) {
									const last =
										/** @type {ContextDependency} */
										(
											parser.state.current.dependencies[
												parser.state.current.dependencies.length - 1
											]
										);
									if (
										last.critical &&
										last.options &&
										last.options.request === "." &&
										last.userRequest === "." &&
										last.options.recursive
									) {
										parser.state.current.dependencies.pop();
									}
								}
								parser.state.module.addPresentationalDependency(dep);
								return true;
							}
						);
					});

				/**
				 * Attaches the compatibility rewrites for a JavaScript parser
				 * instance.
				 * @param {JavascriptParser} parser the parser
				 * @returns {void}
				 */
				const handler = (parser) => {
					// Handle nested requires
					parser.hooks.preStatement.tap(PLUGIN_NAME, (statement) => {
						if (
							statement.type === "FunctionDeclaration" &&
							statement.id &&
							statement.id.name === RuntimeGlobals.require
						) {
							const newName = `__nested_webpack_require_${
								/** @type {Range} */
								(statement.range)[0]
							}__`;
							parser.tagVariable(
								statement.id.name,
								nestedWebpackIdentifierTag,
								{
									name: newName,
									declaration: {
										updated: false,
										loc: /** @type {DependencyLocation} */ (statement.id.loc),
										range: /** @type {Range} */ (statement.id.range)
									}
								}
							);
							return true;
						}
					});
					parser.hooks.pattern
						.for(RuntimeGlobals.require)
						.tap(PLUGIN_NAME, (pattern) => {
							const newName = `__nested_webpack_require_${
								/** @type {Range} */ (pattern.range)[0]
							}__`;
							parser.tagVariable(pattern.name, nestedWebpackIdentifierTag, {
								name: newName,
								declaration: {
									updated: false,
									loc: /** @type {DependencyLocation} */ (pattern.loc),
									range: /** @type {Range} */ (pattern.range)
								}
							});
							if (parser.scope.topLevelScope !== true) {
								return true;
							}
						});
					parser.hooks.pattern
						.for(RuntimeGlobals.exports)
						.tap(PLUGIN_NAME, (pattern) => {
							const newName = "__nested_webpack_exports__";
							parser.tagVariable(pattern.name, nestedWebpackIdentifierTag, {
								name: newName,
								declaration: {
									updated: false,
									loc: /** @type {DependencyLocation} */ (pattern.loc),
									range: /** @type {Range} */ (pattern.range)
								}
							});
							return true;
						});
					// Update single `var __webpack_require__ = {};` and `var __webpack_exports__ = {};` without expression
					parser.hooks.declarator.tap(PLUGIN_NAME, (declarator) => {
						if (
							declarator.id.type === "Identifier" &&
							(declarator.id.name === RuntimeGlobals.exports ||
								declarator.id.name === RuntimeGlobals.require)
						) {
							const { name, declaration } =
								/** @type {CompatibilitySettings} */ (
									parser.getTagData(
										declarator.id.name,
										nestedWebpackIdentifierTag
									)
								);
							if (!declaration.updated) {
								const dep = new ConstDependency(name, declaration.range);
								dep.loc = declaration.loc;
								parser.state.module.addPresentationalDependency(dep);
								declaration.updated = true;
							}
						}
					});
					parser.hooks.expression
						.for(nestedWebpackIdentifierTag)
						.tap(PLUGIN_NAME, (expr) => {
							const { name, declaration } =
								/** @type {CompatibilitySettings} */
								(parser.currentTagData);
							if (!declaration.updated) {
								const dep = new ConstDependency(name, declaration.range);
								dep.loc = declaration.loc;
								parser.state.module.addPresentationalDependency(dep);
								declaration.updated = true;
							}
							const dep = new ConstDependency(
								name,
								/** @type {Range} */ (expr.range)
							);
							dep.loc = /** @type {DependencyLocation} */ (expr.loc);
							parser.state.module.addPresentationalDependency(dep);
							return true;
						});

					// Handle hashbang
					parser.hooks.program.tap(PLUGIN_NAME, (program, comments) => {
						if (comments.length === 0) return;
						const c = comments[0];
						if (c.type === "Line" && /** @type {Range} */ (c.range)[0] === 0) {
							if (parser.state.source.slice(0, 2).toString() !== "#!") return;
							// this is a hashbang comment
							const dep = new ConstDependency("//", 0);
							dep.loc = /** @type {DependencyLocation} */ (c.loc);
							parser.state.module.addPresentationalDependency(dep);
						}
					});
				};

				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_AUTO)
					.tap(PLUGIN_NAME, handler);
				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_DYNAMIC)
					.tap(PLUGIN_NAME, handler);
				normalModuleFactory.hooks.parser
					.for(JAVASCRIPT_MODULE_TYPE_ESM)
					.tap(PLUGIN_NAME, handler);
			}
		);
	}
}

module.exports = CompatibilityPlugin;
module.exports.nestedWebpackIdentifierTag = nestedWebpackIdentifierTag;