/**
 * @fileoverview Rule to enforce grouped require statements for Node.JS
 * @author Raphael Pigulla
 * @deprecated in ESLint v7.0.0
 */

'use strict';

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

/** @type {import('../types').Rule.RuleModule} */
module.exports = {
  meta: {
    deprecated: {
      message: 'Node.js rules were moved out of ESLint core.',
      url: 'https://eslint.org/docs/latest/use/migrating-to-7.0.0#deprecate-node-rules',
      deprecatedSince: '7.0.0',
      availableUntil: null,
      replacedBy: [
        {
          message:
            'eslint-plugin-n now maintains deprecated Node.js-related rules.',
          plugin: {
            name: 'eslint-plugin-n',
            url: 'https://github.com/eslint-community/eslint-plugin-n',
          },
          rule: {
            name: 'no-mixed-requires',
            url: 'https://github.com/eslint-community/eslint-plugin-n/tree/master/docs/rules/no-mixed-requires.md',
          },
        },
      ],
    },

    type: 'suggestion',

    docs: {
      description:
        'Disallow `require` calls to be mixed with regular variable declarations',
      recommended: false,
      url: 'https://eslint.org/docs/latest/rules/no-mixed-requires',
    },

    schema: [
      {
        oneOf: [
          {
            type: 'boolean',
          },
          {
            type: 'object',
            properties: {
              grouping: {
                type: 'boolean',
              },
              allowCall: {
                type: 'boolean',
              },
            },
            additionalProperties: false,
          },
        ],
      },
    ],

    messages: {
      noMixRequire: "Do not mix 'require' and other declarations.",
      noMixCoreModuleFileComputed:
        'Do not mix core, module, file and computed requires.',
    },
  },

  create(context) {
    const options = context.options[0];
    let grouping = false,
      allowCall = false;

    if (typeof options === 'object') {
      grouping = options.grouping;
      allowCall = options.allowCall;
    } else {
      grouping = !!options;
    }

    /**
     * Returns the list of built-in modules.
     * @returns {string[]} An array of built-in Node.js modules.
     */
    function getBuiltinModules() {
      /*
       * This list is generated using:
       * `require("repl")._builtinLibs.concat('repl').sort()`
       * This particular list is as per nodejs v0.12.2 and iojs v0.7.1
       */
      return [
        'assert',
        'buffer',
        'child_process',
        'cluster',
        'crypto',
        'dgram',
        'dns',
        'domain',
        'events',
        'fs',
        'http',
        'https',
        'net',
        'os',
        'path',
        'punycode',
        'querystring',
        'readline',
        'repl',
        'smalloc',
        'stream',
        'string_decoder',
        'tls',
        'tty',
        'url',
        'util',
        'v8',
        'vm',
        'zlib',
      ];
    }

    const BUILTIN_MODULES = getBuiltinModules();

    const DECL_REQUIRE = 'require',
      DECL_UNINITIALIZED = 'uninitialized',
      DECL_OTHER = 'other';

    const REQ_CORE = 'core',
      REQ_FILE = 'file',
      REQ_MODULE = 'module',
      REQ_COMPUTED = 'computed';

    /**
     * Determines the type of a declaration statement.
     * @param {ASTNode} initExpression The init node of the VariableDeclarator.
     * @returns {string} The type of declaration represented by the expression.
     */
    function getDeclarationType(initExpression) {
      if (!initExpression) {
        // "var x;"
        return DECL_UNINITIALIZED;
      }

      if (
        initExpression.type === 'CallExpression' &&
        initExpression.callee.type === 'Identifier' &&
        initExpression.callee.name === 'require'
      ) {
        // "var x = require('util');"
        return DECL_REQUIRE;
      }
      if (
        allowCall &&
        initExpression.type === 'CallExpression' &&
        initExpression.callee.type === 'CallExpression'
      ) {
        // "var x = require('diagnose')('sub-module');"
        return getDeclarationType(initExpression.callee);
      }
      if (initExpression.type === 'MemberExpression') {
        // "var x = require('glob').Glob;"
        return getDeclarationType(initExpression.object);
      }

      // "var x = 42;"
      return DECL_OTHER;
    }

    /**
     * Determines the type of module that is loaded via require.
     * @param {ASTNode} initExpression The init node of the VariableDeclarator.
     * @returns {string} The module type.
     */
    function inferModuleType(initExpression) {
      if (initExpression.type === 'MemberExpression') {
        // "var x = require('glob').Glob;"
        return inferModuleType(initExpression.object);
      }
      if (initExpression.arguments.length === 0) {
        // "var x = require();"
        return REQ_COMPUTED;
      }

      const arg = initExpression.arguments[0];

      if (arg.type !== 'Literal' || typeof arg.value !== 'string') {
        // "var x = require(42);"
        return REQ_COMPUTED;
      }

      if (BUILTIN_MODULES.includes(arg.value)) {
        // "var fs = require('fs');"
        return REQ_CORE;
      }
      if (/^\.{0,2}\//u.test(arg.value)) {
        // "var utils = require('./utils');"
        return REQ_FILE;
      }

      // "var async = require('async');"
      return REQ_MODULE;
    }

    /**
     * Check if the list of variable declarations is mixed, i.e. whether it
     * contains both require and other declarations.
     * @param {ASTNode} declarations The list of VariableDeclarators.
     * @returns {boolean} True if the declarations are mixed, false if not.
     */
    function isMixed(declarations) {
      const contains = {};

      declarations.forEach((declaration) => {
        const type = getDeclarationType(declaration.init);

        contains[type] = true;
      });

      return !!(
        contains[DECL_REQUIRE] &&
        (contains[DECL_UNINITIALIZED] || contains[DECL_OTHER])
      );
    }

    /**
     * Check if all require declarations in the given list are of the same
     * type.
     * @param {ASTNode} declarations The list of VariableDeclarators.
     * @returns {boolean} True if the declarations are grouped, false if not.
     */
    function isGrouped(declarations) {
      const found = {};

      declarations.forEach((declaration) => {
        if (getDeclarationType(declaration.init) === DECL_REQUIRE) {
          found[inferModuleType(declaration.init)] = true;
        }
      });

      return Object.keys(found).length <= 1;
    }

    return {
      VariableDeclaration(node) {
        if (isMixed(node.declarations)) {
          context.report({
            node,
            messageId: 'noMixRequire',
          });
        } else if (grouping && !isGrouped(node.declarations)) {
          context.report({
            node,
            messageId: 'noMixCoreModuleFileComputed',
          });
        }
      },
    };
  },
};