/**
 * @fileoverview Rule to flag assignment of the exception parameter
 * @author Stephen Murray <spmurrayzzz>
 */

'use strict';

const astUtils = require('./utils/ast-utils');

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

/** @type {import('../types').Rule.RuleModule} */
module.exports = {
  meta: {
    type: 'problem',

    docs: {
      description: 'Disallow reassigning exceptions in `catch` clauses',
      recommended: true,
      url: 'https://eslint.org/docs/latest/rules/no-ex-assign',
    },

    schema: [],

    messages: {
      unexpected: 'Do not assign to the exception parameter.',
    },
  },

  create(context) {
    const sourceCode = context.sourceCode;

    /**
     * Finds and reports references that are non initializer and writable.
     * @param {Variable} variable A variable to check.
     * @returns {void}
     */
    function checkVariable(variable) {
      astUtils
        .getModifyingReferences(variable.references)
        .forEach((reference) => {
          context.report({
            node: reference.identifier,
            messageId: 'unexpected',
          });
        });
    }

    return {
      CatchClause(node) {
        sourceCode.getDeclaredVariables(node).forEach(checkVariable);
      },
    };
  },
};