/**
 * @fileoverview Rule to flag use of an lexical declarations inside a case clause
 * @author Erik Arvidsson
 */
'use strict';

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

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

    docs: {
      description: 'Disallow lexical declarations in case clauses',
      recommended: true,
      url: 'https://eslint.org/docs/latest/rules/no-case-declarations',
    },

    hasSuggestions: true,

    schema: [],

    messages: {
      addBrackets: 'Add {} brackets around the case block.',
      unexpected: 'Unexpected lexical declaration in case block.',
    },
  },

  create(context) {
    /**
     * Checks whether or not a node is a lexical declaration.
     * @param {ASTNode} node A direct child statement of a switch case.
     * @returns {boolean} Whether or not the node is a lexical declaration.
     */
    function isLexicalDeclaration(node) {
      switch (node.type) {
        case 'FunctionDeclaration':
        case 'ClassDeclaration':
          return true;
        case 'VariableDeclaration':
          return node.kind !== 'var';
        default:
          return false;
      }
    }

    return {
      SwitchCase(node) {
        for (let i = 0; i < node.consequent.length; i++) {
          const statement = node.consequent[i];

          if (isLexicalDeclaration(statement)) {
            context.report({
              node: statement,
              messageId: 'unexpected',
              suggest: [
                {
                  messageId: 'addBrackets',
                  fix: (fixer) => [
                    fixer.insertTextBefore(node.consequent[0], '{ '),
                    fixer.insertTextAfter(node.consequent.at(-1), ' }'),
                  ],
                },
              ],
            });
          }
        }
      },
    };
  },
};