/**
 * @fileoverview Rule to flag use of an empty block statement
 * @author Nicholas C. Zakas
 */
'use strict';

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

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

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

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

    defaultOptions: [
      {
        allowEmptyCatch: false,
      },
    ],

    docs: {
      description: 'Disallow empty block statements',
      recommended: true,
      url: 'https://eslint.org/docs/latest/rules/no-empty',
    },

    schema: [
      {
        type: 'object',
        properties: {
          allowEmptyCatch: {
            type: 'boolean',
          },
        },
        additionalProperties: false,
      },
    ],

    messages: {
      unexpected: 'Empty {{type}} statement.',
      suggestComment: 'Add comment inside empty {{type}} statement.',
    },
  },

  create(context) {
    const [{ allowEmptyCatch }] = context.options;
    const sourceCode = context.sourceCode;

    return {
      BlockStatement(node) {
        // if the body is not empty, we can just return immediately
        if (node.body.length !== 0) {
          return;
        }

        // a function is generally allowed to be empty
        if (astUtils.isFunction(node.parent)) {
          return;
        }

        if (allowEmptyCatch && node.parent.type === 'CatchClause') {
          return;
        }

        // any other block is only allowed to be empty, if it contains a comment
        if (sourceCode.getCommentsInside(node).length > 0) {
          return;
        }

        context.report({
          node,
          messageId: 'unexpected',
          data: { type: 'block' },
          suggest: [
            {
              messageId: 'suggestComment',
              data: { type: 'block' },
              fix(fixer) {
                const range = [node.range[0] + 1, node.range[1] - 1];

                return fixer.replaceTextRange(range, ' /* empty */ ');
              },
            },
          ],
        });
      },

      SwitchStatement(node) {
        if (typeof node.cases === 'undefined' || node.cases.length === 0) {
          context.report({
            node,
            messageId: 'unexpected',
            data: { type: 'switch' },
          });
        }
      },
    };
  },
};