/**
 * @fileoverview Rule to disallow an empty pattern
 * @author Alberto Rodríguez
 */
'use strict';

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

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

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

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

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

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

    messages: {
      unexpected: 'Unexpected empty {{type}} pattern.',
    },
  },

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

    return {
      ObjectPattern(node) {
        if (node.properties.length > 0) {
          return;
        }

        // Allow {} and {} = {} empty object patterns as parameters when allowObjectPatternsAsParameters is true
        if (
          allowObjectPatternsAsParameters &&
          (astUtils.isFunction(node.parent) ||
            (node.parent.type === 'AssignmentPattern' &&
              astUtils.isFunction(node.parent.parent) &&
              node.parent.right.type === 'ObjectExpression' &&
              node.parent.right.properties.length === 0))
        ) {
          return;
        }

        context.report({
          node,
          messageId: 'unexpected',
          data: { type: 'object' },
        });
      },
      ArrayPattern(node) {
        if (node.elements.length === 0) {
          context.report({
            node,
            messageId: 'unexpected',
            data: { type: 'array' },
          });
        }
      },
    };
  },
};