/**
 * @fileoverview require default case in switch statements
 * @author Aliaksei Shytkin
 */
'use strict';

const DEFAULT_COMMENT_PATTERN = /^no default$/iu;

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

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

    defaultOptions: [{}],

    docs: {
      description: 'Require `default` cases in `switch` statements',
      recommended: false,
      url: 'https://eslint.org/docs/latest/rules/default-case',
    },

    schema: [
      {
        type: 'object',
        properties: {
          commentPattern: {
            type: 'string',
          },
        },
        additionalProperties: false,
      },
    ],

    messages: {
      missingDefaultCase: 'Expected a default case.',
    },
  },

  create(context) {
    const [options] = context.options;
    const commentPattern =
      options.commentPattern ?
        new RegExp(options.commentPattern, 'u')
      : DEFAULT_COMMENT_PATTERN;

    const sourceCode = context.sourceCode;

    //--------------------------------------------------------------------------
    // Helpers
    //--------------------------------------------------------------------------

    /**
     * Shortcut to get last element of array
     * @param {*[]} collection Array
     * @returns {any} Last element
     */
    function last(collection) {
      return collection.at(-1);
    }

    //--------------------------------------------------------------------------
    // Public
    //--------------------------------------------------------------------------

    return {
      SwitchStatement(node) {
        if (!node.cases.length) {
          /*
           * skip check of empty switch because there is no easy way
           * to extract comments inside it now
           */
          return;
        }

        const hasDefault = node.cases.some((v) => v.test === null);

        if (!hasDefault) {
          let comment;

          const lastCase = last(node.cases);
          const comments = sourceCode.getCommentsAfter(lastCase);

          if (comments.length) {
            comment = last(comments);
          }

          if (!comment || !commentPattern.test(comment.value.trim())) {
            context.report({
              node,
              messageId: 'missingDefaultCase',
            });
          }
        }
      },
    };
  },
};