"use strict";

const blockString = require("../../utils/blockString");
const hasBlock = require("../../utils/hasBlock");
const hasEmptyBlock = require("../../utils/hasEmptyBlock");
const report = require("../../utils/report");
const ruleMessages = require("../../utils/ruleMessages");
const validateOptions = require("../../utils/validateOptions");
const whitespaceChecker = require("../../utils/whitespaceChecker");

const ruleName = "block-closing-brace-space-before";

const messages = ruleMessages(ruleName, {
  expectedBefore: () => 'Expected single space before "}"',
  rejectedBefore: () => 'Unexpected whitespace before "}"',
  expectedBeforeSingleLine: () =>
    'Expected single space before "}" of a single-line block',
  rejectedBeforeSingleLine: () =>
    'Unexpected whitespace before "}" of a single-line block',
  expectedBeforeMultiLine: () =>
    'Expected single space before "}" of a multi-line block',
  rejectedBeforeMultiLine: () =>
    'Unexpected whitespace before "}" of a multi-line block'
});

const rule = function(expectation) {
  const checker = whitespaceChecker("space", expectation, messages);

  return (root, result) => {
    const validOptions = validateOptions(result, ruleName, {
      actual: expectation,
      possible: [
        "always",
        "never",
        "always-single-line",
        "never-single-line",
        "always-multi-line",
        "never-multi-line"
      ]
    });
    if (!validOptions) {
      return;
    }

    // Check both kinds of statement: rules and at-rules
    root.walkRules(check);
    root.walkAtRules(check);

    function check(statement) {
      // Return early if blockless or has empty block
      if (!hasBlock(statement) || hasEmptyBlock(statement)) {
        return;
      }

      const source = blockString(statement);
      const statementString = statement.toString();

      let index = statementString.length - 2;
      if (statementString[index - 1] === "\r") {
        index -= 1;
      }

      checker.before({
        source,
        index: source.length - 1,
        err: msg => {
          report({
            message: msg,
            node: statement,
            index,
            result,
            ruleName
          });
        }
      });
    }
  };
};

rule.ruleName = ruleName;
rule.messages = messages;
module.exports = rule;
