"use strict"

const blockString = require("../../utils/blockString")
const hasBlock = require("../../utils/hasBlock")
const hasEmptyBlock = require("../../utils/hasEmptyBlock")
const hasEmptyLine = require("../../utils/hasEmptyLine")
const isSingleLineString = require("../../utils/isSingleLineString")
const report = require("../../utils/report")
const ruleMessages = require("../../utils/ruleMessages")
const validateOptions = require("../../utils/validateOptions")

const ruleName = "block-closing-brace-empty-line-before"

const messages = ruleMessages(ruleName, {
  expected: "Expected empty line before closing brace",
  rejected: "Unexpected empty line before closing brace",
})

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

    // Check both kinds of statements: 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
      }

      // Get whitespace after ""}", ignoring extra semicolon
      const before = (statement.raws.after || "").replace(/;+/, "")
      if (before === undefined) {
        return
      }

      // Calculate index
      const statementString = statement.toString()
      let index = statementString.length - 1
      if (statementString[index - 1] === "\r") {
        index -= 1
      }

      // Set expectation
      const expectEmptyLineBefore = expectation === "always-multi-line"
        && !isSingleLineString(blockString(statement))
          ? true
          : false

      // Check for at least one empty line
      const hasEmptyLineBefore = hasEmptyLine(before)

      // Return if the expectation is met
      if (expectEmptyLineBefore === hasEmptyLineBefore) {
        return
      }

      const message = expectEmptyLineBefore
        ? messages.expected
        : messages.rejected

      report({
        message,
        result,
        ruleName,
        node: statement,
        index,
      })
    }
  }
}

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