"use strict"

const isStandardSyntaxRule = require("../../utils/isStandardSyntaxRule")
const report = require("../../utils/report")
const ruleMessages = require("../../utils/ruleMessages")
const validateOptions = require("../../utils/validateOptions")
const whitespaceChecker = require("../../utils/whitespaceChecker")
const styleSearch = require("style-search")

const ruleName = "selector-list-comma-newline-after"

const messages = ruleMessages(ruleName, {
  expectedAfter: () => "Expected newline after \",\"",
  expectedAfterMultiLine: () => "Expected newline after \",\" in a multi-line list",
  rejectedAfterMultiLine: () => "Unexpected whitespace after \",\" in a multi-line list",
})

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

    root.walkRules(rule => {
      if (!isStandardSyntaxRule(rule)) {
        return
      }
      // Get raw selector so we can allow end-of-line comments, e.g.
      // a, /* comment */
      // b {}
      const selector = rule.raws.selector ? rule.raws.selector.raw : rule.selector
      styleSearch({
        source: selector,
        target: ",",
        functionArguments: "skip",
      }, match => {
        const nextThreeChars = selector.substr(match.endIndex, 3)

        // If there's a // comment, that means there has to be a newline
        // ending the comment so we're fine
        if (nextThreeChars === " //") {
          return
        }

        // If there is a space and then a comment begins, look for the newline
        // after that comment
        const indextoCheckAfter = nextThreeChars === " /*" ? selector.indexOf("*/", match.endIndex) + 1 : match.startIndex
        checker.afterOneOnly({
          source: selector,
          index: indextoCheckAfter,
          err: m => report({
            message: m,
            node: rule,
            index: match.startIndex,
            result,
            ruleName,
          }),
        })
      })
    })
  }
}

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