"use strict"

const atRuleParamIndex = require("../../utils/atRuleParamIndex")
const declarationValueIndex = require("../../utils/declarationValueIndex")
const getUnitFromValueNode = require("../../utils/getUnitFromValueNode")
const report = require("../../utils/report")
const ruleMessages = require("../../utils/ruleMessages")
const validateOptions = require("../../utils/validateOptions")
const valueParser = require("postcss-value-parser")

const ruleName = "unit-case"

const messages = ruleMessages(ruleName, {
  expected: (actual, expected) => `Expected "${actual}" to be "${expected}"`,
})

const rule = function (expectation) {
  return (root, result) => {
    const validOptions = validateOptions(result, ruleName, {
      actual: expectation,
      possible: [
        "lower",
        "upper",
      ],
    })
    if (!validOptions) {
      return
    }

    function check(node, value, getIndex) {
      valueParser(value).walk(valueNode => {
        // Ignore wrong units within `url` function
        if (valueNode.type === "function" && valueNode.value.toLowerCase() === "url") {
          return false
        }

        const unit = getUnitFromValueNode(valueNode)

        if (!unit) {
          return
        }

        const expectedUnit = expectation === "lower" ? unit.toLowerCase() : unit.toUpperCase()

        if (unit === expectedUnit) {
          return
        }

        report({
          index: getIndex(node) + valueNode.sourceIndex,
          message: messages.expected(unit, expectedUnit),
          node,
          result,
          ruleName,
        })
      })
    }

    root.walkAtRules(/^media$/i, atRule => check(atRule, atRule.params, atRuleParamIndex))
    root.walkDecls(decl => check(decl, decl.value, declarationValueIndex))
  }
}

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