module.exports = {
  extends: ['stylelint-config-standard', 'stylelint-config-prettier'],
  customSyntax: 'postcss-less',
  rules: {
    // IE 11 does not seem to support percentage format
    'alpha-value-notation': 'number',

    // fix less detached ruleset
    'at-rule-no-unknown': null,

    // Forbidden the at rule (eg: @keyframes ) to use the browser prefix.
    'at-rule-no-vendor-prefix': true,

    // IE 11 does not support modern css notation
    // https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/rgb#browser_compatibility
    'color-function-notation': 'legacy',

    'declaration-colon-newline-after': null,

    // Specify an allowed-list of attributes and units allowed in the declaration.
    'declaration-property-unit-allowed-list': {
      'font-size': ['px', 'em', '%'],
      '/^animation/': ['s']
    },

    // Allow using Less-specific functions
    'function-no-unknown': [
      true,
      {
        ignoreFunctions: ['fade', 'floor', 'lighten']
      }
    ],

    // Don't check if there is a whitespace after the function.
    // Style-lint can't distinguish less mixin or css function. Disable this check item directly here.
    'function-whitespace-after': null,

    // Limit the depth of nesting allowed.
    'max-nesting-depth': 5,

    // Forbidden @media  use the browser prefix.
    'media-feature-name-no-vendor-prefix': true,

    // Don't forbidden low specificity selectors from appearing after high specificity selectors.
    // [Specificity description]{@link https://www.w3.org/TR/css3-selectors/#specificity}
    'no-descending-specificity': null,

    // Allow placing @import at-rule in style blocks (Less-specific syntax)
    'no-invalid-position-at-import-rule': null,

    // Require a leading zero for fractional numbers less than 1.
    'number-leading-zero': 'always',

    // Forbidden use the browser prefix.
    'property-no-vendor-prefix': true,

    // Class selector naming rules use kebab-case. eg: .class-name
    // FIXME: this regex covers LESS parametric mixin definitions
    //        which was supposed to be ignored from this rule by stylelint
    //        @see https://github.com/stylelint/stylelint/issues/5258
    'selector-class-pattern': '^[a-z0-9]+(-?[a-z0-9]+)*(\\(.*\\))?$',

    // ID selector naming rules use camel case , excepted `icon-`. eg: #loginButton,#icon-login
    'selector-id-pattern': '^([a-z]+([A-Z][a-z]+)?)||(icon-([a-z-]+))$',

    // Limit the number of composite selectors in a selector.
    // TODO consider narrowing this limit
    'selector-max-compound-selectors': 4,

    // Limit the number of ID selectors in a selector.
    // TODO consider narrowing this limit to 0
    'selector-max-id': 1,

    // Limit the number of universal selectors in a selector.
    'selector-max-universal': 1,

    'selector-no-vendor-prefix': true,

    // Specify an allowed-list of allowed pseudo-class selectors.(Only use pseudo-classes supported by IE10+ browsers)
    // [CSS selector browser support]{@link https://labs.qianduan.net/css-selector/}
    'selector-pseudo-class-allowed-list': [
      // CSS 1
      'active',
      'link',
      'visited',
      // CSS 2.1
      'first-child',
      'focus',
      'hover',
      // CSS 3
      'checked',
      'disabled',
      'enabled',
      'empty',
      'first-of-type',
      'indeterminate',
      'last-child',
      'last-of-type',
      'not',
      'nth-child',
      'nth-last-child',
      'nth-of-type',
      'nth-last-of-type',
      'only-child',
      'only-of-type',
      'root',
      'target',
      // Level 4 (including Working Drafts)
      'focus-within',
      'focus-visible'
    ],

    // String using single quotes
    'string-quotes': 'single',

    // font-family can contain uppercase letters
    // @see https://github.com/stylelint/stylelint/issues/4622#issuecomment-594641799
    'value-keyword-case': [
      'lower',
      {
        ignoreKeywords: ['BlinkMacSystemFont']
      }
    ],
    'value-list-comma-newline-after': 'always-multi-line',

    'value-no-vendor-prefix': true
  }
};