"use strict";

const findFontFamily = require("../../utils/findFontFamily");
const isStandardSyntaxValue = require("../../utils/isStandardSyntaxValue");
const isVariable = require("../../utils/isVariable");
const keywordSets = require("../../reference/keywordSets");
const report = require("../../utils/report");
const ruleMessages = require("../../utils/ruleMessages");
const validateOptions = require("../../utils/validateOptions");

const ruleName = "font-family-name-quotes";

const messages = ruleMessages(ruleName, {
  expected: family => `Expected quotes around "${family}"`,
  rejected: family => `Unexpected quotes around "${family}"`
});

function isSystemFontKeyword(font) {
  if (font.indexOf("-apple-") === 0) {
    return true;
  }

  if (font === "BlinkMacSystemFont") {
    return true;
  }

  return false;
}

// "To avoid mistakes in escaping, it is recommended to quote font family names
// that contain white space, digits, or punctuation characters other than hyphens"
// (https://www.w3.org/TR/CSS2/fonts.html#font-family-prop)
function quotesRecommended(family) {
  return !/^[-a-zA-Z]+$/.test(family);
}

// Quotes are required if the family is not a valid CSS identifier
// (regexes from https://mathiasbynens.be/notes/unquoted-font-family)
function quotesRequired(family) {
  return family.split(/\s+/).some(word => {
    return (
      /^(-?\d|--)/.test(word) ||
      !/^[-_a-zA-Z0-9\u{00A0}-\u{10FFFF}]+$/u.test(word)
    );
  });
}

const rule = function(expectation) {
  return (root, result) => {
    const validOptions = validateOptions(result, ruleName, {
      actual: expectation,
      possible: [
        "always-where-required",
        "always-where-recommended",
        "always-unless-keyword"
      ]
    });

    if (!validOptions) {
      return;
    }

    root.walkDecls(/^font(-family)?$/i, decl => {
      const fontFamilies = findFontFamily(decl.value);

      if (fontFamilies.length === 0) {
        return;
      }

      fontFamilies.forEach(fontFamilyNode => {
        let rawFamily = fontFamilyNode.value;

        if (fontFamilyNode.quote) {
          rawFamily = fontFamilyNode.quote + rawFamily + fontFamilyNode.quote;
        }

        checkFamilyName(rawFamily, decl);
      });
    });

    function checkFamilyName(rawFamily, decl) {
      if (!isStandardSyntaxValue(rawFamily)) {
        return;
      }

      if (isVariable(rawFamily)) {
        return;
      }

      const hasQuotes = rawFamily[0] === "'" || rawFamily[0] === '"';

      // Clean the family of its quotes
      const family = rawFamily.replace(/^['"]|['"]$/g, "");

      // Disallow quotes around (case-insensitive) keywords
      // and system font keywords in all cases
      if (
        keywordSets.fontFamilyKeywords.has(family.toLowerCase()) ||
        isSystemFontKeyword(family)
      ) {
        if (hasQuotes) {
          return complain(messages.rejected(family), family, decl);
        }

        return;
      }

      const required = quotesRequired(family);
      const recommended = quotesRecommended(family);

      switch (expectation) {
        case "always-unless-keyword":
          if (!hasQuotes) {
            return complain(messages.expected(family), family, decl);
          }

          return;

        case "always-where-recommended":
          if (!recommended && hasQuotes) {
            return complain(messages.rejected(family), family, decl);
          }

          if (recommended && !hasQuotes) {
            return complain(messages.expected(family), family, decl);
          }

          return;

        case "always-where-required":
          if (!required && hasQuotes) {
            return complain(messages.rejected(family), family, decl);
          }

          if (required && !hasQuotes) {
            return complain(messages.expected(family), family, decl);
          }

          return;
      }
    }

    function complain(message, family, decl) {
      report({
        result,
        ruleName,
        message,
        node: decl,
        word: family
      });
    }
  };
};

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