/* font i18n */
:root {
  /* customizable localized variables */
  :lang(ja) {
    --fonts-override: var(--fonts-default-override-ja);
  }
  :lang(zh-CN) {
    --fonts-override: var(--fonts-default-override-zh-cn);
  }
  :lang(zh-TW) {
    --fonts-override: var(--fonts-default-override-zh-tw);
  }
  :lang(zh-HK) {
    --fonts-override: var(--fonts-default-override-zh-hk);
  }
  :lang(ko) {
    --fonts-override: var(--fonts-default-override-ko);
  }
}

[lang] {
  font-family: var(--fonts-regular);
}

each(@fonts, {
  @weights: .gen-weights-all(@value);
  @locale: replace(@key, "@", "-");
  .font-face-cjk(~"system-ui@{locale}", @weights[@light], 300);
  .font-face-cjk(~"system-ui@{locale}", @weights[@regular], 400);
  .font-face-cjk(~"system-ui@{locale}", @weights[@medium], 500);
  .font-face-cjk(~"system-ui@{locale}", @weights[@bold], 700);
  /* Safari on macOS/iOS */
  @font-face {
    font-family: ~"system-ui@{locale}";
    src: local("HelveticaNeue");
    unicode-range: U+A0;
  }
  /* Other browsers on macOS/iOS */
  @supports not (-webkit-hyphens:none) {
    @font-face {
      font-family: ~"system-ui@{locale}";
      src: local("HelveticaNeue");
      unicode-range: U+20;
    }
  }
  :root {
    /* Special handling for Firefox on Windows/Linux */
    @supports (-moz-appearance:none) {
      --fonts-default-override@{locale}: ~"var(--fonts-proportional), system-ui@{locale}";
    }
    --fonts-default-override@{locale}: ~"system-ui@{locale}, var(--fonts-proportional)";
  }
});

@fonts: {
  @ja:
    "HiraginoSans-:{W2,W4,W5,W6}", "HiraKakuProN-:{W3,W6}", "Hiragino Kaku Gothic ProN :{W3,W6}",
    .shs("JP")[], .shs("J")[], .noto("JP")[], .shs("")[],
    /* https://acetaminophen.hatenablog.com/entry/2016/02/15/225009 */
    "Yu Gothic :{Regular,Medium,Bold}", "YuGothic :{Regular,Medium,Bold}",
    "Droid Sans Japanese:{}", "Meiryo:{, Bold}", "MS PGothic:{}";
  @zh-cn:
    .pingfang("SC")[],
    .shs("CN")[], .shs("SC")[], .noto("SC")[],
    "HiraginoSansGB-:{W3,W6}", "Hiragino Sans GB :{W3,W6}",
    "Microsoft YaHei:{ Light,, Bold}", "Heiti SC :{Light,Medium}", "SimHei:{}";
  @zh-tw:
    .pingfang("TC")[],
    .shs("TW")[], .shs("TC")[], .noto("TC")[],
    "HiraginoSansTC-:{W3,W6}", "Hiragino Sans TC :{W3,W6}",
    "Microsoft JhengHei:{ Light,, Bold}", "Heiti TC :{Light,Medium}", "PMingLiU:{}";
  @zh-hk:
    .pingfang("HK")[],
    .shs("HK")[], .shs("HC")[], .noto("HK")[], .shs("TC")[], .noto("TC")[],
    "HiraginoSansTC-:{W3,W6}", "Hiragino Sans TC :{W3,W6}",
    "Microsoft JhengHei:{ Light,, Bold}", "Heiti TC :{Light,Medium}", "PMingLiU_HKSCS:{}", "PMingLiU:{}";
  @ko:
    "AppleSDGothicNeo-:{Light,Regular,Medium,SemiBold}",
    .shs("KR")[], .shs("K")[], .noto("KR")[],
    "NanumBarunGothic:{ Light,, Bold}",
    "Malgun Gothic:{ Semilight,, Bold}", "Nanum Gothic:{, Bold}", "Dotum:{}";
}

.noto(@suffix) { @value: "Noto Sans CJK @{suffix} ", "NotoSansCJK@{suffix}-"; }
.shs(@suffix) { @value: replace("Source Han Sans @{suffix} ", "  ", " "), "SourceHanSans@{suffix}-"; }
.pingfang(@suffix) { @value: "PingFang@{suffix}-:{Light,Regular,Medium,Semibold}"; }
.font-face-cjk(@family, @src, @weight) {
  @font-face {
    font-family: @family;
    src: @src;
    font-weight: @weight;
    unicode-range: ~"U+11??, U+2E80-4DBF, U+4E00-9FFF, U+A960-A97F, U+AC00-D7FF, U+F900-FAFF, U+FE00-FE6F, U+FF00-FFEF, U+1F2??, U+2????";
  }
}

.gen-weights(@family) when (isstring(@family)) {
  @family-str: replace(@family, ":\{.*\}$", "");
  // apply standard style names if none is given
  // should the font have no styles, use :{}, as in "SimHei:{}"
  @weights-str: if(@family = @family-str, "Light,Regular,Medium,Bold", replace(@family, ".*:\{(.*)\}$", "$1"));
  @lightest: replace(@weights-str, ",.*", "");
  @boldest: replace(@weights-str, ".*,", "");
  @2ndboldest: replace(@weights-str, "(?:.*,|)([^,]*),.*$", "$1");
  @2ndlightest: if(@2ndboldest = @lightest, @lightest, replace(@weights-str, "^.*?,([^,]*).*", "$1"));

  @light: local("@{family-str}@{lightest}");
  @regular: local("@{family-str}@{2ndlightest}");
  @medium: local("@{family-str}@{2ndboldest}");
  @bold: local("@{family-str}@{boldest}");
}
.gen-weights(@family) when not (isstring(@family)) {
  .gen-weights-all(@family);
}
.gen-weights(@family, @last) {
  @this: .gen-weights(@family);

  @light: @last[@light], @this[@light];
  @regular: @last[@regular], @this[@regular];
  @medium: @last[@medium], @this[@medium];
  @bold: @last[@bold], @this[@bold];
}
.gen-weights-all(@family) when not (isstring(@family)) {
  .gen-weights-all(@family, length(@family));
}
.gen-weights-all(@family, 1) when not (isstring(@family)) {
  .gen-weights(extract(@family, 1));
}
.gen-weights-all(@family, @ctr) when not (isstring(@family)) and (@ctr > 1) and (@ctr <= length(@family)) {
  .gen-weights(extract(@family, @ctr), .gen-weights-all(@family, @ctr - 1));
}