const COUNT_UNITS = [
  { value: 1e8, suffix: "亿" },
  { value: 1e4, suffix: "万" },
];

export function formatCount(value) {
  if (value === null || value === undefined || Number.isNaN(Number(value))) return "—";
  const number = Number(value);
  for (const unit of COUNT_UNITS) {
    if (Math.abs(number) >= unit.value) {
      const scaled = number / unit.value;
      return `${trimZero(scaled.toFixed(Math.abs(scaled) >= 1000 ? 0 : 1))}${unit.suffix}`;
    }
  }
  return Math.round(number).toLocaleString("zh-CN");
}

export function formatAxis(value) {
  if (value === null || value === undefined || Number.isNaN(Number(value))) return "";
  const number = Number(value);
  if (Math.abs(number) >= 1e8) return `${trimZero((number / 1e8).toFixed(2))}亿`;
  if (Math.abs(number) >= 1e4) {
    const scaled = number / 1e4;
    return `${trimZero(scaled.toFixed(Math.abs(scaled) >= 100 ? 1 : 2))}万`;
  }
  return Math.round(number).toLocaleString("zh-CN");
}

export function formatNumber(value) {
  if (value === null || value === undefined || Number.isNaN(Number(value))) return "—";
  return Number(value).toLocaleString("zh-CN");
}

export function formatDelta(value) {
  if (value === null || value === undefined || Number.isNaN(Number(value))) return "—";
  const number = Number(value);
  const sign = number > 0 ? "+" : "";
  return `${sign}${formatCount(number)}`;
}

export function formatScore(value, digits = 2) {
  if (value === null || value === undefined || Number.isNaN(Number(value))) return "—";
  return Number(value).toFixed(digits).replace(/\.?0+$/, "");
}

export function formatPercent(value, digits = 2) {
  if (value === null || value === undefined || Number.isNaN(Number(value))) return "—";
  return `${(Number(value) * 100).toFixed(digits)}%`;
}

export function formatDate(timestamp) {
  if (!timestamp) return "—";
  const date = new Date(Number(timestamp) * 1000);
  if (Number.isNaN(date.getTime())) return "—";
  return new Intl.DateTimeFormat("zh-CN", {
    year: "numeric", month: "2-digit", day: "2-digit",
  }).format(date);
}

export function formatDateTime(timestamp) {
  if (!timestamp) return "—";
  const date = new Date(Number(timestamp) * 1000);
  if (Number.isNaN(date.getTime())) return "—";
  return new Intl.DateTimeFormat("zh-CN", {
    month: "2-digit", day: "2-digit", hour: "2-digit", minute: "2-digit",
  }).format(date);
}

export function formatDuration(seconds) {
  if (seconds === null || seconds === undefined || Number(seconds) <= 0) return "—";
  let total = Math.round(Number(seconds));
  const hours = Math.floor(total / 3600);
  total -= hours * 3600;
  const minutes = Math.floor(total / 60);
  const rest = total - minutes * 60;
  if (hours > 0) {
    return `${hours}:${String(minutes).padStart(2, "0")}:${String(rest).padStart(2, "0")}`;
  }
  return `${minutes}:${String(rest).padStart(2, "0")}`;
}

export function formatDay(value) {
  if (!value) return "—";
  return String(value).slice(5);
}

export function trimZero(text) {
  return String(text).replace(/\.0$/, "").replace(/(\.\d)0$/, "$1");
}

export function escapeHtml(value) {
  if (value === null || value === undefined) return "";
  return String(value)
    .replace(/&/g, "&amp;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&#39;");
}

export function escapeAttr(value) {
  return escapeHtml(value).replace(/`/g, "&#96;");
}

export function coverUrl(value) {
  if (!value) return "";
  return value.startsWith("//") ? `https:${value}` : value;
}

export function metricLabel(metric) {
  return ({
    view: "播放",
    like: "点赞",
    coin: "投币",
    favorite: "收藏",
    share: "转发",
    reply: "评论",
    danmaku: "弹幕",
  })[metric] || metric;
}

export function statusLabel(status) {
  return ({
    active: "在库",
    unfaved: "已取消收藏",
    removed: "已失效",
    dropped: "已移出库",
  })[status] || status || "—";
}

export function debounce(fn, wait = 280) {
  let timer = null;
  return (...args) => {
    window.clearTimeout(timer);
    timer = window.setTimeout(() => fn(...args), wait);
  };
}