import { api } from "../api.js";
import { centerActiveChips, emptyState, sectionHeader } from "../components.js";
import { lineChart, themeColor } from "../charts.js";
import {
  escapeAttr, escapeHtml, formatCount, formatDelta, formatNumber,
} from "../format.js";
import { replaceQuery } from "../router.js";

const RANGES = [["7", "7 天"], ["30", "30 天"], ["90", "90 天"], ["3650", "全部"]];

export async function renderFans(root, { query }) {
  const days = query.get("days") || "90";
  const mid = query.get("mid");
  const start = query.get("start") || "";
  const end = query.get("end") || "";
  const customRange = Boolean(start || end);
  const fans = await api("/api/fans", {
    days: customRange ? null : days,
    start,
    end,
    mid,
  });
  const options = fans.options || [];

  root.innerHTML = `<section class="page fans-page">
    <header class="page-head">
      <div>
        <h1>粉丝</h1>
        <p class="page-sub">${escapeHtml(fans.name || "粉丝追踪")}</p>
      </div>
      ${options.length > 1 ? `<select class="select" id="fan-mid">
        ${options.map((item) => `<option value="${item.mid}" ${String(fans.mid) === String(item.mid) ? "selected" : ""}>${escapeHtml(item.name)}</option>`).join("")}
      </select>` : ""}
    </header>

    ${!fans.available ? emptyState("暂无粉丝数据", "每日快照完成后会开始记录粉丝数。")
      : `
      <div class="hero-number">
        <span>当前粉丝</span>
        <strong>${formatCount(fans.follower)}</strong>
        <small>${escapeHtml(fans.stat_date || "—")} · 首次记录 ${escapeHtml(fans.first_date || "—")}</small>
      </div>

      <div class="mini-stats">
        <div><span>日增</span><strong class="${Number(fans.delta_1d) >= 0 ? "up" : "down"}">${fans.delta_1d === null ? "—" : formatDelta(fans.delta_1d)}</strong></div>
        <div><span>7 日净增</span><strong class="${Number(fans.delta_7d) >= 0 ? "up" : "down"}">${fans.delta_7d === null ? "—" : formatDelta(fans.delta_7d)}</strong></div>
        <div><span>累计增长（${escapeHtml(fans.first_date || "—")} 以来）</span><strong class="${Number(fans.delta_cum) >= 0 ? "up" : "down"}">${formatDelta(fans.delta_cum)}</strong></div>
      </div>

      <section class="panel chart-panel">
        ${sectionHeader("粉丝曲线")}
        <div class="chip-row scroll-x">
          ${RANGES.map(([value, label]) => `<button type="button"
            class="chip${!customRange && days === value ? " active" : ""}" data-days="${value}">${label}</button>`).join("")}
        </div>
        <form class="date-range" id="fan-range">
          <input type="date" name="start" value="${escapeAttr(start)}" aria-label="开始日期">
          <span>至</span>
          <input type="date" name="end" value="${escapeAttr(end)}" aria-label="结束日期">
          <button class="button" type="submit">应用</button>
          ${customRange ? `<button class="button ghost" type="button" id="fan-range-clear">清除</button>` : ""}
        </form>
        <div class="chart" id="fans-chart"></div>
        <p class="section-note">
          只绘制粉丝数，不叠加 reaction 视频数据；缺失日断开，不插值。
          ${fans.mode === "monthly"
            ? "当前范围超过一年，按每月粉丝峰值所在日期绘制。"
            : `当前按日绘制（${escapeHtml(fans.range_start || "—")} ~ ${escapeHtml(fans.range_end || "—")}）。`}
        </p>
      </section>

      <section class="panel">
        ${sectionHeader("最近记录")}
        <p class="section-note">默认展示最近 ${fans.recent_days || 14} 天；更早的数据只在曲线中显示。</p>
        <div class="table-wrap">
          <table class="data-table">
            <thead><tr><th>日期</th><th>粉丝</th><th>较上一成功日</th></tr></thead>
            <tbody>
              ${(fans.recent_points || []).slice().reverse().map((point) => `
                <tr class="${point.ok ? "" : "failed-row"}">
                  <td>${escapeHtml(point.stat_date)}</td>
                  <td>${point.ok ? formatNumber(point.follower) : "—"}</td>
                  <td>${point.delta === null || point.delta === undefined ? "—" : formatDelta(point.delta)}</td>
                </tr>`).join("")}
            </tbody>
          </table>
        </div>
      </section>`}
  </section>`;

  root.querySelectorAll("[data-days]").forEach((button) => button.addEventListener("click", () => {
    replaceQuery({ days: button.dataset.days, start: null, end: null });
  }));
  root.querySelector("#fan-mid")?.addEventListener("change", (event) => {
    replaceQuery({ mid: event.target.value });
  });
  root.querySelector("#fan-range")?.addEventListener("submit", (event) => {
    event.preventDefault();
    const form = new FormData(event.target);
    const nextStart = String(form.get("start") || "").trim();
    const nextEnd = String(form.get("end") || "").trim();
    if (nextStart && nextEnd && nextStart > nextEnd) {
      window.alert("开始日期不能晚于结束日期");
      return;
    }
    replaceQuery({ start: nextStart || null, end: nextEnd || null, days: null });
  });
  root.querySelector("#fan-range-clear")?.addEventListener("click", () => {
    replaceQuery({ start: null, end: null, days: null });
  });
  centerActiveChips(root);
  const chartElement = root.querySelector("#fans-chart");
  if (chartElement) {
    lineChart(chartElement, {
      dates: fans.dates || [],
      values: fans.series || [],
      name: "粉丝",
      color: themeColor("accent"),
      scale: true,
    });
  }
}