import { api } from "../api.js";
import { emptyState, mediaCard } from "../components.js";
import {
  escapeAttr, escapeHtml, formatCount, formatDelta,
  formatPercent, formatScore,
} from "../format.js";
import { canAccessProtected } from "../session.js";

function statChip(label, value, { href = null, tone = "" } = {}) {
  const inner = `<span>${escapeHtml(label)}</span><strong>${value}</strong>`;
  if (href) {
    return `<a class="live-chip ${tone}" href="${escapeAttr(href)}">${inner}</a>`;
  }
  return `<div class="live-chip ${tone}">${inner}</div>`;
}

function heatGrid(items) {
  if (!items.length) return emptyState("暂无热度数据", "完成一次快照后这里会出现榜单。");
  return `<div class="media-grid">
    ${items.map((item, index) => mediaCard(item, {
      rank: index + 1,
      highlight: `热度 ${formatScore(item.heat)} · 前 ${Math.max(0, 100 - (item.heat_percentile || 0)).toFixed(0)}%`,
    })).join("")}
  </div>`;
}

function publishedCard(item) {
  return mediaCard(item, {
    highlight: `${formatCount(item.metrics?.view)} 播放 · 互动 ${formatPercent(item.interaction_rate)}`,
  });
}

function growthCard(item, index) {
  const delta = item.growth?.delta;
  let highlight = `${formatCount(item.metrics?.view)} 播放`;
  if (delta !== null && delta !== undefined) {
    const tone = Number(delta) >= 0 ? "up" : "down";
    highlight += ` <span class="${tone}">${formatDelta(delta)}</span>`;
  }
  return mediaCard(item, { rank: index + 1, highlight });
}

export async function renderHome(root) {
  const [overview, published, heat, growth] = await Promise.all([
    api("/api/overview"),
    api("/api/videos", { sort: "published", within_days: 14, limit: 6 }),
    api("/api/videos", { sort: "heat", limit: 6 }),
    // 不带天数：后端按 home_growth_days（默认 auto：有 7 日则 7，否则 1）决定，响应带 days
    api("/api/videos", { sort: "growth", limit: 6 }),
  ]);

  const fans = overview.fans;
  const firstDay = overview.is_first_day;
  const addedLabel = firstDay
    ? formatCount(overview.initial_import_count)
    : formatCount(overview.added_today);
  const activeCount = overview.counts?.active || 0;
  const pending = overview.counts?.candidates_pending || 0;
  // 候选提示仅对已登录（或未启用鉴权）用户可见，访客不展示运行期信息。
  const showCandidates = pending > 0 && canAccessProtected();
  // 以后端返回的 days（与 growth_days 同步）为准，避免前端再探查
  const growthDays = Number(growth.days ?? growth.growth_days) || 1;
  const growthLabel = `近 ${growthDays} 日`;
  const growthEmptyTitle = growth.reason
    || `近 ${growthDays} 日增长暂不可用`;
  const growthEmptyHint = growthDays <= 1
    ? "当前快照不足，完成至少 2 天快照后即可显示播放增量。"
    : `需要至少 ${growthDays + 1} 天快照才能计算近 ${growthDays} 日增长。`;

  root.innerHTML = `<section class="page home-page">
    <header class="page-head home-head">
      <div>
        <h1>最新动态</h1>
        <p class="page-sub">收录视频 ${formatCount(activeCount)}</p>
      </div>
      <button class="icon-button" id="refresh-home" type="button" title="刷新">刷新</button>
    </header>

    <div class="live-strip">
      ${statChip(firstDay ? "首次导入" : "今日入库", escapeHtml(addedLabel), {
        href: "/videos?sort=added&within_days=7", tone: "accent",
      })}
      ${statChip("播放增量", overview.view_delta_available ? formatDelta(overview.view_delta) : "—", {
        href: "/videos?sort=growth&growth_days=1",
      })}
      ${statChip("7 日粉丝变化", fans?.delta_7d === null || fans?.delta_7d === undefined ? "—" : formatDelta(fans.delta_7d), {
        href: "/fans",
      })}
      ${statChip("数据日期", escapeHtml(overview.data_date || "—"))}
    </div>

    ${showCandidates ? `<a class="notice-row" href="/candidates">
      <strong>${formatCount(pending)} 条候选待确认</strong>
      <span>请在 Telegram 中处理 →</span>
    </a>` : ""}

    <section class="home-block">
      <div class="section-head">
        <h2>最近发布</h2>
        <a class="text-link" href="/videos?sort=published&within_days=30">查看全部</a>
      </div>
      <p class="section-note">按视频发布时间排序，与入库时间无关。</p>
      <div class="media-grid">
        ${published.items.length ? published.items.map((item) => publishedCard(item)).join("")
          : emptyState("最近 14 天没有新发布视频", "搜索发现的新视频会逐步补充。")}
      </div>
    </section>

    <section class="home-block">
      <div class="section-head">
        <h2>增长动态 · ${escapeHtml(growthLabel)}</h2>
        <a class="text-link" href="/videos?sort=growth&growth_days=${growthDays}">增长榜</a>
      </div>
      ${growth.available && growth.items.length
        ? `<div class="media-grid">${growth.items.map((item, index) => growthCard(item, index)).join("")}</div>`
        : emptyState(growthEmptyTitle, growthEmptyHint)}
    </section>

    <section class="home-block">
      <div class="section-head">
        <h2>热度速览</h2>
        <a class="text-link" href="/videos?sort=heat">完整榜单</a>
      </div>
      ${heatGrid(heat.items)}
    </section>
  </section>`;

  root.querySelector("#refresh-home")?.addEventListener("click", () => window.location.reload());
}