import { Bot, ChevronsRight, Keyboard } from "lucide-react";
import { useEffect, useMemo, useState } from "react";
import { createPortal } from "react-dom";
import { useLocation } from "react-router";
import { isRunActive, RUN_STATUS_LABEL, useAgentRuns } from "~/api/agent.ts";
import { AGENT_LAUNCHER_ATTR } from "~/components/agent/agent-drawer.tsx";
import {
  agentShortcutLabel,
  isAgentShortcut,
  shortGoalTitle,
  toggleAgentDrawer,
  useAgentDrawer,
} from "~/components/agent/agent-store.ts";
import { cn } from "~/lib/utils.ts";

// Agent 的三处醒目入口:右下角悬浮按钮(FAB)、侧栏最上方主入口、全局快捷键 Ctrl/⌘+J。
// 三者都走 toggleAgentDrawer,行为一致:打开中 → 收起;有最小化的运行 → 恢复;否则带当前页面上下文打开。

/** 进行中的会话数与最近一条的状态摘要(列表里有进行中的会话时 5 秒轮询一次) */
export function useActiveAgentRuns() {
  const runs = useAgentRuns();
  return useMemo(() => {
    const active = (runs.data?.pages ?? []).flatMap((p) => p.items).filter((r) => isRunActive(r.status));
    const latest = active[0];
    return {
      count: active.length,
      summary: latest ? `${RUN_STATUS_LABEL[latest.status]} · ${shortGoalTitle(latest.goal)}` : null,
    };
  }, [runs.data]);
}

/** 全局快捷键:Ctrl/⌘+J 切换抽屉(Esc 关闭由抽屉自身处理) */
function useAgentHotkey() {
  const { pathname } = useLocation();
  useEffect(() => {
    const onKey = (e: KeyboardEvent) => {
      if (e.repeat || !isAgentShortcut(e)) return;
      e.preventDefault();
      toggleAgentDrawer(pathname);
    };
    window.addEventListener("keydown", onKey);
    return () => window.removeEventListener("keydown", onKey);
  }, [pathname]);
}

/** 页面里的底部浮动操作栏(文件页批量操作等):FAB 与它横向重叠时抬到它上面 */
const FLOATING_BARS = '[data-floating-bar], [role="toolbar"][aria-label="批量操作"]';
const BASE_BOTTOM = 16;

function useFloatingBarLift(): number {
  const [lift, setLift] = useState(0);
  useEffect(() => {
    let frame = 0;
    const measure = () => {
      frame = 0;
      let next = 0;
      for (const bar of document.querySelectorAll<HTMLElement>(FLOATING_BARS)) {
        const r = bar.getBoundingClientRect();
        // 只看贴底、且伸到屏幕右侧 FAB 所在区域(右 30%)的栏
        if (r.height === 0 || r.bottom < window.innerHeight - 160 || r.right < window.innerWidth * 0.7) continue;
        next = Math.max(next, window.innerHeight - r.top + 12 - BASE_BOTTOM);
      }
      setLift((prev) => (prev === next ? prev : next));
    };
    const schedule = () => {
      if (!frame) frame = requestAnimationFrame(measure);
    };
    const mo = new MutationObserver(schedule);
    mo.observe(document.body, { childList: true, subtree: true });
    window.addEventListener("resize", schedule);
    measure();
    return () => {
      mo.disconnect();
      window.removeEventListener("resize", schedule);
      if (frame) cancelAnimationFrame(frame);
    };
  }, []);
  return lift;
}

function CountBadge({ count, className }: { count: number; className?: string }) {
  if (!count) return null;
  return (
    <span
      className={cn(
        "grid h-5 min-w-5 place-items-center rounded-full bg-primary px-1 text-label font-semibold text-primary-foreground tabular-nums",
        className,
      )}
    >
      {count > 99 ? "99+" : count}
    </span>
  );
}

/** 进行中的脉冲点:减少动态效果时只留静态点 */
function PulseDot({ className }: { className?: string }) {
  return (
    <span aria-hidden className={cn("relative flex size-2.5", className)}>
      <span className="absolute inline-flex size-full rounded-full bg-primary/60 motion-safe:animate-ping" />
      <span className="relative inline-flex size-2.5 rounded-full bg-primary" />
    </span>
  );
}
/**
 * QA U6:页面向下滚动时 FAB 滑出右侧,向上滚动、停在页底或页面很短时回来,
 * 滚动途中不再盖住右对齐的开关与状态栏。只看页面级滚动区域(高度 ≥ 半屏),列表内小滚动区不算。
 */
function useHideOnScroll(): boolean {
  const [hidden, setHidden] = useState(false);
  useEffect(() => {
    const last = new WeakMap<object, number>();
    const onScroll = (e: Event) => {
      const t = e.target === document ? document.scrollingElement : e.target;
      if (!(t instanceof HTMLElement) || t.clientHeight < window.innerHeight / 2) return;
      const top = t.scrollTop;
      const prev = last.get(t) ?? top;
      last.set(t, top);
      const atBottom = top + t.clientHeight >= t.scrollHeight - 4;
      if (atBottom || top < 80 || top - prev < -8) setHidden(false);
      else if (top - prev > 8) setHidden(true);
    };
    document.addEventListener("scroll", onScroll, { capture: true, passive: true });
    return () => document.removeEventListener("scroll", onScroll, { capture: true });
  }, []);
  return hidden;
}

/**
 * 右下角悬浮按钮 + 全局快捷键。挂在 console layout 里一次。
 * - Agent 会话页本身不显示(页面就是 Agent);最小化小窗在右下角时让位给小窗。
 * - 只在没有侧栏的窄屏显示(xl 起侧栏顶部就是入口);抽屉打开时隐藏,用抽屉自带的关闭钮。
 */
export function AgentLauncher() {
  useAgentHotkey();
  const { pathname } = useLocation();
  const { open, minimized, runId } = useAgentDrawer();
  const { count, summary } = useActiveAgentRuns();
  const lift = useFloatingBarLift();
  const scrolledAway = useHideOnScroll();
  const shortcut = agentShortcutLabel();
  // 挂到 body:外壳是 isolate 的层叠上下文,留在里面的话抽屉打开后"收起"会被遮罩盖住
  const [host, setHost] = useState<HTMLElement | null>(null);
  useEffect(() => setHost(document.body), []);

  const onAgentPage = /^\/console\/agent(\/|$)/.test(pathname);
  if (!host || (onAgentPage && !open) || (minimized && runId && !open)) return null;

  const label = open ? "收起智能体" : count ? `打开智能体（${count} 个会话进行中）` : "打开智能体";
  return createPortal(
    <button
      type="button"
      {...{ [AGENT_LAUNCHER_ATTR]: "" }}
      onClick={() => toggleAgentDrawer(pathname)}
      aria-label={label}
      aria-keyshortcuts="Control+J Meta+J"
      aria-expanded={open}
      title={`${open ? "收起" : "打开"}智能体(${shortcut})${summary && !open ? `\n${summary}` : ""}`}
      style={{ bottom: `calc(${BASE_BOTTOM + lift}px + env(safe-area-inset-bottom))` }}
      className={cn(
        "pg-float prism-ring group pointer-events-auto fixed right-4 z-40 flex h-14 min-w-14 cursor-pointer items-center justify-center gap-3 rounded-full text-foreground outline-none select-none",
        "transition-[transform,bottom,right] duration-layout ease-spring active:scale-[0.96] focus-visible:ring-[3px] focus-visible:ring-ring/50 motion-reduce:transition-none",
        "animate-in fade-in-0 zoom-in-95 duration-base motion-reduce:animate-none",
        "md:px-2 md:pr-5",
        // 桌面(xl 起)侧栏已有入口,抽屉打开时用抽屉自己的关闭钮:这两种情况都不显示悬浮按钮
        open ? "hidden" : "xl:hidden",
        !open && scrolledAway && "translate-x-[calc(100%+2rem)] focus-visible:translate-x-0",
      )}
    >
      <span className="relative grid size-10 shrink-0 place-items-center rounded-full pill-selected">
        {open ? <ChevronsRight className="size-5" /> : <Bot className="size-5" />}
        {count && !open ? <CountBadge count={count} className="absolute -top-1.5 -right-1.5 md:hidden" /> : null}
      </span>
      <span className="hidden min-w-0 flex-col items-start text-left md:flex">
        <span className="flex items-center gap-2 text-control leading-5 font-semibold">
          {open ? "收起" : "智能体"}
          {count && !open ? <PulseDot /> : null}
          {count && !open ? <CountBadge count={count} /> : null}
          <kbd className="rounded-tight border border-border/70 px-1 font-sans text-label leading-4 font-medium text-muted-foreground">
            {shortcut}
          </kbd>
        </span>
        <span className="max-w-56 truncate text-meta leading-4 text-muted-foreground">
          {open ? "Esc 关闭" : (summary ?? "")}
        </span>
      </span>
    </button>,
    host,
  );
}

/** 侧栏最上方的 Agent 主入口:强调样式(棱镜环),显示进行中会话数 */
export function AgentNavEntry({ collapsed = false, onNavigate }: { collapsed?: boolean; onNavigate?: () => void }) {
  const { pathname } = useLocation();
  const { count, summary } = useActiveAgentRuns();
  const shortcut = agentShortcutLabel();
  const activate = () => {
    onNavigate?.();
    toggleAgentDrawer(pathname);
  };
  const title = `智能体(${shortcut})${summary ? `\n${summary}` : ""}`;

  if (collapsed) {
    return (
      <button
        type="button"
        {...{ [AGENT_LAUNCHER_ATTR]: "" }}
        onClick={activate}
        title={title}
        aria-label={count ? `打开智能体（${count} 个会话进行中）` : "打开智能体"}
        aria-keyshortcuts="Control+J Meta+J"
        className="prism-ring relative mb-2 grid h-10 w-10 shrink-0 cursor-pointer place-items-center rounded-xl text-foreground outline-none transition-transform duration-micro active:scale-[0.95] focus-visible:ring-2 focus-visible:ring-ring"
      >
        <Bot className="h-[18px] w-[18px]" />
        {count ? <CountBadge count={count} className="absolute -top-1.5 -right-1.5" /> : null}
      </button>
    );
  }
  return (
    <button
      type="button"
      {...{ [AGENT_LAUNCHER_ATTR]: "" }}
      onClick={activate}
      title={title}
      aria-keyshortcuts="Control+J Meta+J"
      className="prism-ring flex w-full cursor-pointer items-center gap-3 rounded-xl px-2.5 py-2 text-left text-foreground outline-none transition-transform duration-micro active:scale-[0.98] focus-visible:ring-2 focus-visible:ring-ring"
    >
      <span className="grid size-8 shrink-0 place-items-center rounded-lg pill-selected">
        <Bot className="h-4 w-4" />
      </span>
      <span className="flex min-w-0 flex-1 flex-col">
        <span className="flex items-center gap-2 text-sm font-semibold">
          智能体
          {count ? <PulseDot /> : null}
        </span>
        {count ? <span className="truncate text-meta text-muted-foreground">{count} 个会话进行中</span> : null}
      </span>
      {count ? (
        <CountBadge count={count} />
      ) : (
        <kbd className="rounded-tight border border-border/70 px-1 font-sans text-label leading-4 text-muted-foreground">
          {shortcut}
        </kbd>
      )}
    </button>
  );
}

/** 快捷键说明(设置页"快捷键"一节用) */
export function AgentShortcutsHelp() {
  const shortcut = agentShortcutLabel();
  const rows: [string, string][] = [
    [shortcut, "打开 / 收起智能体，附带当前页面"],
    ["Esc", "关闭智能体"],
    ["Enter", "发送目标；Shift+Enter 换行"],
  ];
  return (
    <section aria-labelledby="agent-shortcuts-title" className="space-y-2">
      <h3 id="agent-shortcuts-title" className="flex items-center gap-2 text-sm font-semibold">
        <Keyboard aria-hidden className="size-4 text-muted-foreground" />
        快捷键
      </h3>
      <dl className="grid grid-cols-[auto_1fr] items-center gap-x-4 gap-y-1.5 text-caption">
        {rows.map(([k, v]) => (
          <div key={k} className="contents">
            <dt>
              <kbd className="rounded-tight border border-border/70 px-1.5 py-0.5 font-sans text-label text-foreground">
                {k}
              </kbd>
            </dt>
            <dd className="text-muted-foreground">{v}</dd>
          </div>
        ))}
      </dl>
    </section>
  );
}