import { Bot, ChevronDown, Maximize2, SquarePen, X } from "lucide-react";
import { useEffect, useRef, useState } from "react";
import { Link, useLocation } from "react-router";
import { toast } from "sonner";
import { agentMockEnabled, useAgentRun, useCreateAgentRun } from "~/api/agent.ts";
import { useDownloadTask } from "~/api/downloads.ts";
import { useLibraryDetail } from "~/api/library.ts";
import { useRecord } from "~/api/records.ts";
import { useSite } from "~/api/sites.ts";
import { Button } from "~/components/ui/button.tsx";
import { Popover, PopoverContent, PopoverTrigger } from "~/components/ui/popover.tsx";
import { Sheet, SheetClose, SheetContent, SheetDescription, SheetHeader, SheetTitle } from "~/components/ui/sheet.tsx";
import { errorMessage } from "~/lib/api.ts";
import { DRAFT_DRAWER_GOAL, writeDraft } from "./agent-nav.ts";
import { AgentRunPanel, GoalComposer } from "./agent-run-panel.tsx";
import { AgentSessionList, drawerListMemory } from "./agent-session-list.tsx";
import {
  type AgentContext,
  agentShortcutLabel,
  clearAgentContext,
  contextPrefix,
  newAgentConversation,
  noteAgentReturnPath,
  setAgentDrawerOpen,
  shortGoalTitle,
  showAgentRunInDrawer,
  syncAgentContextToPath,
  takeReturnFocus,
  toggleAgentDrawer,
  useAgentDrawer,
} from "./agent-store.ts";
import { AgentRunOpenContext } from "./agent-subagents.tsx";
import { quickGoalsFor } from "./quick-goals.ts";

/** 侧栏入口、顶栏按钮等"抽屉外但属于抽屉"的控件打这个属性:点它不算点外面(否则先被关掉又被重新打开) */
export const AGENT_LAUNCHER_ATTR = "data-agent-launcher";

/**
 * 上下文的显示名称:页面按钮给的 label(「作品：沙丘2」)去掉类别;按路由推断的只有 ID,按 ID 查名称。
 * 查不到时退回类别名(「这部作品」),不显示 ID。
 */
export function useContextName(ctx: AgentContext | null): string | null {
  const path = !!ctx?.fromPath;
  const entity = useLibraryDetail(path ? ctx?.entityId : undefined);
  const site = useSite(path ? ctx?.siteId : undefined);
  const task = useDownloadTask(path ? ctx?.downloadTaskId : undefined);
  const record = useRecord(path ? ctx?.recordId : undefined);
  if (!ctx) return null;
  if (!path) return ctx.label ? ctx.label.replace(/^(作品|资源|下载|整理记录|站点|任务|后台任务)[：:]\s*/, "") : null;
  if (ctx.entityId) return entity.data?.entity.title ?? "这部作品";
  if (ctx.siteId) return site.data?.name ?? ctx.siteId;
  if (ctx.downloadTaskId) return task.data?.name ?? "这个下载任务";
  if (ctx.recordId) return record.data?.media?.title ?? "这条整理记录";
  if (ctx.taskId) return "这个后台任务";
  return null;
}

/** 抽屉标题 = 最近会话切换:显示当前会话的短标题,点开是和会话页同一份会话列表,点一条在抽屉里打开 */
function RecentSwitcher({ runId }: { runId: string | null }) {
  const [open, setOpen] = useState(false);
  const run = useAgentRun(runId ?? undefined);
  const mock = agentMockEnabled();
  const title = runId ? (run.data ? shortGoalTitle(run.data.run.goal, 28) : "会话") : "新对话";
  return (
    <Popover open={open} onOpenChange={setOpen}>
      <PopoverTrigger asChild>
        <button
          type="button"
          aria-label={`最近会话，当前：${title}`}
          title="切换到最近的会话"
          className="mr-auto flex h-8 min-w-0 cursor-pointer items-center gap-2 rounded-full px-2 text-left outline-none transition-colors duration-micro hover:bg-foreground/[0.04] focus-visible:ring-2 focus-visible:ring-ring data-[state=open]:bg-foreground/[0.06]"
        >
          <Bot aria-hidden className="size-4 shrink-0" />
          <span className="min-w-0 truncate text-lead font-semibold">{title}</span>
          <ChevronDown aria-hidden className="size-3.5 shrink-0 text-muted-foreground" />
        </button>
      </PopoverTrigger>
      <PopoverContent align="start" className="flex h-[min(32rem,70dvh)] w-[min(22rem,calc(100vw-2rem))] flex-col p-2">
        <AgentSessionList
          memory={drawerListMemory}
          limit={20}
          activeId={runId ?? undefined}
          onOpen={(id) => {
            setOpen(false);
            showAgentRunInDrawer(id);
          }}
          className="min-h-0 flex-1"
        />
        <Button asChild variant="ghost" size="sm" className="mt-1 shrink-0 text-muted-foreground">
          <Link to={`/console/agent${mock ? "?mock=1" : ""}`} onClick={() => setAgentDrawerOpen(false)}>
            全部会话
          </Link>
        </Button>
      </PopoverContent>
    </Popover>
  );
}

/**
 * 智能体抽屉:任意页面可打开,带当前页面上下文(作品 / 站点 / 下载任务等)。内容和会话页是同一个组件
 * (新对话 GoalComposer、会话 AgentRunPanel),这里是紧凑版。
 * 头部:标题即最近会话切换、新对话、在页面打开、关闭。关上抽屉会话照常在后台跑,再打开接着看。
 * 挂载:在 console layout 里渲染一次 <AgentDrawer />。页面内打开:openAgentDrawer({ entityId, label, ... })。
 */
export function AgentDrawer() {
  const { open, context, runId } = useAgentDrawer();
  const create = useCreateAgentRun();
  const { pathname, search } = useLocation();
  const content = useRef<HTMLDivElement>(null);
  // 记下最近的非智能体页面:会话页「在侧边打开」回到这里
  useEffect(() => noteAgentReturnPath(pathname, search), [pathname, search]);
  useEffect(() => syncAgentContextToPath(pathname, search), [pathname, search]);
  const name = useContextName(context);
  const mock = agentMockEnabled();
  // 目标前缀带名称和 ID:名称给人看,ID 给模型用
  const prefix = contextPrefix(context && name ? { ...context, label: name } : context);

  return (
    <Sheet open={open} onOpenChange={setAgentDrawerOpen}>
      <SheetContent
        ref={content}
        side="right"
        showCloseButton={false}
        className="w-full gap-0 p-0 sm:max-w-xl"
        // 打开即可输入:焦点直接给输入框,没有输入框时退回抽屉本身
        onOpenAutoFocus={(e) => {
          const ta = content.current?.querySelector<HTMLTextAreaElement>("textarea:not([disabled])");
          if (!ta) return;
          e.preventDefault();
          ta.focus();
          ta.setSelectionRange(ta.value.length, ta.value.length);
        }}
        // 关闭后焦点回到打开前的位置(快捷键打开没有触发元素,缺省会落到 body)
        onCloseAutoFocus={(e) => {
          const el = takeReturnFocus();
          if (!el) return;
          e.preventDefault();
          el.focus();
        }}
        onInteractOutside={(e) => {
          if ((e.target as Element | null)?.closest?.(`[${AGENT_LAUNCHER_ATTR}]`)) e.preventDefault();
        }}
      >
        <SheetHeader className="flex-row items-center gap-1 border-b border-[var(--shell-border)] py-2 pr-3 pl-3">
          <SheetTitle className="sr-only">智能体</SheetTitle>
          <SheetDescription className="sr-only">{`${agentShortcutLabel()} 打开或收起`}</SheetDescription>
          <RecentSwitcher runId={runId} />
          <Button
            variant="ghost"
            size="icon-sm"
            aria-label="新对话"
            title="新对话"
            onClick={newAgentConversation}
            disabled={!runId}
          >
            <SquarePen />
          </Button>
          {runId ? (
            <Button asChild variant="ghost" size="icon-sm" aria-label="在页面打开" title="在页面打开">
              <Link to={`/console/agent/${runId}${mock ? "?mock=1" : ""}`} onClick={() => setAgentDrawerOpen(false)}>
                <Maximize2 />
              </Link>
            </Button>
          ) : null}
          {/* 关闭钮放进标题栏这一行,与其它按钮对齐(Sheet 自带的是绝对定位,偏下 5px) */}
          <SheetClose asChild>
            <Button
              variant="ghost"
              size="icon-sm"
              aria-label="关闭，会话在后台继续"
              title="关闭（Esc），会话在后台继续"
            >
              <X />
            </Button>
          </SheetClose>
        </SheetHeader>
        <div className="flex min-h-0 flex-1 flex-col px-4 py-3">
          {runId ? (
            <AgentRunOpenContext.Provider value={showAgentRunInDrawer}>
              <AgentRunPanel key={runId} runId={runId} compact className="flex-1" onCreated={showAgentRunInDrawer} />
            </AgentRunOpenContext.Provider>
          ) : (
            <GoalComposer
              key={`${context?.entityId ?? ""}${context?.releaseId ?? ""}${context?.goal ?? ""}`}
              suggestions={context?.goal ? undefined : quickGoalsFor(pathname)}
              context={name}
              onClearContext={clearAgentContext}
              defaultGoal={context?.goal ?? ""}
              draftKey={DRAFT_DRAWER_GOAL}
              pending={create.isPending}
              onSubmit={(goal, opts) =>
                create.mutate(
                  { goal: `${prefix}${goal}`, ...opts },
                  {
                    onSuccess: (run) => {
                      writeDraft(DRAFT_DRAWER_GOAL, "");
                      showAgentRunInDrawer(run.id);
                    },
                    onError: (e) => toast.error(errorMessage(e)),
                  },
                )
              }
            />
          )}
        </div>
      </SheetContent>
    </Sheet>
  );
}

/** 顶栏胶囊里的智能体按钮(没有侧栏的窄屏):与快捷键、侧栏入口同一套切换(页面内按钮用 openAgentDrawer 传更完整的上下文) */
export function AgentDrawerTrigger({ className }: { className?: string }) {
  const { pathname, search } = useLocation();
  return (
    <Button
      variant="ghost"
      size="icon-sm"
      aria-label="打开智能体"
      title={`智能体(${agentShortcutLabel()})`}
      className={className}
      {...{ [AGENT_LAUNCHER_ATTR]: "" }}
      onClick={() => toggleAgentDrawer(pathname, search)}
    >
      <Bot />
    </Button>
  );
}