import { useState } from "react";
import { useAppStore } from "../../store/useAppStore";
import { useAuditStore } from "../audit";
import { Notice, PageHeader } from "../components";
import { Button, EmptyState, Surface, Tag } from "../../components/primitives";
import type { BackthinkItem } from "../../lib/types";
import { Icon } from "../../components/Icon";
import { FlowGraphView } from "./FlowGraph";
import { adminBackthink } from "../../lib/api";
import { useAsyncData } from "../../lib/useAsyncData";
import { BACKTHINK_SESSION_ID } from "../../store/sessionCache";

/** 推送路由的中文标签（后端 PushResult.Route 的取值域）。未知取值原样显示，
 *  绝不猜一个更好听的词。 */
const PUSH_ROUTE_LABEL: Record<string, string> = {
  active_client: "活跃客户端",
  im_bridge: "IM 桥",
  rate_limited: "限频拦截",
  none: "无投递目标",
};

/** 推送路由的色调：真的送出去了才用 ok，被限频拦住是 warn。 */
function pushRouteTone(route: string): "ok" | "warn" | "neutral" {
  if (route === "active_client" || route === "im_bridge") return "ok";
  if (route === "rate_limited") return "warn";
  return "neutral";
}

function BackthinkRow({ item }: { item: BackthinkItem }): React.ReactNode {
  const markPushed = useAppStore((s) => s.markBackthinkPushed);
  // 裁决 16.4.2：这条思考的链路图取自**后台思考会话**（`sess-backthink`，design/19 §1
  // 的发布会话范围）的快照，而不是管理端 Flow 页那张「当前会话」图 —— 后者属于用户端
  // 会话，与后台思考的完整链路是两件事，且不会被思考图顶掉。
  const graph = useAppStore((s) => s.flowGraphs[BACKTHINK_SESSION_ID] ?? null);
  const wsStatus = useAppStore((s) => s.wsStatus);
  const [open, setOpen] = useState(false);

  return (
    <Surface className="space-y-2">
      <div className="flex items-center gap-2 text-sm">
        <Tag tone="neutral">{new Date(item.at).toLocaleTimeString()}</Tag>
        <span className="font-medium">{item.trigger}</span>
        <Tag tone={item.shouldNotify ? "warn" : "neutral"}>{item.shouldNotify ? "需要打扰" : "静默"}</Tag>
        <Tag tone={item.pushed ? "ok" : "neutral"}>{item.pushed ? "已推送" : "未推送"}</Tag>
        {item.route ? <Tag tone={pushRouteTone(item.route)}>{PUSH_ROUTE_LABEL[item.route] ?? item.route}</Tag> : null}
        {item.bypassed ? <Tag tone="accent">事件直发</Tag> : null}
        <span className="ml-auto">
          <Button size="sm" variant="ghost" disabled={item.pushed} onClick={() => markPushed(item.id)}>
            {item.pushed ? "已推送" : "推送结果"}
          </Button>
        </span>
      </div>
      {item.conclusion ? (
        <div className="rounded-[var(--mu-radius-sm)] bg-[var(--mu-surface-2)] px-3 py-2 text-xs text-[var(--mu-text-mid)]">
          {item.conclusion}
        </div>
      ) : null}
      {item.detail ? (
        <div className="text-xs text-[var(--mu-text-lo)]">推送说明：{item.detail}</div>
      ) : null}
      <button
        className="text-xs text-[var(--mu-accent-hi)]"
        onClick={() => setOpen((v) => !v)}
      >
        {open ? "收起链路" : "查看完整链路导图"}
      </button>
      {open ? (
        graph ? (
          <FlowGraphView graph={graph} />
        ) : (
          <div className="rounded-[var(--mu-radius-lg)] border border-dashed border-[var(--mu-glass-border)] px-4 py-8 text-center text-xs text-[var(--mu-text-lo)]">
            {wsStatus === "connected"
              ? "后台思考会话尚未产生链路图 —— 该会话还没有 graph_update 快照（本轮思考未跑 span，或后端未发布）。"
              : `实时通道未连接（${wsStatus}），链路图无法更新 —— 这不等于「本轮思考没有链路」。`}
          </div>
        )
      ) : null}
    </Surface>
  );
}

export function BackthinkModule(): React.ReactNode {
  const backthink = useAppStore((s) => s.backthink);
  const log = useAuditStore((s) => s.log);
  const [filter, setFilter] = useState<"all" | "notify" | "silent">("all");
  const [interveneHint, setInterveneHint] = useState(false);
  // Cold-load persisted history once (design/12 §4); real-time updates come from the
  // WS `backthink` events already feeding useAppStore.backthink (head-inserted), so we
  // do NOT poll-replace the array (which would re-render the whole list). Rows are keyed
  // by id → React reconciles incrementally, appending only NEW records.
  const rec = useAsyncData(() => adminBackthink(100), []);
  const byId = new Map<string, BackthinkItem>();
  for (const b of backthink) if (b.id) byId.set(b.id, b);
  for (const b of rec.data ?? []) if (b.id) byId.set(b.id, b);
  const items = Array.from(byId.values())
    .sort((a, b) => (b.at ?? 0) - (a.at ?? 0))
    .filter((b) => {
      if (filter === "notify") return b.shouldNotify === true;
      if (filter === "silent") return b.shouldNotify !== true;
      return true;
    });

  return (
    <div className="space-y-5">
      <PageHeader
        title="后台思考与主动"
        subtitle="触发源 / 时间 / 结论 / 是否打扰 / 推送结果 · 打扰决策可解释"
        actions={
          <Button
            variant="soft"
            onClick={() => {
              log("backthink.intervene", "error");
              setInterveneHint(true);
            }}
          >
            干预
          </Button>
        }
      />

      {interveneHint ? (
        <Notice tone="warn">对后台思考的打断 / 重派需后端 M10+ 能力接入，当前未启用；此处仅展示已产生的思考记录。</Notice>
      ) : null}

      <div className="flex items-center gap-2">
        <FilterPill active={filter === "all"} onClick={() => setFilter("all")}>全部</FilterPill>
        <FilterPill active={filter === "notify"} onClick={() => setFilter("notify")}>需打扰</FilterPill>
        <FilterPill active={filter === "silent"} onClick={() => setFilter("silent")}>静默</FilterPill>
      </div>

      {items.length === 0 ? (
        <EmptyState icon={<Icon name="night" size={32} />} title="暂无后台思考" hint="后台任务完成时按 WS 事件实时呈现（backthink / thinking）。" />
      ) : (
        <div className="space-y-3">
          {items.map((b) => (
            <BackthinkRow key={b.id} item={b} />
          ))}
        </div>
      )}

      <Notice>数据源：/ws/chat 下行 backthink / thinking 事件（实时，主驱动）+ 打开时一次拉取 GET /api/v1/admin/backthink 历史，两者按 id 去重、按时间倒序，新记录增量插入（不整页重渲）。「推送结果」的 route / detail / bypassed 两条路径同名同义：历史拉取取 AdminBackthinkItem 的同名键，实时帧取后端原始 PushResult 的 Route / Detail / Bypassed（解析器已读，见 lib/wsParse.ts#parseBackthinkItem，兼容 camelCase 变体），因此本次会话新到的行同样显示推送路由与推送说明，不再只显示「已推送/未推送」。链路导图取自后台思考会话（sess-backthink）的 graph_update 快照 —— 后端完整链路图始终发布，与管理端 Flow 页的「当前会话」图相互独立（裁决 16.4.2）。干预为后端 M10+ 提供，当前为只读展示。</Notice>
    </div>
  );
}

function FilterPill({ active, onClick, children }: { active: boolean; onClick: () => void; children: React.ReactNode }): React.ReactNode {
  return (
    <button
      onClick={onClick}
      className={`rounded-[var(--mu-radius-pill)] px-3 py-1 text-xs transition-all duration-200 ease-[var(--mu-spring)] ${
        active ? "bg-[var(--mu-accent)]/20 font-medium text-[var(--mu-accent-hi)]" : "bg-[var(--mu-surface-4)] text-[var(--mu-text-mid)]"
      }`}
    >
      {children}
    </button>
  );
}