import { useState } from "react";
import { useAppStore } from "../../store/useAppStore";
import { useAuditStore } from "../audit";
import { CardGrid, Notice, PageHeader, StatCard } from "../components";
import { Button, Surface, Tag } from "../../components/primitives";
import { Icon } from "../../components/Icon";
import { useAsyncData } from "../../lib/useAsyncData";
import { useAutoReload } from "../hooks";
import { adminObservabilityAudit, adminObservabilityMetrics, adminObservabilityTrace } from "../../lib/api";
import type { AdminTraceSpan, AuditRecord } from "../../lib/types";

type Tab = "logs" | "trace" | "metrics" | "audit";

const TABS: ReadonlyArray<{ id: Tab; label: string }> = [
  { id: "logs", label: "实时日志" },
  { id: "trace", label: "Tracing" },
  { id: "metrics", label: "指标" },
  { id: "audit", label: "审计" },
];

const KIND_LABEL: Record<string, string> = {
  llm_call: "LLM",
  tool_call: "工具",
  orchestration: "编排",
  state_transition: "状态",
  subagent: "子代理",
  memory: "记忆",
  guardrail: "护栏",
};

export function ObservabilityModule(): React.ReactNode {
  const [tab, setTab] = useState<Tab>("logs");
  const deviceUpdates = useAppStore((s) => s.deviceUpdates);
  const audit = useAuditStore((s) => s.records);
  const clearAudit = useAuditStore((s) => s.clear);

  return (
    <div className="space-y-5">
      <PageHeader title="可观测性" subtitle="实时日志 tail · Tracing(LLM/工具/编排) · 指标 · 审计" />

      <div className="flex flex-wrap items-center gap-2">
        {TABS.map((t) => (
          <button
            key={t.id}
            onClick={() => setTab(t.id)}
            className={`rounded-[var(--mu-radius)] px-3 py-1.5 text-xs font-medium transition-all duration-200 ease-[var(--mu-spring)] ${
              tab === t.id ? "bg-[var(--mu-accent)]/20 text-[var(--mu-accent-hi)]" : "bg-[var(--mu-surface-4)] text-[var(--mu-text-mid)]"
            }`}
          >
            {t.label}
          </button>
        ))}
      </div>

      {tab === "logs" ? <LogsTail lines={deviceUpdates} /> : null}
      {tab === "trace" ? <TraceView /> : null}
      {tab === "metrics" ? <MetricsView /> : null}
      {tab === "audit" ? <AuditView records={audit} onClear={clearAudit} /> : null}
    </div>
  );
}

function LogsTail({ lines }: { lines: string[] }): React.ReactNode {
  return (
    <Surface className="space-y-3">
      <div className="flex items-center gap-2">
        <h3 className="text-sm font-semibold">实时日志流（WS 事件回显）</h3>
        <Tag tone="ok">tail</Tag>
      </div>
      {lines.length === 0 ? (
        <Notice>暂无实时事件。接入 /ws/chat 后，此处回显 stream / tool / device_update / reminder 等事件。</Notice>
      ) : (
        <pre className="max-h-80 overflow-auto whitespace-pre-wrap rounded-[var(--mu-radius)] bg-[var(--mu-surface-2)] px-3 py-2 font-mono text-xs text-[var(--mu-text-mid)]">
          {lines.join("\n")}
        </pre>
      )}
      <Notice>完整后端日志分级 tail / 过滤 / 导出需后端 M10+ 提供。</Notice>
    </Surface>
  );
}

function TraceView(): React.ReactNode {
  const trace = useAsyncData(() => adminObservabilityTrace(100), []);
  useAutoReload(trace.reload, 3000);
  const spans = trace.data ?? [];

  return (
    <Surface className="space-y-3">
      <div className="flex items-center gap-2">
        <h3 className="text-sm font-semibold">Tracing 视图</h3>
        <Tag tone="ok">实时</Tag>
        <span className="ml-auto text-xs text-[var(--mu-text-lo)]">GET /api/v1/admin/observability/trace</span>
      </div>
      {trace.loading ? (
        <Notice>加载 span 数据…</Notice>
      ) : trace.error ? (
        <Notice tone="warn">trace 后端暂不可用：{trace.error}</Notice>
      ) : spans.length === 0 ? (
        <Notice>暂无 span。接入 /ws/chat 发起会话后，LLM / 工具 / 编排 / 子代理等 span 会实时记录到环形缓冲。</Notice>
      ) : (
        <SpanList spans={spans} />
      )}
      <Notice>数据源：gateway trace 环形缓冲（经 TraceSink 对接 runtime 的 tracer）。可在 TraceSink 注入前展示占位，注入后即真实 span。</Notice>
    </Surface>
  );
}

function SpanList({ spans }: { spans: AdminTraceSpan[] }): React.ReactNode {
  const [openId, setOpenId] = useState<string | null>(null);
  return (
    <div className="space-y-1.5">
      {spans.map((sp) => {
        const open = openId === sp.id;
        return (
          <button
            key={sp.id}
            onClick={() => setOpenId(open ? null : sp.id)}
            className="w-full rounded-[var(--mu-radius-sm)] bg-[var(--mu-surface-2)] px-3 py-2 text-left text-xs transition-colors hover:bg-[var(--mu-surface-3)]"
          >
            <div className="flex flex-wrap items-center gap-2">
              <span className="font-medium text-[var(--mu-text)]">{sp.name}</span>
              <Tag tone="neutral">{KIND_LABEL[sp.kind] ?? sp.kind}</Tag>
              <Tag tone={sp.status === "ok" ? "ok" : "err"}>{sp.status === "ok" ? "成功" : "失败"}</Tag>
              <span className="font-mono text-[var(--mu-text-lo)]">{sp.id}</span>
              <span className="ml-auto font-mono text-[var(--mu-text-lo)]">{fmtDuration(sp.durationNs)}</span>
            </div>
            <div className="mt-1 flex flex-wrap items-center gap-2 text-[var(--mu-text-lo)]">
              <span>{new Date(sp.startedAt).toLocaleString()}</span>
              {sp.parentId ? <span>父 {sp.parentId}</span> : <span>根 span</span>}
            </div>
            {open ? (
              <div className="mt-2 space-y-1.5 rounded-[var(--mu-radius-sm)] bg-[var(--mu-surface-3)]/60 px-3 py-2 text-[var(--mu-text-mid)]">
                {(sp.events?.length ?? 0) === 0 && !sp.props ? (
                  <span className="text-[var(--mu-text-lo)]">无事件/属性。</span>
                ) : null}
                {sp.events?.map((ev, i) => (
                  <div key={i} className="flex items-start gap-2">
                    <span className="shrink-0 font-mono text-[var(--mu-text-lo)]">{new Date(ev.time).toLocaleTimeString()}</span>
                    <span className="font-medium">{ev.type}</span>
                    {ev.props ? (
                      <code className="min-w-0 break-all font-mono text-[var(--mu-text-lo)]">{JSON.stringify(ev.props)}</code>
                    ) : null}
                  </div>
                ))}
                {sp.props ? (
                  <code className="block break-all font-mono text-[var(--mu-text-lo)]">{JSON.stringify(sp.props)}</code>
                ) : null}
              </div>
            ) : null}
          </button>
        );
      })}
    </div>
  );
}

function MetricsView(): React.ReactNode {
  const metrics = useAsyncData(adminObservabilityMetrics, []);
  useAutoReload(metrics.reload, 3000);
  const m = metrics.data;

  const topPaths = Object.entries(m?.perPath ?? {})
    .sort((a, b) => b[1] - a[1])
    .slice(0, 8);

  return (
    <div className="space-y-4">
      <CardGrid>
        <StatCard icon={<Icon name="gear" size={18} />} label="请求 QPS" value={m ? m.qps.toFixed(1) : "—"} sub={m ? `总请求 ${m.totalRequests}` : "网关指标加载中"} tone="accent" />
        <StatCard icon={<Icon name="robot" size={18} />} label="LLM 调用次数" value={m ? m.llmCalls : "—"} sub="从 trace span 累计" tone="neutral" />
        <StatCard icon={<Icon name="agent" size={18} />} label="子代理事件" value={m ? m.subagentEvents : "—"} sub="从 trace span 累计" tone="ok" />
        <StatCard icon={<Icon name="memory" size={18} />} label="工时/Token" value="—" sub="成本后端暂不统计" tone="warn" />
      </CardGrid>

      {metrics.error ? <Notice tone="warn">指标后端暂不可用：{metrics.error}</Notice> : null}

      {m && (topPaths.length > 0 || Object.keys(m.statusCounts).length > 0) ? (
        <Surface className="space-y-3">
          <h3 className="text-sm font-semibold">请求分布（真实网关计数）</h3>
          {topPaths.length > 0 ? (
            <div className="space-y-1">
              {topPaths.map(([path, count]) => (
                <div key={path} className="flex items-center gap-2 text-xs">
                  <code className="min-w-0 flex-1 break-all font-mono text-[var(--mu-text-mid)]">{path}</code>
                  <span className="text-[var(--mu-text-lo)]">{count}</span>
                  <div className="h-1.5 w-24 overflow-hidden rounded-full bg-[var(--mu-surface-3)]">
                    <div className="h-full rounded-full bg-[var(--mu-accent)]/60" style={{ width: `${((count / (m.totalRequests || 1)) * 100).toFixed(1)}%` }} />
                  </div>
                </div>
              ))}
            </div>
          ) : null}
          {Object.keys(m.statusCounts).length > 0 ? (
            <div className="flex flex-wrap items-center gap-2">
              {Object.entries(m.statusCounts).map(([code, count]) => (
                <Tag key={code} tone={code === "200" ? "ok" : Number(code) >= 500 ? "err" : "warn"}>
                  {code} × {count}
                </Tag>
              ))}
              <span className="text-xs text-[var(--mu-text-lo)]">平均 {m.avgLatencyMs.toFixed(1)}ms · 最大 {m.maxLatencyMs}ms</span>
            </div>
          ) : null}
        </Surface>
      ) : null}

      <Notice>LLM 调用次数 / 子代理事件由实际观测到的 trace span 累计；Token / 成本后端暂不统计（不伪造指标）。指标时序图 / 导出需后端 M10+ 提供。</Notice>
    </div>
  );
}

interface AuditViewProps {
  records: AuditRecord[];
  onClear: () => void;
}

function AuditView({ records: local, onClear }: AuditViewProps): React.ReactNode {
  const audit = useAsyncData(() => adminObservabilityAudit(100), []);
  useAutoReload(audit.reload, 5000);
  // Backend is the authoritative source; the local store is a fallback while the
  // endpoint is unavailable.
  const records = audit.data ?? local;
  const source = audit.data ? "后端" : "本地（后端未接入）";

  return (
    <Surface className="space-y-3">
      <div className="flex items-center gap-2">
        <h3 className="text-sm font-semibold">审计日志（who / what / when / result）</h3>
        <Tag tone={audit.data ? "ok" : "warn"}>{source}</Tag>
        <span className="text-xs text-[var(--mu-text-lo)]">管理 + 敏感操作全程落审计</span>
        <span className="ml-auto">
          <Button size="sm" variant="ghost" onClick={onClear}>
            清空本地
          </Button>
        </span>
      </div>
      {audit.error && !audit.data ? <Notice tone="warn">审计端点暂不可用，回退本地记录：{audit.error}</Notice> : null}
      {records.length === 0 ? (
        <Notice>暂无审计记录。本面板的管理/敏感操作（策略写入、主人档案编辑、API key 签发等）都会在此登记。</Notice>
      ) : (
        <table className="w-full text-sm">
          <thead>
            <tr className="border-b border-[var(--mu-glass-border)] text-left text-xs uppercase tracking-wider text-[var(--mu-text-lo)]">
              <th className="px-2 py-1.5">who</th>
              <th className="px-2 py-1.5">what</th>
              <th className="px-2 py-1.5">when</th>
              <th className="px-2 py-1.5">result</th>
            </tr>
          </thead>
          <tbody>
            {records.map((r) => (
              <tr key={r.id} className="border-b border-[var(--mu-glass-border)]/60 last:border-0">
                <td className="px-2 py-2 text-xs">{r.who}</td>
                <td className="px-2 py-2 text-xs font-mono">{r.what}</td>
                <td className="px-2 py-2 text-xs text-[var(--mu-text-lo)]">{new Date(r.when).toLocaleString()}</td>
                <td className="px-2 py-2"><Tag tone={r.result === "ok" ? "ok" : "err"}>{r.result}</Tag></td>
              </tr>
            ))}
          </tbody>
        </table>
      )}
    </Surface>
  );
}

/** Formats a nanosecond duration into a human-readable label. */
function fmtDuration(ns: number): string {
  if (ns >= 1e9) return `${(ns / 1e9).toFixed(2)} s`;
  if (ns >= 1e6) return `${(ns / 1e6).toFixed(2)} ms`;
  if (ns >= 1e3) return `${(ns / 1e3).toFixed(1)} µs`;
  return `${ns} ns`;
}