"use client";

import { useCallback, useEffect, useState } from "react";
import { apiGet, apiPost } from "@/lib/api";
import type { BacktestResult } from "@/lib/types";
import {
  PageHeader,
  Card,
  Pill,
  Btn,
  Banner,
  Empty,
  Metric,
  SkeletonLines,
} from "@/components/ui";
import { Icon } from "@/components/icons";

interface ExperimentMeta {
  id: string;
  kind: string;
  factors: string[];
  period?: [string, string] | null;
  rebalance?: string;
  top_n?: number | null;
  summary_text?: string | null;
  code_version?: string | null;
  created_at?: string;
}

interface ExperimentDetail extends ExperimentMeta {
  spec: { universe?: Record<string, unknown> };
  result: BacktestResult | null;
}

const KIND_MAP: Record<string, { label: string; tone: "accent" | "violet" | "default" }> = {
  backtest: { label: "回测", tone: "accent" },
  factor_test: { label: "因子测试", tone: "violet" },
};

function kindView(kind: string) {
  const k = KIND_MAP[kind] ?? { label: kind, tone: "default" as const };
  return <Pill tone={k.tone}>{k.label}</Pill>;
}

function statusView(status: string) {
  switch (status) {
    case "success":
      return (
        <Pill tone="pos" icon="check">
          完成
        </Pill>
      );
    case "running":
      return (
        <Pill tone="accent" icon="spinner">
          运行中
        </Pill>
      );
    case "queued":
      return (
        <Pill tone="warn" icon="clock">
          排队
        </Pill>
      );
    case "failed":
      return (
        <Pill tone="neg" icon="alert">
          失败
        </Pill>
      );
    case "cancelled":
      return <Pill tone="warn">已取消</Pill>;
    default:
      return <Pill>{status}</Pill>;
  }
}

export default function ExperimentsPage() {
  const [exps, setExps] = useState<ExperimentMeta[]>([]);
  const [loading, setLoading] = useState(true);
  const [detail, setDetail] = useState<ExperimentDetail | null>(null);
  const [detailLoading, setDetailLoading] = useState(false);
  const [jobId, setJobId] = useState("");
  const [jobStatus, setJobStatus] = useState("");
  const [error, setError] = useState("");

  const load = useCallback(() => {
    apiGet<ExperimentMeta[]>("/experiments")
      .then(setExps)
      .catch((e: Error) => setError(e.message))
      .finally(() => setLoading(false));
  }, []);

  useEffect(load, [load]);

  function open(id: string) {
    setDetailLoading(true);
    setDetail(null);
    apiGet<ExperimentDetail>(`/experiments/${id}`)
      .then((d) => {
        setDetail(d);
      })
      .catch((e: Error) => setError(e.message))
      .finally(() => setDetailLoading(false));
  }

  function rerun(exp: ExperimentMeta) {
    setError("");
    setJobId("");
    setJobStatus("submitting");
    apiPost<{ job_id: string; status: string }>(`/experiments/${exp.id}/rerun`, {})
      .then((r) => {
        setJobId(r.job_id);
        setJobStatus(r.status);
        poll(r.job_id);
      })
      .catch((e: Error) => setError(e.message));
  }

  function poll(id: string) {
    let tries = 0;
    const timer = window.setInterval(() => {
      tries += 1;
      apiGet<{ status: string }>(`/jobs/${id}`)
        .then((j) => {
          setJobStatus(j.status);
          if (j.status === "success" || j.status === "failed" || tries > 60) {
            window.clearInterval(timer);
            load();
            setDetail(null);
          }
        })
        .catch(() => window.clearInterval(timer));
    }, 1200);
  }

  const s = detail?.result?.summary;

  return (
    <>
      <PageHeader
        title="实验归档"
        sub="每次因子测试与回测自动归档（含 Research Spec 与代码版本），保证可复现；支持一键复跑。"
        actions={exps.length > 0 ? <Pill tone="accent" icon="archive">共 {exps.length} 个实验</Pill> : undefined}
      />

      {error ? <Banner tone="error">{error}</Banner> : null}

      {jobId ? (
        <Card
          icon="refresh"
          title={`复跑任务 ${jobId}`}
          tools={statusView(jobStatus === "submitting" ? "queued" : jobStatus)}
        >
          <div className="hint">
            任务状态实时轮询；完成后列表自动刷新，可直接展开查看最新结果。
          </div>
        </Card>
      ) : null}

      <Card title="实验列表" icon="archive" flush>
        {loading ? (
          <div style={{ padding: 18 }}>
            <SkeletonLines n={6} />
          </div>
        ) : exps.length === 0 ? (
          <Empty
            icon="archive"
            title="暂无实验"
            hint="在「回测」或「因子研究」中运行一次，即会自动归档于此。"
          />
        ) : (
          <div className="table-wrap">
            <table className="tbl">
              <thead>
                <tr>
                  <th>ID</th>
                  <th>类型</th>
                  <th>因子</th>
                  <th>区间</th>
                  <th>摘要</th>
                  <th>代码版本</th>
                  <th style={{ width: 150, textAlign: "right" }}>操作</th>
                </tr>
              </thead>
              <tbody>
                {exps.map((e) => (
                  <tr key={e.id} className={detail?.id === e.id ? "row-active" : undefined}>
                    <td className="cell-mono cell-strong">{e.id}</td>
                    <td>{kindView(e.kind)}</td>
                    <td>
                      <span className="row" style={{ gap: 4 }}>
                        {e.factors.map((f) => (
                          <span key={f} className="tag tag--mono">
                            {f}
                          </span>
                        ))}
                      </span>
                    </td>
                    <td className="cell-mono">{e.period ? `${e.period[0]}~${e.period[1]}` : "—"}</td>
                    <td className="hint">{e.summary_text ?? "—"}</td>
                    <td>{e.code_version ? <span className="tag tag--mono">{e.code_version}</span> : <span className="hint">—</span>}</td>
                    <td style={{ textAlign: "right" }}>
                      <span className="row" style={{ justifyContent: "flex-end", gap: 6 }}>
                        <Btn size="sm" icon="search" onClick={() => open(e.id)}>
                          详情
                        </Btn>
                        <Btn size="sm" variant="primary" icon="refresh" onClick={() => rerun(e)} disabled={jobStatus === "running" || jobStatus === "queued" || jobStatus === "submitting"}>
                          复跑
                        </Btn>
                      </span>
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        )}
      </Card>

      {detail ? (
        <Card
          icon="book"
          title={`${detail.id} · ${detail.factors.join("、")}`}
          sub={detail.period ? `${detail.period[0]} ~ ${detail.period[1]}` : undefined}
          tools={
            <Btn size="sm" onClick={() => setDetail(null)}>
              <Icon name="x" size={13} />
              关闭
            </Btn>
          }
        >
          {detailLoading ? (
            <SkeletonLines n={3} />
          ) : (
            <>
              {s ? (
                <div className="metric-grid" style={{ marginBottom: 0 }}>
                  <Metric
                    label="区间收益"
                    tone={s.total_return_pct >= 0 ? "pos" : "neg"}
                    value={`${s.total_return_pct >= 0 ? "+" : ""}${s.total_return_pct.toFixed(2)}%`}
                  />
                  <Metric
                    label="年化收益"
                    tone={s.annual_return_pct >= 0 ? "pos" : "neg"}
                    value={`${s.annual_return_pct >= 0 ? "+" : ""}${s.annual_return_pct.toFixed(2)}%`}
                  />
                  <Metric label="Sharpe" value={s.sharpe.toFixed(2)} />
                  <Metric label="最大回撤" tone="neg" value={`${s.max_drawdown_pct.toFixed(2)}%`} />
                </div>
              ) : (
                <div className="hint">该实验没有可展示的汇总结果（可能是因子测试或历史版本）。</div>
              )}
              {detail.spec ? (
                <div className="hint" style={{ marginTop: 12 }}>
                  spec（可复现输入）：<span className="mono">{JSON.stringify(detail.spec).slice(0, 500)}</span>
                  {JSON.stringify(detail.spec).length > 500 ? "…" : ""}
                </div>
              ) : null}
            </>
          )}
        </Card>
      ) : null}
    </>
  );
}