"use client";

/** 股票筛选（选股系统 M6，v2 §14/§21.1）：
 * 评分模式（多因子加权 TopN）与条件模式（结构化条件 AND）；
 * 支持当前/历史 as_of；结果落库可查（selection_id），右侧展示最近选股历史。
 */
import Link from "next/link";
import { useEffect, useState } from "react";
import { apiGet, apiPost } from "@/lib/api";
import { SymbolLink } from "@/lib/symbols";
import { waitJob } from "@/lib/jobs";
import { factorOptionLabel, pickableFactors } from "@/lib/factors";
import type {
  FactorMeta,
  SelectionCondition,
  SelectionMeta,
  SelectionQuery,
  SelectionResult,
  SelectionRun,
} from "@/lib/types";
import {
  PageHeader,
  Card,
  Pill,
  Field,
  Btn,
  Banner,
  Empty,
  SkeletonLines,
} from "@/components/ui";

const FIELD_OPTIONS: { value: string; label: string; kind: "num" | "str" | "ref" }[] = [
  { value: "static.industry", label: "行业 industry", kind: "str" },
  { value: "static.market", label: "市场 market", kind: "str" },
  { value: "momentum_20", label: "动量 20 日", kind: "num" },
  { value: "momentum_60", label: "动量 60 日", kind: "num" },
  { value: "close", label: "收盘价 close", kind: "num" },
  { value: "close_ma60_ref", label: "收盘 > MA60", kind: "ref" },
  { value: "volume_ratio_5_60", label: "量比", kind: "num" },
  { value: "fundamental.roe", label: "ROE(%)", kind: "num" },
  { value: "fundamental.eps", label: "EPS", kind: "num" },
];
const OPS = ["gt", "gte", "lt", "lte", "eq", "ne", "in"];

/**
 * 读取后端 payload 里的 name（若存在）。
 *
 * 为什么用宽松读取而非直接 `c.name`：`lib/types.ts` 的 SelectionCandidate 目前没有
 * 声明 name 字段（该文件由其他改动维护），直接访问会类型报错；但后端可能已经返回更权威的
 * 中文名。这里只做「有且非空则用」的读取，取不到就交给 SymbolLink 渲染占位「—」，
 * 绝不编造名称（AGENT §24）。
 */
function payloadName(row: unknown): string | undefined {
  if (row && typeof row === "object" && "name" in row) {
    const n = (row as { name?: unknown }).name;
    if (typeof n === "string" && n.trim()) return n;
  }
  return undefined;
}

function emptyCondition(): SelectionCondition {
  return { field: "static.industry", op: "eq", value: "白酒" };
}

export default function SelectionPage() {
  const [factors, setFactors] = useState<FactorMeta[]>([]);
  const [mode, setMode] = useState<"score" | "condition">("score");
  const [asOf, setAsOf] = useState(""); // 空 = 最近交易日
  const [excludeSt, setExcludeSt] = useState(true);
  const [topN, setTopN] = useState(20);
  const [factorRows, setFactorRows] = useState([{ name: "momentum_60", weight: 1 }]);
  const [conds, setConds] = useState<SelectionCondition[]>([emptyCondition()]);
  const [result, setResult] = useState<SelectionResult | null>(null);
  const [selectionId, setSelectionId] = useState("");
  /**
   * 已落库的 selection_id —— 只有「同步选股(SelectionRun.selection_id)」和「从历史列表打开(id)」两条路径才有。
   *
   * 为什么不能直接用 selectionId：异步路径（POST /selections/jobs）拿到的是 JOB id，
   * 后端不会为它写 selection 记录（backend/app/api/selections.py 只在同步接口里 selection_repo.save），
   * 拿它拼 /backtest?from_selection=<JOB id> 会让接收端 GET /api/selections/{id} 404 → 坏链接。
   */
  const [savedSelectionId, setSavedSelectionId] = useState("");
  const [running, setRunning] = useState(false);
  const [asyncBusy, setAsyncBusy] = useState(false);
  const [error, setError] = useState("");
  const [history, setHistory] = useState<SelectionMeta[] | null>(null);

  useEffect(() => {
    let alive = true;
    apiGet<FactorMeta[]>("/factors")
      // 停用/算不出来的因子不摆进候选（停用仍可被既有策略解析，只是不该再被选中）
      .then((list) => alive && list.length > 0 && setFactors(pickableFactors(list)))
      .catch((e: Error) => alive && setError(e.message));
    apiGet<SelectionMeta[]>("/selections?limit=8")
      .then((rows) => alive && setHistory(rows))
      .catch(() => alive && setHistory([]));
    return () => {
      alive = false;
    };
  }, []);

  function buildQuery(): SelectionQuery {
    if (mode === "score") {
      return {
        universe: { exclude_st: excludeSt, min_listing_days: 0 },
        as_of: asOf || null,
        method: "score",
        factors: factorRows.filter((r) => r.name),
        conditions: [],
        top_n: topN,
      };
    }
    return {
      universe: { exclude_st: excludeSt, min_listing_days: 0 },
      as_of: asOf || null,
      method: "condition",
      factors: [],
      conditions: conds.map((c) => ({
        ...c,
        ...(c.field === "close_ma60_ref"
          ? { field: "close", op: c.op, ref: "ma60", value: null }
          : {}),
      })),
      top_n: null,
    };
  }

  async function run() {
    setRunning(true);
    setError("");
    setResult(null);
    // 新一轮结果尚未落库/尚未返回：先清掉旧的 selection_id，避免「结果 A + 直通到记录 B」的错配链接
    setSavedSelectionId("");
    try {
      const run = await apiPost<SelectionRun>("/selections", buildQuery());
      setSelectionId(run.selection_id);
      setSavedSelectionId(run.selection_id);
      setResult(run.result);
      apiGet<SelectionMeta[]>("/selections?limit=8").then(setHistory).catch(() => undefined);
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setRunning(false);
    }
  }

  /** 异步（全市场等长任务）：提交 Job 后台执行并轮询（解决同步 60s+）。 */
  async function runAsync() {
    setAsyncBusy(true);
    setError("");
    setResult(null);
    // 同上：异步任务不落库选股记录，直通回测必须隐藏按钮（不给坏链接）
    setSavedSelectionId("");
    try {
      const { job_id } = await apiPost<{ job_id: string }>("/selections/jobs", buildQuery());
      const out = await waitJob<SelectionResult>(job_id);
      if (out.status === "success" && out.result) {
        setSelectionId(job_id);
        setResult(out.result);
        apiGet<SelectionMeta[]>("/selections?limit=8").then(setHistory).catch(() => undefined);
      } else {
        setError(`任务${out.status}${out.error ? `：${out.error}` : ""}`);
      }
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setAsyncBusy(false);
    }
  }

  async function openHistory(id: string) {
    setError("");
    try {
      const detail = await apiGet<SelectionResult>(`/selections/${id}`);
      setSelectionId(id);
      setSavedSelectionId(id);
      setResult(detail);
    } catch (e) {
      setError((e as Error).message);
    }
  }

  return (
    <>
      <PageHeader
        title="股票筛选"
        sub="以因子评分 TopN 或结构化条件筛选股票，支持当前 / 历史时点；每次选股落库可复现、可解释（为什么选它）。"
        actions={
          selectionId ? (
            <Pill tone="violet" icon="check">
              {selectionId}
            </Pill>
          ) : null
        }
      />

      <Card title="选股条件" icon="filter">
        <div className="form-grid">
          <Field label="方式">
            <select
              className="input"
              value={mode}
              onChange={(e) => setMode(e.target.value as "score" | "condition")}
            >
              <option value="score">因子评分（TopN）</option>
              <option value="condition">条件筛选（AND）</option>
            </select>
          </Field>
          <Field label="选股时点 as_of" hint="留空 = 最近可用交易日">
            <input type="date" className="input" value={asOf} onChange={(e) => setAsOf(e.target.value)} />
          </Field>
          <Field label="标的范围" hint="ST 按当时名称判定">
            <label className="check">
              <input type="checkbox" checked={excludeSt} onChange={(e) => setExcludeSt(e.target.checked)} />
              剔除 ST
            </label>
          </Field>
        </div>

        {mode === "score" ? (
          <>
            <div className="form-section__title" style={{ margin: "12px 0 8px" }}>
              评分因子与权重
            </div>
            {/* 与回测页同一套「表头 + 栅格行」：列宽由 CSS 决定，不再用 flex 拉伸
                （flex:1 会把权重框拉到几百像素宽，与一位小数的内容完全不匹配） */}
            <div className="factor-rows">
              <div className="factor-rows__head" aria-hidden="true">
                <span>因子</span>
                <span>权重</span>
                <span />
              </div>
              {factorRows.map((r, i) => (
                <div className="factor-row" key={i}>
                  <select
                    className="input"
                    aria-label={`第 ${i + 1} 个因子的名称`}
                    value={r.name}
                    onChange={(e) => {
                      const next = [...factorRows];
                      next[i] = { ...next[i], name: e.target.value };
                      setFactorRows(next);
                    }}
                  >
                    {factors.map((f) => (
                      <option key={f.name} value={f.name}>{factorOptionLabel(f)}</option>
                    ))}
                  </select>
                  <input
                    className="input mono"
                    type="number"
                    inputMode="decimal"
                    step="0.1"
                    min={0}
                    aria-label={`第 ${i + 1} 个因子的权重`}
                    value={r.weight}
                    onChange={(e) => {
                      const next = [...factorRows];
                      next[i] = { ...next[i], weight: Number(e.target.value) };
                      setFactorRows(next);
                    }}
                  />
                  <Btn
                    icon="x"
                    disabled={factorRows.length <= 1}
                    aria-label={`删除第 ${i + 1} 个因子`}
                    title="删除该因子"
                    onClick={() => setFactorRows(factorRows.filter((_, j) => j !== i))}
                  />
                </div>
              ))}
            </div>
            <div className="row" style={{ gap: 10, marginTop: 10, alignItems: "flex-end" }}>
              <Btn
                icon="layers"
                size="sm"
                onClick={() => setFactorRows([...factorRows, { name: "momentum_60", weight: 1 }])}
              >
                添加因子
              </Btn>
              <Field label="Top N" hint="按综合分排序取前 N 只">
                <input
                  className="input"
                  type="number"
                  inputMode="numeric"
                  min={1}
                  value={topN}
                  onChange={(e) => setTopN(Number(e.target.value))}
                />
              </Field>
            </div>
          </>
        ) : (
          <>
            <div className="form-section__title" style={{ margin: "12px 0 8px" }}>
              条件（全部满足才入选）
            </div>
            <div className="cond-rows">
              <div className="cond-rows__head" aria-hidden="true">
                <span>字段</span>
                <span>比较</span>
                <span>取值</span>
                <span />
              </div>
              {conds.map((c, i) => {
                const meta = FIELD_OPTIONS.find((f) => f.value === (c.field === "close" && c.ref ? "close_ma60_ref" : c.field));
                const isRef = c.field === "close" && c.ref === "ma60";
                return (
                  <div className="cond-row" key={i}>
                    <select
                      className="input"
                      aria-label={`第 ${i + 1} 个条件的字段`}
                      value={isRef ? "close_ma60_ref" : c.field}
                      onChange={(e) => {
                        const next = [...conds];
                        const v = e.target.value;
                        next[i] = v === "close_ma60_ref"
                          ? { field: "close", op: "gt", ref: "ma60", value: null }
                          : { field: v, op: c.op, value: v.startsWith("static.") ? "" : 0 };
                        setConds(next);
                      }}
                    >
                      {FIELD_OPTIONS.map((f) => (
                        <option key={f.value} value={f.value}>{f.label}</option>
                      ))}
                    </select>
                    <select
                      className="input"
                      aria-label={`第 ${i + 1} 个条件的比较符`}
                      value={c.op}
                      onChange={(e) => {
                        const next = [...conds];
                        next[i] = { ...next[i], op: e.target.value as SelectionCondition["op"] };
                        setConds(next);
                      }}
                    >
                      {OPS.map((o) => <option key={o} value={o}>{o}</option>)}
                    </select>
                    {!isRef ? (
                      <input
                        className="input mono"
                        aria-label={`第 ${i + 1} 个条件的取值`}
                        placeholder={c.op === "in" ? "逗号分隔多个值" : "值"}
                        value={String(c.value ?? "")}
                        onChange={(e) => {
                          const next = [...conds];
                          const raw = e.target.value;
                          const val = c.op === "in"
                            ? raw.split(/[,，]/).map((s) => s.trim()).filter(Boolean)
                            : (meta?.kind === "num" && !c.field.startsWith("static.")
                              ? Number(raw)
                              : raw);
                          next[i] = { ...next[i], value: val as never };
                          setConds(next);
                        }}
                      />
                    ) : (
                      /* 占位保持第四列（操作列）不串位 */
                      <span />
                    )}
                    <Btn
                      icon="x"
                      disabled={conds.length <= 1}
                      aria-label={`删除第 ${i + 1} 个条件`}
                      title="删除该条件"
                      onClick={() => setConds(conds.filter((_, j) => j !== i))}
                    />
                  </div>
                );
              })}
            </div>
            <div style={{ marginTop: 10 }}>
              <Btn icon="layers" size="sm" onClick={() => setConds([...conds, emptyCondition()])}>
                添加条件
              </Btn>
            </div>
          </>
        )}

        <div style={{ marginTop: 14 }}>
          <Btn variant="primary" icon="play" loading={running} disabled={running || asyncBusy} onClick={run}>
            {running ? "筛选中…" : "执行选股"}
          </Btn>
          <Btn variant="ghost" icon="clock" loading={asyncBusy} disabled={running || asyncBusy} onClick={runAsync}>
            {asyncBusy ? "后台执行中…" : "异步（全市场）"}
          </Btn>
        </div>
        {error ? (
          <div style={{ marginTop: 12 }}>
            <Banner tone="error">{error}</Banner>
          </div>
        ) : null}
      </Card>

      {!result && !running && history === null ? <SkeletonLines n={4} /> : null}

      {result ? <ResultView result={result} selectionId={savedSelectionId} /> : null}

      {history && history.length > 0 ? (
        <Card title="最近选股记录" icon="archive">
          <div className="chips">
            {history.map((m) => (
              <button
                key={m.id}
                className="chip"
                style={{ cursor: "pointer" }}
                onClick={() => openHistory(m.id)}
                title={`${m.id} · ${m.method} · ${m.selected} 只`}
              >
                <b className="mono">{m.as_of}</b>
                {m.method} · {m.selected} 只
              </button>
            ))}
          </div>
        </Card>
      ) : null}
    </>
  );
}

function ResultView({ result, selectionId }: { result: SelectionResult; selectionId: string }) {
  const s = result.statistics;
  if (result.candidates.length === 0) {
    return (
      <Card>
        <Empty
          icon="filter"
          title="无符合条件/可评分的股票"
          hint={`范围 ${s.universe_size} 只，可评分 ${s.evaluated} 只。可放宽条件或选择更早的 as_of。`}
        />
      </Card>
    );
  }
  return (
    <Card
      icon="target"
      title={`选股结果 · ${result.as_of_date} · ${result.method}`}
      tools={
        <>
          <Pill>范围 {s.universe_size}</Pill>
          <Pill>评分 {s.evaluated}</Pill>
          <Pill tone="pos">选出 {s.selected}</Pill>
          {/* 选股 → 回测直通：只带「已落库」的 selection_id；没有它（如异步任务未落库）就不渲染按钮，避免坏链接 */}
          {selectionId ? (
            <Link
              href={`/backtest?from_selection=${encodeURIComponent(selectionId)}`}
              className="btn btn--sm"
              title="把这次的规则（条件/因子/TopN/口径）预填到回测页；回测会在每个择股日按同一规则重新选股，不是固定持有这批股票"
            >
              <span>按此条件回测</span>
            </Link>
          ) : null}
        </>
      }
    >
      {selectionId ? (
        <div className="hint" style={{ marginBottom: 10 }}>
          按此条件回测：把这次的规则（条件 / 因子 / TopN / 口径）预填到回测页；回测会在每个择股日按同一规则重新选股，<b>不是固定持有这批股票</b>。
        </div>
      ) : null}
      <div className="table-wrap">
        <table className="tbl">
          <thead>
            <tr>
              <th>#</th>
              <th>代码 / 名称</th>
              <th>得分</th>
              <th>因子值</th>
              <th>入选理由</th>
            </tr>
          </thead>
          <tbody>
            {result.candidates.map((c) => (
              <tr key={c.symbol}>
                <td className="mono dim">{c.rank}</td>
                <td>
                  {/* 后端 payload 若已带 name 就用它（更权威），否则回落到全局名称表 */}
                  <SymbolLink symbol={c.symbol} name={payloadName(c)} />
                </td>
                <td className="mono">{c.score.toFixed(4)}</td>
                <td style={{ fontSize: 12 }}>
                  {Object.entries(c.factor_values)
                    .map(([k, v]) => `${k}=${typeof v === "number" ? v.toFixed(4) : v}`)
                    .join("  ")}
                </td>
                <td>
                  <div className="chips">
                    {c.selection_reason.map((r) => (
                      <span className="chip" key={r}>{r.slice(0, 40)}</span>
                    ))}
                  </div>
                </td>
              </tr>
            ))}
          </tbody>
        </table>
      </div>
      {result.unimplemented.length ? (
        <div style={{ marginTop: 10 }}>
          <Banner tone="info">{result.unimplemented.join("；")}</Banner>
        </div>
      ) : null}
    </Card>
  );
}