"use client";

/**
 * 策略库（/strategies）—— 策略的命名资产中心。
 *
 * 职责：
 * - 列表 + 检索：每个策略显示**一句话说明**与**计算公式**（后端 describe_strategy 推导）。
 * - 新建 / 编辑：复用 StrategyParamsForm（与回测页同一份参数模型与校验）。
 * - 一键回测：`POST /strategies/{id}/expand`（补 period + 资金）→ `POST /jobs` → 轮询 →
 *   就地展示核心指标，并提供「查看实验详情 / 回到回测页看曲线」。
 * - 去回测页：`/backtest?strategy={id}`（回测页载入后可保存为策略、可微调）。
 *
 * 设计取舍：编辑不弹窗而是就地展开表单（页面滚动位置不丢，参数多，弹窗太挤）。
 */
import Link from "next/link";
import { useCallback, useEffect, useMemo, useState } from "react";
import { apiDelete, apiGet, apiPost, apiPut } from "@/lib/api";
import { STAGE_LABEL, submitJob, waitJob, type JobOutcome } from "@/lib/jobs";
import { recentRange } from "@/lib/dates";
import type { BacktestResult, FactorMeta, StrategyDefinition } from "@/lib/types";
import {
  Btn,
  Banner,
  Card,
  Empty,
  Loading,
  PageHeader,
  Pill,
  Progress,
  BacktestMetrics,
  Field,
} from "@/components/ui";
import {
  StrategyParamsForm,
  casePreset,
  emptyParams,
  paramsFromStrategy,
  strategyFromParams,
  validateParams,
  type StrategyParams,
} from "@/components/StrategyParamsForm";
import { StrategyDocBody, StrategyDocCard } from "@/components/StrategyDocCard";
import { useStrategyDoc, useStrategyDocById } from "@/lib/strategy";

export default function StrategiesPage() {
  const [list, setList] = useState<StrategyDefinition[] | null>(null);
  const [factors, setFactors] = useState<FactorMeta[]>([]);
  const [query, setQuery] = useState("");
  const [err, setErr] = useState("");
  const [msg, setMsg] = useState("");
  const [editing, setEditing] = useState<StrategyParams | null>(null);
  const [editingId, setEditingId] = useState<string | null>(null);
  // 保存被拦下过 → 立即展开全部校验错误（见 StrategyParamsFormProps.revealErrors）
  const [revealErrors, setRevealErrors] = useState(false);
  const [busy, setBusy] = useState(false);
  const [docId, setDocId] = useState<string | null>(null);

  const range = useMemo(() => recentRange(), []);

  const load = useCallback(async () => {
    try {
      const rows = await apiGet<StrategyDefinition[]>("/strategies");
      setList(rows);
      setErr("");
    } catch (e) {
      setErr((e as Error).message);
      setList([]);
    }
  }, []);

  useEffect(() => {
    void load();
    let alive = true;
    apiGet<FactorMeta[]>("/factors")
      .then((f) => alive && setFactors(f))
      .catch(() => alive && setFactors([]));
    return () => {
      alive = false;
    };
  }, [load]);

  const filtered = useMemo(() => {
    if (!list) return null;
    const q = query.trim().toLowerCase();
    if (!q) return list;
    return list.filter((s) => {
      const hay = [
        s.name,
        s.description,
        (s.factors ?? []).map((f) => f.name).join(" "),
        (s.conditions ?? []).map((c) => c.field).join(" "),
      ]
        .join(" ")
        .toLowerCase();
      return hay.includes(q);
    });
  }, [list, query]);

  /* ---------- 新建 / 编辑 ---------- */
  function startCreate() {
    setEditingId(null);
    setEditing(emptyParams(range));
    setDocId(null);
    setMsg("");
    setErr("");
    setRevealErrors(false);
  }

  function startEdit(s: StrategyDefinition) {
    setEditingId(s.id ?? null);
    setEditing(paramsFromStrategy(s, { ...emptyParams(range) }));
    setDocId(s.id ?? null);
    setMsg("");
    setErr("");
    setRevealErrors(false);
  }

  async function save() {
    if (!editing) return;
    const errors = validateParams(editing, { requireMeta: true });
    if (Object.keys(errors).length) {
      setErr(Object.values(errors)[0]);
      setRevealErrors(true); // 一次把问题全列出来，而不是让用户逐个试
      return;
    }
    setBusy(true);
    setErr("");
    try {
      const body = strategyFromParams(editing, editingId ?? undefined);
      if (editingId) {
        await apiPut<StrategyDefinition>(`/strategies/${encodeURIComponent(editingId)}`, body);
        setMsg(`已更新策略「${body.name}」`);
      } else {
        const saved = await apiPost<StrategyDefinition>("/strategies", body);
        setMsg(`已保存策略「${saved.name}」（${saved.id}）`);
      }
      setEditing(null);
      setEditingId(null);
      setDocId(null);
      await load();
    } catch (e) {
      setErr((e as Error).message);
    } finally {
      setBusy(false);
    }
  }

  async function remove(s: StrategyDefinition) {
    if (!s.id) return;
    if (!window.confirm(`删除策略「${s.name}」？此操作不可撤销（已跑过的实验不受影响）。`)) return;
    setBusy(true);
    try {
      await apiDelete(`/strategies/${encodeURIComponent(s.id)}`);
      setMsg(`已删除策略「${s.name}」`);
      await load();
    } catch (e) {
      setErr((e as Error).message);
    } finally {
      setBusy(false);
    }
  }

  return (
    <>
      <PageHeader
        title="策略库"
        sub="把调好的参数存成命名策略：每个策略都有「一句话说明 + 计算公式 + 执行步骤」，可一键回测、可复现、可对比。"
        actions={
          <div className="row" style={{ gap: 8 }}>
            <Link href="/experiments" className="btn">
              <span>查看实验</span>
            </Link>
            <Btn variant="primary" icon="plus" onClick={startCreate} disabled={busy}>
              新建策略
            </Btn>
          </div>
        }
      />

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

      {/* ---------- 编辑器 ---------- */}
      {editing ? (
        <Card
          icon={editingId ? "edit" : "plus"}
          title={editingId ? `编辑策略 · ${editingId}` : "新建策略"}
          tools={
            <div className="row" style={{ gap: 8 }}>
              <Btn onClick={() => { setEditing(null); setEditingId(null); setDocId(null); }} disabled={busy}>
                取消
              </Btn>
              <Btn variant="primary" icon="check" loading={busy} onClick={save} disabled={busy}>
                {editingId ? "保存修改" : "保存到策略库"}
              </Btn>
            </div>
          }
        >
          <StrategyParamsForm
            value={editing}
            onChange={setEditing}
            factorOptions={factors}
            showMeta
            showPeriod={false}
            disabled={busy}
            errors={validateParams(editing, { requireMeta: true })}
            revealErrors={revealErrors}
          />
          <div className="hint" style={{ marginTop: 10 }}>
            策略只保存「怎么选股/怎么调仓/怎么收费」，**不含回测区间与初始资金** ——
            这两项在运行回测时才指定，因此同一策略可用于不同区间的复现与对比。
          </div>
          <div className="row" style={{ marginTop: 12, gap: 8 }}>
            <Btn
              icon="target"
              disabled={busy}
              onClick={() =>
                setEditing({
                  ...casePreset(range),
                  name: editing.name,
                  description: editing.description,
                })
              }
            >
              载入高股息案例默认参数
            </Btn>
          </div>
        </Card>
      ) : null}

      {editing ? (
        <EditingDoc params={editing} savedId={editingId} />
      ) : null}

      {docId && !editing ? <SavedDoc id={docId} onClose={() => setDocId(null)} /> : null}

      {/* ---------- 列表 ---------- */}
      <Card
        icon="archive"
        title={`已保存策略${list ? ` · ${list.length}` : ""}`}
        tools={
          <input
            className="input input--search"
            placeholder="搜索策略名 / 说明 / 因子 / 条件"
            value={query}
            onChange={(e) => setQuery(e.target.value)}
            aria-label="搜索策略"
          />
        }
      >
        {filtered === null ? (
          <Loading label="读取策略库…" />
        ) : filtered.length === 0 ? (
          <Empty
            icon="archive"
            title={list && list.length ? "没有匹配的策略" : "策略库还是空的"}
            hint={
              list && list.length
                ? "换个关键词试试。"
                : "点右上角「新建策略」保存第一个策略；也可以先去回测页调好参数，再点「保存为策略」。"
            }
          />
        ) : (
          <div className="strategy-grid">
            {filtered.map((s) => (
              <StrategyCard
                key={s.id ?? s.name}
                s={s}
                range={range}
                busy={busy}
                onEdit={() => startEdit(s)}
                onDelete={() => remove(s)}
                onDoc={() => setDocId(s.id ?? null)}
              />
            ))}
          </div>
        )}
      </Card>
    </>
  );
}

/* ------------------------------------------------------------------ */

/** 未保存参数的实时说明预览 */
function EditingDoc({ params, savedId }: { params: StrategyParams; savedId: string | null }) {
  const live = useStrategyDoc(params, !savedId);
  const saved = useStrategyDocById(savedId);
  const state = savedId ? saved : live;
  return (
    <StrategyDocCard
      doc={state.doc}
      loading={state.loading}
      error={state.error}
      title="策略说明与计算公式（随参数实时更新）"
    />
  );
}

function SavedDoc({ id, onClose }: { id: string; onClose: () => void }) {
  const state = useStrategyDocById(id);
  return (
    <Card
      icon="book"
      title={`策略说明 · ${id}`}
      tools={<Btn size="sm" onClick={onClose}>收起</Btn>}
    >
      {state.doc ? (
        <StrategyDocBody doc={state.doc} />
      ) : (
        <div className="hint">
          {state.loading
            ? "正在生成说明与公式…"
            : `说明暂不可用${state.error ? `：${state.error}` : "（后端 /api/strategies/{id}/describe 未就绪）"}。`}
        </div>
      )}
    </Card>
  );
}

/** 单个策略卡片：说明 + 参数摘要 + 一键回测 */
function StrategyCard({
  s,
  range,
  busy,
  onEdit,
  onDelete,
  onDoc,
}: {
  s: StrategyDefinition;
  range: { start: string; end: string };
  busy: boolean;
  onEdit: () => void;
  onDelete: () => void;
  onDoc: () => void;
}) {
  const [start, setStart] = useState("2020-01-01");
  const [end, setEnd] = useState(range.end);
  const [capital, setCapital] = useState(1_000_000);
  const [running, setRunning] = useState(false);
  const [jobId, setJobId] = useState("");
  const [result, setResult] = useState<BacktestResult | null>(null);
  const [stage, setStage] = useState("");
  const [expId, setExpId] = useState("");
  const [error, setError] = useState("");
  const [open, setOpen] = useState(false);

  const sel = s.selection ?? {};
  const costs = s.costs ?? {};

  async function run() {
    if (!s.id) return;
    if (start >= end) {
      setError("开始日期必须早于结束日期");
      return;
    }
    setRunning(true);
    setError("");
    setResult(null);
    setExpId("");
    try {
      const spec = await apiPost<Record<string, unknown>>(
        `/strategies/${encodeURIComponent(s.id)}/expand`,
        { period: [start, end], initial_capital: capital }
      );
      const { job_id } = await submitJob(spec as never);
      setJobId(job_id);
      setStage("queued");
      const out: JobOutcome<BacktestResult> = await waitJob<BacktestResult>(job_id, 900_000, (info) =>
        setStage(info.stage)
      );
      if (out.status === "success" && out.result) {
        setResult(out.result);
        setExpId(out.experimentId ?? "");
      } else {
        setError(`任务${out.status}${out.error ? `：${out.error}` : ""}`);
      }
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setRunning(false);
      setJobId("");
      setStage("");
    }
  }

  return (
    <div className="card" style={{ display: "flex", flexDirection: "column", gap: 10 }}>
      <div className="between">
        <div style={{ minWidth: 0 }}>
          <div className="card__title" style={{ marginBottom: 2 }}>
            {s.name}
          </div>
          <div className="row" style={{ gap: 6, flexWrap: "wrap" }}>
            <span className="mono hint">{s.id}</span>
            {s.created_at ? <span className="hint">创建 {String(s.created_at).slice(0, 10)}</span> : null}
          </div>
        </div>
        <Pill tone="violet" icon="target">
          {s.factors?.map((f) => f.name).join(" + ") || "—"}
        </Pill>
      </div>

      <div className="strategy-desc">{s.description || "（无说明：建议补一句话说明，便于日后识别）"}</div>

      <div className="chips">
        <span className="chip">
          候选池 <b>{sel.top_n ?? "—"}</b> → 持仓 <b>{sel.hold_top_x ?? sel.top_n ?? "—"}</b>
        </span>
        <span className="chip">
          择股 <b>{s.selection_interval_months ?? "跟随 y"}</b> 月 / 调仓{" "}
          <b>{s.rebalance_interval_months ?? "跟随 m"}</b> 月
        </span>
        <span className="chip">
          复权 <b>{adjLabel(s.price_adjustment)}</b>
        </span>
        <span className="chip">
          {s.universe?.exclude_st ? "剔除 ST" : "含 ST"} · 费率{" "}
          <b>{((costs.commission_rate ?? 0) * 100).toFixed(3)}%</b> + 印花{" "}
          <b>{((costs.stamp_tax_rate ?? 0) * 100).toFixed(2)}%</b>
        </span>
        {(s.conditions ?? []).length ? (
          <span className="chip">
            条件 <b>{(s.conditions ?? []).map((c) => `${c.field} ${opLabel(c.op)} ${c.value ?? ""}`).join(" 且 ")}</b>
          </span>
        ) : null}
      </div>

      <div className="strategy-actions">
        <Btn size="sm" variant="primary" icon="play" loading={running} disabled={running || busy} onClick={run}>
          {running ? "后台运行中…" : "一键回测"}
        </Btn>
        <Link href={`/backtest?strategy=${encodeURIComponent(s.id ?? "")}`} className="btn btn--sm">
          <span>载入回测页（可微调）</span>
        </Link>
        <Btn size="sm" icon="book" onClick={onDoc} disabled={busy}>
          看说明/公式
        </Btn>
        <Btn size="sm" icon="edit" onClick={onEdit} disabled={busy}>
          编辑
        </Btn>
        <Btn size="sm" variant="danger" icon="trash" onClick={onDelete} disabled={busy}>
          删除
        </Btn>
      </div>

      {/* 运行区间（默认 2020-01-01 ~ 最近交易日） */}
      <details open={open} onToggle={(e) => setOpen((e.target as HTMLDetailsElement).open)}>
        <summary className="hint" style={{ cursor: "pointer" }}>
          回测区间与资金（一键回测使用）
        </summary>
        <div className="form-grid" style={{ marginTop: 8 }}>
          <Field label="开始日期">
            <input type="date" className="input" value={start} onChange={(e) => setStart(e.target.value)} disabled={running} />
          </Field>
          <Field label="结束日期">
            <input type="date" className="input" value={end} onChange={(e) => setEnd(e.target.value)} disabled={running} />
          </Field>
          <Field label="初始资金（元）">
            <input
              type="number"
              className="input"
              step={100000}
              min={10000}
              value={capital}
              onChange={(e) => setCapital(Number(e.target.value))}
              disabled={running}
            />
          </Field>
        </div>
      </details>

      {running ? (
        <Progress
          value={35}
          label={
            <>
              任务 <span className="mono">{jobId || "排队中…"}</span> 后台执行中（全市场回测通常 1~5 分钟）
            </>
          }
        />
      ) : null}
      {error ? <Banner tone="error">{error}</Banner> : null}

      {result ? (
        <div>
          <div className="between" style={{ marginBottom: 8 }}>
            <Pill tone="pos" icon="check">
              回测完成
            </Pill>
            <Link
              href={expId ? `/experiments?exp=${encodeURIComponent(expId)}` : "/experiments"}
              className="btn btn--sm"
            >
              <span>在实验中对比</span>
            </Link>
            {expId ? (
              <>
                <Link href={`/experiments/${encodeURIComponent(expId)}`} className="btn btn--sm">
                  <span>打开归档（完整快照）</span>
                </Link>
                <Link href={`/backtest?from_experiment=${encodeURIComponent(expId)}`} className="btn btn--sm">
                  <span>以此参数再跑</span>
                </Link>
              </>
            ) : null}
          </div>
          <BacktestMetrics s={result.summary} />
        </div>
      ) : null}
    </div>
  );
}

function adjLabel(m?: string): string {
  return m === "hfq" ? "后复权" : m === "qfq" ? "前复权" : "不复权";
}

function opLabel(op: string): string {
  return (
    { gt: ">", gte: "≥", lt: "<", lte: "≤", eq: "=", ne: "≠", in: "属于", not_in: "不属于" }[op] ?? op
  );
}