"use client";

import { useCallback, useEffect, useState } from "react";
import { Database, HardDrive, Trash2, Activity } from "lucide-react";
import { AdminSettingRow, AdminStatCard, AdminSwitch } from "@/components/admin";
import ConfirmDialog from "@/components/ConfirmDialog";
import { apiStatsPurge, apiStatsSaveSettings, apiStatsSettings, type VisitSettingsPayload } from "@/lib/api";
import { StatsState, formatBytes, formatInt } from "../ui";

/** 保留天数输入边界（与后端 service 一致） */
const RETENTION_MIN = 7;
const RETENTION_MAX = 365;

export default function SettingsPage() {
  const [data, setData] = useState<VisitSettingsPayload | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState("");
  const [enabled, setEnabled] = useState(true);
  const [retention, setRetention] = useState(90);
  const [saving, setSaving] = useState(false);
  const [savedMsg, setSavedMsg] = useState("");
  // 立即清理：天数输入 + 确认弹窗 + 受理提示
  const [purgeDays, setPurgeDays] = useState(90);
  const [purgeOpen, setPurgeOpen] = useState(false);
  const [purging, setPurging] = useState(false);
  const [purgeMsg, setPurgeMsg] = useState("");

  const load = useCallback(() => {
    apiStatsSettings()
      .then((d) => {
        setData(d);
        setEnabled(d.enabled);
        setRetention(d.retention_days);
        setPurgeDays(d.retention_days);
        setError("");
      })
      .catch(() => setError("加载失败，请稍后重试"))
      .finally(() => setLoading(false));
  }, []);
  useEffect(() => {
    load();
  }, [load]);

  const save = (nextEnabled: boolean, nextRetention: number) => {
    setSaving(true);
    setSavedMsg("");
    apiStatsSaveSettings(nextEnabled, nextRetention)
      .then((d) => {
        setData(d);
        setEnabled(d.enabled);
        setRetention(d.retention_days);
        setSavedMsg("已保存");
        setTimeout(() => setSavedMsg(""), 2000);
      })
      .catch(() => setError("保存失败，请稍后重试"))
      .finally(() => setSaving(false));
  };

  const toggleEnabled = () => {
    if (saving) return;
    save(!enabled, retention);
  };

  const submitRetention = () => {
    if (saving) return;
    const v = Math.min(RETENTION_MAX, Math.max(RETENTION_MIN, Math.round(Number(retention) || 90)));
    setRetention(v);
    save(enabled, v);
  };

  const doPurge = () => {
    setPurging(true);
    apiStatsPurge(purgeDays)
      .then(() => {
        setPurgeMsg(`清理任务已受理（删除 ${purgeDays} 天前的明细），稍后刷新本页查看容量变化。`);
        setTimeout(load, 3000);
      })
      .catch(() => setPurgeMsg("清理请求失败，请稍后重试。"))
      .finally(() => {
        setPurging(false);
        setPurgeOpen(false);
      });
  };

  if (!data) return <StatsState loading={loading} error={error || undefined} />;

  const clampPurge = (v: number) =>
    Math.min(RETENTION_MAX, Math.max(1, Math.round(Number(v) || 1)));

  return (
    <div className="flex flex-col gap-4">
      {error ? <StatsState error={error} /> : null}
      {purgeMsg ? (
        <div className="panel p-4 text-[13px]" style={{ color: "var(--ink-2)" }}>
          {purgeMsg}
        </div>
      ) : null}

      <div className="grid gap-3 grid-cols-2 xl:grid-cols-4">
        <AdminStatCard label="明细行数" value={formatInt(data.usage.rows)} icon={<Database size={17} />} />
        <AdminStatCard
          label="磁盘占用"
          value={formatBytes(data.usage.bytes)}
          hint="含索引（pg_total_relation_size）"
          icon={<HardDrive size={17} />}
          color="var(--ok)"
          soft="var(--ok-soft, var(--panel-2))"
        />
        <AdminStatCard label="保留天数" value={`${data.retention_days} 天`} hint="超期明细每日 04:30 自动清理" icon={<Activity size={17} />} color="var(--gold)" soft="var(--gold-soft)" />
        <AdminStatCard
          label="采集丢弃"
          value={formatInt(data.dropped)}
          hint="写入队列满时丢弃的事件数（进程启动以来）"
          icon={<Trash2 size={17} />}
          color="var(--ink-2)"
          soft="var(--panel-2)"
        />
      </div>

      <AdminSettingRow
        title="访问统计采集"
        description="关闭后前端埋点与后端捕获中间件立即停止写入（返回 204），已有数据保留。"
        control={<AdminSwitch checked={enabled} disabled={saving} onChange={toggleEnabled} label="访问统计采集开关" />}
      />

      <AdminSettingRow
        title="明细保留期"
        description={`超过保留期的访问明细每日 04:30 自动分批清理；日聚合趋势不受影响。范围 ${RETENTION_MIN}–${RETENTION_MAX} 天。`}
      >
        <div className="flex items-center gap-2 flex-wrap">
          <input
            type="number"
            min={RETENTION_MIN}
            max={RETENTION_MAX}
            value={retention}
            onChange={(e) => setRetention(Number(e.target.value))}
            onBlur={submitRetention}
            onKeyDown={(e) => e.key === "Enter" && submitRetention()}
            className="admin-field-input"
            style={{ width: 120 }}
            aria-label="明细保留天数"
          />
          <span className="text-[13px]" style={{ color: "var(--ink-3)" }}>
            天
          </span>
          {saving ? <span className="meta text-[12px]">保存中…</span> : null}
          {savedMsg ? (
            <span className="text-[12px]" style={{ color: "var(--ok)" }}>
              {savedMsg}
            </span>
          ) : null}
        </div>
      </AdminSettingRow>

      <AdminSettingRow
        title="立即清理"
        description="手动删除指定天数之前的明细记录，异步执行，不影响正常访问。"
      >
        <div className="flex items-center gap-2 flex-wrap">
          <input
            type="number"
            min={1}
            max={RETENTION_MAX}
            value={purgeDays}
            onChange={(e) => setPurgeDays(clampPurge(Number(e.target.value)))}
            className="admin-field-input"
            style={{ width: 120 }}
            aria-label="清理多少天前的明细"
          />
          <span className="text-[13px]" style={{ color: "var(--ink-3)" }}>
            天前的明细
          </span>
          <button
            type="button"
            className="btn btn-line btn-sm"
            onClick={() => setPurgeOpen(true)}
            disabled={purging}
          >
            <Trash2 size={14} /> 立即清理
          </button>
        </div>
      </AdminSettingRow>

      <ConfirmDialog
        open={purgeOpen}
        title="确认立即清理"
        message={`将删除 ${purgeDays} 天前的全部访问明细（当前共 ${formatInt(data.usage.rows)} 行）。该操作不可恢复，日聚合趋势不受影响。确认执行？`}
        confirmLabel="确认清理"
        danger
        busy={purging}
        onConfirm={doPurge}
        onCancel={() => setPurgeOpen(false)}
      />
    </div>
  );
}