import { useState, type ReactNode } from "react";
import {
  adminSystemBackup,
  adminSystemRestore,
  adminSystemRevokeKeys,
  adminSystemRotateJWT,
  getStoredRole,
} from "../../lib/api";
import type {
  SystemBackupResp,
  SystemRestoreResp,
  SystemRevokeKeysResp,
  SystemRotateJwtResp,
} from "../../lib/types";
import { useAuditStore } from "../audit";
import { KeyValueRow, Notice, PageHeader } from "../components";
import { Button, Surface, Tag } from "../../components/primitives";
import { Icon } from "../../components/Icon";

/**
 * 系统设置 (design/10 §3 模块14 + design/11 §4 敏感操作代审)。后端已实现 4 个
 * owner-only 且审计的**可写**系统操作：吊销全部 API key / 轮换 JWT 密钥 / 备份 /
 * 恢复（见 internal/services/gateway/admin_system.go）。这里把它们做成真实可点的
 * Miuix 卡片，每步带确认弹窗防误触；只读事实卡保持不变。
 * 未实现（编辑环境变量 / 重启服务 / 检查更新）诚实标注为「后端未实现，不提供」。
 */
export function SystemModule(): React.ReactNode {
  const isOwner = getStoredRole() === "owner";
  const log = useAuditStore((s) => s.log);

  // 结果反馈（成功 tone="ok" / 失败 tone="err"）。
  const [msg, setMsg] = useState<{ text: string; tone: "ok" | "err" } | null>(null);
  const [busy, setBusy] = useState(false);

  // 当前打开的确认弹窗（null 表示无）。rotate / restore 需要输入，故各自持有字段。
  const [pending, setPending] = useState<"revoke" | "rotate" | "backup" | "restore" | null>(null);
  const [newSecret, setNewSecret] = useState("");
  const [secretErr, setSecretErr] = useState<string | null>(null);
  const [restorePath, setRestorePath] = useState("");
  const [restoreErr, setRestoreErr] = useState<string | null>(null);

  const close = () => {
    setPending(null);
    setSecretErr(null);
    setRestoreErr(null);
  };

  const done = (tone: "ok" | "err", text: string) => setMsg({ tone, text });

  const doRevoke = (): void => {
    setBusy(true);
    setMsg(null);
    adminSystemRevokeKeys()
      .then((r: SystemRevokeKeysResp) => {
        log("system.revoke_keys", "ok");
        done("ok", `已吊销 ${r.revoked} 个 API key；这些 key 立即失效。`);
        close();
      })
      .catch((e: unknown) => {
        log("system.revoke_keys", "error");
        done("err", errText(e, "吊销失败"));
      })
      .finally(() => setBusy(false));
  };

  const doRotate = (): void => {
    const secret = newSecret.trim();
    if (secret.length < 32) {
      setSecretErr("新密钥长度不足 32 位");
      return;
    }
    setBusy(true);
    setMsg(null);
    adminSystemRotateJWT(secret)
      .then((r: SystemRotateJwtResp) => {
        log("system.rotate_jwt", "ok");
        done("ok", `JWT 密钥已轮换。${r.note}——请返回登录页重新登录以继续。`);
        setNewSecret("");
        close();
      })
      .catch((e: unknown) => {
        log("system.rotate_jwt", "error");
        done("err", errText(e, "轮换失败"));
      })
      .finally(() => setBusy(false));
  };

  const doBackup = (): void => {
    setBusy(true);
    setMsg(null);
    adminSystemBackup()
      .then((r: SystemBackupResp) => {
        log("system.backup", "ok");
        done("ok", `备份完成：${formatBytes(r.size)} → ${r.path}`);
        close();
      })
      .catch((e: unknown) => {
        log("system.backup", "error");
        done("err", errText(e, "备份失败"));
      })
      .finally(() => setBusy(false));
  };

  const doRestore = (): void => {
    const path = restorePath.trim();
    if (!path) {
      setRestoreErr("请填写要恢复的备份文件路径");
      return;
    }
    setBusy(true);
    setMsg(null);
    adminSystemRestore(path)
      .then((r: SystemRestoreResp) => {
        log("system.restore", "ok");
        done("ok", `已安排恢复：${r.note}（恢复前已备份到 ${r.backup}）`);
        setRestorePath("");
        close();
      })
      .catch((e: unknown) => {
        log("system.restore", "error");
        done("err", errText(e, "恢复失败"));
      })
      .finally(() => setBusy(false));
  };

  const genSecret = (): void => {
    let out = "";
    if (typeof crypto !== "undefined" && "getRandomValues" in crypto) {
      const bytes = new Uint8Array(24);
      crypto.getRandomValues(bytes);
      out = Array.from(bytes, (b) => b.toString(16).padStart(2, "0")).join("");
    } else {
      for (let i = 0; i < 48; i += 1) out += Math.floor(Math.random() * 16).toString(16);
    }
    setNewSecret(out);
    setSecretErr(null);
  };

  return (
    <div className="space-y-5">
      <PageHeader title="系统设置" subtitle="安全(密钥/JWT) + 运行时 + 存储 + 环境变量（只读）；可写系统操作见「可写操作」" />

      <div className="grid grid-cols-1 gap-4 lg:grid-cols-2">
        <Surface className="space-y-1">
          <SectionTitle icon={<Icon name="shield" size={18} />} title="安全 & 密钥" ownerOnly />
          <KeyValueRow label="JWT 密钥" value="••••••••" mono />
          <KeyValueRow label="鉴权" value="JWT + RBAC + API key" />
          <KeyValueRow label="审计" value="who / what / when / result" />
        </Surface>

        <Surface className="space-y-1">
          <SectionTitle icon={<Icon name="storage" size={18} />} title="存储" />
          <KeyValueRow label="默认" value="SQLite" />
          <KeyValueRow label="可选增强" value="PG / pgvector（语义/向量路径）" />
          <KeyValueRow label="单二进制 / 单端口" value=":8080 · 零跨进程 IPC" />
        </Surface>

        <Surface className="space-y-1">
          <SectionTitle icon={<Icon name="package" size={18} />} title="环境变量" />
          {/* 键名必须与 `.env` / `.env.example` **逐字一致**：面板是只读事实卡，
              用户会照着这里抄键名去改 .env —— 写错一个字母就是静默不生效（AGENTS §10 E6）。
              真键：HOST / PORT / ADMIN_USERNAME / ADMIN_PASSWORD（见 .env.example）。 */}
          <KeyValueRow label="HOST" value="0.0.0.0" mono />
          <KeyValueRow label="PORT" value="8080" mono />
          <KeyValueRow label="ADMIN_USERNAME" value="admin" mono />
          <KeyValueRow label="ADMIN_PASSWORD" value="••••••••" mono />
          <p className="pt-1 text-xs text-[var(--mu-text-lo)]">
            以上为 <span className="font-mono">.env.example</span> 的默认值（这几条没有只读读取端点，不是运行实例的实时值；
            带凭据的键面板刻意不回值）。改值请编辑 <span className="font-mono">.env</span> 后重启服务。
          </p>
          <p className="pt-1 text-xs text-[var(--mu-text-lo)]">
            要看运行实例的实时生效值，去两处只读事实卡：记忆管理页的「记忆整理」与后台思考页的「安静时段」
            （<span className="font-mono">GET /api/v1/admin/config-facts</span>，契约 v0.68）。
          </p>
        </Surface>

        <Surface className="space-y-1">
          <SectionTitle icon={<Icon name="refresh" size={18} />} title="运行时" />
          <KeyValueRow label="部署形态" value="单二进制 · 单端口 · 零跨进程 IPC" />
          <KeyValueRow label="日志级别" value="后端配置，面板暂不可改" />
        </Surface>
      </div>

      {msg ? <Notice tone={msg.tone}>{msg.text}</Notice> : null}

      <Surface className="space-y-3">
        <div className="flex items-center gap-2">
          <h3 className="text-sm font-semibold">可写系统操作</h3>
          <Tag tone="warn">owner 专属</Tag>
          <span className="text-xs text-[var(--mu-text-lo)]">真实读写 · 已审计 · 每步需确认</span>
        </div>

        <div className="grid grid-cols-1 gap-4 lg:grid-cols-2">
          <WriteAction
            icon={<Icon name="lock" size={18} />}
            title="吊销全部 API key"
            desc="清空 key 表：所有已注册的 API key 立即失效，需重新签发。不可撤销。"
            buttonText="吊销"
            variant="danger"
            disabled={!isOwner || busy}
            onClick={() => setPending("revoke")}
          />
          <WriteAction
            icon={<Icon name="refresh" size={18} />}
            title="轮换 JWT 密钥"
            desc="换用新的签名密钥（≥32 位）。现有 token 立即失效，需重新登录；新密钥不回显。"
            buttonText="轮换"
            variant="outline"
            disabled={!isOwner || busy}
            onClick={() => setPending("rotate")}
          />
          <WriteAction
            icon={<Icon name="storage" size={18} />}
            title="备份数据库"
            desc="用 SQLite VACUUM INTO 快照当前库（含已提交 WAL）到数据目录，返回路径与大小。"
            buttonText="备份"
            variant="primary"
            disabled={!isOwner || busy}
            onClick={() => setPending("backup")}
          />
          <WriteAction
            icon={<Icon name="package" size={18} />}
            title="恢复数据库"
            desc="从数据目录内的备份文件恢复；恢复前自动备份当前库，替换需重启服务生效。"
            buttonText="恢复"
            variant="danger"
            disabled={!isOwner || busy}
            onClick={() => setPending("restore")}
          />
        </div>
      </Surface>

      <Notice tone="warn">
        以下系统操作后端尚未实现，当前不提供：编辑环境变量 · 重启服务 · 检查更新。均为真实读写，未实现前不做占位按钮。
      </Notice>

      {!isOwner ? (
        <Notice tone="warn">安全 / 密钥 / 系统设置类敏感操作仅 owner 可执行；当前角色 {getStoredRole()}。</Notice>
      ) : null}

      {pending === "revoke" ? (
        <ConfirmDialog
          danger
          busy={busy}
          title="吊销全部 API key"
          confirmText="确认吊销"
          body={
            <p className="text-xs text-[var(--mu-text-mid)]">
              将吊销<b>全部</b>已注册的 API key；操作完成后所有使用这些 key 的客户端立即失效，
              需重新签发。此操作<b>不可撤销</b>，确定继续？
            </p>
          }
          onConfirm={doRevoke}
          onClose={close}
        />
      ) : null}

      {pending === "rotate" ? (
        <ConfirmDialog
          busy={busy}
          title="轮换 JWT 密钥"
          confirmText="确认轮换"
          body={
            <>
              <p className="text-xs text-[var(--mu-text-mid)]">
                输入新的 JWT 签名密钥（≥32 位）。轮换后<b>所有现有 token 立即失效，需重新登录</b>；
                新密钥<b>不会被后端回显</b>，请在提交前保存好（提交后输入框即清空）。
              </p>
              <label className="block space-y-1">
                <span className="text-xs text-[var(--mu-text-lo)]">新密钥（≥32 位）</span>
                <input
                  value={newSecret}
                  onChange={(e) => {
                    setNewSecret(e.target.value);
                    setSecretErr(null);
                  }}
                  className={`${inputCls} font-mono`}
                  placeholder="至少 32 位，可点「随机生成」"
                />
              </label>
              {secretErr ? <span className="text-xs text-[var(--mu-err)]">{secretErr}</span> : null}
              <Button size="sm" variant="ghost" disabled={busy} onClick={genSecret}>
                随机生成
              </Button>
            </>
          }
          onConfirm={doRotate}
          onClose={close}
        />
      ) : null}

      {pending === "backup" ? (
        <ConfirmDialog
          busy={busy}
          title="备份数据库"
          confirmText="确认备份"
          body={
            <p className="text-xs text-[var(--mu-text-mid)]">
              用 SQLite <span className="font-mono">VACUUM INTO</span> 把当前数据库
              （含已提交 WAL 内容）快照到数据目录，返回备份文件的路径与大小。不会影响正在运行的服务。
            </p>
          }
          onConfirm={doBackup}
          onClose={close}
        />
      ) : null}

      {pending === "restore" ? (
        <ConfirmDialog
          danger
          busy={busy}
          title="恢复数据库"
          confirmText="确认恢复"
          body={
            <>
              <p className="text-xs text-[var(--mu-text-mid)]">
                从<b>数据目录内</b>的备份文件恢复。恢复前会自动备份当前数据库；替换后需
                <b>重启服务</b> 才生效，且会<b>覆盖现有数据</b>。
              </p>
              <label className="block space-y-1">
                <span className="text-xs text-[var(--mu-text-lo)]">备份文件路径（须在数据目录内）</span>
                <input
                  value={restorePath}
                  onChange={(e) => {
                    setRestorePath(e.target.value);
                    setRestoreErr(null);
                  }}
                  className={`${inputCls} font-mono`}
                  placeholder="如 backup-20260908T120000.000000000Z.db"
                />
              </label>
              {restoreErr ? <span className="text-xs text-[var(--mu-err)]">{restoreErr}</span> : null}
            </>
          }
          onConfirm={doRestore}
          onClose={close}
        />
      ) : null}
    </div>
  );
}

function SectionTitle({ icon, title, ownerOnly = false }: { icon: ReactNode; title: string; ownerOnly?: boolean }): ReactNode {
  return (
    <h3 className="flex items-center gap-2 text-sm font-semibold">
      <span className="text-[var(--mu-accent)]">{icon}</span>
      <span>{title}</span>
      {ownerOnly ? <Tag tone="warn">owner</Tag> : null}
    </h3>
  );
}

interface WriteActionProps {
  icon: ReactNode;
  title: string;
  desc: string;
  buttonText: string;
  variant: "primary" | "soft" | "ghost" | "outline" | "danger";
  disabled: boolean;
  onClick: () => void;
}

/** One owner-only write action as a Miuix card; clicking opens the confirm dialog. */
function WriteAction({ icon, title, desc, buttonText, variant, disabled, onClick }: WriteActionProps): ReactNode {
  return (
    <Surface className="flex flex-col gap-2">
      <div className="flex items-center gap-2">
        <span className="text-[var(--mu-accent)]">{icon}</span>
        <span className="text-sm font-semibold">{title}</span>
        <Tag tone="ok" className="ml-auto">已实现</Tag>
      </div>
      <p className="text-xs text-[var(--mu-text-lo)]">{desc}</p>
      <div className="mt-auto pt-1">
        <Button variant={variant} size="sm" disabled={disabled} onClick={onClick}>
          {buttonText}
        </Button>
      </div>
    </Surface>
  );
}

interface ConfirmDialogProps {
  title: string;
  body: ReactNode;
  confirmText: string;
  danger?: boolean;
  busy: boolean;
  onConfirm: () => void;
  onClose: () => void;
}

/** A Miuix confirmation overlay (防误触). Blocks the action until the owner confirms. */
function ConfirmDialog({ title, body, confirmText, danger = false, busy, onConfirm, onClose }: ConfirmDialogProps): ReactNode {
  return (
    <div className="fixed inset-0 z-50 flex items-start justify-center overflow-y-auto bg-black/40 p-4 backdrop-blur-sm" onClick={onClose}>
      <div className="w-full max-w-lg rounded-[var(--mu-radius-lg)] bg-[var(--mu-surface-1)] shadow-2xl" onClick={(e) => e.stopPropagation()}>
        <div className="flex items-center gap-2 border-b border-[var(--mu-glass-border)] px-5 py-3">
          <span className="text-sm font-semibold">{title}</span>
          <span className="ml-auto text-xs text-[var(--mu-text-lo)]">确认操作</span>
          <Tag tone={danger ? "err" : "warn"}>{danger ? "危险" : "请确认"}</Tag>
        </div>
        <div className="space-y-3 px-5 py-4">{body}</div>
        <div className="flex items-center justify-end gap-2 border-t border-[var(--mu-glass-border)] px-5 py-3">
          <Button size="sm" variant="ghost" disabled={busy} onClick={onClose}>
            取消
          </Button>
          <Button size="sm" variant={danger ? "danger" : "primary"} disabled={busy} onClick={onConfirm}>
            {busy ? "处理中…" : confirmText}
          </Button>
        </div>
      </div>
    </div>
  );
}

const inputCls =
  "w-full rounded-[var(--mu-radius)] bg-[var(--mu-surface-2)] px-3 py-2 text-sm outline-none focus:ring-1 focus:ring-[var(--mu-accent)]";

function errText(err: unknown, fallback: string): string {
  return err instanceof Error ? err.message : fallback;
}

/** Human-readable byte size (MiB default unit for a DB snapshot). */
function formatBytes(n: number): string {
  if (n < 1024) return `${n} B`;
  const units = ["KiB", "MiB", "GiB", "TiB"];
  let v = n;
  let u = -1;
  do {
    v /= 1024;
    u += 1;
  } while (v >= 1024 && u < units.length - 1);
  return `${v.toFixed(1)} ${units[u]}`;
}