import { useCallback, useEffect, useMemo, useState } from "react";
import { Check, Copy, ExternalLink, RefreshCw } from "lucide-react";
import {
  getMcpInstall,
  getMcpPolicy,
  saveMcpPolicy,
  type McpInstallInfo,
  type McpPolicy,
} from "./api";
import { useWorkspaceStore } from "./store";
import { openExternal } from "./openExternal";

const MCP_DOCS_URL = "http://127.0.0.1:8788/docs/mcp";
const NPM_PKG = "@rlwj-lab/opsxdb-mcp";

type ClientTab = "cursor" | "claude-code" | "vscode" | "windsurf" | "codex" | "claude-desktop";

const CLIENT_TABS: Array<{ id: ClientTab; label: string }> = [
  { id: "cursor", label: "Cursor" },
  { id: "claude-code", label: "Claude Code" },
  { id: "vscode", label: "VS Code" },
  { id: "windsurf", label: "Windsurf" },
  { id: "codex", label: "Codex" },
  { id: "claude-desktop", label: "Claude Desktop" },
];

function buildClientSnippet(tab: ClientTab, goBin: string): { path: string; json: string } {
  const env: Record<string, string> = {};
  if (goBin) env.OPSXDB_MCP_BIN = goBin;

  const npxServer = {
    command: "npx",
    args: ["-y", NPM_PKG],
    ...(Object.keys(env).length ? { env } : {}),
  };
  const absServer = goBin
    ? { command: goBin, args: [] as string[] }
    : npxServer;

  switch (tab) {
    case "claude-code":
      return {
        path: "项目根目录 .mcp.json",
        json: JSON.stringify({ mcpServers: { opsxdb: npxServer } }, null, 2),
      };
    case "cursor":
      return {
        path: "~/.cursor/mcp.json 或项目 .cursor/mcp.json",
        json: JSON.stringify({ mcpServers: { opsxdb: npxServer } }, null, 2),
      };
    case "vscode":
      return {
        path: ".vscode/mcp.json",
        json: JSON.stringify(
          {
            servers: {
              opsxdb: {
                type: "stdio",
                command: npxServer.command,
                args: npxServer.args,
                ...(npxServer.env ? { env: npxServer.env } : {}),
              },
            },
          },
          null,
          2,
        ),
      };
    case "windsurf":
      return {
        path: "~/.codeium/windsurf/mcp_config.json",
        json: JSON.stringify({ mcpServers: { opsxdb: npxServer } }, null, 2),
      };
    case "codex":
      return {
        path: "~/.codex/config.toml（MCP 段）或对应 mcp.json",
        json: JSON.stringify({ mcpServers: { opsxdb: absServer } }, null, 2),
      };
    case "claude-desktop":
      return {
        path: "Claude Desktop → Developer → Edit Config",
        json: JSON.stringify({ mcpServers: { opsxdb: npxServer } }, null, 2),
      };
  }
}

function StatusBadge({ status }: { status: string }) {
  const map: Record<string, { label: string; color: string; bg: string }> = {
    checking: { label: "检测中", color: "var(--ops-muted)", bg: "var(--ops-surface-2)" },
    ready: { label: "已就绪", color: "var(--ops-accent)", bg: "color-mix(in srgb, var(--ops-accent) 14%, transparent)" },
    partial: { label: "部分就绪", color: "var(--ops-warning, #d97706)", bg: "color-mix(in srgb, #d97706 14%, transparent)" },
    not_installed: { label: "未安装", color: "var(--ops-warning, #d97706)", bg: "color-mix(in srgb, #d97706 14%, transparent)" },
  };
  const m = map[status] ?? map.not_installed;
  return (
    <span
      className="inline-flex items-center rounded-full px-2 py-0.5 text-[11px] font-medium"
      style={{ color: m.color, background: m.bg }}
    >
      {m.label}
    </span>
  );
}

/** 设置 → MCP：权限状态、授权连接、客户端接入 */
export function McpSettings() {
  const notify = useWorkspaceStore((s) => s.notify);
  const connections = useWorkspaceStore((s) => s.connections);

  const [install, setInstall] = useState<McpInstallInfo | null>(null);
  const [policy, setPolicy] = useState<McpPolicy | null>(null);
  const [loading, setLoading] = useState(true);
  const [installLoading, setInstallLoading] = useState(true);
  const [installError, setInstallError] = useState("");
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState("");
  const [clientTab, setClientTab] = useState<ClientTab>("cursor");
  const [copied, setCopied] = useState<"install" | "snippet" | "">("");
  const [tick, setTick] = useState(0);

  const reload = useCallback(() => setTick((n) => n + 1), []);

  useEffect(() => {
    let alive = true;
    setLoading(true);
    setError("");
    getMcpPolicy()
      .then((pol) => {
        if (!alive) return;
        setPolicy(pol.policy);
      })
      .catch((e) => {
        if (alive) setError(e instanceof Error ? e.message : String(e));
      })
      .finally(() => {
        if (alive) setLoading(false);
      });
    setInstallLoading(true);
    setInstallError("");
    getMcpInstall()
      .then((inst) => { if (alive) setInstall(inst); })
      .catch((e) => { if (alive) setInstallError(e instanceof Error ? e.message : String(e)); })
      .finally(() => { if (alive) setInstallLoading(false); });
    return () => {
      alive = false;
    };
  }, [tick]);

  const readOnly = !policy || policy.mode !== "read_write";
  const allowDangerous = !!policy?.allow_dangerous;
  const allowed = new Set(policy?.allowed_connection_ids ?? []);

  const snippet = useMemo(
    () => buildClientSnippet(clientTab, install?.goBinaryPath || ""),
    [clientTab, install?.goBinaryPath],
  );

  const persist = async (next: McpPolicy) => {
    setSaving(true);
    try {
      const res = await saveMcpPolicy(next);
      setPolicy(res.policy);
      notify({ kind: "success", title: "MCP", message: "策略已保存", mode: "toast", durationMs: 1400 });
    } catch (e) {
      notify({ kind: "error", title: "MCP", message: e instanceof Error ? e.message : String(e), mode: "modal" });
    } finally {
      setSaving(false);
    }
  };

  const copyText = async (text: string, which: "install" | "snippet") => {
    try {
      await navigator.clipboard.writeText(text);
      setCopied(which);
      setTimeout(() => setCopied(""), 1600);
      notify({ kind: "success", title: "已复制", message: which === "install" ? "安装命令" : "配置片段", mode: "toast", durationMs: 1200 });
    } catch {
      notify({ kind: "error", title: "复制失败", message: "请手动选中复制", mode: "toast", durationMs: 2000 });
    }
  };

  const toggleConn = (id: string) => {
    if (!policy) return;
    const set = new Set(policy.allowed_connection_ids ?? []);
    if (set.has(id)) set.delete(id);
    else set.add(id);
    void persist({ ...policy, allowed_connection_ids: Array.from(set) });
  };

  if (loading) return <p role="status" className="text-xs" style={{ color: "var(--ops-muted)" }}>正在读取 MCP 设置…</p>;
  if (error) {
    return (
      <div role="alert" className="space-y-2 text-xs">
        <p>{error}</p>
        <button type="button" className="ops-btn-secondary" onClick={reload}>重试</button>
      </div>
    );
  }

  const installCmd = install?.installCommand || `npm install -g ${NPM_PKG}@latest`;

  return (
    <div className="space-y-5 text-[12.5px]" style={{ color: "var(--ops-text)" }}>
      {/* Header */}
      <div className="flex flex-wrap items-center gap-2">
        <h3 className="text-[13px] font-semibold">MCP Server</h3>
        <StatusBadge status={installLoading && !install ? "checking" : install?.status || "not_installed"} />
        <button
          type="button"
          className="ops-btn-ghost ml-auto inline-flex h-6 items-center gap-1 px-2 text-[11px]"
          onClick={() => void openExternal(MCP_DOCS_URL)}
          title="打开 MCP 文档"
        >
          MCP 指南 <ExternalLink className="h-3 w-3" strokeWidth={1.5} />
        </button>
      </div>
      {installError && <p role="alert" className="text-[11px]" style={{ color: "var(--ops-warning, #d97706)" }}>安装检测失败：{installError}。连接白名单与权限设置仍可使用。</p>}

      {/* Version grid */}
      <div className="grid grid-cols-2 gap-2">
        {[
          ["当前版本", install?.currentVersion || (installLoading ? "检测中…" : install?.goBinaryFound ? "native" : "未检测到全局安装")],
          ["最新版本", install?.latestVersion ? `v${install.latestVersion}` : "—"],
          ["Node.js", install?.nodeVersion || (installLoading ? "检测中…" : "未检测到")],
          ["npm", install?.npmAvailable ? (install.npmVersion || "可用") : installLoading ? "检测中…" : "不可用"],
        ].map(([k, v]) => (
          <div key={k} className="rounded-lg border px-2.5 py-2" style={{ borderColor: "var(--ops-border-soft)", background: "var(--ops-surface-2)" }}>
            <div className="text-[10px] uppercase tracking-wide" style={{ color: "var(--ops-muted)" }}>{k}</div>
            <div className="mt-0.5 truncate font-mono text-[11.5px]">{v}</div>
          </div>
        ))}
      </div>
      {install?.goBinaryPath && (
        <p className="text-[11px]" style={{ color: "var(--ops-muted)" }}>
          Go 二进制：<span className="font-mono">{install.goBinaryPath}</span>
        </p>
      )}
      {install?.hint && (
        <p className="text-[11px] leading-relaxed" style={{ color: "var(--ops-muted)" }}>{install.hint}</p>
      )}

      {/* Install command */}
      <div className="space-y-1.5">
        <div className="text-[12px] font-medium">安装命令</div>
        <div className="flex gap-1.5">
          <code
            className="min-w-0 flex-1 overflow-x-auto rounded border px-2 py-1.5 font-mono text-[11px]"
            style={{ borderColor: "var(--ops-border)", background: "var(--ops-surface-2)" }}
          >
            {installCmd}
          </code>
          <button
            type="button"
            className="ops-btn-secondary inline-flex h-8 w-8 shrink-0 items-center justify-center"
            aria-label="复制安装命令"
            onClick={() => void copyText(installCmd, "install")}
          >
            {copied === "install" ? <Check className="h-3.5 w-3.5" /> : <Copy className="h-3.5 w-3.5" />}
          </button>
        </div>
        <p className="text-[11px] leading-relaxed" style={{ color: "var(--ops-muted)" }}>
          npm 包是 Node 启动器；还需本机 Go 二进制（<code className="font-mono">go build -o bin/opsxdb-mcp ./cmd/opsxdb-mcp</code>），
          并在客户端配置里设置 <code className="font-mono">OPSXDB_MCP_BIN</code>。
        </p>
      </div>

      <div className="space-y-2 border-t pt-3" style={{ borderColor: "var(--ops-border-soft)" }}>
        <div className="flex flex-wrap items-center gap-2 text-xs">
          <span className="rounded-md px-2 py-1" style={{ background: "var(--ops-surface-2)" }}>{readOnly ? "只读模式" : "读写模式"}</span>
          {!readOnly && allowDangerous && <span className="rounded-md px-2 py-1" style={{ background: "var(--ops-surface-2)" }}>允许危险 SQL</span>}
          {(readOnly || !allowDangerous) && <button type="button" className="ops-btn-secondary" disabled={saving || !policy} onClick={() => {
            if (policy) void persist({ ...policy, mode: "read_write", allow_dangerous: true });
          }}>使用默认权限</button>}
        </div>
        <p className="text-[11px]" style={{ color: "var(--ops-muted)" }}>Agent 写入前确认具体命令、连接与数据库。</p>
      </div>

      {/* Whitelist */}
      <div className="space-y-2 border-t pt-3" style={{ borderColor: "var(--ops-border-soft)" }}>
        <div className="text-[12px] font-medium">连接白名单</div>
        <p className="text-[11px] leading-relaxed" style={{ color: "var(--ops-muted)" }}>
          仅可访问勾选的连接。
        </p>
        {connections.length === 0 ? (
          <p className="text-[11px]" style={{ color: "var(--ops-muted)" }}>暂无已保存连接。请先在侧栏新建连接。</p>
        ) : (
          <div className="max-h-36 space-y-1 overflow-y-auto rounded border p-2" style={{ borderColor: "var(--ops-border-soft)" }}>
            {connections.map((c) => (
              <label key={c.id} className="flex cursor-pointer items-center gap-2 rounded px-1 py-0.5 hover:bg-[color-mix(in_srgb,var(--ops-accent)_8%,transparent)]">
                <input
                  type="checkbox"
                  checked={allowed.has(c.id)}
                  disabled={saving}
                  onChange={() => toggleConn(c.id)}
                />
                <span className="min-w-0 flex-1 truncate">{c.name || c.id}</span>
                <span className="shrink-0 font-mono text-[10px]" style={{ color: "var(--ops-muted)" }}>{c.driver}</span>
              </label>
            ))}
          </div>
        )}
      </div>

      {/* Client configs */}
      <div className="space-y-2 border-t pt-3" style={{ borderColor: "var(--ops-border-soft)" }}>
        <div className="text-[12px] font-medium">MCP 配置</div>
        <div className="flex flex-wrap gap-1">
          {CLIENT_TABS.map((t) => (
            <button
              key={t.id}
              type="button"
              className={`rounded px-2 py-1 text-[11px] ${clientTab === t.id ? "ops-tree-item-active" : "ops-btn-ghost"}`}
              onClick={() => setClientTab(t.id)}
            >
              {t.label}
            </button>
          ))}
        </div>
        <p className="text-[11px]" style={{ color: "var(--ops-muted)" }}>写入位置：{snippet.path}</p>
        <div className="relative">
          <pre
            className="max-h-48 overflow-auto rounded border p-2 font-mono text-[10.5px] leading-relaxed"
            style={{ borderColor: "var(--ops-border)", background: "var(--ops-surface-2)" }}
          >
            {snippet.json}
          </pre>
          <button
            type="button"
            className="ops-btn-secondary absolute right-2 top-2 inline-flex h-7 items-center gap-1 px-2 text-[11px]"
            onClick={() => void copyText(snippet.json, "snippet")}
          >
            {copied === "snippet" ? <Check className="h-3 w-3" /> : <Copy className="h-3 w-3" />}
            复制
          </button>
        </div>
      </div>

      <div className="flex flex-wrap gap-2 border-t pt-3" style={{ borderColor: "var(--ops-border-soft)" }}>
        <button type="button" className="ops-btn-secondary inline-flex h-7 items-center gap-1 px-2.5 text-[11px]" onClick={reload} disabled={loading || installLoading}>
          <RefreshCw className="h-3 w-3" /> 重新检查
        </button>
      </div>
    </div>
  );
}