/**
 * MCP 配置拉取与持久化模块
 *
 * 负责:
 * - 通过 WSClient 发送 aibot_get_mcp_config 请求
 * - 解析服务端响应，提取 MCP 配置 (url、type、is_authed)
 * - 将配置写入 ~/.openclaw/wecomConfig/config.json 的 mcpConfig 字段
 */

import os from "os";
import path from "path";
import type { WSClient } from "@wecom/aibot-node-sdk";
import { generateReqId } from "@wecom/aibot-node-sdk";
import { resolveFileIoHelpers } from "./compat/plugin-sdk-shim.js";
import type { WecomRuntimeEnv } from "./monitor/types.js";
import { withTimeout } from "./timeout.js";

// ============================================================================
// 常量
// ============================================================================

/** 获取 MCP 配置的 WebSocket 命令 */
const MCP_GET_CONFIG_CMD = "aibot_get_mcp_config";

/** MCP 配置拉取超时时间（毫秒） */
const MCP_CONFIG_FETCH_TIMEOUT_MS = 15_000;

// ============================================================================
// 类型
// ============================================================================

/**
 * MCP 配置响应体
 */
export interface McpConfigBody {
    /** MCP Server 的 StreamableHttp URL */
    url: string;
    /** 连接类型，如 "doc" */
    type?: string;
    /** 是否已授权 */
    is_authed?: boolean;
}

// ============================================================================
// MCP 配置拉取
// ============================================================================

/**
 * 通过 WSClient 发送 aibot_get_mcp_config 命令，获取 MCP 配置
 *
 * @param wsClient - 已认证的 WSClient 实例
 * @returns MCP 配置 (url、type、is_authed)
 * @throws 响应错误码非 0 或缺少 url 字段时抛出错误
 */
export async function fetchMcpConfig(
    wsClient: WSClient,
): Promise<McpConfigBody> {
    const reqId = generateReqId("mcp_config");

    // 通过 reply 方法发送自定义命令
    const response = await withTimeout(
        wsClient.reply(
            { headers: { req_id: reqId } },
            { biz_type: "doc" },
            MCP_GET_CONFIG_CMD,
        ),
        MCP_CONFIG_FETCH_TIMEOUT_MS,
        `MCP config fetch timed out after ${MCP_CONFIG_FETCH_TIMEOUT_MS}ms`,
    );

    // 校验响应错误码
    if (response.errcode && response.errcode !== 0) {
        throw new Error(
            `MCP config request failed: errcode=${response.errcode}, errmsg=${response.errmsg ?? "unknown"}`,
        );
    }

    // 提取并校验 body
    const body = response.body as McpConfigBody | undefined;
    if (!body?.url) {
        throw new Error(
            "MCP config response missing required 'url' field",
        );
    }

    return {
        url: body.url,
        type: "doc",
        is_authed: body.is_authed,
    };
}

// ============================================================================
// 配置持久化
// ============================================================================

/**
 * 将 MCP 配置写入 ~/.openclaw/wecomConfig/config.json 的 mcpConfig 字段
 *
 * 使用 OpenClaw SDK 提供的文件锁和原子写入，保证并发安全。
 * 配置格式: { mcpConfig: { [type]: { type, url } } }
 */
async function saveMcpConfigToPluginJson(
    config: McpConfigBody,
    runtime: WecomRuntimeEnv,
): Promise<void> {
    const wecomConfigDir = path.join(os.homedir(), ".openclaw", "wecomConfig");
    const wecomConfigPath = path.join(wecomConfigDir, "config.json");

    const lockOptions = {
        stale: 60_000,
        retries: {
            retries: 6,
            factor: 1.35,
            minTimeout: 8,
            maxTimeout: 1200,
            randomize: true,
        },
    };

    const { withFileLock, readJsonFileWithFallback, writeJsonFileAtomically } =
        await resolveFileIoHelpers();

    await withFileLock(wecomConfigPath, lockOptions, async () => {
        // 读取现有配置（不存在时使用空对象）
        const { value: pluginJson } = await readJsonFileWithFallback<Record<string, unknown>>(
            wecomConfigPath,
            {},
        );

        // 确保 mcpConfig 字段存在且为对象
        if (!pluginJson.mcpConfig || typeof pluginJson.mcpConfig !== "object") {
            pluginJson.mcpConfig = {};
        }

        // 使用 type 作为键存储配置
        const typeKey = config.type || "default";
        (pluginJson.mcpConfig as Record<string, unknown>)[typeKey] = {
            type: config.type,
            url: config.url,
        };

        // 原子写入
        await writeJsonFileAtomically(wecomConfigPath, pluginJson);

        runtime.log?.(`[WeCom] MCP config saved to ${wecomConfigPath}`);
    });
}

// ============================================================================
// 组合入口
// ============================================================================

/**
 * 拉取 MCP 配置并持久化到 ~/.openclaw/wecomConfig/config.json
 *
 * 认证成功后调用。失败仅记录日志，不影响 WebSocket 消息正常收发。
 *
 * @param wsClient - 已认证的 WSClient 实例
 * @param accountId - 账户 ID（用于日志）
 * @param runtime - 运行时环境（用于日志）
 */
export async function fetchAndSaveMcpConfig(
    wsClient: WSClient,
    accountId: string,
    runtime: WecomRuntimeEnv,
): Promise<void> {
    try {
        runtime.log?.(`[${accountId}] Fetching MCP config...`);

        const config = await fetchMcpConfig(wsClient);
        runtime.log?.(
            `[${accountId}] MCP config fetched: url=${config.url}, type=${config.type ?? "N/A"}, is_authed=${config.is_authed ?? "N/A"}`,
        );

        await saveMcpConfigToPluginJson(config, runtime);
    } catch (err) {
        runtime.error?.(
            `[${accountId}] Failed to fetch/save MCP config: ${String(err)}`,
        );
    }
}