/**
 * HTTP 请求工具（1 个）
 *
 * http_request — 发送 HTTP/REST API 请求
 *
 * 使用 Node.js 18+ 内置 fetch API。
 * 响应体截断到 50KB 防止结果过大。
 */

import type { IMetonaTool, ToolExecutionContext } from '../../types/metona-tool';
import type { MetonaToolDef } from '../../../harness/types';
import { MetonaToolCategory, MetonaRiskLevel } from '../../../harness/types';

const ALLOWED_METHODS = ['GET', 'POST', 'PUT', 'PATCH', 'DELETE', 'HEAD'] as const;
const MAX_BODY_BYTES = 50 * 1024; // 50KB

export class HttpRequestTool implements IMetonaTool {
  readonly definition: MetonaToolDef = {
    name: 'http_request',
    description: 'Send an HTTP/REST API request. Supports GET/POST/PUT/PATCH/DELETE/HEAD methods with custom headers and body. Response body is truncated to 50KB.',
    parameters: {
      type: 'object',
      properties: {
        url: { type: 'string', description: 'Request URL (must start with http:// or https://)' },
        method: {
          type: 'string',
          description: 'HTTP method (default GET)',
          enum: ['GET', 'POST', 'PUT', 'PATCH', 'DELETE', 'HEAD'],
        },
        headers: { type: 'object', description: 'Request headers as key-value pairs' },
        body: { type: 'string', description: 'Request body (string)' },
        timeout: { type: 'number', description: 'Timeout in milliseconds (default 30000, max 60000)' },
      },
      required: ['url'],
    },
    category: MetonaToolCategory.NETWORK,
    riskLevel: MetonaRiskLevel.LOW,
    requiresPermission: false,
    timeoutMs: 30_000,
  };

  async execute(args: Record<string, unknown>, _context: ToolExecutionContext): Promise<unknown> {
    try {
      const url = args.url as string;
      const method = ((args.method as string) ?? 'GET').toUpperCase();
      const headers = (args.headers as Record<string, string> | undefined) ?? undefined;
      const body = args.body as string | undefined;
      const timeout = Math.min(60_000, Math.max(1, (args.timeout as number) ?? 30_000));

      // 校验 URL
      if (!url || !/^https?:\/\//i.test(url)) {
        return { error: 'Invalid URL', success: false };
      }

      // 校验 method
      if (!(ALLOWED_METHODS as readonly string[]).includes(method)) {
        return {
          error: `Invalid method: ${method}. Must be one of: ${ALLOWED_METHODS.join(', ')}`,
          success: false,
        };
      }

      // 超时控制
      const controller = new AbortController();
      const timer = setTimeout(() => controller.abort(), timeout);

      try {
        const fetchOptions: RequestInit = {
          method,
          headers,
          signal: controller.signal,
          redirect: 'follow',
        };
        // GET/HEAD 不应携带 body
        if (body !== undefined && method !== 'GET' && method !== 'HEAD') {
          fetchOptions.body = body;
        }

        const response = await fetch(url, fetchOptions);
        const text = await response.text();

        // 截断到 50KB
        const truncated = text.length > MAX_BODY_BYTES;
        const safeBody = truncated ? text.slice(0, MAX_BODY_BYTES) : text;

        // 只返回 content-type 和 content-length
        const filteredHeaders: Record<string, string> = {};
        const contentType = response.headers.get('content-type');
        if (contentType) filteredHeaders['content-type'] = contentType;
        const contentLength = response.headers.get('content-length');
        if (contentLength) filteredHeaders['content-length'] = contentLength;

        return {
          status: response.status,
          statusText: response.statusText,
          headers: filteredHeaders,
          body: safeBody,
          truncated,
          ok: response.ok,
          success: true,  // v0.3.1 修复 WARN-4: 成功路径添加 success 字段
        };
      } finally {
        clearTimeout(timer);
      }
    } catch (error) {
      // 区分超时（AbortError）与其他网络错误
      if (error instanceof Error && error.name === 'AbortError') {
        return { error: 'Request timeout', success: false };
      }
      const errMsg = error instanceof Error ? error.message : String(error);
      return { error: errMsg, success: false };
    }
  }
}