import { DynamicStructuredTool } from '@langchain/core/tools';
import { z } from 'zod';
import type { FastifyBaseLogger } from 'fastify';
import type { WebExploreSubagent } from '../../harness/subagents/web-explore/index.js';
import type { SubagentContext } from '../../harness/subagents/base-subagent.js';

export interface WebExploreAgentToolConfig {
  webExploreSubagent: WebExploreSubagent;
  context: SubagentContext;
  logger: FastifyBaseLogger;
}

/**
 * Creates a LangChain tool that delegates to the web-explore subagent.
 * The subagent decides whether to use web search or arXiv based on the instruction.
 */
export function createWebExploreAgentTool(config: WebExploreAgentToolConfig): DynamicStructuredTool {
  const { webExploreSubagent, context, logger } = config;

  return new DynamicStructuredTool({
    name: 'web_explore',
    description: `Search the web or academic databases and return a summarized answer.

Use this tool when the user asks about:
- Current events, news, or real-time information
- Documentation, tutorials, or how-to guides
- Academic papers, research findings, or scientific topics
- Any topic that benefits from external sources

The subagent will search the web (or arXiv for academic queries), fetch relevant content, and return a markdown summary with cited sources.`,
    schema: z.object({
      instruction: z.string().describe(
        'What to search for and summarize. Be specific — include the topic, what aspects matter, ' +
        'and any context that helps narrow the search (e.g. "recent papers on momentum factor in equities" ' +
        'or "how to configure rate limiting in Fastify").'
      ),
    }),
    func: async ({ instruction }: { instruction: string }): Promise<string> => {
      logger.info({ instruction: instruction.substring(0, 100) }, 'Delegating to web-explore subagent');

      try {
        return await webExploreSubagent.execute(context, instruction);
      } catch (error) {
        logger.error({ error, errorMessage: (error as Error)?.message }, 'Web explore subagent failed');
        throw error;
      }
    },
  });
}