/**
 * `memory_get` — safe snippet read.
 *
 * Port of upstream `createMemoryGetTool` at
 * `upstream reference`.
 */
import { tool } from '@langchain/core/tools';
import {
  MEMORY_GET_DESCRIPTION,
  MEMORY_GET_TOOL_NAME,
} from '@/memory/constants';
import {
  MemoryGetSchema,
  type MemoryGetToolResult,
  type MemoryToolBinding,
} from './shared';

// eslint-disable-next-line @typescript-eslint/explicit-function-return-type
export function createMemoryGetTool(binding: MemoryToolBinding) {
  return tool(
    async (args): Promise<string> => {
      try {
        const result = await binding.backend.get(binding.scope, {
          path: args.path,
          from: args.from,
          lines: args.lines,
        });
        if (!result) {
          const payload: MemoryGetToolResult = { path: args.path, text: '' };
          return JSON.stringify(payload);
        }
        const payload: MemoryGetToolResult = {
          path: result.path,
          text: result.text,
        };
        return JSON.stringify(payload);
      } catch (err) {
        const payload: MemoryGetToolResult = {
          path: args.path,
          text: '',
          disabled: true,
          error: err instanceof Error ? err.message : String(err),
        };
        return JSON.stringify(payload);
      }
    },
    {
      name: MEMORY_GET_TOOL_NAME,
      description: MEMORY_GET_DESCRIPTION,
      schema: MemoryGetSchema,
    }
  );
}