lmagent

import { tool, text } from "@lmstudio/sdk";
import { z } from "zod";
import {
  readFile,
  writeFile,
  readdir,
  unlink,
  rename,
} from "fs/promises";
import { stat } from "fs/promises";

import DiffMatchPatch from "diff-match-patch";

const dmp = new DiffMatchPatch();

/* ---------------------------
   READ FILE
--------------------------- */
export function createReadFileTool() {
  return tool({
    name: "read_file",
    description: text`Read a file`,
    parameters: {
      path: z.string(),
    },
    implementation: async ({ path }) => {
      const content = await readFile(path, "utf-8");
      return { path, content };
    },
  });
}

/* ---------------------------
   WRITE FILE (FULL)
--------------------------- */
export function createWriteFileTool() {
  return tool({
    name: "write_file",
    description: text`Overwrite a file completely`,
    parameters: {
      path: z.string(),
      content: z.string(),
    },
    implementation: async ({ path, content }) => {
      await writeFile(path, content, "utf-8");
      return { path, status: "written" };
    },
  });
}

/* ---------------------------
   WRITE FILE (DIFF PATCH)
--------------------------- */
export function createWriteFileDiffTool() {
  return tool({
    name: "write_file_diff",
    description: text`
Apply a unified diff patch to a file.

Safer than full overwrite. Only modifies changed sections.
`,
    parameters: {
      path: z.string(),
      diff: z.string(),
    },

    implementation: async ({ path, diff }) => {
      const original = await readFile(path, "utf-8");

      const patches = dmp.patch_fromText(diff);
      const [result, applied] = dmp.patch_apply(patches, original);

      const success = applied.every(Boolean);

      if (!success) {
        return {
          ok: false,
          error: "patch failed to apply",
        };
      }

      await writeFile(path, result, "utf-8");

      return {
        ok: true,
        path,
        changed: true,
      };
    },
  });
}

/* ---------------------------
   LIST DIR
--------------------------- */
export function createListDirTool() {
  return tool({
    name: "list_dir",
    description: text`List directory`,
    parameters: {
      path: z.string(),
    },
    implementation: async ({ path }) => {
      const files = await readdir(path, { withFileTypes: true });

      return files.map(f => ({
        name: f.name,
        is_dir: f.isDirectory(),
      }));
    },
  });
}

/* ---------------------------
   DELETE FILE
--------------------------- */
export function createDeleteFileTool() {
  return tool({
    name: "delete_file",
    description: text`Delete file`,
    parameters: {
      path: z.string(),
    },
    implementation: async ({ path }) => {
      await unlink(path);
      return { path, deleted: true };
    },
  });
}

/* ---------------------------
   MOVE FILE
--------------------------- */
export function createMoveFileTool() {
  return tool({
    name: "move_file",
    description: text`Move/rename file`,
    parameters: {
      from: z.string(),
      to: z.string(),
    },
    implementation: async ({ from, to }) => {
      await rename(from, to);
      return { from, to, moved: true };
    },
  });
}

export function createFileInfoTool(cwd: string) {
  return tool({
    name: "file_info",
    description: text`Get file metadata`,
    parameters: {
      path: z.string(),
    },

    implementation: async ({ path }) => {
      const full = `${cwd}/${path}`;
      const s = await stat(full);

      return {
        path,
        size: s.size,
        is_file: s.isFile(),
        is_dir: s.isDirectory(),
        modified: s.mtime,
      };
    },
  });
}