"""edit_file.py – tool for str_replace editing of files inside the sandbox."""

from __future__ import annotations

from typing import TYPE_CHECKING

from langchain_core.tools import BaseTool, tool
from loguru import logger

if TYPE_CHECKING:
    from docker_agent_sandbox.sandbox import DockerSandbox


def make_edit_file_tool(sandbox: "DockerSandbox") -> BaseTool:
    """Return an edit_file tool bound to *sandbox*."""

    @tool
    def edit_file(path: str, old_str: str, new_str: str) -> str:
        """
        Replace the first exact occurrence of *old_str* with *new_str* in *path*.

        This is the standard ``str_replace`` editing primitive: read the file,
        find the unique snippet you want to change, and supply the replacement.

        Rules:
        - *old_str* must match **exactly** (including whitespace and indentation).
        - *old_str* must appear **at least once**; the tool returns an error if it
          is not found.
        - If *old_str* appears more than once the tool refuses and asks you to
          provide more surrounding context to make it unique.
        - To insert text without removing anything, set *old_str* to a line that
          will remain and include it verbatim in *new_str* (i.e. keep the anchor
          line and add your new lines around it).
        - To delete a block, set *new_str* to an empty string ``""``.

        Returns a confirmation with the number of lines affected, or an error.
        """
        _MAX_EDIT_BYTES = 1_000_000  # 1 MB

        logger.debug("Editing file inside sandbox: {!r}", path)
        try:
            data = sandbox.read_file(path)
        except (FileNotFoundError, IsADirectoryError, RuntimeError) as exc:
            return f"[ERROR reading {path!r} for edit] {exc}"

        if len(data) > _MAX_EDIT_BYTES:
            return (
                f"[ERROR] {path!r} is {len(data)} bytes; edit_file only supports files "
                f"up to {_MAX_EDIT_BYTES} bytes."
            )

        content = data.decode("utf-8", errors="replace")
        count = content.count(old_str)
        if count == 0:
            return (
                f"[ERROR] old_str not found in {path!r}. "
                "Check that whitespace and indentation match exactly."
            )
        if count > 1:
            return (
                f"[ERROR] old_str appears {count} times in {path!r}. "
                "Provide more surrounding context to make it unique."
            )

        new_content = content.replace(old_str, new_str, 1)
        old_lines = old_str.count("\n") + 1
        new_lines = new_str.count("\n") + 1 if new_str else 0
        try:
            sandbox.write_file(path, new_content)
        except Exception as exc:
            return f"[ERROR writing {path!r} after edit] {exc}"
        return f"[OK] Replaced {old_lines} line(s) with {new_lines} line(s) in {path}"

    return edit_file