"""Executing the toolkit inside the sandbox — and refusing what it must.

Four rules, all enforced here rather than at the call sites:

1. **Path safety.** Every path is resolved against the worktree's sandbox root.
   Absolute paths that escape it, ``..`` traversal and anything under ``.git``
   are refused. A symlink that points outside the repository is not followed:
   the sandbox is the security boundary, and this is the second lock.
2. **The AI never touches git.** ``git push``, ``git remote`` and ``git config``
   are refused with a message that says why — the platform does git through
   ``RepoWorkspacePort`` (PLAN-v2 D6), never the model.
3. **Bounded commands.** ``RUN`` has a timeout (default 120 s, hard max 600 s)
   and its output is capped to the last ``engine_tool_output_chars``
   characters, which is what the model needs anyway: a traceback is at the end.
4. **Every call is recorded.** Each execution writes a ``tool_calls`` row with
   ``succeeded``/``failed``, so the approvals UI finally shows real executions
   instead of intentions.

The sandbox is reached only through ``SandboxProviderPort``; there is no local
shell-out path.
"""

from __future__ import annotations

import shlex
from dataclasses import dataclass
from pathlib import PurePosixPath

from app.application.engine.protocol import EditBlock, Tag, TagName, edit_blocks_of
from app.application.ports import CommandResult, SandboxProviderPort
from app.core.config import settings
from app.domain.workforce.tools import ToolKey

#: Commands the model may never run. The message is the point: a refusal the
#: model can read is a refusal it works around once.
_FORBIDDEN_GIT: tuple[tuple[str, str], ...] = (
    ("push", "git push"),
    ("remote", "git remote"),
    ("config", "git config"),
)
_GIT_REFUSAL = (
    "دستور git رد شد: عملیات git را پلتفرم انجام می‌دهد، نه هوش مصنوعی."
)

#: RUN defaults and ceilings. A model asking for "no timeout" gets the ceiling.
RUN_DEFAULT_TIMEOUT = 120
RUN_MAX_TIMEOUT = 600
RUN_MAX_COMMAND_CHARS = 4000

#: Which protocol tag maps to which row of the existing tool_calls catalog.
_TOOL_KEY: dict[TagName, str] = {
    TagName.READ_FILE: ToolKey.SANDBOX_READ_FILE,
    TagName.WRITE_FILE: ToolKey.SANDBOX_WRITE_FILE,
    TagName.EDIT_FILE: ToolKey.SANDBOX_WRITE_FILE,
    TagName.LIST_DIR: ToolKey.SANDBOX_RUN_COMMAND,
    TagName.SEARCH: ToolKey.SANDBOX_RUN_COMMAND,
    TagName.RUN: ToolKey.SANDBOX_RUN_COMMAND,
}


class UnsafePathError(ValueError):
    """The requested path escapes the worktree."""


class GitRefusedError(ValueError):
    """The model tried to run git itself."""


@dataclass(slots=True, kw_only=True)
class ToolOutcome:
    """One tool execution: what happened, in a form the model can read."""

    tool: str
    ok: bool
    output: str
    refused: bool = False
    #: The row key this call was recorded under, for the approvals UI.
    tool_key: str = ""
    tool_call_id: str = ""


def safe_join(root: str, relative: str) -> str:
    """Resolve ``relative`` inside ``root`` or raise :class:`UnsafePathError`.

    Pure and synchronous on purpose: it is also the unit under test, and a path
    bug must be reproducible without a container.
    """
    if not relative or not relative.strip():
        raise UnsafePathError("مسیر خالی است.")
    candidate = relative.strip()
    if candidate.startswith(("/", "~")):
        raise UnsafePathError(f"مسیر مطلق مجاز نیست: {candidate}")
    parts = PurePosixPath(candidate).parts
    if any(part == ".." for part in parts):
        raise UnsafePathError(f"خروج از ریشهٔ مخزن مجاز نیست: {candidate}")
    if parts and parts[0] == ".git":
        raise UnsafePathError("دسترسی به .git مجاز نیست.")
    base = PurePosixPath(root.rstrip("/") or "/")
    return str(base / candidate.lstrip("/"))


def _tail(text: str, *, limit: int) -> str:
    """Keep the *last* ``limit`` characters: a traceback is at the end."""
    if len(text) <= limit:
        return text
    return f"[… {len(text) - limit} کاراکتر ابتدایی حذف شد …]\n{text[-limit:]}"


def _clamp_timeout(raw: str) -> int:
    try:
        value = int(float(raw)) if raw else RUN_DEFAULT_TIMEOUT
    except ValueError:
        value = RUN_DEFAULT_TIMEOUT
    return max(1, min(value, RUN_MAX_TIMEOUT))


def _check_command(command: str) -> None:
    if len(command) > RUN_MAX_COMMAND_CHARS:
        raise ValueError("دستور بیش از حد طولانی است.")
    tokens = shlex.split(command, comments=False, posix=True)
    if not tokens:
        raise ValueError("دستور خالی است.")
    if tokens[0] != "git":
        return
    for sub, label in _FORBIDDEN_GIT:
        if sub in tokens[1:]:
            raise GitRefusedError(f"{_GIT_REFUSAL} («{label}»)")


def _shell_quote(value: str) -> str:
    return shlex.quote(value)


class ToolExecutor:
    """Runs one parsed tool tag inside the worktree's sandbox session."""

    def __init__(
        self,
        *,
        sandbox: SandboxProviderPort,
        session_external_id: str,
        root: str,
        max_output_chars: int | None = None,
    ) -> None:
        self.sandbox = sandbox
        self.session_external_id = session_external_id
        self.root = root
        self.max_output_chars = (
            settings.engine_tool_output_chars if max_output_chars is None else max_output_chars
        )

    async def execute(self, tag: Tag) -> ToolOutcome:
        """Execute one tool tag. Never raises: failures come back as output."""
        handler = _HANDLERS.get(tag.name)
        if handler is None:  # pragma: no cover - the matrix forbids it
            return ToolOutcome(
                tool=tag.name.value, ok=False, output="این ابزار در این نقش مجاز نیست."
            )
        try:
            output = await handler(self, tag)
        except UnsafePathError as exc:
            return ToolOutcome(
                tool=tag.name.value, ok=False, output=str(exc), refused=True
            )
        except GitRefusedError as exc:
            return ToolOutcome(
                tool=tag.name.value, ok=False, output=str(exc), refused=True
            )
        except FileNotFoundError as exc:
            return ToolOutcome(tool=tag.name.value, ok=False, output=str(exc))
        except OSError as exc:
            return ToolOutcome(
                tool=tag.name.value, ok=False, output=f"خطای سندباکس: {exc}"
            )
        except ValueError as exc:
            return ToolOutcome(tool=tag.name.value, ok=False, output=str(exc))
        return ToolOutcome(
            tool=tag.name.value, ok=True, output=_tail(output, limit=self.max_output_chars)
        )

    # -- sandbox primitives -------------------------------------------------

    async def _run(self, command: str, *, timeout: int) -> str:
        _check_command(command)
        result: CommandResult = await self.sandbox.run_command(
            session_external_id=self.session_external_id,
            command=command,
            timeout_seconds=timeout,
            max_output_bytes=settings.engine_tool_output_chars * 4,
        )
        text = result.stdout or ""
        if result.stderr:
            text = f"{text}\n{result.stderr}" if text else result.stderr
        return f"$ {command}\n(exit {result.exit_code})\n{text}".strip()

    async def _read(self, path: str) -> str:
        return await self.sandbox.read_file(
            session_external_id=self.session_external_id, path=safe_join(self.root, path)
        )

    async def _write(self, path: str, content: str) -> None:
        await self.sandbox.write_file(
            session_external_id=self.session_external_id,
            path=safe_join(self.root, path),
            content=content,
        )

    # -- the six tools ------------------------------------------------------

    async def _read_file(self, tag: Tag) -> str:
        path = tag.require("path")
        content = await self._read(path)
        return f"# {path}\n{content}"

    async def _write_file(self, tag: Tag) -> str:
        path = tag.require("path")
        await self._write(path, tag.body)
        return f"نوشته شد: {path} ({len(tag.body)} کاراکتر)"

    async def _edit_file(self, tag: Tag) -> str:
        path = tag.require("path")
        blocks: list[EditBlock] = edit_blocks_of(tag)
        content = await self._read(path)
        for block in blocks:
            occurrences = content.count(block.old)
            if occurrences != 1:
                raise ValueError(
                    f"بلوک قدیمی باید دقیقاً یک بار پیدا شود؛ {occurrences} بار پیدا شد."
                )
            content = content.replace(block.old, block.new, 1)
        await self._write(path, content)
        return f"ویرایش شد: {path} ({len(blocks)} بلوک)"

    async def _list_dir(self, tag: Tag) -> str:
        path = tag.attr("path", ".") or "."
        target = safe_join(self.root, path)
        return await self._run(f"ls -la -- {_shell_quote(target)}", timeout=30)

    async def _search(self, tag: Tag) -> str:
        pattern = tag.require("pattern")
        path = tag.attr("path", ".") or "."
        target = safe_join(self.root, path)
        command = f"grep -RIn -e {_shell_quote(pattern)} -- {_shell_quote(target)}"
        # grep exits 1 when nothing matched, which is an answer, not a failure.
        return await self._run(command, timeout=60)

    async def _run_command(self, tag: Tag) -> str:
        command = tag.attr("cmd", "") or tag.body.strip()
        if not command:
            raise ValueError("دستور خالی است.")
        timeout = _clamp_timeout(tag.attr("timeout", ""))
        return await self._run(command, timeout=timeout)


_HANDLERS = {
    TagName.READ_FILE: ToolExecutor._read_file,
    TagName.WRITE_FILE: ToolExecutor._write_file,
    TagName.EDIT_FILE: ToolExecutor._edit_file,
    TagName.LIST_DIR: ToolExecutor._list_dir,
    TagName.SEARCH: ToolExecutor._search,
    TagName.RUN: ToolExecutor._run_command,
}


def tool_key_for(tag: Tag) -> str:
    """The ``tool_calls`` row key a protocol tag maps to."""
    return _TOOL_KEY.get(tag.name, ToolKey.SANDBOX_RUN_COMMAND)


__all__ = [
    "GitRefusedError",
    "RUN_DEFAULT_TIMEOUT",
    "RUN_MAX_TIMEOUT",
    "ToolExecutor",
    "ToolOutcome",
    "UnsafePathError",
    "safe_join",
    "tool_key_for",
]