# -*- coding: utf-8 -*-
"""ToolRegistry — Single source of truth for tool metadata.

Each tool declares on registration:
    - Type (file / network / shell / internal)
    - Target parameter name (file_path / command / url …)
    - Python function name → policy tool name mapping

Relationship with policy.yaml:
    ToolRegistry: what a tool is (type, parameter name)
        → static, registered in code
    policy.yaml:  what a tool can do (rules, default perms)
        → dynamic, generated by user/approve
"""

from __future__ import annotations

import logging
import os
import threading
from typing import Any, Dict, List, Optional, Tuple

logger = logging.getLogger(__name__)


class ToolRegistry:
    """Tool metadata registry."""

    def __init__(self) -> None:
        self._types: Dict[str, str] = {}
        self._target_params: Dict[str, str] = {}
        self._python_name_map: Dict[str, str] = {}
        # Tools whose target should combine path + pattern
        # (e.g. Glob: pattern is a file glob, so path+pattern
        # forms a complete filesystem path pattern for rule matching).
        self._pattern_params: Dict[str, str] = {}
        # Tools that refuse to run (fail closed) unless a sandbox_config is
        # supplied — as opposed to shell tools like Bash that execute directly
        # when unsandboxed. See ``requires_sandbox`` for why this matters.
        self._sandbox_required: Dict[str, bool] = {}

    def register(
        self,
        tool_name: str,
        tool_type: str,
        target_param: str,
        pattern_param: str = "",
        sandbox_required: bool = False,
    ) -> None:
        """Register a tool.

        Args:
            tool_name: policy-layer tool name, e.g. "Read"
            tool_type: "file" | "network" | "shell" | "internal"
            target_param: target parameter name, e.g. "file_path", "command"
            pattern_param: for file-search tools (e.g. Glob), the parameter
                name holding the glob pattern. When set, ``extract_target``
                combines path + pattern into a single filesystem path pattern.
            sandbox_required: ``True`` for tools that **fail closed** without a
                ``sandbox_config`` (e.g. ``recall_history_python``, which runs
                model-authored Python and returns ``DENIED`` when no sandbox is
                supplied). Distinct from mere shell-type: ``Bash`` is shell but
                fail-*open* — it executes unsandboxed when no config is given.
                Consumed by the approval_level=OFF path, which must still
                compile a sandbox for these tools instead of letting them dead
                -end in a sandbox-violation → approval loop.
        """
        self._types[tool_name] = tool_type
        self._target_params[tool_name] = target_param
        if pattern_param:
            self._pattern_params[tool_name] = pattern_param
        if sandbox_required:
            self._sandbox_required[tool_name] = True

    def register_python_name(self, python_name: str, policy_name: str) -> None:
        """Register a python function name → policy tool name mapping."""
        self._python_name_map[python_name] = policy_name

    def get_type(self, tool_name: str) -> str:
        """Return the tool's type. Returns "unknown" if not registered."""
        return self._types.get(tool_name, "unknown")

    def get_target_param(self, tool_name: str) -> str:
        """Return the tool's target parameter name.

        Returns "" if not registered.
        """
        return self._target_params.get(tool_name, "")

    def get_pattern_param(self, tool_name: str) -> str:
        """Return the optional pattern parameter name (e.g. Glob)."""
        return self._pattern_params.get(tool_name, "")

    def get_mapped_policy_name(self, python_name: str) -> Optional[str]:
        """Return explicit python→policy mapping, or ``None`` if unset."""
        return self._python_name_map.get(python_name)

    def requires_sandbox(self, tool_name: str) -> bool:
        """Whether the tool fails closed without a ``sandbox_config``.

        ``True`` only for tools that refuse to run unsandboxed (the REPL).
        Returns ``False`` for unregistered tools and for fail-open shell
        tools like ``Bash`` that execute directly when no sandbox is given.
        """
        return self._sandbox_required.get(tool_name, False)

    def python_to_policy_name(self, python_name: str) -> str:
        """Map a python function name to a policy tool name.

        Checks explicit mapping first; if no mapping exists, converts
        snake_case → PascalCase.
        """
        override = self._python_name_map.get(python_name)
        if override:
            return override
        parts = python_name.split("_")
        return "".join(p.capitalize() for p in parts)

    def extract_target(
        self,
        tool_name: str,
        input_data: dict[str, Any],
        workspace_dir: str = "",
    ) -> str:
        """Extract the target from tool call arguments."""
        param = self.get_target_param(tool_name)
        if not param:
            return ""

        # 1) Get base path from input
        path = input_data.get(param, "")
        path = str(path) if path else ""

        # Expand a leading ``~`` to the user's home directory
        if path:
            path = os.path.expanduser(path)

        # 2) For file tools, resolve empty/relative path using workspace_dir
        if self._types.get(tool_name) == "file" and workspace_dir:
            if not path:
                path = workspace_dir
            elif not os.path.isabs(path):
                path = os.path.join(workspace_dir, path)

        # 3) Append pattern for file-search tools (e.g. Glob)
        pattern_param = self._pattern_params.get(tool_name)
        if pattern_param:
            pattern = input_data.get(pattern_param, "")
            if pattern:
                path = (
                    os.path.join(path, str(pattern)) if path else str(pattern)
                )

        return path

    def get_all_tool_names(self) -> List[str]:
        """Return all registered tool names."""
        return list(self._types.keys())

    def get_identity(
        self,
        tool_name: str,
    ) -> Tuple[str, str, str, bool]:
        """Return (type, target, pattern, sandbox_required) for comparisons."""
        return (
            self.get_type(tool_name),
            self.get_target_param(tool_name),
            self.get_pattern_param(tool_name),
            self.requires_sandbox(tool_name),
        )


# ---------------------------------------------------------------------------
# Shared registration helpers
# ---------------------------------------------------------------------------


def snake_to_pascal(name: str) -> str:
    """Convert ``snake_case`` to ``PascalCase``."""
    return "".join(p.capitalize() for p in name.split("_"))


class GovernanceRegistrationConflict(ValueError):
    """Raised when a governance policy identity would be reused unsafely."""


def register_tool_governance(
    registry: ToolRegistry,
    python_name: str,
    tool_type: str,
    target_param: str = "",
    policy_name: str = "",
    pattern_param: str = "",
    sandbox_required: bool = False,
) -> str:
    """Register one tool into the governance registry.

    Idempotent only when the existing policy identity is owned by the same
    ``python_name`` and metadata (type / target / pattern / sandbox) match.
    Conflicting re-registration fails closed.

    Used by:
    - builtin ``@tool_descriptor`` scan (``_register_from_descriptors``)
    - ``PluginApi.register_tool`` (issue #6114)
    - goal-mode ``register_goal_tools_governance``

    Returns the policy-layer tool name that was registered
    (or already present with identical metadata).
    """
    pname = policy_name or snake_to_pascal(python_name)
    new_identity = (
        tool_type,
        target_param or "",
        pattern_param or "",
        bool(sandbox_required),
    )
    existing_type = registry.get_type(pname)
    existing_map = registry.get_mapped_policy_name(python_name)

    if existing_map is not None and existing_map != pname:
        raise GovernanceRegistrationConflict(
            f"Python tool {python_name!r} already maps to policy "
            f"{existing_map!r}; cannot remap to {pname!r}",
        )

    if existing_type == "unknown":
        registry.register(
            pname,
            tool_type,
            target_param,
            pattern_param=pattern_param,
            sandbox_required=sandbox_required,
        )
        registry.register_python_name(python_name, pname)
        return pname

    existing_identity = registry.get_identity(pname)
    if existing_identity != new_identity:
        raise GovernanceRegistrationConflict(
            f"Governance policy identity conflict for {pname!r}: "
            f"existing type/target/pattern/sandbox="
            f"{existing_identity!r}, requested {new_identity!r}",
        )

    if existing_map is None:
        # Another python name already owns this policy identity.
        raise GovernanceRegistrationConflict(
            f"Policy name {pname!r} is already registered; refusing to map "
            f"additional python tool {python_name!r} onto it "
            f"(name-fold / ownership collision)",
        )

    # Same python_name + identical metadata → idempotent.
    return pname


def _register_from_descriptors(registry: ToolRegistry) -> None:
    """Register builtins that declare governance.tool_type on descriptors."""
    try:
        # Side-effect import so @tool_descriptor registrations run.
        from ..agents import tools as _agents_tools  # noqa: F401
        from ..runtime.tool_registry import get_builtin_tool_funcs

        _ = _agents_tools
    except Exception as exc:  # noqa: BLE001
        logger.error(
            "Failed to import agents.tools for governance registration: %s. "
            "Built-in tools will be missing from the governance whitelist "
            "and denied at Phase 0 until import succeeds.",
            exc,
            exc_info=True,
        )
        return

    for fn in get_builtin_tool_funcs():
        desc = getattr(fn, "_tool_descriptor", None)
        if desc is None:
            continue
        gov = getattr(desc, "governance", None)
        if gov is None or not gov.tool_type:
            continue
        register_tool_governance(
            registry,
            python_name=desc.name,
            tool_type=gov.tool_type,
            target_param=gov.target_param,
            policy_name=gov.policy_name,
            pattern_param=gov.pattern_param,
            sandbox_required=gov.fail_without_sandbox,
        )


def _register_non_descriptor_tools(registry: ToolRegistry) -> None:
    """Register tools that intentionally skip ``@tool_descriptor`` collection.

    Exception path for dynamic / mode-scoped tools that must not appear in
    the global builtin set (scroll ``recall_history*``, memory manager
    ``memory_search``). Keep this list documented when adding similar tools.
    """
    # Scroll strategy tools — hand-built descriptors, not global builtins.
    register_tool_governance(
        registry,
        python_name="recall_history",
        tool_type="internal",
        target_param="op",
        policy_name="RecallHistory",
    )
    register_tool_governance(
        registry,
        python_name="recall_history_python",
        tool_type="shell",
        target_param="source",
        policy_name="RecallHistoryPython",
        sandbox_required=True,
    )
    # Memory manager tool — registered dynamically outside agents.tools.
    register_tool_governance(
        registry,
        python_name="memory_search",
        tool_type="internal",
        target_param="",
        policy_name="MemorySearch",
    )


def _collect_governance_gaps(registry: ToolRegistry) -> list[str]:
    """Return names of collected builtins missing a governance identity.

    Every function in the builtin runtime collection must declare a non-empty
    ``governance.tool_type`` and be present in ``registry``. Empty tool_type
    is itself a gap — tools must not appear in toolkit/UI without Phase 0
    metadata.
    """
    from ..runtime.tool_registry import get_builtin_tool_funcs

    gaps: list[str] = []
    for fn in get_builtin_tool_funcs():
        desc = getattr(fn, "_tool_descriptor", None)
        if desc is None:
            continue
        gov = getattr(desc, "governance", None)
        if gov is None or not gov.tool_type:
            gaps.append(desc.name)
            logger.error(
                "Governance gap: tool %r is runtime-registered but has no "
                "governance.tool_type (Phase 0 DENY / invisible to registry).",
                desc.name,
            )
            continue
        pname = gov.policy_name or snake_to_pascal(desc.name)
        if registry.get_type(pname) == "unknown":
            gaps.append(pname)
            logger.error(
                "Governance gap: tool %r (policy %r) is runtime-registered "
                "but missing from the governance registry (Phase 0 DENY).",
                desc.name,
                pname,
            )
    return gaps


def assert_no_governance_gaps() -> list[str]:
    """Return names of collected builtins missing governance identity.

    Includes descriptors with empty ``governance.tool_type``.
    """
    return _collect_governance_gaps(DEFAULT_REGISTRY)


# ---------------------------------------------------------------------------
# Default registry (lazy singleton)
# ---------------------------------------------------------------------------


def _create_default_registry() -> ToolRegistry:
    """Create and populate the default ToolRegistry."""
    registry = ToolRegistry()
    _register_from_descriptors(registry)
    _register_non_descriptor_tools(registry)
    gaps = _collect_governance_gaps(registry)
    if gaps:
        logger.warning(
            "Governance registry built with %d gap(s): %s",
            len(gaps),
            ", ".join(gaps),
        )
    return registry


class _LazyDefaultRegistry:
    """Proxy that builds the real registry on first attribute access.

    Keeps the public name ``DEFAULT_REGISTRY`` stable for call sites while
    delaying construction until after ``agents.tools`` imports can run.
    """

    __slots__ = ("_instance", "_lock")

    def __init__(self) -> None:
        object.__setattr__(self, "_instance", None)
        object.__setattr__(self, "_lock", threading.Lock())

    def _get(self) -> ToolRegistry:
        inst = object.__getattribute__(self, "_instance")
        if inst is not None:
            return inst
        lock = object.__getattribute__(self, "_lock")
        with lock:
            inst = object.__getattribute__(self, "_instance")
            if inst is None:
                inst = _create_default_registry()
                object.__setattr__(self, "_instance", inst)
            return inst

    def __getattr__(self, name: str) -> Any:
        return getattr(self._get(), name)

    def __copy__(self) -> "_LazyDefaultRegistry":
        # Singleton: copy must not duplicate the lock.
        return self

    def __deepcopy__(self, memo: dict[int, Any]) -> "_LazyDefaultRegistry":
        memo[id(self)] = self
        return self

    def _reset_for_tests(self) -> None:
        """Drop the cached instance (test helper only)."""
        lock = object.__getattribute__(self, "_lock")
        with lock:
            object.__setattr__(self, "_instance", None)


DEFAULT_REGISTRY: Any = _LazyDefaultRegistry()
