"""The model's side of hooks: Python callables, and the inner-tool gate."""

import albedo_hooks
from albedo_api import PythonApi


class Hooks:
    """Python hooks: around your own tool calls (the `python` tool, and inside
    cells `run` as `Bash` and `files.read/edit/write` as `Read`, `Edit`,
    `Write`), on each user prompt, and when a turn is about to end."""

    def register(self, event: str, callback, matcher: str | None = None):
        """Call `callback(input)` around matching tool calls. `event` is
        "PreToolUse", "PostToolUse", "UserPromptSubmit" or "Stop"; `matcher`
        is a regex on the tool name (None matches all; tool events only).
        `input` is a dict like a command hook's stdin: hook_event_name, then
        tool_name, tool_input (and tool_response after) for tool events,
        prompt for UserPromptSubmit, last_assistant_message and
        stop_hook_active for Stop. "Stop" with a block keeps the turn going.
        Return None, or a dict in the Claude Code hook output format, e.g.
        {"decision": "block", "reason": "..."}, {"hookSpecificOutput":
        {"permissionDecision": "deny", "permissionDecisionReason": "..."}},
        {"hookSpecificOutput": {"permissionDecision": "allow", "updatedInput":
        {...}}}, or {"hookSpecificOutput": {"additionalContext": "..."}}.
        A blocked call raises PermissionError. Callbacks run before command
        hooks, sync or async, and fail open if they raise. They live and die
        with this kernel. Answers a function that removes the callback."""
        return albedo_hooks.register(event, callback, matcher)

    def registered(self) -> list[tuple[str, str | None]]:
        """The (event, matcher) of every callback registered here."""
        return [(event, matcher) for event, matcher, _ in albedo_hooks.registered()]

    def clear(self) -> None:
        """Remove every callback registered here."""
        albedo_hooks.clear()

    def __repr__(self) -> str:
        return f"hooks({len(albedo_hooks.registered())} callbacks)"


def setup(api: PythonApi) -> dict[str, object]:
    albedo_hooks.install(api.host_sync)

    def shutdown() -> None:
        albedo_hooks.install(None)
        albedo_hooks.clear()

    api.on_shutdown(shutdown)
    return {"hooks": Hooks()}