Mini Shell

"""
Tracing utils
"""
from __future__ import annotations

from typing import Any
from typing import Callable
from typing import Sequence
from typing import Tuple


_Writer = Callable[[str], None]
_Processor = Callable[[Tuple[str, ...], Tuple[Any, ...]], None]


class TagTracer:
    def __init__(self) -> None:
        self._tags2proc: dict[tuple[str, ...], _Processor] = {}
        self._writer: _Writer | None = None
        self.indent = 0

    def get(self, name: str) -> TagTracerSub:
        return TagTracerSub(self, (name,))

    def _format_message(self, tags: Sequence[str], args: Sequence[object]) -> str:
        if isinstance(args[-1], dict):
            extra = args[-1]
            args = args[:-1]
        else:
            extra = {}

        content = " ".join(map(str, args))
        indent = "  " * self.indent

        lines = ["{}{} [{}]\n".format(indent, content, ":".join(tags))]

        for name, value in extra.items():
            lines.append(f"{indent}    {name}: {value}\n")

        return "".join(lines)

    def _processmessage(self, tags: tuple[str, ...], args: tuple[object, ...]) -> None:
        if self._writer is not None and args:
            self._writer(self._format_message(tags, args))
        try:
            processor = self._tags2proc[tags]
        except KeyError:
            pass
        else:
            processor(tags, args)

    def setwriter(self, writer: _Writer) -> None:
        self._writer = writer

    def setprocessor(self, tags: str | tuple[str, ...], processor: _Processor) -> None:
        if isinstance(tags, str):
            tags = tuple(tags.split(":"))
        else:
            assert isinstance(tags, tuple)
        self._tags2proc[tags] = processor


class TagTracerSub:
    def __init__(self, root: TagTracer, tags: tuple[str, ...]) -> None:
        self.root = root
        self.tags = tags

    def __call__(self, *args: object) -> None:
        self.root._processmessage(self.tags, args)

    def get(self, name: str) -> TagTracerSub:
        return self.__class__(self.root, self.tags + (name,))