"""Deterministic task routing for GAIA Level 1."""

from __future__ import annotations

import re
from dataclasses import dataclass
from enum import Enum
from pathlib import Path
from typing import Any


class Route(str, Enum):
    WEB = "web_research"
    YOUTUBE = "youtube_transcript"
    AUDIO = "audio_transcription"
    IMAGE_CHESS = "image_chess"
    PYTHON = "python_execution"
    SPREADSHEET = "spreadsheet"
    MARKDOWN_TABLE = "markdown_table"
    TEXT_TRANSFORM = "text_transformation"
    GENERAL = "general_reasoning"


@dataclass(frozen=True)
class RouteDecision:
    route: Route
    reason: str
    requires_llm: bool


def _looks_reversed(text: str) -> bool:
    reversed_text = text[::-1].lower()
    clues = ("write ", "answer", "sentence", "opposite", "reverse")
    return sum(clue in reversed_text for clue in clues) >= 2


class TaskRouter:
    def route(
        self, task: dict[str, Any], file_path: Path | None = None
    ) -> RouteDecision:
        question = str(task.get("question", ""))
        suffix = (
            file_path.suffix
            if file_path
            else Path(str(task.get("file_name", ""))).suffix
        ).lower()
        if suffix in {".mp3", ".wav", ".m4a", ".ogg", ".flac"}:
            return RouteDecision(Route.AUDIO, f"audio attachment ({suffix})", True)
        if suffix in {".png", ".jpg", ".jpeg", ".webp"}:
            return RouteDecision(
                Route.IMAGE_CHESS, f"image attachment ({suffix})", True
            )
        if suffix == ".py":
            return RouteDecision(Route.PYTHON, "Python attachment", False)
        if suffix in {".xlsx", ".xls"}:
            return RouteDecision(Route.SPREADSHEET, "spreadsheet attachment", True)
        if re.search(r"(?:youtube\.com/watch|youtu\.be/)", question, re.IGNORECASE):
            return RouteDecision(Route.YOUTUBE, "YouTube URL", True)
        if _looks_reversed(question) or re.search(
            r"\b(reverse|alphabeti[sz]e|uppercase|lowercase|replace every|rot-?13|numeric(?:ally)? sort|calculate|compute|evaluate|extract the \d+)\b",
            question,
            re.IGNORECASE,
        ):
            return RouteDecision(
                Route.TEXT_TRANSFORM, "deterministic text operation", False
            )
        if re.search(r"^\s*\|.+\|\s*$", question, re.MULTILINE):
            return RouteDecision(Route.MARKDOWN_TABLE, "Markdown table", True)
        if re.search(
            r"https?://|\b(what|who|when|where|which|how many|latest|wikipedia|article|published)\b",
            question,
            re.IGNORECASE,
        ):
            return RouteDecision(Route.WEB, "requires external facts", True)
        return RouteDecision(Route.GENERAL, "no deterministic specialist matched", True)