from collections import defaultdict
from pathlib import Path
from typing import Optional

from ..entry import Entry, EntryDetector
from .util import PresetUtil

__all__ = ("PresetEntryDetector",)


class PresetEntryDetector(EntryDetector):
    def __init__(self, filename: Path):
        self._preset = PresetUtil.resolve_preset(filename)

    def detect_entry(self, basepath: Path) -> Optional["Entry"]:
        tasks = defaultdict(list)
        for preset_name, preset in self._preset.presets.items():
            filename = basepath / preset.filename
            if filename.exists():
                loader = PresetUtil.resolve_loader(preset.loader)
                with open(filename, "rb") as fd:
                    data = loader(fd)
                for task_name, task_pack in preset.tasks.items():
                    for task_item_name, task in task_pack.items():
                        if PresetUtil.check_conditions(data, task.conditions):
                            tasks[task_name] += task.commands
        if tasks:
            return Entry(tasks, basepath)