import typing as t
from collections import defaultdict
from functools import reduce
from operator import and_, or_
from pathlib import Path
from types import MappingProxyType

import yaml
from django.conf import settings


def _transform_name(resource_name: str) -> str:
    return resource_name.title().replace('And', 'and', -1)


Resource = dict[str, t.Union[str, list[dict[str, str]], dict[str, list[str]]]]

RESOURCES_PATH = Path(settings.BASE_DIR, "pydis_site", "apps", "resources", "resources")

RESOURCES: MappingProxyType[str, Resource] = MappingProxyType({
    path.stem: yaml.safe_load(path.read_text())
    for path in RESOURCES_PATH.rglob("*.yaml")
})

_resource_table = {category: defaultdict(set) for category in (
    "topics",
    "payment_tiers",
    "complexity",
    "type"
)}

for name, resource in RESOURCES.items():
    for category, tags in resource['tags'].items():
        for tag in tags:
            _resource_table[category][_transform_name(tag)].add(name)

# Freeze the resources table
RESOURCE_TABLE = MappingProxyType({
    category: MappingProxyType(d)
    for category, d in _resource_table.items()
})

ALL_RESOURCE_NAMES = frozenset(RESOURCES.keys())


def get_resources_from_search(search_categories: dict[str, set[str]]) -> list[Resource]:
    """Returns a list of all resources that match the given search terms."""
    resource_names_that_match = reduce(
        and_,
        (
            reduce(
                or_,
                (RESOURCE_TABLE[category][label] for label in labels),
                set()
            ) or ALL_RESOURCE_NAMES
            for category, labels in search_categories.items()
        )
    )
    return [RESOURCES[name_] for name_ in resource_names_that_match]