"""Set of functions to interact with the UTBM UV api."""

import requests
from django.conf import settings
from django.utils.functional import cached_property

from pedagogy.schemas import ShortUvList, UtbmFullUvSchema, UtbmShortUvSchema, UvSchema


class UtbmApiClient(requests.Session):
    """A wrapper around `requests.Session` to perform requests to the UTBM UV API."""

    BASE_URL = settings.SITH_PEDAGOGY_UTBM_API
    _cache = {}

    @cached_property
    def current_year(self) -> int:
        """Fetch from the API the latest existing year"""
        url = f"{self.BASE_URL}/guides/fr"
        response = self.get(url)
        return response.json()[-1]["annee"]

    def fetch_short_uvs(
        self, lang: str = "fr", year: int | None = None
    ) -> list[UtbmShortUvSchema]:
        """Get the list of UVs in their short format from the UTBM API"""
        if year is None:
            year = self.current_year
        if "short_uvs" not in self._cache:
            self._cache["short_uvs"] = {}
        if lang not in self._cache["short_uvs"]:
            self._cache["short_uvs"][lang] = {}
        if year not in self._cache["short_uvs"][lang]:
            url = f"{self.BASE_URL}/uvs/{lang}/{year}"
            response = self.get(url)
            uvs = ShortUvList.validate_json(response.content)
            self._cache["short_uvs"][lang][year] = uvs
        return self._cache["short_uvs"][lang][year]

    def find_uv(self, lang: str, code: str, year: int | None = None) -> UvSchema | None:
        """Find an UV from the UTBM API."""
        # query the UV list
        if not year:
            year = self.current_year
        # the UTBM API has no way to fetch a single short uv,
        # and short uvs contain infos that we need and are not
        # in the full uv schema, so we must fetch everything.
        short_uvs = self.fetch_short_uvs(lang, year)
        short_uv = next((uv for uv in short_uvs if uv.code == code), None)
        if short_uv is None:
            return None

        # get detailed information about the UV
        uv_url = f"{self.BASE_URL}/uv/{lang}/{year}/{code}/{short_uv.code_formation}"
        response = requests.get(uv_url)
        full_uv = UtbmFullUvSchema.model_validate_json(response.content)
        return make_clean_uv(short_uv, full_uv)


def make_clean_uv(short_uv: UtbmShortUvSchema, full_uv: UtbmFullUvSchema) -> UvSchema:
    """Cleans the data up so that it corresponds to our data representation.

    Some of the needed information are in the short uv schema, some
    other in the full uv schema.
    Thus we combine those information to obtain a data schema suitable
    for our needs.
    """
    if full_uv.departement == "Pôle Humanités":
        department = "HUMA"
    else:
        department = {
            "AL": "IMSI",
            "AE": "EE",
            "GI": "GI",
            "GC": "EE",
            "GM": "MC",
            "TC": "TC",
            "GP": "IMSI",
            "ED": "EDIM",
            "AI": "GI",
            "AM": "MC",
        }.get(short_uv.code_formation, "NA")

    match short_uv.ouvert_printemps, short_uv.ouvert_automne:
        case True, True:
            semester = "AUTUMN_AND_SPRING"
        case True, False:
            semester = "SPRING"
        case False, True:
            semester = "AUTUMN"
        case _:
            semester = "CLOSED"

    return UvSchema(
        title=full_uv.libelle,
        code=full_uv.code,
        credit_type=short_uv.code_categorie,
        semester=semester,
        language=short_uv.code_langue.upper(),
        credits=full_uv.credits_ects,
        department=department,
        hours_THE=next((i.nbh for i in full_uv.activites if i.code == "THE"), 0) // 60,
        hours_TD=next((i.nbh for i in full_uv.activites if i.code == "TD"), 0) // 60,
        hours_TP=next((i.nbh for i in full_uv.activites if i.code == "TP"), 0) // 60,
        hours_TE=next((i.nbh for i in full_uv.activites if i.code == "TE"), 0) // 60,
        hours_CM=next((i.nbh for i in full_uv.activites if i.code == "CM"), 0) // 60,
        manager=full_uv.respo_automne or full_uv.respo_printemps or "",
        objectives=full_uv.objectifs,
        program=full_uv.programme,
        skills=full_uv.acquisition_competences,
        key_concepts=full_uv.acquisition_notions,
    )