"""Planification de la synchronisation CalDAV.

Ce module compare les données Pronote normalisées aux événements distants
marqués comme gérés par ``pronote-sync`` et produit un plan de synchronisation
CalDAV (ajouts, mises à jour, suppressions) pour chaque catégorie d'événement :
cours, devoirs et événements scolaires.

Le plan est calculé de manière pure et déterministe : deux entrées identiques
produisent un plan identique, et un événement dont la signature sémantique
n'a pas changé n'apparaît dans aucune liste du plan (idempotence).
"""

from __future__ import annotations

from typing import Any

from pronote_sync.models.agenda import Lesson, SchoolEvent
from pronote_sync.models.homework import Homework
from pronote_sync.models.pronote import PronoteData
from pronote_sync.models.sync import CalDAVSyncPlan
from pronote_sync.sync.serialization import (
    component_to_signature,
    homework_to_vevent,
    lesson_to_vevent,
    school_event_to_vevent,
)


def compute_plan(
    pronote_data: PronoteData,
    remote_managed: list[tuple[str, Any]],
) -> CalDAVSyncPlan:
    """Calcule le plan de synchronisation CalDAV.

    :param pronote_data: Données Pronote normalisées (cours, devoirs, événements).
    :param remote_managed: Liste de couples (uid, vevent) pour les événements
        distants marqués comme gérés par pronote-sync.
    :return: Plan de synchronisation avec les listes d'ajouts, mises à jour et
        suppressions pour chaque type d'événement.
    :rtype: CalDAVSyncPlan
    """
    remote_signatures: dict[str, str] = {}
    for uid, vevent in remote_managed:
        remote_signatures[uid] = component_to_signature(vevent)

    lessons_to_add: list[Lesson] = []
    lessons_to_update: list[Lesson] = []
    lessons_to_remove: list[str] = []

    local_lessons_by_uid: dict[str, Lesson] = {lesson.id: lesson for lesson in pronote_data.lessons}
    for lesson in pronote_data.lessons:
        local_sig = component_to_signature(lesson_to_vevent(lesson))
        if lesson.id not in remote_signatures:
            lessons_to_add.append(lesson)
        elif remote_signatures[lesson.id] != local_sig:
            lessons_to_update.append(lesson)
    for uid in remote_signatures:
        if (
            uid not in local_lessons_by_uid
            and not uid.startswith("homework-")
            and not uid.startswith("school-event-")
        ):
            lessons_to_remove.append(uid)

    homeworks_to_add: list[Homework] = []
    homeworks_to_update: list[Homework] = []
    homeworks_to_remove: list[str] = []

    local_homeworks_by_uid: dict[str, Homework] = {
        f"homework-{homework.id}": homework for homework in pronote_data.homeworks
    }
    for homework in pronote_data.homeworks:
        uid = f"homework-{homework.id}"
        local_sig = component_to_signature(homework_to_vevent(homework))
        if uid not in remote_signatures:
            homeworks_to_add.append(homework)
        elif remote_signatures[uid] != local_sig:
            homeworks_to_update.append(homework)
    for uid in remote_signatures:
        if uid.startswith("homework-") and uid not in local_homeworks_by_uid:
            homeworks_to_remove.append(uid)

    school_events_to_add: list[SchoolEvent] = []
    school_events_to_update: list[SchoolEvent] = []
    school_events_to_remove: list[str] = []

    local_school_events_by_uid: dict[str, SchoolEvent] = {
        f"school-event-{event.label}-{event.from_date.isoformat()}": event
        for event in pronote_data.school_events
    }
    for school_event in pronote_data.school_events:
        uid = f"school-event-{school_event.label}-{school_event.from_date.isoformat()}"
        local_sig = component_to_signature(school_event_to_vevent(school_event))
        if uid not in remote_signatures:
            school_events_to_add.append(school_event)
        elif remote_signatures[uid] != local_sig:
            school_events_to_update.append(school_event)
    for uid in remote_signatures:
        if uid.startswith("school-event-") and uid not in local_school_events_by_uid:
            school_events_to_remove.append(uid)

    return CalDAVSyncPlan(
        lessons_to_add=lessons_to_add,
        lessons_to_update=lessons_to_update,
        lessons_to_remove=lessons_to_remove,
        homeworks_to_add=homeworks_to_add,
        homeworks_to_update=homeworks_to_update,
        homeworks_to_remove=homeworks_to_remove,
        school_events_to_add=school_events_to_add,
        school_events_to_update=school_events_to_update,
        school_events_to_remove=school_events_to_remove,
    )