"""Types d'entrée et de sortie du moteur de validation.

Découplé de la base : le moteur ne connaît que ces structures simples, jamais
les modèles SQLModel. La couche appelante construit l'entrée depuis la base.
"""

import datetime as dt
from dataclasses import dataclass
from enum import StrEnum

from pydantic import BaseModel, Field

from app.models import AvailabilityStatus


class Severity(StrEnum):
    BLOCKING = "BLOCKING"
    WARNING = "WARNING"


class ViolationCode(StrEnum):
    SHIFT_OVERLAP = "SHIFT_OVERLAP"
    OUTSIDE_AVAILABILITY = "OUTSIDE_AVAILABILITY"
    DAILY_HOURS_EXCEEDED = "DAILY_HOURS_EXCEEDED"
    INSUFFICIENT_REST = "INSUFFICIENT_REST"
    MISSING_REQUIRED_SKILL = "MISSING_REQUIRED_SKILL"


SEVERITY_BY_CODE: dict[ViolationCode, Severity] = {
    ViolationCode.SHIFT_OVERLAP: Severity.BLOCKING,
    ViolationCode.OUTSIDE_AVAILABILITY: Severity.WARNING,
    ViolationCode.DAILY_HOURS_EXCEEDED: Severity.WARNING,
    ViolationCode.INSUFFICIENT_REST: Severity.WARNING,
    ViolationCode.MISSING_REQUIRED_SKILL: Severity.WARNING,
}


class Violation(BaseModel):
    """Une violation : un **code** + des paramètres structurés, jamais de phrase
    (traduction via `locales/fr.json`, clés `validation.<CODE>`)."""

    code: ViolationCode
    severity: Severity
    params: dict[str, str | int] = Field(default_factory=dict)

    @classmethod
    def of(cls, code: ViolationCode, **params: str | int) -> "Violation":
        return cls(code=code, severity=SEVERITY_BY_CODE[code], params=params)


@dataclass(frozen=True)
class ShiftInfo:
    id: str
    starts_at: dt.datetime
    ends_at: dt.datetime
    required_skill_codes: frozenset[str] = frozenset()


@dataclass(frozen=True)
class DayPartWindow:
    code: str
    start_time: dt.time
    # end_time <= start_time  ⇒  la demi-journée passe minuit.
    end_time: dt.time
    order: int


@dataclass(frozen=True)
class AvailabilityDeclaration:
    date: dt.date
    day_part_code: str
    status: AvailabilityStatus


@dataclass(frozen=True)
class ValidationInput:
    """Tout ce qu'il faut pour valider une affectation candidate.

    `existing_shifts` = les créneaux des autres affectations **actives**
    (`PROPOSED` / `CONFIRMED`) du même bénévole ; le filtrage par statut est à
    la charge de l'appelant.
    """

    candidate_shift: ShiftInfo
    volunteer_skill_codes: frozenset[str] = frozenset()
    existing_shifts: tuple[ShiftInfo, ...] = ()
    availabilities: tuple[AvailabilityDeclaration, ...] = ()
    day_parts: tuple[DayPartWindow, ...] = ()