import datetime
import decimal
import logging
from dataclasses import dataclass
from typing import NamedTuple
from zoneinfo import ZoneInfo, ZoneInfoNotFoundError

from pydantic import AwareDatetime, BaseModel, Field

logger = logging.getLogger(__name__)


class CampaignSendTimezone(BaseModel):
    iana_tz_id: str = Field(alias="ianaTzId")
    utc_offset_std: decimal.Decimal = Field(alias="utcOffsetStd")
    state_provinces: list[str] | None = Field(alias="stateProvinces")
    quiet_hours_min: str = Field(alias="quietHoursMin")
    quiet_hours_max: str = Field(alias="quietHoursMax")
    next_safe_time: AwareDatetime | None = Field(alias="nextSafeTime")
    is_in_safe_hours: bool = Field(alias="isInSafeHours")
    is_adjusted: bool = Field(default=False, alias="isAdjusted")
    send_at_local: datetime.datetime = Field(alias="sendAtLocal")

    @property
    def is_sendable(self) -> bool:
        """Safe to send now, either naturally or via an explicit marketer override."""
        return self.is_in_safe_hours or self.is_adjusted

    @property
    def safe_until(self) -> datetime.datetime | None:
        if not self.is_in_safe_hours:
            return None

        try:
            hour, minute = (int(part) for part in self.quiet_hours_max.split(":")[:2])
            tzinfo = ZoneInfo(self.iana_tz_id)
            local_close = datetime.datetime.combine(
                self.send_at_local.date(), datetime.time(hour, minute)
            )
        except (ValueError, ZoneInfoNotFoundError) as exc:
            logger.warning(
                "Could not resolve safe-hours end for timezone `%s`: %s",
                self.iana_tz_id,
                exc,
                extra={"iana_tz_id": self.iana_tz_id},
            )
            return None

        return local_close.replace(tzinfo=tzinfo).astimezone(datetime.UTC)


class CampaignSendCountry(BaseModel):
    country_code: str = Field(alias="countryCode")
    timezones: list[CampaignSendTimezone]


class CampaignSendTimezonesResponse(BaseModel):
    countries: list[CampaignSendCountry]


@dataclass(frozen=True, slots=True)
class BatchGate:
    is_sendable: bool
    safe_until: datetime.datetime | None


class FanGroupCount(NamedTuple):
    country_code: str
    state_province: str | None
    recipient_count: int


class BatchSend(NamedTuple):
    batch_id: int
    campaign_id: str
    country_code: str
    state_province: str | None
    messages_to_send: int
    safe_until: datetime.datetime | None