from __future__ import annotations

from datetime import datetime
from typing import ClassVar
from uuid import UUID
from zoneinfo import ZoneInfo, ZoneInfoNotFoundError

from pydantic import BaseModel, ConfigDict, Field, field_validator

from schemas.inbox.messages import (
    CalendarContent,
    CalendarDeleteContent,
    CalendarInviteContent,
    CalendarUpdateContent,
    parse_calendar_content,
)
from schemas.schedule.items import (
    AttachmentType,
    ScheduleItemMetadata,
    ScheduleItemMetadataAttachment,
    ScheduleItemSourceType,
    ScheduleItemStatus,
)

__all__ = [
    "AttachmentType",
    "CalendarContent",
    "CalendarDeleteContent",
    "CalendarInviteContent",
    "CalendarUpdateContent",
    "ScheduleItemMetadata",
    "ScheduleItemMetadataAttachment",
    "ScheduleItemSourceType",
    "ScheduleItemStatus",
    "parse_calendar_content",
    "ScheduleItemCreateRequest",
    "ScheduleItemUpdateRequest",
    "ScheduleItemResponse",
    "ScheduleItemListItem",
    "ScheduleItemListRequest",
    "ScheduleItemShareRequest",
    "ScheduleItemShareResponse",
]


class ScheduleItemCreateRequest(BaseModel):
    model_config: ClassVar[ConfigDict] = ConfigDict(extra="forbid")

    title: str = Field(min_length=1, max_length=255)
    description: str | None = Field(default=None, max_length=2000)
    start_at: datetime
    end_at: datetime | None = None
    timezone: str = Field(..., min_length=1, max_length=50)
    metadata: ScheduleItemMetadata | None = None

    @field_validator("timezone")
    @classmethod
    def validate_timezone(cls, value: str) -> str:
        try:
            ZoneInfo(value)
        except ZoneInfoNotFoundError as exc:
            raise ValueError("timezone must be a valid IANA timezone") from exc
        return value

    @field_validator("start_at", "end_at")
    @classmethod
    def validate_datetime_tzinfo(cls, value: datetime | None) -> datetime | None:
        if value is None:
            return None
        if value.tzinfo is None:
            raise ValueError("datetime must include timezone offset")
        return value


class ScheduleItemUpdateRequest(BaseModel):
    model_config: ClassVar[ConfigDict] = ConfigDict(extra="forbid")

    title: str | None = Field(default=None, min_length=1, max_length=255)
    description: str | None = Field(default=None, max_length=2000)
    start_at: datetime | None = None
    end_at: datetime | None = None
    timezone: str | None = Field(default=None, max_length=50)
    metadata: ScheduleItemMetadata | None = None
    status: ScheduleItemStatus | None = None

    @field_validator("timezone")
    @classmethod
    def validate_timezone(cls, value: str | None) -> str | None:
        if value is None:
            return None
        try:
            ZoneInfo(value)
        except ZoneInfoNotFoundError as exc:
            raise ValueError("timezone must be a valid IANA timezone") from exc
        return value

    @field_validator("start_at", "end_at")
    @classmethod
    def validate_datetime_tzinfo(cls, value: datetime | None) -> datetime | None:
        if value is None:
            return None
        if value.tzinfo is None:
            raise ValueError("datetime must include timezone offset")
        return value


class ScheduleItemResponse(BaseModel):
    model_config: ClassVar[ConfigDict] = ConfigDict(from_attributes=True)

    id: UUID
    owner_id: UUID
    title: str
    description: str | None = None
    start_at: datetime
    end_at: datetime | None = None
    timezone: str
    metadata: ScheduleItemMetadata | None = None
    status: ScheduleItemStatus
    source_type: ScheduleItemSourceType
    created_at: datetime
    updated_at: datetime
    permission: int = 1
    is_owner: bool = False


class ScheduleItemListItem(BaseModel):
    model_config: ClassVar[ConfigDict] = ConfigDict(from_attributes=True)

    id: UUID
    title: str
    start_at: datetime
    end_at: datetime | None = None
    timezone: str
    status: ScheduleItemStatus


class ScheduleItemListRequest(BaseModel):
    start_at: datetime
    end_at: datetime

    @field_validator("start_at", "end_at")
    @classmethod
    def validate_datetime_tzinfo(cls, value: datetime) -> datetime:
        if value.tzinfo is None:
            raise ValueError("datetime must include timezone offset")
        return value


_PERMISSION_VIEW = 1
_PERMISSION_INVITE = 2
_PERMISSION_EDIT = 4


class ScheduleItemShareRequest(BaseModel):
    model_config: ClassVar[ConfigDict] = ConfigDict(extra="forbid")

    phone: str = Field(
        ...,
        pattern=r"^\+861[3-9]\d{9}$",
        description="Phone of user to share with",
    )
    permission_view: bool = Field(True, description="Grant view permission")
    permission_edit: bool = Field(False, description="Grant edit permission")
    permission_invite: bool = Field(False, description="Grant invite permission")

    def _permission_value(self) -> int:
        value = 0
        if self.permission_view:
            value |= _PERMISSION_VIEW
        if self.permission_edit:
            value |= _PERMISSION_EDIT
        if self.permission_invite:
            value |= _PERMISSION_INVITE
        return value


class ScheduleItemShareResponse(BaseModel):
    message: str