import re
from pydantic import BaseModel, ConfigDict, field_validator
from datetime import datetime
from typing import Literal, Optional

AccentColor = Literal["cyan", "blue", "green", "purple", "red", "orange", "pink", "yellow"]

_NTFY_TOPIC_RE = re.compile(r'^[a-zA-Z0-9_-]{1,64}$')


class SettingsUpdate(BaseModel):
    accent_color: Optional[AccentColor] = None
    upcoming_days: int | None = None
    preferred_name: str | None = None
    weather_city: str | None = None
    weather_lat: float | None = None
    weather_lon: float | None = None
    first_day_of_week: int | None = None

    # ntfy configuration fields
    ntfy_server_url: Optional[str] = None
    ntfy_topic: Optional[str] = None
    # Empty string means "clear the token"; None means "leave unchanged"
    ntfy_auth_token: Optional[str] = None
    ntfy_enabled: Optional[bool] = None
    ntfy_events_enabled: Optional[bool] = None
    ntfy_reminders_enabled: Optional[bool] = None
    ntfy_todos_enabled: Optional[bool] = None
    ntfy_projects_enabled: Optional[bool] = None
    ntfy_event_lead_minutes: Optional[int] = None
    ntfy_todo_lead_days: Optional[int] = None
    ntfy_project_lead_days: Optional[int] = None

    @field_validator('first_day_of_week')
    @classmethod
    def validate_first_day(cls, v: int | None) -> int | None:
        if v is not None and v not in (0, 1):
            raise ValueError('first_day_of_week must be 0 (Sunday) or 1 (Monday)')
        return v

    @field_validator('weather_lat')
    @classmethod
    def validate_lat(cls, v: float | None) -> float | None:
        if v is not None and (v < -90 or v > 90):
            raise ValueError('Latitude must be between -90 and 90')
        return v

    @field_validator('weather_lon')
    @classmethod
    def validate_lon(cls, v: float | None) -> float | None:
        if v is not None and (v < -180 or v > 180):
            raise ValueError('Longitude must be between -180 and 180')
        return v

    @field_validator('ntfy_server_url')
    @classmethod
    def validate_ntfy_url(cls, v: Optional[str]) -> Optional[str]:
        if v is None or v == "":
            return None
        from urllib.parse import urlparse
        parsed = urlparse(v)
        if parsed.scheme not in ("http", "https"):
            raise ValueError("ntfy server URL must use http or https")
        if not parsed.netloc:
            raise ValueError("ntfy server URL must include a hostname")
        # Strip trailing slash — ntfy base URL must not have one
        return v.rstrip("/")

    @field_validator('ntfy_topic')
    @classmethod
    def validate_ntfy_topic(cls, v: Optional[str]) -> Optional[str]:
        if v is None or v == "":
            return None
        if not _NTFY_TOPIC_RE.match(v):
            raise ValueError(
                "ntfy topic must be 1-64 alphanumeric characters, hyphens, or underscores"
            )
        return v

    @field_validator('ntfy_auth_token')
    @classmethod
    def validate_ntfy_token(cls, v: Optional[str]) -> Optional[str]:
        # Empty string signals "clear the token" — normalise to None for storage
        if v == "":
            return None
        if v is not None and len(v) > 500:
            raise ValueError("ntfy auth token must be at most 500 characters")
        return v

    @field_validator('ntfy_event_lead_minutes')
    @classmethod
    def validate_event_lead(cls, v: Optional[int]) -> Optional[int]:
        if v is not None and not (1 <= v <= 1440):
            raise ValueError("ntfy_event_lead_minutes must be between 1 and 1440")
        return v

    @field_validator('ntfy_todo_lead_days')
    @classmethod
    def validate_todo_lead(cls, v: Optional[int]) -> Optional[int]:
        if v is not None and not (0 <= v <= 30):
            raise ValueError("ntfy_todo_lead_days must be between 0 and 30")
        return v

    @field_validator('ntfy_project_lead_days')
    @classmethod
    def validate_project_lead(cls, v: Optional[int]) -> Optional[int]:
        if v is not None and not (0 <= v <= 30):
            raise ValueError("ntfy_project_lead_days must be between 0 and 30")
        return v


class SettingsResponse(BaseModel):
    id: int
    user_id: int
    accent_color: str
    upcoming_days: int
    preferred_name: str | None = None
    weather_city: str | None = None
    weather_lat: float | None = None
    weather_lon: float | None = None
    first_day_of_week: int = 0

    # ntfy fields — ntfy_auth_token is NEVER included here (security requirement 6.2)
    ntfy_server_url: Optional[str] = None
    ntfy_topic: Optional[str] = None
    ntfy_enabled: bool = False
    ntfy_events_enabled: bool = True
    ntfy_reminders_enabled: bool = True
    ntfy_todos_enabled: bool = True
    ntfy_projects_enabled: bool = True
    ntfy_event_lead_minutes: int = 15
    ntfy_todo_lead_days: int = 1
    ntfy_project_lead_days: int = 2
    # Derived field: computed via Settings.ntfy_has_token property (from_attributes reads it)
    ntfy_has_token: bool = False

    created_at: datetime
    updated_at: datetime

    model_config = ConfigDict(from_attributes=True)