from datetime import datetime, timezone
from enum import StrEnum
from typing import Self
from uuid import UUID

from pydantic import BaseModel, ConfigDict, Field, HttpUrl, model_validator


class State(StrEnum):
    UNKNOWN = "unknown"
    UP = "up"
    DOWN = "down"
    ERROR = "error"


class CurrentStatus(BaseModel):
    model_config = ConfigDict(extra="forbid")
    state: State = State.UNKNOWN
    checked_at: datetime | None = None
    latency_ms: float | None = Field(default=None, ge=0)
    http_status: int | None = Field(default=None, ge=100, le=599)
    final_url: str | None = None
    error: str | None = None


class MonitorCreate(BaseModel):
    model_config = ConfigDict(extra="forbid")
    name: str = Field(min_length=1, max_length=120)
    url: HttpUrl

    @model_validator(mode="after")
    def safe_url_shape(self) -> Self:
        if self.url.scheme not in {"http", "https"}:
            raise ValueError("only http and https URLs are supported")
        if self.url.username is not None or self.url.password is not None:
            raise ValueError("URL credentials are not allowed")
        return self


class MonitorUpdate(BaseModel):
    model_config = ConfigDict(extra="forbid")
    name: str | None = Field(default=None, min_length=1, max_length=120)
    url: HttpUrl | None = None

    @model_validator(mode="after")
    def validate_update(self) -> Self:
        if self.name is None and self.url is None:
            raise ValueError("at least one field is required")
        if self.url is not None:
            if self.url.scheme not in {"http", "https"}:
                raise ValueError("only http and https URLs are supported")
            if self.url.username is not None or self.url.password is not None:
                raise ValueError("URL credentials are not allowed")
        return self


class Monitor(BaseModel):
    model_config = ConfigDict(extra="forbid")
    id: UUID
    name: str
    url: HttpUrl
    created_at: datetime
    updated_at: datetime
    current_status: CurrentStatus


def utcnow() -> datetime:
    return datetime.now(timezone.utc)