from datetime import datetime
from typing import Literal

from pydantic import BaseModel, Field, field_validator

from app.schemas.validators import normalize_required_text, validate_host, validate_ssh_username


ConnectionType = Literal["ssh", "docker_api", "agent"]
EnvironmentName = Literal["production", "staging", "development", "other"]


class ServerBase(BaseModel):
    name: str = Field(min_length=1, max_length=128)
    host: str = Field(min_length=1, max_length=255)
    port: int = Field(default=22, ge=1, le=65535)
    ssh_username: str | None = Field(default=None, min_length=1, max_length=128)
    connection_type: ConnectionType = "ssh"
    environment: EnvironmentName = "production"
    is_active: bool = True

    @field_validator("name")
    @classmethod
    def validate_name_value(cls, value: str) -> str:
        return normalize_required_text(value, field_name="name")

    @field_validator("host")
    @classmethod
    def validate_host_value(cls, value: str) -> str:
        return validate_host(value)

    @field_validator("ssh_username")
    @classmethod
    def validate_ssh_username_value(cls, value: str | None) -> str | None:
        return validate_ssh_username(value)


class ServerCreate(ServerBase):
    pass


class ServerUpdate(BaseModel):
    name: str | None = Field(default=None, min_length=1, max_length=128)
    host: str | None = Field(default=None, min_length=1, max_length=255)
    port: int | None = Field(default=None, ge=1, le=65535)
    ssh_username: str | None = Field(default=None, min_length=1, max_length=128)
    connection_type: ConnectionType | None = None
    environment: EnvironmentName | None = None
    is_active: bool | None = None

    @field_validator("name")
    @classmethod
    def validate_name_value(cls, value: str | None) -> str | None:
        if value is None:
            return None
        return normalize_required_text(value, field_name="name")

    @field_validator("host")
    @classmethod
    def validate_host_value(cls, value: str | None) -> str | None:
        if value is None:
            return None
        return validate_host(value)

    @field_validator("ssh_username")
    @classmethod
    def validate_ssh_username_value(cls, value: str | None) -> str | None:
        return validate_ssh_username(value)


class ServerRead(ServerBase):
    id: int
    created_at: datetime

    model_config = {"from_attributes": True}


class ServerHealthRead(BaseModel):
    server_id: int
    reachable: bool
    status: str
    checked_at: datetime
    detail: str | None = None


class ServerMetricsRead(BaseModel):
    server_id: int
    cpu_percent: float
    memory_percent: float
    disk_percent: float
    uptime_seconds: int
    load_average: list[float]
    collected_at: datetime