import re
from datetime import datetime
from typing import Literal

from pydantic import BaseModel, Field, field_validator, model_validator

ALLOWED_NAME_REGEX = re.compile(r"^[A-Za-z0-9_-]+$")
DeviceType = Literal["routeros", "switchos"]


class RouterBase(BaseModel):
    name: str = Field(min_length=1, max_length=120)
    device_type: DeviceType = "routeros"
    host: str = Field(min_length=1, max_length=255)
    port: int | None = Field(default=None, ge=1, le=65535)
    ssh_user: str | None = Field(default=None, max_length=120)
    ssh_key: str | None = None
    ssh_password: str | None = None

    @field_validator("name")
    @classmethod
    def validate_name(cls, value: str) -> str:
        if not ALLOWED_NAME_REGEX.match(value):
            raise ValueError("Only letters, digits, dashes and underscores are allowed")
        return value

    @field_validator("host", "ssh_user", "ssh_key", "ssh_password", mode="before")
    @classmethod
    def normalize_text(cls, value: str | None) -> str | None:
        normalized = (value or "").strip()
        return normalized or None

    @model_validator(mode="after")
    def apply_device_defaults(self):
        if self.device_type == "routeros":
            self.port = self.port or 22
            self.ssh_user = self.ssh_user or "admin"
            return self

        self.port = self.port or 80
        self.ssh_key = None
        return self


class RouterCreate(RouterBase):
    pass


class RouterUpdate(BaseModel):
    name: str | None = None
    device_type: DeviceType | None = None
    host: str | None = None
    port: int | None = Field(default=None, ge=1, le=65535)
    ssh_user: str | None = None
    ssh_key: str | None = None
    ssh_password: str | None = None

    @field_validator("name", "host", "ssh_user", "ssh_key", "ssh_password", mode="before")
    @classmethod
    def normalize_text(cls, value: str | None) -> str | None:
        normalized = (value or "").strip()
        return normalized or None


class RouterResponse(RouterBase):
    id: int
    owner_id: int
    effective_username: str | None = None
    uses_global_ssh_key: bool = False
    has_effective_ssh_key: bool = False
    uses_global_switchos_credentials: bool = False
    has_effective_password: bool = False
    supports_export: bool = False
    supports_restore_upload: bool = False
    last_connection_status: bool | None = None
    last_connection_tested_at: datetime | None = None
    last_connection_error: str | None = None
    last_connection_hostname: str | None = None
    last_connection_model: str | None = None
    last_connection_version: str | None = None
    last_connection_uptime: str | None = None
    last_connection_transport: str | None = None
    last_connection_server: str | None = None
    last_connection_auth_mode: str | None = None
    last_connection_http_status: str | None = None
    last_connection_backup_available: bool | None = None
    created_at: datetime | None = None

    model_config = {"from_attributes": True}


class RouterTestConnection(BaseModel):
    success: bool
    tested_at: datetime
    model: str
    uptime: str
    hostname: str
    version: str | None = None
    error: str | None = None
    transport: str | None = None
    server: str | None = None
    auth_mode: str | None = None
    http_status: str | None = None
    backup_available: bool | None = None