from pathlib import Path
import tomllib
from typing import Literal

from pydantic import BaseModel, ConfigDict, Field, field_validator


class ProviderConfig(BaseModel):
    model_config = ConfigDict(extra="forbid")
    base_url: str = "http://127.0.0.1:1234/v1"
    model: str = ""
    api_key_env: str = "LM_STUDIO_API_KEY"
    timeout: float = Field(default=180, gt=0, le=3600)
    temperature: float = Field(default=0.2, ge=0, le=2)
    max_tokens: int = Field(default=4096, ge=1, le=131072)
    prompt_style: Literal["generic", "hy_mt"] = "generic"
    top_p: float | None = Field(default=None, gt=0, le=1)
    top_k: int | None = Field(default=None, ge=0)
    repetition_penalty: float | None = Field(default=None, gt=0, le=3)
    autostart: bool = False
    startup_timeout: float = Field(default=90, gt=0, le=600)
    load_model: str = ""
    load_context_length: int = Field(default=8192, ge=512, le=262144)

    @field_validator("base_url")
    @classmethod
    def validate_url(cls, value: str) -> str:
        from urllib.parse import urlsplit
        url = urlsplit(value)
        if url.scheme not in {"http", "https"} or not url.hostname or url.username or url.password or url.query or url.fragment:
            raise ValueError("Expected an HTTP(S) base URL without credentials, query or fragment")
        return value.rstrip("/")


class Settings(BaseModel):
    model_config = ConfigDict(extra="forbid")
    database: str = "data/translations.sqlite3"
    port: int = Field(default=8787, ge=1, le=65535)
    providers: dict[str, ProviderConfig] = Field(default_factory=lambda: {
        "lmstudio": ProviderConfig(prompt_style="hy_mt", temperature=0.7, top_p=0.6, top_k=20, repetition_penalty=1.05)
    })


def load_settings(path: str = "config.toml") -> Settings:
    config_path = Path(path).resolve()
    if config_path.exists():
        with config_path.open("rb") as stream:
            settings = Settings.model_validate(tomllib.load(stream))
    else:
        settings = Settings()
    db = Path(settings.database)
    if not db.is_absolute():
        settings.database = str(config_path.parent / db)
    return settings