from __future__ import annotations

import os
from collections.abc import Mapping
from dataclasses import dataclass

DEFAULT_MODEL = "claude-haiku-4-5"
DEFAULT_TIMEOUT_SECONDS = 5.0

ENABLED_ENV = "SEMANTIC_ENRICHMENT_ENABLED"
MODEL_ENV = "SEMANTIC_MODEL"
TIMEOUT_ENV = "SEMANTIC_TIMEOUT_SECONDS"


@dataclass(frozen=True)
class SemanticConfig:
    enabled: bool = False
    model: str = DEFAULT_MODEL
    timeout: float = DEFAULT_TIMEOUT_SECONDS


def load_config(env: Mapping[str, str] | None = None) -> SemanticConfig:
    values = env or os.environ
    return SemanticConfig(
        enabled=_parse_bool(values.get(ENABLED_ENV), default=False),
        model=values.get(MODEL_ENV) or DEFAULT_MODEL,
        timeout=_parse_timeout(values.get(TIMEOUT_ENV)),
    )


def _parse_bool(value: str | None, *, default: bool) -> bool:
    if value is None:
        return default
    return value.strip().lower() in {"1", "true", "yes", "on", "enabled"}


def _parse_timeout(value: str | None) -> float:
    if value is None:
        return DEFAULT_TIMEOUT_SECONDS
    try:
        timeout = float(value)
    except ValueError:
        return DEFAULT_TIMEOUT_SECONDS
    return timeout if timeout > 0 else DEFAULT_TIMEOUT_SECONDS