import os
from dataclasses import dataclass


def _as_bool(value: str, default: bool) -> bool:
    if value is None:
        return default
    return value.strip() not in {"0", "false", "False", ""}


def _env_path(key: str, default_path: str) -> str:
    return os.path.abspath(os.environ.get(key, default_path))


@dataclass(frozen=True)
class ModelPaths:
    classification: str
    projection: str
    detection: str


@dataclass(frozen=True)
class AppConfig:
    models: ModelPaths
    postprocessing: bool
    interpolate_missing: bool
    results_dir: str
    detect_eps_px: float
    detect_min_len: int
    detect_zero_gap: int
    detect_edge_zero_extend: int
    merge_max_gap: int
    min_cobb_main: float
    min_cobb_second_abs: float
    min_cobb_second_rel: float
    min_len_struct_small: int
    min_len_struct_large: int
    min_apex_margin_small: int
    min_apex_margin_large: int


def load_config() -> AppConfig:
    base_dir = os.path.dirname(__file__)
    default_results = os.path.join(base_dir, "results")

    models = ModelPaths(
        classification=_env_path(
            "MODEL_CLASSIFICATION",
            os.path.join(base_dir, "models", "classification.pt"),
        ),
        projection=_env_path(
            "MODEL_PROJECTION",
            os.path.join(base_dir, "models", "projection.pt"),
        ),
        detection=_env_path(
            "MODEL_DETECTION",
            os.path.join(base_dir, "models", "1_best_yolo8(L).pt"),
        ),
    )

    return AppConfig(
        models=models,
        postprocessing=_as_bool(os.environ.get("POSTPROCESSING"), True),
        interpolate_missing=_as_bool(os.environ.get("INTERPOLATE_MISSING"), False),
        results_dir=_env_path("RESULTS_DIR", default_results),
        detect_eps_px=float(os.environ.get("DETECT_EPS_PX", 1.0)),
        detect_min_len=int(os.environ.get("DETECT_MIN_LEN", 2)),
        detect_zero_gap=int(os.environ.get("DETECT_ZERO_GAP", 2)),
        detect_edge_zero_extend=int(os.environ.get("DETECT_EDGE_ZERO_EXTEND", 3)),
        merge_max_gap=int(os.environ.get("MERGE_MAX_GAP", 1)),
        min_cobb_main=float(os.environ.get("MIN_COBB_MAIN", 1.0)),
        min_cobb_second_abs=float(os.environ.get("MIN_COBB_SECOND_ABS", 5.0)),
        min_cobb_second_rel=float(os.environ.get("MIN_COBB_SECOND_REL", 0.35)),
        min_len_struct_small=int(os.environ.get("MIN_LEN_STRUCT_SMALL", 3)),
        min_len_struct_large=int(os.environ.get("MIN_LEN_STRUCT_LARGE", 4)),
        min_apex_margin_small=int(os.environ.get("MIN_APEX_MARGIN_SMALL", 1)),
        min_apex_margin_large=int(os.environ.get("MIN_APEX_MARGIN_LARGE", 2)),
    )