from __future__ import annotations

from dataclasses import dataclass
from pathlib import Path
import tomllib

from .models import Severity


DEFAULT_EXCLUDES = (".git", ".venv", "__pycache__", "build", "dist", "node_modules")


@dataclass(frozen=True, slots=True)
class Config:
    max_file_bytes: int = 2 * 1024 * 1024
    minimum_severity: Severity = Severity.LOW
    exclude: tuple[str, ...] = DEFAULT_EXCLUDES
    enabled_rules: tuple[str, ...] | None = None

    @classmethod
    def from_file(cls, path: Path | None) -> "Config":
        if path is None:
            return cls()
        with path.open("rb") as handle:
            data = tomllib.load(handle)
        scan = data.get("scan", {})
        rules = data.get("rules", {})
        max_bytes = int(scan.get("max_file_bytes", cls.max_file_bytes))
        if max_bytes < 1:
            raise ValueError("scan.max_file_bytes must be positive")
        excluded = tuple(str(item) for item in scan.get("exclude", DEFAULT_EXCLUDES))
        enabled = rules.get("enabled")
        return cls(
            max_file_bytes=max_bytes,
            minimum_severity=Severity.parse(str(scan.get("minimum_severity", "low"))),
            exclude=excluded,
            enabled_rules=tuple(str(item) for item in enabled) if enabled is not None else None,
        )


STARTER_CONFIG = """[scan]
max_file_bytes = 2097152
minimum_severity = "low"
exclude = [".git", ".venv", "__pycache__", "build", "dist", "node_modules"]

[rules]
enabled = [
  "AAISA-SECRET-001",
  "AAISA-PROMPT-001",
  "AAISA-DEPENDENCY-001",
  "AAISA-CONTAINER-001",
  "AAISA-PROVENANCE-001",
  "AAISA-AGENT-001",
  "AAISA-PROVENANCE-002",
  "AAISA-MLBOM-001",
]
"""