import json
import os
from pathlib import Path


# ===== Settings Persistence Model =====
class LocalSettings:
    # ===== Defaults =====
    def __init__(self):
        self.chamber_id = ""
        self.reverse_z_wafer = False
        self.master = {}  # Dict[str, str]
        self.wafer_data_size = {}  # Dict[str, int]
        self.debug = False
        self.wafer_read_retries = 8
        # Timeout in msec for reading from the wafer (default 2 min)
        self.wafer_read_timeout = 120000
        self.wafer_detect_timeout = 5000
        self.split_threshold = 40.0

    # ===== File Path Helpers =====
    @classmethod
    def _settings_path(cls, directory: str) -> Path:
        return Path(directory) / "settings.json"

    # ===== Load/Save =====
    @classmethod
    def read_settings(cls, directory: str) -> "LocalSettings":
        """Read settings from settings.json in the provided directory."""
        settings = cls()
        path = cls._settings_path(directory)

        if not path.exists():
            return settings

        try:
            with open(path, "r", encoding="utf-8") as f:
                data = json.load(f)
            for key, value in data.items():
                if hasattr(settings, key):
                    setattr(settings, key, value)
        except Exception as e:
            print(f"Error reading setting file: {e}")

        return settings

    @classmethod
    def save_settings(cls, directory: str, settings: "LocalSettings") -> None:
        """Save the current settings instance to settings.json."""
        path = cls._settings_path(directory)
        path.parent.mkdir(parents=True, exist_ok=True)
        data = settings.__dict__.copy()

        try:
            with open(path, "w", encoding="utf-8") as f:
                json.dump(data, f, indent=4)
        except Exception as e:
            print(f"Error saving settings: {e}")

    # ===== Master File Helpers =====
    @classmethod
    def get_master(cls, directory: str, wtype: str) -> str:
        """Return the full path to a master file if it exists."""
        settings = cls.read_settings(directory)
        if wtype not in settings.master:
            return ""

        file_path = Path(directory) / settings.master[wtype]
        if file_path.exists():
            return str(file_path)
        return ""

    @classmethod
    def set_master(cls, directory: str, wtype: str, filename: str) -> None:
        """Store a master filename for a wafer type and save settings."""
        settings = cls.read_settings(directory)
        settings.master[wtype] = os.path.basename(filename)
        cls.save_settings(directory, settings)

    # ===== Wafer Sizing =====
    def get_wafer_data_size(self, wtype: str) -> int:
        """Return the expected transfer size in bytes for a wafer type."""
        if not wtype:
            return 393216

        if wtype in self.wafer_data_size:
            return self.wafer_data_size[wtype]

        if wtype == "P":
            return 393216
        if wtype == "X":
            return 1310720
        return 393216