import os
import machine
from machine import Pin, SDCard

class SDCardManager:
    """Utility class to mount and manage the onboard microSD card slot.
    
    Uses SDMMC 1-bit mode on Pins: sck=2, cmd=1, data0=3.
    """
    
    def __init__(self, mount_point='/sd'):
        self.mount_point = mount_point
        self.sd = None
        self.mounted = False

    def mount(self):
        """Initializes the SD card and mounts it to the filesystem.
        
        Returns:
            bool: True if mounted successfully, False otherwise.
        """
        if self.mounted:
            print(f"SD card already mounted at {self.mount_point}")
            return True
            
        try:
            print("Initializing SDCard (SDMMC 1-bit mode: sck=2, cmd=1, data0=3)...")
            # slot=1 uses the SDMMC peripheral on the ESP32-S3
            self.sd = SDCard(slot=1, width=1, sck=2, cmd=1, data=(3,))
            
            print(f"Mounting SD card to {self.mount_point}...")
            os.mount(self.sd, self.mount_point)
            self.mounted = True
            print("SD card mounted successfully!")
            return True
        except Exception as e:
            print(f"Failed to mount SD card: {e}")
            self.sd = None
            self.mounted = False
            return False

    def unmount(self):
        """Unmounts the SD card from the filesystem."""
        if not self.mounted:
            return True
            
        try:
            print(f"Unmounting SD card from {self.mount_point}...")
            os.umount(self.mount_point)
            self.mounted = False
            self.sd = None
            print("SD card unmounted.")
            return True
        except Exception as e:
            print(f"Failed to unmount SD card: {e}")
            return False

    def is_mounted(self):
        """Returns True if the card is currently mounted."""
        return self.mounted

    def list_files(self):
        """Lists files on the SD card if mounted.
        
        Returns:
            list: List of filenames or None if not mounted.
        """
        if not self.mounted:
            print("SD card is not mounted.")
            return None
        try:
            return os.listdir(self.mount_point)
        except Exception as e:
            print(f"Error listing SD card files: {e}")
            return None

    def get_info(self):
        """Returns storage information of the SD card.
        
        Returns:
            dict: {total_bytes, free_bytes} or None on error.
        """
        if not self.mounted:
            return None
        try:
            stat = os.statvfs(self.mount_point)
            block_size = stat[0]
            total_blocks = stat[2]
            free_blocks = stat[3]
            
            return {
                "total_bytes": total_blocks * block_size,
                "free_bytes": free_blocks * block_size
            }
        except Exception as e:
            print(f"Error getting SD card info: {e}")
            return None