import machine
import os
import time

# --- Configuration for M5Stack CoreS3 SD Card ---
SD_SCK = 36
SD_MISO = 35
SD_MOSI = 37
SD_CS = 4

# Configuration for machine.SDCard
SD_SLOT = 2       # Typically used for SPI access on ESP32/S3
SD_FREQ = 1000000 # 1MHz frequency for reliable initialization
MOUNT_POINT = "/sd"
TEST_FILE_PATH = MOUNT_POINT + "/cores3_test_log.txt"

def initialize_and_mount_sd():
    """Initializes the SD card interface and mounts the filesystem."""
    print("Attempting to initialize SD card...")
    try:
        # Initialize the SDCard object using the specific pins for the CoreS3
        sd = machine.SDCard(
            slot=SD_SLOT,
            sck=machine.Pin(SD_SCK),
            miso=machine.Pin(SD_MISO),
            mosi=machine.Pin(SD_MOSI),
            cs=machine.Pin(SD_CS),
            freq=SD_FREQ
        )
        print("Hardware initialized.")

        # Mount the SD card filesystem (VfsFat)
        vfs = os.VfsFat(sd)
        os.mount(vfs, MOUNT_POINT)
        print(f"SD Card successfully mounted at {MOUNT_POINT}")
        return vfs
    except Exception as e:
        print(f"ERROR initializing or mounting SD card: {e}")
        print("Please ensure the SD card is inserted correctly and formatted (FAT32).")
        return None

def write_demo(filepath):
    """Writes sample data to a file on the SD card."""
    print(f"\n--- Writing Demo ---")
    content = "Hello from M5Stack CoreS3!\n"
    content += f"MicroPython SD Card Test.\nTimestamp: {time.time()}"

    try:
        # Open the file in write mode ('w')
        with open(filepath, "w") as f:
            bytes_written = f.write(content)
        print(f"Successfully wrote {bytes_written} bytes to {filepath}")
        return True
    except Exception as e:
        print(f"ERROR writing to file: {e}")
        return False

def read_demo(filepath):
    """Reads data from the file on the SD card."""
    print(f"\n--- Reading Demo ---")
    try:
        # Open the file in read mode ('r')
        with open(filepath, "r") as f:
            data = f.read()
        print(f"Contents of {filepath}:")
        print("-" * 30)
        print(data)
        print("-" * 30)
    except Exception as e:
        print(f"ERROR reading from file: {e}")

def list_directory_demo(path):
    """Lists the contents of the directory with file sizes."""
    print(f"\n--- Directory Listing Demo ({path}) ---")
    try:
        items = os.listdir(path)
        if not items:
            print("(Empty Directory)")
            return

        print(f"{'Name':<25} {'Size (Bytes)':>15}")
        print("-" * 41)
        for item in items:
            try:
                # os.stat returns a tuple; index 6 contains the file size
                stats = os.stat(path + "/" + item)
                size = stats[6]
                print(f"{item:<25} {size:>15}")
            except Exception as e:
                print(f"{item:<25} (Error getting stats)")
    except Exception as e:
        print(f"ERROR listing directory: {e}")

def unmount_sd(mount_point):
    """Unmounts the SD card filesystem."""
    print("\n--- Unmounting ---")
    try:
        # Crucial to prevent corruption
        os.umount(mount_point)
        print("SD Card unmounted successfully.")
    except Exception as e:
        print(f"ERROR unmounting SD Card: {e}")

def main():
    print("Starting M5Stack CoreS3 SD Card Demo")
    
    # 1. Initialize and Mount
    vfs = initialize_and_mount_sd()

    if vfs:
        # 2. List initial contents
        list_directory_demo(MOUNT_POINT)
        
        # 3. Write data
        if write_demo(TEST_FILE_PATH):
            # 4. Read data back
            read_demo(TEST_FILE_PATH)
        
        # 5. List contents again to show the new file and size
        list_directory_demo(MOUNT_POINT)
        
        # 6. Unmount
        unmount_sd(MOUNT_POINT)
    else:
        print("Demo aborted due to SD card initialization failure.")

if __name__ == "__main__":
    main()