import hashlib
import os

def calculate_checksum(file_name):
    sha256_hash = hashlib.sha256()

    with open(file_name, 'rb') as file:
        for chunk in iter(lambda: file.read(4096), b''):
            sha256_hash.update(chunk)

    return sha256_hash.hexdigest()

def upload_file(target, file_name):
    try:
        file_size = os.path.getsize(file_name)
        chunk_size = 1024  # Set the chunk size for file transfer
        total_bytes = 0  # Track the total bytes transferred

        checksum = calculate_checksum(file_name)

        with open(file_name, 'rb') as file:
            while True:
                chunk = file.read(chunk_size)
                if not chunk:
                    break  # Exit the loop when the end of file is reached

                try:
                    target.sendall(chunk)
                    total_bytes += len(chunk)

                    # Calculate and display the upload progress
                    progress = (total_bytes / file_size) * 100
                    print(f"Uploading {file_name}: {progress:.2f}% completed")

                except Exception as e:
                    print(f"An error occurred during file upload: {str(e)}")
                    break

        print(f"File '{file_name}' uploaded successfully. Total bytes transferred: {total_bytes}")

        # Verify checksum on the server side
        reliable_send(target, checksum)
        verification_status = reliable_recv(target)
        if verification_status:
            print("Checksum verification successful.")
        else:
            print("Checksum verification failed.")

    except FileNotFoundError:
        print(f"Error: File '{file_name}' not found.")
    except IOError as e:
        print(f"Error reading file '{file_name}': {str(e)}")
    except Exception as e:
        print(f"An error occurred while handling file '{file_name}': {str(e)}")

import hashlib

def calculate_checksum(data):
    sha256_hash = hashlib.sha256()
    sha256_hash.update(data)
    return sha256_hash.hexdigest()

def download_file(target, file_name, type):
    try:
        f = open(file_name, 'wb')
        if type == 1:
            target.settimeout(2)
            chunk = target.recv(1024)
            while chunk:
                f.write(chunk)
                try:
                    chunk = target.recv(1024)
                except socket.timeout as e:
                    break
        elif type == 2:
            target.settimeout(5)
            try:
                chunk = target.recv(10485760)
            except:
                pass

            while chunk:
                f.write(chunk)
                try:
                    chunk = target.recv(10485760)
                except:
                    break
        target.settimeout(None)
        f.close()

        # Verify checksum after file download
        file_data = open(file_name, 'rb').read()
        received_checksum = reliable_recv(target)
        calculated_checksum = calculate_checksum(file_data)

        if received_checksum == calculated_checksum:
            reliable_send(target, True)  # Send checksum verification success status
            print(f"File '{file_name}' downloaded successfully. Checksum verification successful.")
        else:
            reliable_send(target, False)  # Send checksum verification failure status
            print(f"File '{file_name}' downloaded successfully. Checksum verification failed.")

    except Exception as e:
        print(f"An error occurred during file download: {str(e)}")