#!/bin/bash

# Check integrity of files after being copied and report results.


set -e

print_usage() {
    echo "Usage: $(basename $0) [options] <filename> <destination path>"
    echo "Options:"
    echo "    -r  <size MB>       generate and use random data file of specified size (MB)"
    echo "    -l  <count>         loop process a specified number of times" 
    echo "    -v                  verbose output"
}

print_results() {
    echo "Passed: $pass"
    echo "Failed: $fail"
}

# Parse options
rand_file=0
loop_count=1
verbose=0
while getopts r:l:v opt; do
    case $opt in
        r)
            rand_file=1
            rand_file_size=$OPTARG
            ;;
        l)
            loop_count=$OPTARG
            ;;
        v)
            verbose=1
            ;;
        ?)
            print_usage
            exit 2
            ;;
    esac
done
shift $((OPTIND - 1))

# Check for arguments
filename=$1
dest_path=$2
if [ -z "$filename" ] || [ -z "$dest_path" ]; then
    print_usage
    exit 1
fi

# Verify destination path
if [ ! -d "$dest_path" ]; then
    echo "Destination path does not exist"
    exit 1
fi

pass=0
fail=0

for ((i = 1; i <= $loop_count; i++)); do
    # Generate random file
    if [ "$rand_file" -eq 1 ]; then
        if [ "$verbose" -eq 1 ]; then
            echo -e "Generating random file of size "$rand_file_size"MB...\n"
        fi
        dd if=/dev/random of="$filename" bs=1M count="$rand_file_size" 2> /dev/null
    fi
    
    # Copy source file to destination path
    if [ "$verbose" -eq 1 ]; then
        echo -e "Copying source file to destination path...\n"
    fi
    cp "$filename" "$dest_path"
    
    # Calculate hashes
    if [ "$verbose" -eq 1 ]; then
        echo -e "Calculating hashes...\n"
    fi
    src_hash=$(md5sum $filename | awk '{print $1}')
    dest_hash=$(md5sum $dest_path/$filename | awk '{print $1}')
    if [ "$verbose" -eq 1 ]; then
        echo "$src_hash  (source)"
        echo -e "$dest_hash  (destination)\n"
    fi
    
    # Count hashes that pass or fail
    if [ "$src_hash" = "$dest_hash" ]; then
        ((++pass))
    else
        ((++fail))
    fi

    # Print results occasionally
    if [ "$verbose" -eq 1 ] && [ $(($i % 5)) -eq 0 ] && [ "$i" -ne "$loop_count" ]; then
        print_results 
        echo
    fi
    
done

print_results