#!/bin/bash
# maravento.com
#
################################################################################
#
# makemd5 - Create MD5 checksum files using zenity
#
# Nautilus Path: ~/.local/share/nautilus/scripts or ~/.config/nautilus/scripts
# Caja Path: ~/.config/caja/scripts
# Thunar Path: ~/.local/share/Thunar/scripts or ~/.config/Thunar/scripts
# Nemo Path: ~/.local/share/nemo/scripts
#
################################################################################

set -uo pipefail

# check no-root
if [ "$(id -u)" == "0" ]; then
    echo "[ERROR] This script should not be run as root."
    exit 1
fi

echo "Start MakeMD5. Wait..."

show_error() {
    zenity --error --title="Make MD5" --text="$1"
    exit 1
}

show_info() {
    zenity --info --title="Make MD5" --text="$1"
}

if ! command -v zenity &> /dev/null; then
    echo "Error: zenity is required but not installed."
    exit 1
fi

if ! command -v md5sum &> /dev/null; then
    show_error "Error: md5sum is required but not installed."
fi

files=()

if [ -n "${NAUTILUS_SCRIPT_SELECTED_FILE_PATHS:-}" ]; then
    IFS=$'\n' read -d '' -r -a files <<< "$NAUTILUS_SCRIPT_SELECTED_FILE_PATHS"
elif [ -n "${THUNAR_SELECTION:-}" ]; then
    IFS=$'\n' read -d '' -r -a files <<< "$THUNAR_SELECTION"
elif [ -n "${NEMO_SCRIPT_SELECTED_FILE_PATHS:-}" ]; then
    IFS=$'\n' read -d '' -r -a files <<< "$NEMO_SCRIPT_SELECTED_FILE_PATHS"
elif [ "$#" -gt 0 ]; then
    files=("$@")
else
    selection=$(zenity --file-selection \
                       --multiple \
                       --separator='|' \
                       --title="Select files to create checksums for")
    zenity_exit=$?
    [ "$zenity_exit" -ne 0 ] && exit 0
    IFS='|' read -r -a files <<< "$selection"
fi

if [ "${#files[@]}" -eq 0 ]; then
    show_error "No files selected."
fi

for file in "${files[@]}"; do
    if [ ! -e "$file" ]; then
        show_error "'$file' does not exist."
    fi
    if [ -d "$file" ]; then
        show_error "'$file' is a directory.\nThis script only works with files."
    fi
    if [ ! -r "$file" ]; then
        show_error "Cannot read '$file'.\nCheck file permissions."
    fi
done

if [ "${#files[@]}" -eq 1 ]; then
    single_file="${files[0]}"
    default_name="$(basename "$single_file").md5"
    dialog_text="Creating checksum for: $(basename "$single_file")\n\nChecksum file name:"
else
    default_name="checksums.md5"
    dialog_text="Creating checksums for ${#files[@]} files.\n\nChecksum file name:"
fi

choice=$(zenity --list \
               --title="MD5 Checksum Generation" \
               --text="$dialog_text" \
               --radiolist \
               --column="Select" \
               --column="Option" \
               --column="Description" \
               TRUE "auto" "Use automatic naming: $default_name" \
               FALSE "custom" "Choose custom name" \
               --height=350 \
               --width=800)

case "$choice" in
    "auto")
        if [ "${#files[@]}" -eq 1 ]; then
            checksum_file="$(dirname "${files[0]}")/$default_name"
        else
            checksum_file="$(dirname "${files[0]}")/$default_name"
        fi
        ;;
    "custom")
        checksum_file=$(zenity --file-selection \
                              --save \
                              --confirm-overwrite \
                              --filename="$default_name" \
                              --title="Save MD5 checksum file as...")
        zenity_exit=$?
        [ "$zenity_exit" -ne 0 ] && exit 0
        ;;
    *)
        exit 0
        ;;
esac

if [ -z "$checksum_file" ]; then
    show_error "No checksum file name specified."
fi

if [ "$choice" = "auto" ] && [ -e "$checksum_file" ]; then
    if ! zenity --question \
                --title="File Exists" \
                --text="Checksum file already exists:\n$(basename "$checksum_file")\n\nDo you want to overwrite it?"; then
        show_info "Operation cancelled."
        exit 0
    fi
fi

temp_dir=$(mktemp -d)
manifest_file="$temp_dir/files.txt"
trap 'rm -rf "$temp_dir"' EXIT

checksum_dir=$(dirname "$checksum_file")
for file in "${files[@]}"; do
    if [[ "$file" == "$checksum_dir"* ]]; then
        rel_path=$(realpath --relative-to="$checksum_dir" "$file")
        echo "$rel_path" >> "$manifest_file"
    else
        echo "$file" >> "$manifest_file"
    fi
done

(
    echo "# Calculating MD5 checksums..."
    echo "10"

    total_files=${#files[@]}
    current=0

    > "$checksum_file"

    while IFS= read -r file_path; do
        current=$((current + 1))
        progress=$((10 + (current * 80 / total_files)))

        echo "$progress"
        echo "# Processing $(basename "$file_path") ($current/$total_files)..."

        if [[ "$file_path" == /* ]]; then
            actual_file="$file_path"
        else
            actual_file="$checksum_dir/$file_path"
        fi

        if hash=$(md5sum "$actual_file" 2>/dev/null); then
            checksum_only=$(echo "$hash" | awk '{print $1}')
            printf '%s %s\n' "$checksum_only" "$file_path" >> "$checksum_file"
        else
            echo "Error processing $file_path" >&2
            exit 1
        fi
    done < "$manifest_file"

    echo "100"
    echo "# Complete!"

) | zenity --progress \
           --title="Creating MD5 Checksums" \
           --text="Initializing..." \
           --percentage=0 \
           --auto-close

progress_exit=$?

if [ "$progress_exit" -eq 0 ] && [ -s "$checksum_file" ]; then
    file_count=$(wc -l < "$checksum_file")
    show_info "SUCCESS\n\nChecksum file created: $(basename "$checksum_file")\nFiles processed: $file_count\nLocation: $(dirname "$checksum_file")\n\nYou can now use this file to verify the integrity of your files."
else
    show_error "FAILED\n\nUnable to create checksum file.\nCheck that you have write permissions in the target directory."
fi