---

#!/bin/bash

# === Настройки ===
TARGET_DIR="${1:-.}"
DRY_RUN=false
FORCE_ALL=true
REPLACE_SPACES=false

# === Защищённые расширения (файлы с такими расширениями пропускаются) ===
# OpenPGP/GnuPG: sig, asc, pgp, gpg
# S/MIME PKCS#7: p7s, p7c, p7b, p7d, p7r, spc
# КриптоПро/ГОСТ: sgn, sign
PROTECTED_EXT=("sig" "asc" "pgp" "gpg" "p7s" "p7c" "p7b" "p7d" "p7r" "spc" "sgn" "sign")

# === Таблица MIME -> расширение ===
declare -A MIME_TO_EXT=(
    ["application/pdf"]="pdf"
    ["application/vnd.openxmlformats-officedocument.wordprocessingml.document"]="docx"
    ["application/msword"]="doc"
    ["application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"]="xlsx"
    ["application/vnd.ms-excel"]="xls"
    ["application/vnd.openxmlformats-officedocument.presentationml.presentation"]="pptx"
    ["application/vnd.ms-powerpoint"]="ppt"
    ["application/zip"]="zip"
    ["application/x-tar"]="tar"
    ["application/gzip"]="gz"
    ["application/x-bzip2"]="bz2"
    ["application/x-xz"]="xz"
    ["image/jpeg"]="jpg"
    ["image/png"]="png"
    ["image/gif"]="gif"
    ["image/svg+xml"]="svg"
    ["text/plain"]="txt"
    ["text/html"]="html"
    ["text/x-shellscript"]="sh"
    ["inode/x-empty"]=""
)

rename_file() {
    local oldpath="$1"
    local newpath="$2"
    if [[ "$oldpath" == "$newpath" ]]; then
        return
    fi
    if [[ "$DRY_RUN" == true ]]; then
        echo "[DRY RUN] mv '$oldpath' '$newpath'"
    else
        mv -n "$oldpath" "$newpath" && echo "✓ $oldpath -> $newpath"
    fi
}

export DRY_RUN REPLACE_SPACES PROTECTED_EXT
export -f rename_file
export MIME_TO_EXT

find "$TARGET_DIR" -type f -print0 | while IFS= read -r -d '' filepath; do
    filename=$(basename -- "$filepath")
    dirname=$(dirname -- "$filepath")

    # Определяем расширение (часть после последней точки)
    if [[ "$filename" == *.* ]]; then
        ext="${filename##*.}"
    else
        ext=""
    fi

    # Пропускаем файлы с защищёнными расширениями
    if [[ -n "$ext" ]] && [[ " ${PROTECTED_EXT[@]} " =~ " ${ext} " ]]; then
        continue
    fi

    # Базовое имя (до первой точки или всё, если точки нет)
    if [[ "$filename" == *.* ]]; then
        base="${filename%%.*}"
    else
        base="$filename"
    fi

    if [[ "$REPLACE_SPACES" == true ]]; then
        base="${base// /_}"
    fi

    mime=$(file --mime-type -b "$filepath" 2>/dev/null)
    if [[ -z "$mime" ]]; then
        echo "⚠ Не удалось определить MIME-тип: $filepath" >&2
        continue
    fi

    new_ext="${MIME_TO_EXT[$mime]}"
    if [[ -z "$new_ext" ]]; then
        continue
    fi

    new_filename="${base}.${new_ext}"
    new_filepath="${dirname}/${new_filename}"

    rename_file "$filepath" "$new_filepath"
done

echo "Готово."