#!/bin/bash

# ─── Config ───────────────────────────────────────────────────────────────────
CONFIG_DIR="$HOME/.config/backup_project"
INSTALL_PATH="/usr/local/bin/backup_project"

# ─── Help ─────────────────────────────────────────────────────────────────────
if [[ "$1" == "--help" || "$1" == "-h" ]]; then
  cat <<EOF

backup_project — Incremental folder backup with versioned naming

USAGE:
  backup_project [folder]                    Back up a folder (or current dir)
  backup_project --set-version X.Y.Z [folder]  Set the next version number (respects existing folders)
  backup_project --force X.Y.Z [folder]        Force exact version number (ignores existing folders, one-time)
  backup_project --install                   Install script system-wide to /usr/local/bin
  backup_project --help                      Show this help message

EXAMPLES:
  backup_project                             # backs up current directory
  backup_project ~/Documents/this-project   # backs up specified folder
  backup_project --set-version 2.0.15       # next backup will be 2.0.15 (or higher if folders exist)
  backup_project --force 2.0.15             # next backup will be exactly 2.0.15
  backup_project --force 2.0.15 ~/Documents/this-project

NOTES:
  - On first run for any folder, you will be prompted for a starting version (e.g. 2.0.12)
  - Each folder has its own config stored in ~/.config/backup_project/
  - Backups are created in the same parent directory as the source folder
  - To reset a folder's config:  rm ~/.config/backup_project/<config>.cfg
  - To view all configs:         ls ~/.config/backup_project/
  - To uninstall:                sudo rm /usr/local/bin/backup_project

EOF
  exit 0
fi

# ─── Self-install ─────────────────────────────────────────────────────────────
if [[ "$1" == "--install" ]]; then
  echo "Installing backup_project to $INSTALL_PATH ..."
  sudo cp "$0" "$INSTALL_PATH"
  sudo chmod +x "$INSTALL_PATH"
  echo "Done! You can now run 'backup_project [folder]' from anywhere."
  exit 0
fi

# ─── Set version override ─────────────────────────────────────────────────────
# Usage: backup_project --set-version 2.0.15 [folder]
if [[ "$1" == "--set-version" ]]; then
  NEW_VERSION="$2"
  SOURCE="$(realpath "${3:-$(pwd)}")"

  if ! echo "$NEW_VERSION" | grep -qP '^\d+(\.\d+)*\.\d+
# If no argument given, use current directory
if [ -z "$1" ]; then
  SOURCE="$(pwd)"
else
  SOURCE="$1"
fi

# Strip trailing slash, resolve to absolute path
SOURCE="$(realpath "${SOURCE%/}")"

if [ ! -d "$SOURCE" ]; then
  echo "Error: '$SOURCE' is not a directory."
  exit 1
fi

# ─── Load or create config for this source folder ────────────────────────────
mkdir -p "$CONFIG_DIR"

CONFIG_KEY=$(echo "$SOURCE" | tr '/' '_' | tr ' ' '_')
FOLDER_CONFIG="$CONFIG_DIR/${CONFIG_KEY}.cfg"

if [ ! -f "$FOLDER_CONFIG" ]; then
  echo "First time backing up '$(basename "$SOURCE")'."
  read -rp "Enter starting version (e.g. 2.0.12): " FULL_VERSION

  # Validate format: must be X.Y.Z (digits and dots, at least one dot, ends in digits)
  if ! echo "$FULL_VERSION" | grep -qP '^\d+(\.\d+)*\.\d+$'; then
    echo "Error: version must be in format like 2.0.12 or 1.0.0"
    exit 1
  fi

  # Split into prefix (everything before last dot) and starting minor (last number)
  BASE_VERSION="${FULL_VERSION%.*}"   # e.g. 2.0
  START_MINOR="${FULL_VERSION##*.}"   # e.g. 12

  echo "BASE_VERSION=$BASE_VERSION" > "$FOLDER_CONFIG"
  echo "START_MINOR=$START_MINOR"  >> "$FOLDER_CONFIG"
  echo "Saved: prefix='$BASE_VERSION', starting minor='$START_MINOR' for '$(basename "$SOURCE")'."
else
  source "$FOLDER_CONFIG"
fi

# ─── Find next version number ─────────────────────────────────────────────────
BASE_NAME=$(basename "$SOURCE")
PARENT_DIR=$(dirname "$SOURCE")

if [ -n "$FORCE_MINOR" ]; then
  # --force: use exactly this number, ignore existing folders, then clear the force
  NEXT="$FORCE_MINOR"
  echo "BASE_VERSION=$BASE_VERSION"  > "$FOLDER_CONFIG"
  echo "START_MINOR=$FORCE_MINOR"   >> "$FOLDER_CONFIG"
  echo "FORCE_MINOR="               >> "$FOLDER_CONFIG"
else
  # Find highest existing minor version >= START_MINOR
  LAST=$(ls -d "${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}".* 2>/dev/null \
    | grep -oP '\d+

DEST="${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}.${NEXT}"

# ─── Copy ─────────────────────────────────────────────────────────────────────
cp -r "$SOURCE" "$DEST"
echo "✓ Backed up '$(basename "$SOURCE")' → '$DEST'"
; then
    echo "Error: version must be in format like 2.0.15"
    exit 1
  fi

  CONFIG_KEY=$(echo "$SOURCE" | tr '/' '_' | tr ' ' '_')
  FOLDER_CONFIG="$CONFIG_DIR/${CONFIG_KEY}.cfg"

  if [ ! -f "$FOLDER_CONFIG" ]; then
    echo "Error: no config found for '$SOURCE'. Run a backup first."
    exit 1
  fi

  BASE_VERSION="${NEW_VERSION%.*}"
  START_MINOR="${NEW_VERSION##*.}"

  echo "BASE_VERSION=$BASE_VERSION"   > "$FOLDER_CONFIG"
  echo "START_MINOR=$START_MINOR"   >> "$FOLDER_CONFIG"
  echo "FORCE_MINOR="               >> "$FOLDER_CONFIG"
  echo "✓ Next backup of '$(basename "$SOURCE")' will be '$NEW_VERSION'"
  exit 0
fi

# ─── Force version override ───────────────────────────────────────────────────
# Usage: backup_project --force 2.0.15 [folder]
if [[ "$1" == "--force" ]]; then
  NEW_VERSION="$2"
  SOURCE="$(realpath "${3:-$(pwd)}")"

  if ! echo "$NEW_VERSION" | grep -qP '^\d+(\.\d+)*\.\d+

# ─── Resolve source folder ────────────────────────────────────────────────────
# If no argument given, use current directory
if [ -z "$1" ]; then
  SOURCE="$(pwd)"
else
  SOURCE="$1"
fi

# Strip trailing slash, resolve to absolute path
SOURCE="$(realpath "${SOURCE%/}")"

if [ ! -d "$SOURCE" ]; then
  echo "Error: '$SOURCE' is not a directory."
  exit 1
fi

# ─── Load or create config for this source folder ────────────────────────────
mkdir -p "$CONFIG_DIR"

CONFIG_KEY=$(echo "$SOURCE" | tr '/' '_' | tr ' ' '_')
FOLDER_CONFIG="$CONFIG_DIR/${CONFIG_KEY}.cfg"

if [ ! -f "$FOLDER_CONFIG" ]; then
  echo "First time backing up '$(basename "$SOURCE")'."
  read -rp "Enter starting version (e.g. 2.0.12): " FULL_VERSION

  # Validate format: must be X.Y.Z (digits and dots, at least one dot, ends in digits)
  if ! echo "$FULL_VERSION" | grep -qP '^\d+(\.\d+)*\.\d+$'; then
    echo "Error: version must be in format like 2.0.12 or 1.0.0"
    exit 1
  fi

  # Split into prefix (everything before last dot) and starting minor (last number)
  BASE_VERSION="${FULL_VERSION%.*}"   # e.g. 2.0
  START_MINOR="${FULL_VERSION##*.}"   # e.g. 12

  echo "BASE_VERSION=$BASE_VERSION" > "$FOLDER_CONFIG"
  echo "START_MINOR=$START_MINOR"  >> "$FOLDER_CONFIG"
  echo "Saved: prefix='$BASE_VERSION', starting minor='$START_MINOR' for '$(basename "$SOURCE")'."
else
  source "$FOLDER_CONFIG"
fi

# ─── Find next version number ─────────────────────────────────────────────────
BASE_NAME=$(basename "$SOURCE")
PARENT_DIR=$(dirname "$SOURCE")

# Find highest existing minor version, but only consider numbers >= START_MINOR
LAST=$(ls -d "${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}".* 2>/dev/null \
  | grep -oP '\d+$' \
  | awk -v start="$START_MINOR" '$1 >= start' \
  | sort -n \
  | tail -1)

if [ -z "$LAST" ]; then
  NEXT="$START_MINOR"
else
  NEXT=$((LAST + 1))
fi

DEST="${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}.${NEXT}"

# ─── Copy ─────────────────────────────────────────────────────────────────────
cp -r "$SOURCE" "$DEST"
echo "✓ Backed up '$(basename "$SOURCE")' → '$DEST'"
; then
    echo "Error: version must be in format like 2.0.15"
    exit 1
  fi

  CONFIG_KEY=$(echo "$SOURCE" | tr '/' '_' | tr ' ' '_')
  FOLDER_CONFIG="$CONFIG_DIR/${CONFIG_KEY}.cfg"

  if [ ! -f "$FOLDER_CONFIG" ]; then
    echo "Error: no config found for '$SOURCE'. Run a backup first."
    exit 1
  fi

  BASE_VERSION="${NEW_VERSION%.*}"
  FORCE_MINOR="${NEW_VERSION##*.}"

  echo "BASE_VERSION=$BASE_VERSION"     > "$FOLDER_CONFIG"
  echo "START_MINOR=$FORCE_MINOR"      >> "$FOLDER_CONFIG"
  echo "FORCE_MINOR=$FORCE_MINOR"      >> "$FOLDER_CONFIG"
  echo "✓ Next backup of '$(basename "$SOURCE")' will be forced to '$NEW_VERSION' (ignoring existing folders)"
  exit 0
fi

# ─── Resolve source folder ────────────────────────────────────────────────────
# If no argument given, use current directory
if [ -z "$1" ]; then
  SOURCE="$(pwd)"
else
  SOURCE="$1"
fi

# Strip trailing slash, resolve to absolute path
SOURCE="$(realpath "${SOURCE%/}")"

if [ ! -d "$SOURCE" ]; then
  echo "Error: '$SOURCE' is not a directory."
  exit 1
fi

# ─── Load or create config for this source folder ────────────────────────────
mkdir -p "$CONFIG_DIR"

CONFIG_KEY=$(echo "$SOURCE" | tr '/' '_' | tr ' ' '_')
FOLDER_CONFIG="$CONFIG_DIR/${CONFIG_KEY}.cfg"

if [ ! -f "$FOLDER_CONFIG" ]; then
  echo "First time backing up '$(basename "$SOURCE")'."
  read -rp "Enter starting version (e.g. 2.0.12): " FULL_VERSION

  # Validate format: must be X.Y.Z (digits and dots, at least one dot, ends in digits)
  if ! echo "$FULL_VERSION" | grep -qP '^\d+(\.\d+)*\.\d+$'; then
    echo "Error: version must be in format like 2.0.12 or 1.0.0"
    exit 1
  fi

  # Split into prefix (everything before last dot) and starting minor (last number)
  BASE_VERSION="${FULL_VERSION%.*}"   # e.g. 2.0
  START_MINOR="${FULL_VERSION##*.}"   # e.g. 12

  echo "BASE_VERSION=$BASE_VERSION" > "$FOLDER_CONFIG"
  echo "START_MINOR=$START_MINOR"  >> "$FOLDER_CONFIG"
  echo "Saved: prefix='$BASE_VERSION', starting minor='$START_MINOR' for '$(basename "$SOURCE")'."
else
  source "$FOLDER_CONFIG"
fi

# ─── Find next version number ─────────────────────────────────────────────────
BASE_NAME=$(basename "$SOURCE")
PARENT_DIR=$(dirname "$SOURCE")

# Find highest existing minor version, but only consider numbers >= START_MINOR
LAST=$(ls -d "${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}".* 2>/dev/null \
  | grep -oP '\d+$' \
  | awk -v start="$START_MINOR" '$1 >= start' \
  | sort -n \
  | tail -1)

if [ -z "$LAST" ]; then
  NEXT="$START_MINOR"
else
  NEXT=$((LAST + 1))
fi

DEST="${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}.${NEXT}"

# ─── Copy ─────────────────────────────────────────────────────────────────────
cp -r "$SOURCE" "$DEST"
echo "✓ Backed up '$(basename "$SOURCE")' → '$DEST'"
 \
    | awk -v start="$START_MINOR" '$1 >= start' \
    | sort -n \
    | tail -1)

  if [ -z "$LAST" ]; then
    NEXT="$START_MINOR"
  else
    NEXT=$((LAST + 1))
  fi
fi

DEST="${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}.${NEXT}"

# ─── Copy ─────────────────────────────────────────────────────────────────────
cp -r "$SOURCE" "$DEST"
echo "✓ Backed up '$(basename "$SOURCE")' → '$DEST'"
; then
    echo "Error: version must be in format like 2.0.15"
    exit 1
  fi

  CONFIG_KEY=$(echo "$SOURCE" | tr '/' '_' | tr ' ' '_')
  FOLDER_CONFIG="$CONFIG_DIR/${CONFIG_KEY}.cfg"

  if [ ! -f "$FOLDER_CONFIG" ]; then
    echo "Error: no config found for '$SOURCE'. Run a backup first."
    exit 1
  fi

  BASE_VERSION="${NEW_VERSION%.*}"
  START_MINOR="${NEW_VERSION##*.}"

  echo "BASE_VERSION=$BASE_VERSION"   > "$FOLDER_CONFIG"
  echo "START_MINOR=$START_MINOR"   >> "$FOLDER_CONFIG"
  echo "FORCE_MINOR="               >> "$FOLDER_CONFIG"
  echo "✓ Next backup of '$(basename "$SOURCE")' will be '$NEW_VERSION'"
  exit 0
fi

# ─── Force version override ───────────────────────────────────────────────────
# Usage: backup_project --force 2.0.15 [folder]
if [[ "$1" == "--force" ]]; then
  NEW_VERSION="$2"
  SOURCE="$(realpath "${3:-$(pwd)}")"

  if ! echo "$NEW_VERSION" | grep -qP '^\d+(\.\d+)*\.\d+

# ─── Resolve source folder ────────────────────────────────────────────────────
# If no argument given, use current directory
if [ -z "$1" ]; then
  SOURCE="$(pwd)"
else
  SOURCE="$1"
fi

# Strip trailing slash, resolve to absolute path
SOURCE="$(realpath "${SOURCE%/}")"

if [ ! -d "$SOURCE" ]; then
  echo "Error: '$SOURCE' is not a directory."
  exit 1
fi

# ─── Load or create config for this source folder ────────────────────────────
mkdir -p "$CONFIG_DIR"

CONFIG_KEY=$(echo "$SOURCE" | tr '/' '_' | tr ' ' '_')
FOLDER_CONFIG="$CONFIG_DIR/${CONFIG_KEY}.cfg"

if [ ! -f "$FOLDER_CONFIG" ]; then
  echo "First time backing up '$(basename "$SOURCE")'."
  read -rp "Enter starting version (e.g. 2.0.12): " FULL_VERSION

  # Validate format: must be X.Y.Z (digits and dots, at least one dot, ends in digits)
  if ! echo "$FULL_VERSION" | grep -qP '^\d+(\.\d+)*\.\d+$'; then
    echo "Error: version must be in format like 2.0.12 or 1.0.0"
    exit 1
  fi

  # Split into prefix (everything before last dot) and starting minor (last number)
  BASE_VERSION="${FULL_VERSION%.*}"   # e.g. 2.0
  START_MINOR="${FULL_VERSION##*.}"   # e.g. 12

  echo "BASE_VERSION=$BASE_VERSION" > "$FOLDER_CONFIG"
  echo "START_MINOR=$START_MINOR"  >> "$FOLDER_CONFIG"
  echo "Saved: prefix='$BASE_VERSION', starting minor='$START_MINOR' for '$(basename "$SOURCE")'."
else
  source "$FOLDER_CONFIG"
fi

# ─── Find next version number ─────────────────────────────────────────────────
BASE_NAME=$(basename "$SOURCE")
PARENT_DIR=$(dirname "$SOURCE")

# Find highest existing minor version, but only consider numbers >= START_MINOR
LAST=$(ls -d "${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}".* 2>/dev/null \
  | grep -oP '\d+$' \
  | awk -v start="$START_MINOR" '$1 >= start' \
  | sort -n \
  | tail -1)

if [ -z "$LAST" ]; then
  NEXT="$START_MINOR"
else
  NEXT=$((LAST + 1))
fi

DEST="${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}.${NEXT}"

# ─── Copy ─────────────────────────────────────────────────────────────────────
cp -r "$SOURCE" "$DEST"
echo "✓ Backed up '$(basename "$SOURCE")' → '$DEST'"
; then
    echo "Error: version must be in format like 2.0.15"
    exit 1
  fi

  CONFIG_KEY=$(echo "$SOURCE" | tr '/' '_' | tr ' ' '_')
  FOLDER_CONFIG="$CONFIG_DIR/${CONFIG_KEY}.cfg"

  if [ ! -f "$FOLDER_CONFIG" ]; then
    echo "Error: no config found for '$SOURCE'. Run a backup first."
    exit 1
  fi

  BASE_VERSION="${NEW_VERSION%.*}"
  FORCE_MINOR="${NEW_VERSION##*.}"

  echo "BASE_VERSION=$BASE_VERSION"     > "$FOLDER_CONFIG"
  echo "START_MINOR=$FORCE_MINOR"      >> "$FOLDER_CONFIG"
  echo "FORCE_MINOR=$FORCE_MINOR"      >> "$FOLDER_CONFIG"
  echo "✓ Next backup of '$(basename "$SOURCE")' will be forced to '$NEW_VERSION' (ignoring existing folders)"
  exit 0
fi

# ─── Resolve source folder ────────────────────────────────────────────────────
# If no argument given, use current directory
if [ -z "$1" ]; then
  SOURCE="$(pwd)"
else
  SOURCE="$1"
fi

# Strip trailing slash, resolve to absolute path
SOURCE="$(realpath "${SOURCE%/}")"

if [ ! -d "$SOURCE" ]; then
  echo "Error: '$SOURCE' is not a directory."
  exit 1
fi

# ─── Load or create config for this source folder ────────────────────────────
mkdir -p "$CONFIG_DIR"

CONFIG_KEY=$(echo "$SOURCE" | tr '/' '_' | tr ' ' '_')
FOLDER_CONFIG="$CONFIG_DIR/${CONFIG_KEY}.cfg"

if [ ! -f "$FOLDER_CONFIG" ]; then
  echo "First time backing up '$(basename "$SOURCE")'."
  read -rp "Enter starting version (e.g. 2.0.12): " FULL_VERSION

  # Validate format: must be X.Y.Z (digits and dots, at least one dot, ends in digits)
  if ! echo "$FULL_VERSION" | grep -qP '^\d+(\.\d+)*\.\d+$'; then
    echo "Error: version must be in format like 2.0.12 or 1.0.0"
    exit 1
  fi

  # Split into prefix (everything before last dot) and starting minor (last number)
  BASE_VERSION="${FULL_VERSION%.*}"   # e.g. 2.0
  START_MINOR="${FULL_VERSION##*.}"   # e.g. 12

  echo "BASE_VERSION=$BASE_VERSION" > "$FOLDER_CONFIG"
  echo "START_MINOR=$START_MINOR"  >> "$FOLDER_CONFIG"
  echo "Saved: prefix='$BASE_VERSION', starting minor='$START_MINOR' for '$(basename "$SOURCE")'."
else
  source "$FOLDER_CONFIG"
fi

# ─── Find next version number ─────────────────────────────────────────────────
BASE_NAME=$(basename "$SOURCE")
PARENT_DIR=$(dirname "$SOURCE")

# Find highest existing minor version, but only consider numbers >= START_MINOR
LAST=$(ls -d "${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}".* 2>/dev/null \
  | grep -oP '\d+$' \
  | awk -v start="$START_MINOR" '$1 >= start' \
  | sort -n \
  | tail -1)

if [ -z "$LAST" ]; then
  NEXT="$START_MINOR"
else
  NEXT=$((LAST + 1))
fi

DEST="${PARENT_DIR}/${BASE_NAME}-${BASE_VERSION}.${NEXT}"

# ─── Copy ─────────────────────────────────────────────────────────────────────
cp -r "$SOURCE" "$DEST"
echo "✓ Backed up '$(basename "$SOURCE")' → '$DEST'"