#!/bin/bash

# Colors for better output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Emojis for visual feedback
INFO="ℹ️"
SUCCESS="✅"
WARNING="⚠️"
ERROR="❌"
BACKUP="📦"
RESTORE="🔄"
INSTALL="🔧"

MODE="$1"
TARGET_DIR="$2"
shift 2
VOLUMES=("$@")

BUSYBOX_IMAGE="busybox"
INSTALL_DIR="/usr/local/bin"

print_usage() {
  echo -e "${BLUE}Docker Volume Backup and Restore Utility by @vksh (https://vksh.fyi)${NC}"
  echo -e "${BLUE}=======================================${NC}\n"
  echo -e "${INFO} Usage:"
  echo -e "  $0 backup <backup-dir> <volume1> [volume2 ...]"
  echo -e "  $0 restore <backup-dir> <new_name=backup_name> [more...]"
  echo -e "  $0 install"
  echo
  echo -e "${INFO} Installation Options:"
  echo -e "  install - Interactive installation that will:"
  echo -e "    - Ask for installation type (system-wide or user-only)"
  echo -e "    - System-wide: Install to /usr/local/bin (requires sudo)"
  echo -e "    - User-only: Install to ~/.local/bin and update PATH"
  echo
  echo -e "${INFO} Examples:"
  echo -e "  $0 backup ./backups solr_data postgres_data"
  echo -e "  $0 restore ./backups solr_data postgres_data"
  echo -e "  $0 restore ./backups my_pg=postgres_data my_solr=solr_data"
  echo -e "  $0 install"
  echo
  exit 1
}

# Function to install the script
install_script() {
  echo -e "${INSTALL} Installation Options:"
  echo -e "1. System-wide installation (requires sudo)"
  echo -e "2. User-only installation"
  
  read -p "Choose installation type (1/2): " install_type
  
  case $install_type in
    1)
      INSTALL_DIR="/usr/local/bin"
      echo -e "${INSTALL} Installing dvbackup to ${BLUE}${INSTALL_DIR}${NC} (requires sudo)"
      
      # Check if script is already installed
      if [[ -f "${INSTALL_DIR}/dvbackup" ]]; then
        echo -e "${WARNING} dvbackup is already installed at ${INSTALL_DIR}/dvbackup"
        read -p "Do you want to overwrite it? (y/N) " -n 1 -r
        echo
        if [[ ! $REPLY =~ ^[Yy]$ ]]; then
          echo -e "${INFO} Installation cancelled"
          exit 0
        fi
      fi

      # Get the absolute path of the current script
      SCRIPT_PATH="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/$(basename "${BASH_SOURCE[0]}")"
      
      # Copy the script to the install directory
      if sudo cp "$SCRIPT_PATH" "${INSTALL_DIR}/dvbackup" && sudo chmod +x "${INSTALL_DIR}/dvbackup"; then
        echo -e "${SUCCESS} dvbackup has been installed successfully!"
        echo -e "${INFO} You can now use it from anywhere by typing: ${GREEN}dvbackup${NC}"
      else
        echo -e "${ERROR} Failed to install dvbackup"
        exit 1
      fi
      ;;
      
    2)
      INSTALL_DIR="$HOME/.local/bin"
      echo -e "${INSTALL} Installing dvbackup to ${BLUE}${INSTALL_DIR}${NC}"
      
      # Create directory if it doesn't exist
      mkdir -p "$INSTALL_DIR"
      
      # Check if script is already installed
      if [[ -f "${INSTALL_DIR}/dvbackup" ]]; then
        echo -e "${WARNING} dvbackup is already installed at ${INSTALL_DIR}/dvbackup"
        read -p "Do you want to overwrite it? (y/N) " -n 1 -r
        echo
        if [[ ! $REPLY =~ ^[Yy]$ ]]; then
          echo -e "${INFO} Installation cancelled"
          exit 0
        fi
      fi

      # Get the absolute path of the current script
      SCRIPT_PATH="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/$(basename "${BASH_SOURCE[0]}")"
      
      # Copy the script to the install directory
      if cp "$SCRIPT_PATH" "${INSTALL_DIR}/dvbackup" && chmod +x "${INSTALL_DIR}/dvbackup"; then
        # Add to PATH if not already there
        if [[ ":$PATH:" != *":$INSTALL_DIR:"* ]]; then
          echo -e "${INFO} Adding ${INSTALL_DIR} to your PATH"
          if [[ -f "$HOME/.bashrc" ]]; then
            echo "export PATH=\"$INSTALL_DIR:\$PATH\"" >> "$HOME/.bashrc"
            echo -e "${INFO} Added to ~/.bashrc. Run 'source ~/.bashrc' to update your current shell"
          elif [[ -f "$HOME/.zshrc" ]]; then
            echo "export PATH=\"$INSTALL_DIR:\$PATH\"" >> "$HOME/.zshrc"
            echo -e "${INFO} Added to ~/.zshrc. Run 'source ~/.zshrc' to update your current shell"
          fi
        fi
        
        echo -e "${SUCCESS} dvbackup has been installed successfully!"
        echo -e "${INFO} You can now use it from anywhere by typing: ${GREEN}dvbackup${NC}"
      else
        echo -e "${ERROR} Failed to install dvbackup"
        exit 1
      fi
      ;;
      
    *)
      echo -e "${ERROR} Invalid option. Please choose 1 or 2."
      exit 1
      ;;
  esac
}

if [[ "$MODE" == "install" ]]; then
  install_script
  exit 0
fi

if [[ -z "$MODE" || -z "$TARGET_DIR" || "${#VOLUMES[@]}" -eq 0 ]]; then
  print_usage
fi

echo -e "${BLUE}Docker Volume Backup and Restore Utility${NC}"
echo -e "${BLUE}=======================================${NC}\n"

set -e

# Function to check if a volume exists
volume_exists() {
  docker volume inspect "$1" >/dev/null 2>&1
}

# Function to validate backup directory
validate_backup_dir() {
  if [[ ! -d "$1" ]]; then
    echo -e "${ERROR} Backup directory does not exist: $1"
    exit 1
  fi
}

# Function to validate volume names
validate_volume_name() {
  if [[ ! "$1" =~ ^[a-zA-Z0-9][a-zA-Z0-9_.-]*$ ]]; then
    echo -e "${ERROR} Invalid volume name: $1"
    echo -e "${INFO} Volume names must start with a letter or number and can only contain letters, numbers, underscores, dots, and hyphens."
    exit 1
  fi
}

# Function to check if a container is using the volume
is_volume_in_use() {
  local volume_name="$1"
  local containers=()
  
  while IFS= read -r container; do
    if docker inspect --format '{{range .Mounts}}{{if eq .Type "volume"}}{{.Name}}{{end}}{{end}}' "$container" | grep -q "$volume_name"; then
      containers+=("$container")
    fi
  done < <(docker ps --format '{{.Names}}')
  
  if [[ ${#containers[@]} -gt 0 ]]; then
    echo "${containers[@]}"
    return 0
  fi
  return 1
}

# Resolve absolute path safely for macOS, Linux, and Git Bash
if [[ "$OSTYPE" == "msys" || "$OSTYPE" == "win32" ]]; then
  # Git Bash on Windows
  ABS_BACKUP_DIR="$(cd "$TARGET_DIR" && pwd -W)"
else
  # macOS and Linux
  ABS_BACKUP_DIR="$(cd "$TARGET_DIR" && pwd)"
fi

mkdir -p "$ABS_BACKUP_DIR"

if [[ "$MODE" == "backup" ]]; then
  for VOLUME in "${VOLUMES[@]}"; do
    validate_volume_name "$VOLUME"
    
    if ! volume_exists "$VOLUME"; then
      echo -e "${ERROR} Volume does not exist: $VOLUME"
      exit 1
    fi

    ARCHIVE="${ABS_BACKUP_DIR}/${VOLUME}.tar.gz"
    echo -e "${BACKUP} Backing up volume: ${BLUE}$VOLUME${NC} → ${GREEN}$ARCHIVE${NC}"
    
    # Check if volume is in use
    containers=$(is_volume_in_use "$VOLUME")
    if [[ $? -eq 0 ]]; then
      echo -e "${WARNING} Volume is in use by containers:"
      for container in $containers; do
        echo -e "  - ${YELLOW}$container${NC}"
      done
      if [[ "$FORCE" != "true" ]]; then
        echo -e "${INFO} Using read-only mount for safety"
        MOUNT_OPTION=":ro"
      else
        echo -e "${WARNING} Force mode enabled - using regular mount"
        MOUNT_OPTION=""
      fi
    else
      MOUNT_OPTION=""
    fi
    
    docker run --rm \
      -v "${VOLUME}:/source${MOUNT_OPTION}" \
      -v "$ABS_BACKUP_DIR:/backup" \
      "$BUSYBOX_IMAGE" \
      tar czf "/backup/${VOLUME}.tar.gz" -C /source .
    
    echo -e "${SUCCESS} Backup completed for volume: $VOLUME"
  done

elif [[ "$MODE" == "restore" ]]; then
  for VOLUME_ARG in "${VOLUMES[@]}"; do
    if [[ "$VOLUME_ARG" == *"="* ]]; then
      NEW_VOLUME="${VOLUME_ARG%%=*}"
      ARCHIVE_NAME="${VOLUME_ARG##*=}"
    else
      NEW_VOLUME="$VOLUME_ARG"
      ARCHIVE_NAME="$VOLUME_ARG"
    fi

    validate_volume_name "$NEW_VOLUME"
    ARCHIVE="${ABS_BACKUP_DIR}/${ARCHIVE_NAME}.tar.gz"

    if [[ ! -f "$ARCHIVE" ]]; then
      echo -e "${ERROR} Archive not found: $ARCHIVE"
      exit 1
    fi

    if volume_exists "$NEW_VOLUME"; then
      echo -e "${WARNING} Volume already exists: $NEW_VOLUME"
      echo -e "${INFO} Please choose a different name or remove the existing volume first."
      exit 1
    fi

    echo -e "${RESTORE} Restoring: ${BLUE}${ARCHIVE_NAME}.tar.gz${NC} → volume '${GREEN}${NEW_VOLUME}${NC}'"
    docker volume create "$NEW_VOLUME" >/dev/null

    docker run --rm \
      -v "${NEW_VOLUME}:/restore" \
      -v "$ABS_BACKUP_DIR:/backup" \
      "$BUSYBOX_IMAGE" \
      tar xzf "/backup/${ARCHIVE_NAME}.tar.gz" -C /restore
    
    echo -e "${SUCCESS} Restore completed for volume: $NEW_VOLUME"
  done

else
  echo -e "${ERROR} Invalid mode: $MODE. Use 'backup' or 'restore'."
  print_usage
fi

echo -e "\n${SUCCESS} Operation completed successfully!"