checkpoint.bash_completion

#!/usr/bin/env bash
# shellcheck disable=SC2207  # COMPREPLY assignment is standard bash-completion pattern
# checkpoint.bash_completion - Bash completion for checkpoint utility
#
# Installation:
#   System-wide: sudo cp checkpoint.bash_completion /usr/share/bash-completion/completions/checkpoint
#   User-only:   cp checkpoint.bash_completion ~/.local/share/bash-completion/completions/checkpoint
#
# Or source directly: source checkpoint.bash_completion
#
# Provides tab completion for all checkpoint options and dynamic
# completion of checkpoint IDs for restore/compare operations.

# _checkpoint_find_backup_dir: Locate backup directory from args or defaults
# Searches command line for -d/--backup-dir, falls back to environment/defaults
# Returns: backup directory path on stdout
_checkpoint_find_backup_dir() {
  local i dir=""

  # Check command line for explicit --backup-dir or -d
  for ((i = 1; i < ${#COMP_WORDS[@]}; i++)); do
    case "${COMP_WORDS[i]}" in
      --backup-dir|--backup-dir=*|-d)
        if [[ "${COMP_WORDS[i]}" == *=* ]]; then
          dir="${COMP_WORDS[i]#*=}"
        elif ((i + 1 < ${#COMP_WORDS[@]})); then
          dir="${COMP_WORDS[i+1]}"
        fi
        break
        ;;
    esac
  done

  # Fall back to environment variable
  if [[ -z "$dir" ]]; then
    dir="${CHECKPOINT_BACKUP_DIR:-}"
  fi

  # Fall back to default locations based on source directory
  if [[ -z "$dir" ]]; then
    # Try to find source directory from remaining args
    local src_dir=""
    for ((i = ${#COMP_WORDS[@]} - 1; i >= 1; i--)); do
      if [[ "${COMP_WORDS[i]}" != -* ]] && [[ -d "${COMP_WORDS[i]}" ]]; then
        src_dir="${COMP_WORDS[i]}"
        break
      fi
    done
    [[ -z "$src_dir" ]] && src_dir="$PWD"

    local dir_name
    dir_name=$(basename "$src_dir")

    # Check default locations
    if [[ -d "/var/backups/$dir_name" ]]; then
      dir="/var/backups/$dir_name"
    elif [[ -d "$HOME/.checkpoint/$dir_name" ]]; then
      dir="$HOME/.checkpoint/$dir_name"
    elif [[ -d "$src_dir/.gudang" ]]; then
      dir="$src_dir/.gudang"
    fi
  fi

  echo "$dir"
}

# _checkpoint_list_ids: List available checkpoint IDs for completion
# Uses backup directory to find checkpoint directories (20* timestamp format)
# Returns: space-separated list of checkpoint IDs
_checkpoint_list_ids() {
  local backup_dir
  backup_dir=$(_checkpoint_find_backup_dir)

  if [[ -n "$backup_dir" ]] && [[ -d "$backup_dir" ]]; then
    # List directories matching timestamp pattern (with optional suffix)
    local ids=()
    while IFS= read -r -d '' dir; do
      ids+=("$(basename "$dir")")
    done < <(find "$backup_dir" -maxdepth 1 -type d -name "20*" -print0 2>/dev/null | sort -z -r)
    echo "${ids[*]}"
  fi
}

# _checkpoint_completion: Main completion function for checkpoint command
_checkpoint_completion() {
  local cur prev
  COMPREPLY=()
  cur="${COMP_WORDS[COMP_CWORD]}"
  prev="${COMP_WORDS[COMP_CWORD-1]}"

  # All long options
  local long_opts="--backup-dir --suffix --no-hardlink --hardlink --quiet
    --verbose --list --exclude --no-sudo --version --help
    --keep --age --prune-only
    --no-lock --lock-timeout --force-unlock
    --restore --from --to --dry-run --diff --compare-with --detailed --files"

  # All short options
  local short_opts="-d -s -n -q -v -l -x -r -f -t -p -V -h"

  # Context-sensitive completion based on previous word
  case "$prev" in
    # Directory completion
    --backup-dir|-d|--to|-t)
      COMPREPLY=($(compgen -d -- "$cur"))
      return 0
      ;;

    # File/pattern completion
    --exclude|-x|--files)
      COMPREPLY=($(compgen -f -- "$cur"))
      return 0
      ;;

    # Dynamic checkpoint ID completion
    --from|-f|--compare-with)
      local ids
      ids=$(_checkpoint_list_ids)
      if [[ -n "$ids" ]]; then
        COMPREPLY=($(compgen -W "$ids" -- "$cur"))
      fi
      return 0
      ;;

    # Free text - no completion
    --suffix|-s)
      return 0
      ;;

    # Numeric values - no completion
    --keep|--age|--lock-timeout)
      return 0
      ;;
  esac

  # Option completion when current word starts with -
  if [[ "$cur" == -* ]]; then
    COMPREPLY=($(compgen -W "$long_opts $short_opts" -- "$cur"))
    return 0
  fi

  # Default: directory completion for source directory argument
  COMPREPLY=($(compgen -d -- "$cur"))
  return 0
}

# Register completion for checkpoint and chkpoint commands
complete -F _checkpoint_completion checkpoint
complete -F _checkpoint_completion chkpoint

#fin