install.sh

#!/usr/bin/env bash
set -ue

DRY_RUN=0
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd -P)"
TARGETS_FILE="$SCRIPT_DIR/.linktargets"

helpmsg() {
  command echo "Usage: $0 [--help | -h] [--debug | -d] [--dry-run | -n]" 0>&2
  command echo ""
  command echo "Targets file: $TARGETS_FILE" 0>&2
  command echo ""
}

run_cmd() {
  if [[ "$DRY_RUN" -eq 1 ]]; then
    command printf '[dry-run] %s\n' "$*"
  else
    "$@"
  fi
}

link_target() {
  local src="$1"
  local dest="$2"
  local backup_dir="$3"

  if [[ -L "$dest" ]]; then
    local current
    current="$(readlink "$dest")"
    if [[ "$current" == "$src" ]]; then
      command echo "skip: $dest already links to $src"
      return
    fi

    command echo "backup symlink: $dest -> $current"
    run_cmd mv "$dest" "$backup_dir/"
  elif [[ -e "$dest" ]]; then
    command echo "backup existing: $dest"
    run_cmd mv "$dest" "$backup_dir/"
  fi
}

link_to_homedir() {
  local dotdir="$SCRIPT_DIR"
  local backup_root="$HOME/.dotbackup"
  local backup_dir="$backup_root/$(date +%Y%m%d-%H%M%S)"

  if [[ "$HOME" != "$dotdir" ]]; then
    if [[ ! -f "$TARGETS_FILE" ]]; then
      command echo "targets file not found: $TARGETS_FILE" 0>&2
      exit 1
    fi

    command echo "backup old dotfiles..."
    if [ ! -d "$backup_root" ]; then
      command echo "$backup_root not found. Auto Make it"
      run_cmd mkdir -p "$backup_root"
    fi

    run_cmd mkdir -p "$backup_dir"

    local name
    while IFS= read -r name || [[ -n "$name" ]]; do
      [[ -z "$name" ]] && continue
      [[ "$name" =~ ^[[:space:]]*# ]] && continue

      local src="$dotdir/$name"
      local dest="$HOME/$name"

      if [[ ! -e "$src" && ! -L "$src" ]]; then
        command echo "skip: source not found: $src"
        continue
      fi

      run_cmd mkdir -p "$(dirname "$dest")"
      link_target "$src" "$dest" "$backup_dir"
      command echo "link: $dest -> $src"
      run_cmd ln -snf "$src" "$dest"
    done < "$TARGETS_FILE"
  else
    command echo "same install src dest"
  fi
}

while [ $# -gt 0 ]; do
  case ${1} in
  --debug | -d)
    set -uex
    ;;
  --dry-run | -n)
    DRY_RUN=1
    ;;
  --help | -h)
    helpmsg
    exit 1
    ;;
  *) ;;
  esac
  shift
done

link_to_homedir
command echo -e "\e[1;36m Install completed!!!! \e[m"