#!/usr/bin/env bash

set -Eeuo pipefail

readonly APP_NAME='dotfiles'
readonly REPO_URI="${REPO_URI:-https://github.com/Donaldttt/dotfiles.git}"
readonly REPO_BRANCH="${REPO_BRANCH:-main}"

SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" 2>/dev/null && pwd -P || true)"
if [[ -n "$SCRIPT_DIR" && -e "$SCRIPT_DIR/.git" ]]; then
  APP_PATH="${APP_PATH:-$SCRIPT_DIR}"
else
  APP_PATH="${APP_PATH:-$HOME/.$APP_NAME}"
fi
readonly APP_PATH
readonly VIM_PATH="${VIM_PATH:-$HOME/.vim}"
readonly MANAGED_START='# >>> dotfiles >>>'
readonly MANAGED_END='# <<< dotfiles <<<'

info() { printf '\033[34m[•]\033[0m %s\n' "$*"; }
success() { printf '\033[32m[✔]\033[0m %s\n' "$*"; }
warn() { printf '\033[33m[!]\033[0m %s\n' "$*" >&2; }
die() { printf '\033[31m[✘]\033[0m %s\n' "$*" >&2; exit 1; }

usage() {
  cat <<'EOF'
Usage: ./install.sh [all|vim|shell|tmux]...

With no arguments, installs every component. Components can be combined, for
example: ./install.sh vim tmux
EOF
}

require() {
  command -v "$1" >/dev/null 2>&1 || die "Required program not found: $1"
}

ensure_repo() {
  require git
  if [[ -d "$APP_PATH/.git" ]]; then
    return
  fi
  [[ ! -e "$APP_PATH" ]] || die "$APP_PATH exists but is not a Git repository."
  info "Cloning $REPO_URI into $APP_PATH"
  git clone --branch "$REPO_BRANCH" --depth 1 "$REPO_URI" "$APP_PATH"
}

backup_path() {
  local target=$1
  if [[ -e "$target" || -L "$target" ]]; then
    local backup="${target}.backup.$(date +%Y%m%d_%H%M%S)" suffix=0
    while [[ -e "$backup" || -L "$backup" ]]; do
      ((suffix += 1))
      backup="${target}.backup.$(date +%Y%m%d_%H%M%S).$suffix"
    done
    mv -- "$target" "$backup"
    warn "Backed up $target to $backup"
  fi
}

link_config() {
  local source=$1 target=$2 current=''
  if [[ -L "$target" ]]; then
    current=$(readlink "$target" || true)
    [[ "$current" == "$source" ]] && return
  fi
  backup_path "$target"
  ln -s "$source" "$target"
  success "Linked $target -> $source"
}

remove_managed_block() {
  local file=$1 temp
  [[ -f "$file" ]] || return
  temp=$(mktemp)
  awk -v start="$MANAGED_START" -v end="$MANAGED_END" '
    $0 == start { managed = 1; next }
    $0 == end { managed = 0; next }
    !managed { print }
  ' "$file" > "$temp"
  cat "$temp" > "$file"
  rm -f "$temp"
}

install_vim() {
  require vim
  require curl
  if ! vim --clean -Nu NONE -n -es \
    '+if v:version < 900 | cquit | endif' '+qall'; then
    die 'Vim 9 or newer is required.'
  fi

  link_config "$APP_PATH/.vimrc" "$HOME/.vimrc"
  mkdir -p "$VIM_PATH/autoload"
  local temp
  temp=$(mktemp)
  curl --fail --location --silent --show-error \
    https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim \
    --output "$temp"
  mv "$temp" "$VIM_PATH/autoload/plug.vim"
  vim -Nu "$APP_PATH/.vimrc" -n -es \
    '+set nomore' '+PlugInstall --sync' '+qall'
  success 'Installed Vim configuration and plugins.'
}

install_shell() {
  local bashrc="$HOME/.bashrc" quoted_source
  touch "$bashrc"
  remove_managed_block "$bashrc"
  printf -v quoted_source '%q' "$APP_PATH/bash_tools.sh"
  {
    printf '\n%s\n' "$MANAGED_START"
    printf '[ -r %s ] && source %s\n' "$quoted_source" "$quoted_source"
    printf 'command -v zoxide >/dev/null 2>&1 && eval "$(zoxide init bash)"\n'
    printf '%s\n' "$MANAGED_END"
  } >> "$bashrc"
  success "Installed managed Bash block in $bashrc"
}

install_tmux() {
  require tmux
  link_config "$APP_PATH/.tmux.conf" "$HOME/.tmux.conf"
  local tpm="$HOME/.tmux/plugins/tpm"
  if [[ ! -d "$tpm/.git" ]]; then
    [[ ! -e "$tpm" ]] || die "$tpm exists but is not a Git repository."
    mkdir -p "$(dirname "$tpm")"
    git clone --depth 1 https://github.com/tmux-plugins/tpm "$tpm"
  fi
  success 'Installed tmux configuration and TPM.'
}

main() {
  case "${1:-}" in
    -h|--help) usage; return ;;
  esac

  ensure_repo
  local components=("$@") component
  ((${#components[@]})) || components=(all)
  for component in "${components[@]}"; do
    case "$component" in
      all)
        install_vim
        install_shell
        install_tmux
        ;;
      vim) install_vim ;;
      shell) install_shell ;;
      tmux) install_tmux ;;
      *) usage; die "Unknown component: $component" ;;
    esac
  done
}

main "$@"