#!/usr/bin/env bash
# Shared helpers for the arch-i3 bootstrap scripts.
# Sourced, never executed directly.

set -Eeuo pipefail

# --- paths -----------------------------------------------------------------
REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
DOTFILES_DIR="$REPO_ROOT/dotfiles"
PACKAGES_DIR="$REPO_ROOT/packages"
WALLPAPER_DIR="${XDG_DATA_HOME:-$HOME/.local/share}/wallpapers"
BACKUP_DIR="$HOME/.config-backup-$(date +%Y%m%d-%H%M%S)"

# --- flags (exported by install.sh) ---------------------------------------
: "${DRY_RUN:=0}"
: "${ASSUME_YES:=0}"

# --- colours ---------------------------------------------------------------
if [[ -t 1 ]]; then
  C_RESET=$'\e[0m'; C_BOLD=$'\e[1m'; C_DIM=$'\e[2m'
  C_BLUE=$'\e[38;5;111m'; C_GREEN=$'\e[38;5;115m'
  C_YELLOW=$'\e[38;5;222m'; C_RED=$'\e[38;5;210m'; C_MAUVE=$'\e[38;5;140m'
else
  C_RESET=''; C_BOLD=''; C_DIM=''
  C_BLUE=''; C_GREEN=''; C_YELLOW=''; C_RED=''; C_MAUVE=''
fi

log()     { printf '%s==>%s %s\n'      "$C_BLUE$C_BOLD" "$C_RESET" "$*"; }
step()    { printf '%s  ->%s %s\n'     "$C_MAUVE"       "$C_RESET" "$*"; }
ok()      { printf '%s  ok%s %s\n'     "$C_GREEN"       "$C_RESET" "$*"; }
warn()    { printf '%s  !!%s %s\n'     "$C_YELLOW"      "$C_RESET" "$*" >&2; }
die()     { printf '%serror%s %s\n'    "$C_RED$C_BOLD"  "$C_RESET" "$*" >&2; exit 1; }
skip()    { printf '%s  --%s %s\n'     "$C_DIM"         "$C_RESET" "$*"; }

# Run a command, honouring DRY_RUN.
run() {
  if [[ "$DRY_RUN" == "1" ]]; then
    printf '%s  dry%s %s\n' "$C_DIM" "$C_RESET" "$*"
    return 0
  fi
  "$@"
}

confirm() {
  [[ "$ASSUME_YES" == "1" ]] && return 0
  [[ "$DRY_RUN"    == "1" ]] && return 0
  local reply
  read -rp "$(printf '%s  ??%s %s [y/N] ' "$C_YELLOW" "$C_RESET" "$1")" reply
  [[ "$reply" =~ ^[Yy]$ ]]
}

have() { command -v "$1" >/dev/null 2>&1; }

# Print a path with $HOME collapsed to '~'. Done as a function because the
# obvious ${path/#$HOME/~} keeps a literal backslash in the replacement.
tildify() {
  local p="$1"
  if [[ "$p" == "$HOME"/* ]]; then
    printf '~/%s' "${p#"$HOME"/}"
  elif [[ "$p" == "$HOME" ]]; then
    printf '~'
  else
    printf '%s' "$p"
  fi
}

# Read a package list file, dropping comments and blanks.
read_pkg_list() {
  local file="$1"
  [[ -f "$file" ]] || die "package list not found: $file"
  sed -e 's/#.*$//' -e 's/[[:space:]]\+$//' "$file" | grep -v '^[[:space:]]*$' || true
}

# Guard rails common to every stage.
require_arch() {
  [[ -f /etc/arch-release ]] || die "this bootstrap targets Arch Linux (no /etc/arch-release found)"
}

require_not_root() {
  [[ "$(id -u)" -ne 0 ]] || die "run this as your normal user, not root — sudo is invoked where needed"
}

require_sudo() {
  have sudo || die "sudo is not installed; install it and add your user to the wheel group first"
  if [[ "$DRY_RUN" != "1" ]]; then
    sudo -v || die "sudo authentication failed"
    # Keep the sudo timestamp alive for the length of the run.
    ( while true; do sudo -n true; sleep 50; kill -0 "$$" 2>/dev/null || exit; done ) &
    SUDO_KEEPALIVE_PID=$!
    trap 'kill "$SUDO_KEEPALIVE_PID" 2>/dev/null || true' EXIT
  fi
}

# Back up a path (file, dir or symlink) into $BACKUP_DIR, preserving structure.
backup_path() {
  local target="$1"
  [[ -e "$target" || -L "$target" ]] || return 0
  local rel="${target#"$HOME"/}"
  local dest="$BACKUP_DIR/$rel"
  step "backing up $(tildify "$target") -> $(tildify "$dest")"
  run mkdir -p "$(dirname "$dest")"
  run mv "$target" "$dest"
}

# Copy a file from the repo into place, backing up whatever was there.
install_file() {
  local src="$1" dest="$2" mode="${3:-644}"
  [[ -f "$src" ]] || die "missing source file: $src"
  if [[ -f "$dest" ]] && cmp -s "$src" "$dest"; then
    skip "$(tildify "$dest") already up to date"
    return 0
  fi
  backup_path "$dest"
  run mkdir -p "$(dirname "$dest")"
  run install -m "$mode" "$src" "$dest"
  ok "installed $(tildify "$dest")"
}