#!/usr/bin/env bash
# install.sh — bootstrap zsh + oh-my-zsh + powerlevel10k + atuin and link dotfiles.
# Supports: Debian/Ubuntu (apt), Fedora/RHEL (dnf), Arch (pacman), macOS (brew).
# Idempotent: safe to re-run.
#
# Usage:
#   git clone https://github.com/<you>/dotfiles ~/dotfiles && cd ~/dotfiles && ./install.sh
# or:
#   curl -fsSL https://raw.githubusercontent.com/<you>/dotfiles/main/install.sh | bash
#   (the curl form will git clone this repo to ~/dotfiles before running.)

set -euo pipefail

REPO_URL="${DOTFILES_REPO:-https://github.com/<you>/dotfiles}"
DOTFILES_DIR="${DOTFILES_DIR:-$HOME/dotfiles}"

log()  { printf '\033[1;34m==>\033[0m %s\n' "$*"; }
warn() { printf '\033[1;33m!! \033[0m %s\n' "$*" >&2; }
die()  { printf '\033[1;31mxx \033[0m %s\n' "$*" >&2; exit 1; }

# ---------------------------------------------------------------------------
# 0. If we're being curl|bashed, the script lives in /dev/stdin and there's no
#    repo on disk. Clone, then re-exec from the checkout so $SCRIPT_DIR works.
# ---------------------------------------------------------------------------
if [ ! -t 0 ] && [ ! -f "${BASH_SOURCE[0]:-}" ] || [ "${BASH_SOURCE[0]:-}" = "/dev/stdin" ]; then
  command -v git >/dev/null || die "git is required to clone the dotfiles repo"
  if [ ! -d "$DOTFILES_DIR/.git" ]; then
    log "Cloning $REPO_URL → $DOTFILES_DIR"
    git clone "$REPO_URL" "$DOTFILES_DIR"
  fi
  exec bash "$DOTFILES_DIR/install.sh" "$@"
fi

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# ---------------------------------------------------------------------------
# 1. Detect package manager and install prerequisites.
# ---------------------------------------------------------------------------
SUDO=""
if [ "$(id -u)" -ne 0 ] && command -v sudo >/dev/null; then SUDO="sudo"; fi

install_pkgs() {
  local pkgs=("$@")
  if command -v apt-get >/dev/null; then
    $SUDO apt-get update -y
    $SUDO DEBIAN_FRONTEND=noninteractive apt-get install -y "${pkgs[@]}"
  elif command -v dnf >/dev/null; then
    $SUDO dnf install -y "${pkgs[@]}"
  elif command -v pacman >/dev/null; then
    $SUDO pacman -Sy --noconfirm --needed "${pkgs[@]}"
  elif command -v brew >/dev/null; then
    brew install "${pkgs[@]}"
  else
    die "No supported package manager found (apt/dnf/pacman/brew)."
  fi
}

log "Installing prerequisites (zsh, git, curl)"
install_pkgs zsh git curl

# ---------------------------------------------------------------------------
# 2. Oh My Zsh.
# ---------------------------------------------------------------------------
export ZSH="$HOME/.oh-my-zsh"
if [ ! -d "$ZSH" ]; then
  log "Installing oh-my-zsh"
  RUNZSH=no CHSH=no KEEP_ZSHRC=yes \
    sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"
else
  log "oh-my-zsh already installed"
fi

ZSH_CUSTOM="${ZSH_CUSTOM:-$ZSH/custom}"

# ---------------------------------------------------------------------------
# 3. Powerlevel10k theme.
# ---------------------------------------------------------------------------
P10K_DIR="$ZSH_CUSTOM/themes/powerlevel10k"
if [ ! -d "$P10K_DIR" ]; then
  log "Installing powerlevel10k"
  git clone --depth=1 https://github.com/romkatv/powerlevel10k.git "$P10K_DIR"
else
  log "powerlevel10k already installed; pulling latest"
  git -C "$P10K_DIR" pull --ff-only --quiet || warn "p10k pull failed (continuing)"
fi

# ---------------------------------------------------------------------------
# 4. zsh-autosuggestions plugin.
# ---------------------------------------------------------------------------
AUTOSUG_DIR="$ZSH_CUSTOM/plugins/zsh-autosuggestions"
if [ ! -d "$AUTOSUG_DIR" ]; then
  log "Installing zsh-autosuggestions"
  git clone --depth=1 https://github.com/zsh-users/zsh-autosuggestions "$AUTOSUG_DIR"
else
  log "zsh-autosuggestions already installed"
fi

# ---------------------------------------------------------------------------
# 5. Atuin (shell history sync). Works on bash and zsh.
# ---------------------------------------------------------------------------
if ! command -v atuin >/dev/null && [ ! -x "$HOME/.atuin/bin/atuin" ]; then
  log "Installing atuin"
  curl --proto '=https' --tlsv1.2 -LsSf https://setup.atuin.sh | sh
else
  log "atuin already installed"
fi

# ---------------------------------------------------------------------------
# 6. Link dotfiles. Backs up anything already there to *.backup.<timestamp>.
# ---------------------------------------------------------------------------
TS="$(date +%Y%m%d-%H%M%S)"
link_file() {
  local src="$1" dest="$2"
  if [ -e "$dest" ] && [ ! -L "$dest" ]; then
    log "Backing up $dest → $dest.backup.$TS"
    mv "$dest" "$dest.backup.$TS"
  elif [ -L "$dest" ]; then
    rm "$dest"
  fi
  ln -s "$src" "$dest"
  log "Linked $dest → $src"
}

link_file "$SCRIPT_DIR/.zshrc"    "$HOME/.zshrc"
link_file "$SCRIPT_DIR/.p10k.zsh" "$HOME/.p10k.zsh"

# ---------------------------------------------------------------------------
# 7. Change default shell to zsh (no-op if already zsh).
# ---------------------------------------------------------------------------
ZSH_BIN="$(command -v zsh)"
if [ -n "$ZSH_BIN" ] && [ "${SHELL:-}" != "$ZSH_BIN" ]; then
  if grep -qx "$ZSH_BIN" /etc/shells 2>/dev/null || echo "$ZSH_BIN" | $SUDO tee -a /etc/shells >/dev/null; then
    log "Setting login shell to $ZSH_BIN"
    chsh -s "$ZSH_BIN" "$USER" || warn "chsh failed — run it manually: chsh -s $ZSH_BIN"
  fi
else
  log "Default shell already zsh"
fi

# ---------------------------------------------------------------------------
# 8. Done.
# ---------------------------------------------------------------------------
cat <<EOF

  ✔ Dotfiles installed.

  Next steps:
    • Start a new shell:   exec zsh -l
    • For machine-specific overrides (API keys, conda init, nvm, etc.),
      drop them in:        ~/.zshrc.local   (already sourced by .zshrc, ignored by git)
    • If powerlevel10k icons look wrong, install a Nerd Font:
        https://github.com/romkatv/powerlevel10k#meslo-nerd-font-patched-for-powerlevel10k
    • Atuin sync (optional):  atuin register -u <user> -e <email>   /   atuin login

EOF