#!/usr/bin/env bash
# Install managed easyzsh shell layout into a home directory.
# Overwrites: ~/.zshenv ~/.zshrc ~/.zprofile ~/.config/zsh/{env,interactive,login}
# Never overwrites: ~/.config/zsh/local/**  ~/.config/zshrc/**  ~/.local/bin/**
#
# Usage:
#   ./deploy.sh
#   ./deploy.sh --home /path/to/home
#   ./deploy.sh --migrate-zprofile   # move existing ~/.zprofile body into login.local

set -euo pipefail

ROOT=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
TARGET_HOME="${HOME}"
MIGRATE_ZPROFILE=0

while [[ $# -gt 0 ]]; do
  case "$1" in
    --home)
      TARGET_HOME="$2"
      shift 2
      ;;
    --migrate-zprofile)
      MIGRATE_ZPROFILE=1
      shift
      ;;
    -h|--help)
      sed -n '2,12p' "$0"
      exit 0
      ;;
    *)
      echo "Unknown argument: $1" >&2
      exit 2
      ;;
  esac
done

if [[ ! -d "$TARGET_HOME" ]]; then
  echo "Home does not exist: $TARGET_HOME" >&2
  exit 1
fi

ZSH_CFG="${TARGET_HOME}/.config/zsh"
ts=$(date +%Y%m%d-%H%M%S)

backup_file() {
  local f="$1"
  if [[ -e "$f" || -L "$f" ]]; then
    cp -Pp "$f" "${f}.backup.${ts}"
    echo "Backed up $f -> ${f}.backup.${ts}"
  fi
}

echo "Deploying easyzsh managed shell layout into $TARGET_HOME"

mkdir -p \
  "${ZSH_CFG}/env" \
  "${ZSH_CFG}/interactive" \
  "${ZSH_CFG}/login" \
  "${ZSH_CFG}/local" \
  "${TARGET_HOME}/.config/zshrc" \
  "${TARGET_HOME}/.cache/zsh" \
  "${TARGET_HOME}/.local/bin"

# Migrate legacy early env if present and new path missing.
if [[ -f "${TARGET_HOME}/.config/zshenv.local" && ! -f "${ZSH_CFG}/local/env.local.zsh" ]]; then
  cp -Pp "${TARGET_HOME}/.config/zshenv.local" "${ZSH_CFG}/local/env.local.zsh"
  echo "Migrated ~/.config/zshenv.local -> ~/.config/zsh/local/env.local.zsh"
fi

# Optionally migrate existing zprofile body into login.local (strip redundant PATH).
if [[ "$MIGRATE_ZPROFILE" -eq 1 ]]; then
  if [[ -f "${TARGET_HOME}/.zprofile" && ! -f "${ZSH_CFG}/local/login.local.zsh" ]]; then
    # Drop easyzsh stub lines and pipx ~/.local/bin PATH (now owned by env/00-path.zsh).
    awk '
      /^# easyzsh stub/ { next }
      /^EASYZSH_HOME=/ { next }
      /for _easyzsh_f in/ { skip=1 }
      skip && /unset _easyzsh_f/ { skip=0; next }
      skip { next }
      /login\.local\.zsh/ { next }
      /Created by `pipx`/ { skip_pipx=1; next }
      skip_pipx && /local\/bin/ { skip_pipx=0; next }
      skip_pipx { next }
      { print }
    ' "${TARGET_HOME}/.zprofile" > "${ZSH_CFG}/local/login.local.zsh"
    # Trim trailing blank lines noise if file became empty-ish
    if ! grep -q '[^[:space:]]' "${ZSH_CFG}/local/login.local.zsh"; then
      rm -f "${ZSH_CFG}/local/login.local.zsh"
      echo "Existing .zprofile had no login-local content after migration"
    else
      echo "Migrated ~/.zprofile body -> ~/.config/zsh/local/login.local.zsh"
    fi
  fi
fi

backup_file "${TARGET_HOME}/.zshenv"
backup_file "${TARGET_HOME}/.zshrc"
backup_file "${TARGET_HOME}/.zprofile"

install -m 644 "${ROOT}/.zshenv" "${TARGET_HOME}/.zshenv"
install -m 644 "${ROOT}/.zshrc" "${TARGET_HOME}/.zshrc"
install -m 644 "${ROOT}/.zprofile" "${TARGET_HOME}/.zprofile"

# Replace managed modules only (never touch local/).
rm -f "${ZSH_CFG}/env"/*.zsh
rm -f "${ZSH_CFG}/interactive"/*.zsh
rm -f "${ZSH_CFG}/login"/*.zsh
install -m 644 "${ROOT}/config/env/"*.zsh "${ZSH_CFG}/env/"
install -m 644 "${ROOT}/config/interactive/"*.zsh "${ZSH_CFG}/interactive/"
# login may be empty of modules
if compgen -G "${ROOT}/config/login/"*.zsh > /dev/null; then
  install -m 644 "${ROOT}/config/login/"*.zsh "${ZSH_CFG}/login/"
fi

# Seed examples only when missing (never overwrite user locals).
for example in env.local.zsh login.local.zsh interactive.local.zsh; do
  src="${ROOT}/local/${example}.example"
  dst="${ZSH_CFG}/local/${example}.example"
  if [[ -f "$src" ]]; then
    install -m 644 "$src" "$dst"
  fi
done

# Ensure intentional grok shim when the binary tree exists.
if [[ -e "${TARGET_HOME}/.grok/bin/grok" ]]; then
  ln -sfn "${TARGET_HOME}/.grok/bin/grok" "${TARGET_HOME}/.local/bin/grok"
  echo "Ensured ~/.local/bin/grok -> ~/.grok/bin/grok"
fi

echo "Deploy complete."
echo "Verify: env -i HOME=\"$TARGET_HOME\" PATH=/usr/bin:/bin zsh -c '. ~/.zshenv; command -v grok; echo PATH=\$PATH'"