#!/usr/bin/env bash
# Install easyzsh shell stubs into a home directory.
# Overwrites: ~/.zshenv ~/.zshrc ~/.zprofile
# Never overwrites: ~/.config/zsh/local.zsh  ~/.config/zshrc/**  ~/.local/bin/**
#
# Usage:
#   ./deploy.sh
#   ./deploy.sh --home /path/to/home
#   ./deploy.sh --migrate-zprofile   # fold pre-easyzsh ~/.zprofile into local.zsh

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="${TARGET_HOME}/.config/zsh"
LOCAL_ZSH="${ZSH_CFG}/local.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
}

file_has_content() {
  [[ -f "$1" ]] && grep -q '[^[:space:]]' "$1"
}

echo "Deploying easyzsh shell stubs into $TARGET_HOME"

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

# Migrate legacy fragments into local.zsh once.
if [[ ! -f "$LOCAL_ZSH" ]]; then
  tmp=$(mktemp)
  : >"$tmp"
  if file_has_content "${TARGET_HOME}/.config/zshenv.local"; then
    cat "${TARGET_HOME}/.config/zshenv.local" >>"$tmp"
    printf '\n' >>"$tmp"
  fi
  if [[ -d "${ZSH_CFG}/local" ]]; then
    for part in env.local.zsh login.local.zsh interactive.local.zsh; do
      if file_has_content "${ZSH_CFG}/local/${part}"; then
        cat "${ZSH_CFG}/local/${part}" >>"$tmp"
        printf '\n' >>"$tmp"
      fi
    done
  fi
  if file_has_content "$tmp"; then
    cp "$tmp" "$LOCAL_ZSH"
    echo "Migrated machine-local fragments -> ~/.config/zsh/local.zsh"
  fi
  rm -f "$tmp"
fi

# Fold a pre-easyzsh ~/.zprofile into local.zsh. Skip easyzsh stub / empty files.
if [[ "$MIGRATE_ZPROFILE" -eq 1 && -f "${TARGET_HOME}/.zprofile" ]]; then
  if grep -Eq 'easyzsh|PATH lives in|Machine-local env' "${TARGET_HOME}/.zprofile" 2>/dev/null \
     || grep -Fq 'Leave this file empty' "${TARGET_HOME}/.zprofile" 2>/dev/null; then
    echo "Skipping zprofile migration: already easyzsh-managed"
  elif [[ ! -f "$LOCAL_ZSH" ]]; then
    zprofile_extract=$(mktemp)
    awk '
      /Created by `pipx`/ { skip_pipx=1; next }
      skip_pipx && /local\/bin/ { skip_pipx=0; next }
      skip_pipx { next }
      { print }
    ' "${TARGET_HOME}/.zprofile" >"$zprofile_extract"
    if file_has_content "$zprofile_extract"; then
      cp "$zprofile_extract" "$LOCAL_ZSH"
      echo "Migrated ~/.zprofile body -> ~/.config/zsh/local.zsh"
    fi
    rm -f "$zprofile_extract"
  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"

# Remove obsolete managed-tree layout and examples from earlier deploys.
/bin/rm -rf \
  "${ZSH_CFG}/env" \
  "${ZSH_CFG}/interactive" \
  "${ZSH_CFG}/login" \
  "${ZSH_CFG}/local"
/bin/rm -f \
  "${ZSH_CFG}/local.zsh.example" \
  "${TARGET_HOME}/.config/zshenv.local"

# 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'"