#!/usr/bin/env bash
# Install easyzsh shell stubs into a home directory.
# Overwrites: ~/.zshenv ~/.zshrc
# Installs: ~/.zprofile (re-applies ~/.zshenv after macOS path_helper)
# Never overwrites: ~/.config/zsh/local.zsh  ~/.config/zshrc/**  ~/.local/bin/**
# Extra ~/.zprofile lines stay as login-only hooks unless --migrate-zprofile
# folds them into local.zsh.
#
# Usage:
#   ./deploy.sh
#   ./deploy.sh --home /path/to/home
#   ./deploy.sh --migrate-zprofile   # fold extra ~/.zprofile lines 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"
ZPROFILE="${TARGET_HOME}/.zprofile"
ts=$(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"
}

ZPROFILE_MARKER='# easyzsh: reapply always-on PATH after macOS path_helper'
PYENV_LOGIN_HOOK='[[ -f "${XDG_CONFIG_HOME:-$HOME/.config}/zsh/pyenv.zsh" ]] && . "${XDG_CONFIG_HOME:-$HOME/.config}/zsh/pyenv.zsh"'

is_easyzsh_zprofile_stub() {
  local f="$1"
  [[ -f "$f" ]] || return 1
  # Comment-only placeholder from earlier easyzsh deploys.
  if grep -Eqv '^[[:space:]]*(#|$)' "$f"; then
    return 1
  fi
  grep -Eq 'easyzsh|PATH lives in|Leave this file empty|prefer.*local\.zsh' "$f"
}

is_pyenv_only_zprofile() {
  local f="$1"
  local body
  [[ -f "$f" ]] || return 1
  body=$(grep -Ev '^[[:space:]]*(#|$)' "$f" || true)
  [[ "$body" == "$PYENV_LOGIN_HOOK" ]]
}

# Lines that are not the managed path_helper block or the old pyenv login hook.
zprofile_extras() {
  local f="$1"
  [[ -f "$f" ]] || return 0
  awk -v marker="$ZPROFILE_MARKER" -v hook="$PYENV_LOGIN_HOOK" '
    $0 == marker { in_block=1; next }
    in_block && $0 == "fi" { in_block=0; next }
    in_block { next }
    $0 == hook { next }
    { print }
  ' "$f"
}

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

# ~/.zprofile re-applies ~/.zshenv after macOS path_helper.
# Replace comment-only stubs and the old pyenv-only hook. Keep other login
# lines, or fold them into local.zsh when --migrate-zprofile is set.
zprofile_extras_file=$(mktemp)
: >"$zprofile_extras_file"
if [[ -f "$ZPROFILE" ]] && ! is_easyzsh_zprofile_stub "$ZPROFILE" && ! is_pyenv_only_zprofile "$ZPROFILE"; then
  zprofile_extras "$ZPROFILE" | awk '
    /Created by `pipx`/ { skip_pipx=1; next }
    skip_pipx && /local\/bin/ { skip_pipx=0; next }
    skip_pipx { next }
    { print }
  ' >"$zprofile_extras_file"
fi

if [[ "$MIGRATE_ZPROFILE" -eq 1 ]] && file_has_content "$zprofile_extras_file"; then
  if [[ -f "$LOCAL_ZSH" ]]; then
    printf '\n' >>"$LOCAL_ZSH"
    cat "$zprofile_extras_file" >>"$LOCAL_ZSH"
  else
    cp "$zprofile_extras_file" "$LOCAL_ZSH"
  fi
  echo "Migrated extra ~/.zprofile lines -> ~/.config/zsh/local.zsh"
  : >"$zprofile_extras_file"
fi

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

install -m 644 "${ROOT}/.zshenv" "${TARGET_HOME}/.zshenv"
install -m 644 "${ROOT}/.zshrc" "${TARGET_HOME}/.zshrc"
if file_has_content "$zprofile_extras_file"; then
  {
    cat "${ROOT}/.zprofile"
    printf '\n'
    cat "$zprofile_extras_file"
  } >"$ZPROFILE"
  echo "Installed ~/.zprofile (kept extra login lines)"
else
  install -m 644 "${ROOT}/.zprofile" "$ZPROFILE"
  echo "Installed ~/.zprofile"
fi
rm -f "$zprofile_extras_file"

# 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"

# Grok is `grok`. Cursor owns `agent` when its CLI is present.
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

agent_link="${TARGET_HOME}/.local/bin/agent"
cursor_agent="${TARGET_HOME}/.local/bin/cursor-agent"
agent_target=""
if [[ -L "$agent_link" ]]; then
  agent_target=$(readlink "$agent_link")
fi
if [[ -x "$cursor_agent" ]]; then
  if [[ ! -e "$agent_link" || "$agent_target" == *'/.grok/'* ]]; then
    ln -sfn "$cursor_agent" "$agent_link"
    echo "Ensured ~/.local/bin/agent -> cursor-agent"
  fi
elif [[ -L "$agent_link" && "$agent_target" == *'/.grok/'* ]]; then
  rm -f "$agent_link"
  echo "Removed ~/.local/bin/agent (was Grok; Cursor is not installed)"
fi

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