#!/bin/bash
# Automatically prepare OpenWRT build environment.
# - Clone or update repository
# - Support selecting release/beta/snapshot versions
# - Normalize helper checkout into openwrt/helper
# - Update and install feeds
# - Prepare .config for build

set -e
umask 022

REPO_URL="https://github.com/openwrt/openwrt.git"
SCRIPT_PATH="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd -P)/$(basename "${BASH_SOURCE[0]}")"
SCRIPT_DIR="$(dirname "$SCRIPT_PATH")"
WORK_ROOT=""
HELPER_DIR=""

echo "========================================"
echo " OpenWRT Build Environment Setup Script"
echo "========================================"

# --- Helpers ---
is_openwrt_repo() {
  local dir="$1"

  [ -f "$dir/feeds.conf.default" ] &&
    [ -f "$dir/Makefile" ] &&
    git -C "$dir" rev-parse --is-inside-work-tree >/dev/null 2>&1
}

is_helper_checkout() {
  local dir="$1"

  [ -f "$dir/prepare-openwrt.sh" ] &&
    [ -f "$dir/prepare-openwrt-env.sh" ] &&
    [ -f "$dir/add-external-repos.sh" ]
}

has_remote_branch() {
  local branch="$1"
  git show-ref --verify --quiet "refs/remotes/origin/$branch"
}

has_tag() {
  local tag="$1"
  git rev-parse --verify "refs/tags/$tag" >/dev/null 2>&1
}

ensure_helper_target_available() {
  local target_helper="$1"
  local source_dir="$2"
  local existing_path=""
  local source_path=""

  if [ ! -e "$target_helper" ]; then
    return
  fi

  existing_path="$(cd "$target_helper" && pwd -P)"
  source_path="$(cd "$source_dir" && pwd -P)"

  if [ "$existing_path" = "$source_path" ]; then
    return
  fi

  echo "[ERROR] Helper destination already exists at '$target_helper'."
  echo "[ERROR] Refusing to overwrite a different helper checkout."
  exit 1
}

ensure_target_root_ready() {
  local target_root="$1"
  local first_entry=""

  if [ ! -e "$target_root" ]; then
    return
  fi

  if [ ! -d "$target_root" ]; then
    echo "[ERROR] Target OpenWrt root '$target_root' exists but is not a directory."
    exit 1
  fi

  if is_openwrt_repo "$target_root"; then
    return
  fi

  first_entry="$(find "$target_root" -mindepth 1 -maxdepth 1 ! -name helper -print -quit 2>/dev/null || true)"
  if [ -z "$first_entry" ]; then
    return
  fi

  echo "[ERROR] Target OpenWrt root '$target_root' already contains unexpected files."
  echo "[ERROR] Refusing to merge the helper checkout into a non-OpenWrt directory."
  exit 1
}

normalize_structure() {
  local source_dir="$SCRIPT_DIR"
  local source_name
  local parent_dir
  local target_root
  local target_helper
  local temp_dir

  source_name="$(basename "$source_dir")"
  parent_dir="$(dirname "$source_dir")"

  if [ "$source_name" = "helper" ] && [ "$(basename "$parent_dir")" = "openwrt" ]; then
    WORK_ROOT="$parent_dir"
    HELPER_DIR="$source_dir"
    cd "$WORK_ROOT"
    echo "[INFO] Reusing existing normalized layout at '$WORK_ROOT'."
    return
  fi

  if is_openwrt_repo "$source_dir"; then
    WORK_ROOT="$source_dir"
    HELPER_DIR="$source_dir/helper"
    cd "$WORK_ROOT"
    echo "[INFO] Script is already running from an OpenWrt source root at '$WORK_ROOT'."
    echo "[INFO] Skipping relocation to avoid moving an existing OpenWrt tree."
    return
  fi

  if ! is_helper_checkout "$source_dir"; then
    echo "[ERROR] '$source_dir' does not look like a helper checkout."
    echo "[ERROR] Refusing to relocate an unexpected directory."
    exit 1
  fi

  target_root="$parent_dir/openwrt"
  target_helper="$target_root/helper"

  if [ "$source_dir" != "$target_root" ]; then
    ensure_target_root_ready "$target_root"
  fi
  ensure_helper_target_available "$target_helper" "$source_dir"

  if [ "$source_dir" = "$target_root" ]; then
    echo "[INFO] Helper checkout already uses the target root name. Normalizing in place."
    temp_dir="$parent_dir/.openwrt-helper-relocate-$$"

    if [ -e "$temp_dir" ]; then
      echo "[ERROR] Temporary relocation path already exists: '$temp_dir'."
      exit 1
    fi

    cd "$parent_dir"
    mv "$source_dir" "$temp_dir"
    mkdir -p "$target_root"
    mv "$temp_dir" "$target_helper"
  else
    echo "[INFO] Relocating helper checkout to '$target_helper'."
    mkdir -p "$target_root"
    cd "$parent_dir"
    mv "$source_dir" "$target_helper"
  fi

  WORK_ROOT="$target_root"
  HELPER_DIR="$target_helper"
  cd "$WORK_ROOT"

  echo "[INFO] OpenWrt source root: '$WORK_ROOT'."
  echo "[INFO] Helper checkout: '$HELPER_DIR'."
}

ensure_origin_remote() {
  local current_url=""

  if git remote get-url origin >/dev/null 2>&1; then
    current_url="$(git remote get-url origin)"
    if [ "$current_url" != "$REPO_URL" ]; then
      echo "[INFO] Updating git remote 'origin' to '$REPO_URL'."
      git remote set-url origin "$REPO_URL"
    fi
  else
    git remote add origin "$REPO_URL"
  fi
}

prepare_openwrt_repo() {
  cd "$WORK_ROOT"

  if is_openwrt_repo "$WORK_ROOT"; then
    echo "[INFO] Existing OpenWrt repository detected at '$WORK_ROOT'. Updating refs..."
    ensure_origin_remote
    git fetch --tags origin
    return
  fi

  if [ -e "$WORK_ROOT/.git" ]; then
    echo "[ERROR] '$WORK_ROOT' already contains a Git repository that does not look like OpenWrt."
    exit 1
  fi

  if [ -f "$WORK_ROOT/feeds.conf.default" ] || [ -f "$WORK_ROOT/Makefile" ] || [ -d "$WORK_ROOT/package" ]; then
    echo "[ERROR] '$WORK_ROOT' contains files that look like an incomplete OpenWrt tree."
    echo "[ERROR] Refusing to initialize over an unexpected directory state."
    exit 1
  fi

  echo "[INFO] Initializing OpenWrt repository in '$WORK_ROOT'..."
  git init .
  ensure_origin_remote
  git fetch --tags origin
}

checkout_or_update_branch() {
  local branch="$1"

  if [ ! "$(git rev-parse --abbrev-ref HEAD 2>/dev/null)" = "$branch" ]; then
    if git show-ref --verify --quiet "refs/heads/$branch"; then
      git checkout "$branch"
    else
      git checkout -b "$branch" --track "origin/$branch"
    fi
  fi

  git pull --ff-only origin "$branch"
}

# --- Function: choose version ---
choose_version() {
  echo
  echo "Select OpenWRT version type:"
  echo "  1) Stable release (e.g., 24.10.4)"
  echo "  2) Beta (e.g., 24.10-SNAPSHOT or openwrt-24.10)"
  echo "  3) Latest snapshot (master branch)"
  echo -n "Enter choice [1-3, default=1]: "
  read -r choice

  case "$choice" in
    2)
      echo -n "Enter beta version (e.g. 24.10 or openwrt-24.10): "
      read -r VERSION
      SELECTED_TYPE="beta"
      ;;
    3)
      SELECTED_TYPE="snapshot"
      VERSION="master"
      ;;
    *)
      echo -n "Enter stable version number (e.g. 24.10.4, default: latest): "
      read -r VERSION
      SELECTED_TYPE="stable"
      ;;
  esac
}

# --- Start ---
normalize_structure
choose_version
prepare_openwrt_repo

pushd "$WORK_ROOT" >/dev/null

# --- Version selection logic ---
if [ "$SELECTED_TYPE" == "snapshot" ]; then
  echo "[INFO] Checking out latest master (snapshot)..."
  if has_remote_branch "master"; then
    checkout_or_update_branch "master"
  else
    echo "[ERROR] Remote branch 'master' not found."
    exit 1
  fi
elif [ "$SELECTED_TYPE" == "beta" ]; then
  local_branch=""
  local_tag=""

  if [[ "$VERSION" == openwrt-* ]]; then
    local_branch="$VERSION"
    local_tag="v${VERSION#openwrt-}-SNAPSHOT"
  elif [[ "$VERSION" == v*-SNAPSHOT ]]; then
    local_tag="$VERSION"
    local_branch="openwrt-${VERSION#v}"
    local_branch="${local_branch%-SNAPSHOT}"
  else
    local_branch="openwrt-${VERSION}"
    local_tag="v${VERSION}-SNAPSHOT"
  fi

  if has_remote_branch "$local_branch"; then
    echo "[INFO] Checking out beta branch '$local_branch'..."
    checkout_or_update_branch "$local_branch"
  elif has_tag "$local_tag"; then
    echo "[INFO] Checking out beta tag '$local_tag'..."
    git checkout "$local_tag"
  else
    echo "[ERROR] Beta branch or tag not found for version '$VERSION'."
    exit 1
  fi
else
  # Stable version
  if [ -z "$VERSION" ]; then
    LATEST_TAG=$(git tag -l "v*" | sort -V | tail -n 1)
    if [ -z "$LATEST_TAG" ]; then
      echo "[ERROR] No stable tags found in remote repository."
      exit 1
    fi
    echo "[INFO] No version specified, using latest stable tag: $LATEST_TAG"
    VERSION="$LATEST_TAG"
  else
    if [[ "$VERSION" != v* ]]; then
      VERSION="v${VERSION}"
    fi
  fi

  if has_tag "$VERSION"; then
    git checkout "$VERSION"
  else
    echo "[ERROR] Version tag '$VERSION' not found."
    exit 1
  fi
fi

# --- Update feeds ---
echo "[INFO] Updating and installing all feeds..."
./scripts/feeds update -a
./scripts/feeds install -a

# --- Run defconfig ---
echo "[INFO] Running make defconfig..."
make defconfig

CURRENT_VERSION=$(git describe --tags 2>/dev/null || git rev-parse --abbrev-ref HEAD)

popd >/dev/null

echo
echo "========================================"
echo "✅ OpenWRT source is ready."
echo "   Version: $CURRENT_VERSION"
echo "   Root: $WORK_ROOT"
echo "========================================"
echo
echo "👉 Next steps:"
echo "   cd $WORK_ROOT"
echo "   make menuconfig"
echo "   make -j\$(nproc) download world"
echo