#!/bin/sh

: "${REPO_API_URL:=https://api.github.com/repos/caidaoli/ccload/releases/latest}"
: "${RUNTIME_DIR:=/tmp/runtime}"
: "${RELEASES_DIR:=$RUNTIME_DIR/releases}"
: "${CURRENT_LINK:=$RUNTIME_DIR/current}"
: "${CURRENT_TAG_FILE:=$RUNTIME_DIR/current.tag}"
: "${DOWNLOADS_DIR:=$RUNTIME_DIR/downloads}"
: "${SUPERVISOR_CONF:=/etc/supervisord.conf}"
: "${SUPERVISOR_PROGRAM_NAME:=app}"
: "${SUPERVISOR_UPDATER_PROGRAM_NAME:=${SUPERVISOR_PROGRAM_NAME}-updater}"
: "${CURRENT_BINARY_NAME:=app}"
: "${APP_BINARY_NAMES:=}"

log() {
  timestamp=$(date '+%Y-%m-%d %H:%M:%S %z')
  printf '[%s] %s\n' "$timestamp" "$*" >&2
}

tag_to_dir_name() {
  printf '%s\n' "$1" | tr '/:' '__'
}

release_dir_for_tag() {
  printf '%s/%s\n' "$RELEASES_DIR" "$(tag_to_dir_name "$1")"
}

ensure_runtime_dirs() {
  mkdir -p "$RUNTIME_DIR" "$RELEASES_DIR" "$DOWNLOADS_DIR"
}

current_tag() {
  if [ -f "$CURRENT_TAG_FILE" ]; then
    tr -d '\n' < "$CURRENT_TAG_FILE"
  fi
}

current_binary_path() {
  printf '%s/%s\n' "$CURRENT_LINK" "$CURRENT_BINARY_NAME"
}

fetch_latest_release_info() {
  response=$(curl -fsSL "$REPO_API_URL") || return 1

  tag_name=$(
    printf '%s\n' "$response" \
      | grep -Eo '"tag_name"[[:space:]]*:[[:space:]]*"[^"]+"' \
      | head -n 1 \
      | cut -d '"' -f 4 \
      || true
  )
  asset_url=$(
    printf '%s\n' "$response" \
      | grep -Eo '"browser_download_url"[[:space:]]*:[[:space:]]*"[^"]*"' \
      | cut -d '"' -f 4 \
      | grep -E '/[^/]*linux[-_]amd64(\.tar\.gz)?$' \
      | head -n 1 \
      || true
  )

  if [ -z "$tag_name" ] || [ -z "$asset_url" ]; then
    return 1
  fi

  printf '%s|%s\n' "$tag_name" "$asset_url"
}

load_latest_release() {
  release_info=$(fetch_latest_release_info) || return 1
  LATEST_TAG=${release_info%%|*}
  LATEST_ASSET_URL=${release_info#*|}
}

find_release_binary() {
  release_dir=$1

  for name in $APP_BINARY_NAMES; do
    if [ -f "$release_dir/$name" ]; then
      printf '%s\n' "$release_dir/$name"
      return 0
    fi
  done

  for name in $APP_BINARY_NAMES; do
    binary_path=$(find "$release_dir" -maxdepth 3 -type f -name "$name" | head -n 1)
    if [ -n "$binary_path" ]; then
      printf '%s\n' "$binary_path"
      return 0
    fi
  done

  file_list=$(find "$release_dir" -maxdepth 3 -type f ! -name '._*' ! -path '*/__MACOSX/*' | sort)
  first_file=$(printf '%s\n' "$file_list" | sed -n '1p')
  second_file=$(printf '%s\n' "$file_list" | sed -n '2p')
  if [ -n "$first_file" ] && [ -z "$second_file" ]; then
    printf '%s\n' "$first_file"
    return 0
  fi

  return 1
}

activate_release() {
  tag_name=$1
  release_dir=$2

  rm -f "$CURRENT_LINK"
  ln -s "$release_dir" "$CURRENT_LINK"
  printf '%s\n' "$tag_name" > "$CURRENT_TAG_FILE"
}

extract_release_binary() {
  source_dir=$1
  target_path=$2
  binary_path=$(find_release_binary "$source_dir" || true)

  if [ -z "$binary_path" ]; then
    return 1
  fi

  if [ "$binary_path" != "$target_path" ]; then
    cp "$binary_path" "$target_path"
  fi
  chmod +x "$target_path"
}

cleanup_workspace() {
  workspace=$1
  if [ -n "$workspace" ] && [ -d "$workspace" ]; then
    rm -rf "$workspace"
  fi
}

install_release() {
  tag_name=$1
  asset_url=$2

  ensure_runtime_dirs
  release_dir=$(release_dir_for_tag "$tag_name")
  release_binary="$release_dir/$CURRENT_BINARY_NAME"

  if [ -x "$release_binary" ]; then
    activate_release "$tag_name" "$release_dir"
    return 0
  fi

  workspace=$(mktemp -d "$RUNTIME_DIR/install.XXXXXX") || return 1
  download_name=$(basename "$asset_url")
  if [ -z "$download_name" ] || [ "$download_name" = "/" ] || [ "$download_name" = "." ]; then
    download_name="release.asset"
  fi
  download_path="$DOWNLOADS_DIR/$download_name"
  stage_dir="$workspace/stage"

  rm -f "$download_path" || {
    cleanup_workspace "$workspace"
    return 1
  }
  mkdir -p "$stage_dir" || {
    cleanup_workspace "$workspace"
    return 1
  }
  curl -fsSL "$asset_url" -o "$download_path" || {
    cleanup_workspace "$workspace"
    return 1
  }

  case "$download_path" in
    *.tar.gz)
      tar -xzf "$download_path" -C "$stage_dir" || {
        cleanup_workspace "$workspace"
        return 1
      }
      extract_release_binary "$stage_dir" "$stage_dir/$CURRENT_BINARY_NAME" || {
        cleanup_workspace "$workspace"
        return 1
      }
      ;;
    *)
      cp "$download_path" "$stage_dir/$CURRENT_BINARY_NAME" || {
        cleanup_workspace "$workspace"
        return 1
      }
      chmod +x "$stage_dir/$CURRENT_BINARY_NAME" || {
        cleanup_workspace "$workspace"
        return 1
      }
      ;;
  esac

  rm -rf "$release_dir" || {
    cleanup_workspace "$workspace"
    return 1
  }
  mv "$stage_dir" "$release_dir" || {
    cleanup_workspace "$workspace"
    return 1
  }
  cleanup_workspace "$workspace"

  activate_release "$tag_name" "$release_dir"
}

ensure_initial_release() {
  if load_latest_release; then
    if install_release "$LATEST_TAG" "$LATEST_ASSET_URL"; then
      return 0
    fi
    log "警告: 安装最新版本失败，尝试使用已有版本继续启动"
  fi

  [ -x "$(current_binary_path)" ]
}

restart_managed_service() {
  supervisorctl -c "$SUPERVISOR_CONF" restart "$SUPERVISOR_PROGRAM_NAME"
}

update_if_needed() {
  load_latest_release || {
    log "检查最新版本失败"
    return 1
  }

  installed_tag=$(current_tag)
  if [ "$LATEST_TAG" = "$installed_tag" ]; then
    log "当前已是最新版本: $LATEST_TAG"
    return 0
  fi

  log "发现新版本: ${installed_tag:-<none>} -> $LATEST_TAG"
  install_release "$LATEST_TAG" "$LATEST_ASSET_URL" || {
    log "安装新版本失败: $LATEST_TAG"
    return 1
  }

  if [ -n "$installed_tag" ]; then
    restart_managed_service
  fi
}