#!/bin/bash
# Copyright 2020 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

function list_optional_features {
  echo \
    "fxtest_auto_publishes_packages" \
    "incremental" \
    "incremental_legacy" \
    "incremental_new" \
    "legacy_fastboot" \
    "legacy_fxtest" \
    "foreground_repo_server"
}

# Return 0 (true) if the default of the given feature is enabled, 1 (false) otherwise.
function is_feature_enabled_by_default {
  case "$1" in
  "fxtest_auto_publishes_publishes") return 0;;
  "incremental") return 0 ;;
  "incremental_legacy") return 1 ;;
  "incremental_new") return 1 ;;
  "legacy_fastboot") return 1 ;;
  "legacy_fxtest") return 1 ;;
  "foreground_repo_server") return 0 ;;
  esac

  # global default is enabled
  return 0
}

_FX_INDENT="      "
function help_optional_feature {
  local h=()
  case "$1" in
  "fxtest_auto_publishes_packages")
    h=(
      "Enables 'fx test' to automatically publish packages to the package"
      "repository server."
      )
    ;;
  "incremental_legacy")
    h=(
      "Packages are published and served incrementally by 'fx serve'"
      "as they are built using the legacy incremental publisher. Explicit"
      "'fx build' is not required for most operations."
      )
    ;;
  "incremental" | "incremental_new")
    h=(
      "Packages are published and served incrementally by 'fx serve'"
      "as they are built. Explicit 'fx build' is not required for most operations."
      )
    ;;
  "legacy_fastboot")
    h=(
      "Device provisioning based on legacy fastboot instead of ffx."
      )
    ;;
  "legacy_fxtest")
    h=(
      "Use the old Dart implementation of fx test rather than the new Python one."
      )
    ;;
  "foreground_repo_server")
    h=(
      "Run repository server and device registration as a foreground process,"
      "using 'ffx repository serve'"
      )
    ;;
  esac
  printf "${_FX_INDENT}${_FX_INDENT}%s\n" "${h[@]}"
}

function help_optional_features {
  for el in $(list_optional_features); do
    local default current
    is_feature_enabled_by_default $el && default="enabled" || default="disabled"
    is_feature_enabled $el && current="enabled" || current="disabled"
    echo "${_FX_INDENT}${el}"
    echo "${_FX_INDENT}${_FX_INDENT}(default=$default, current=$current)"
    help_optional_feature $el
  done
}

function warn_if_feature_enabled {
  local feature
  feature="$1"
  if is_feature_enabled "$feature"; then
    echo "Feature \"$feature\" is enabled."
  fi
}

function is_valid_feature {
  local el feature
  feature="$1"
  for el in $(list_optional_features); do
    if [[ "${el}" == "${feature}" ]]; then
      return 0
    fi
  done
  return 1
}

function get_fx_flags_non_default_features {
  local out=()
  for el in $(list_optional_features); do
    local default=false
    local current=false
    is_feature_enabled_by_default $el && default=true
    is_feature_enabled $el && current=true
    if $default && ! $current; then
      out+=("--disable=$el")
    elif ! $default && $current; then
      out+=("--enable=$el")
    fi
  done
  echo "${out[@]}"
}

function get_disable_feature_env_name {
  local feature
  feature="$1"
  echo "FUCHSIA_DISABLED_${feature}"
}

# Return code 0 (true) if the given feature is enabled, 1 (false) otherwise.
function is_feature_enabled {
  local feature
  feature="$1"
  if ! is_valid_feature "${feature}"; then
    return 1
  fi
  local disabled_env
  disabled_env="$(get_disable_feature_env_name "${feature}")"

  # if ${disabled_env} is not set, use the default
  if [[ -z ${!disabled_env+x} ]]; then
    is_feature_enabled_by_default "$feature"
  else
    test "${!disabled_env}" != "1"
  fi
}

function get_env_vars_non_default_features {
  local out=()
  for el in $(list_optional_features); do
    local default=false
    local current=false
    is_feature_enabled_by_default $el && default=true
    is_feature_enabled $el && current=true
    if $default && ! $current; then
      out+=("$(get_disable_feature_env_name $el)=1")
    elif ! $default && $current; then
      out+=("$(get_disable_feature_env_name $el)=0")
    fi
  done
  echo "${out[@]}"
}