#!/bin/bash
set -e

# felt: a command-line utility for building and testing Flutter web engine.
#       It stands for Flutter Engine Local Tester.
# TODO: Add git fetch --tags step. Tags are critical for the correct Dart
# version.

FELT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"

KERNEL_NAME=`uname`
CPU_NAME=`uname -m`
ENGINE_SRC_DIR="$(dirname $(dirname $(dirname $(dirname ${FELT_DIR}))))"
FLUTTER_DIR="${ENGINE_SRC_DIR}/flutter"
SDK_PREBUILTS_DIR="${FLUTTER_DIR}/prebuilts"

# If set to 0 (the default) will run felt non-incrementally. For example, it will
# run pub get.
# If set to 1 (via the -i option) will run felt incrementally.
INCREMENTAL=0

# All arguments passed to felt, except -i, if any.
ARGS=""
for arg in "$@" ; do
  case "$arg" in
    -i)
      INCREMENTAL=1
      shift
      ;;
    *)
      ARGS="${ARGS} ${arg}"
      ;;
  esac
done

if [ -z "${DART_SDK_DIR}" ]
then
  if [[ $KERNEL_NAME == *"Darwin"* ]]
  then
    TARGET_OS="macos"
  elif [[ $KERNEL_NAME == *"Linux"* ]]
  then
    TARGET_OS="linux"
  else
    echo "Unrecognized kernel name: ${KERNEL_NAME}"
    exit 1
  fi

  if [[ $CPU_NAME == *"x86_64"* ]]
  then
    TARGET_ARCH="x64"
  elif [[ $CPU_NAME == *"arm64"* ]]
  then
    TARGET_ARCH="arm64"
  else
    echo "Unrecognized architecture: ${CPU_NAME}"
    exit 1
  fi

  PREBUILT_TARGET="${TARGET_OS}-${TARGET_ARCH}"
  DART_SDK_DIR="${SDK_PREBUILTS_DIR}/${PREBUILT_TARGET}/dart-sdk"

  if [ ! -d "$DART_SDK_DIR" ]
  then
    echo "Prebuilt dart sdk for ${PREBUILT_TARGET} not found."
    echo "Note: You can specify your own path to a built dart sdk with the DART_SDK_DIR environment variable."
    exit 1
  fi

else
  if [ ! -d "$DART_SDK_DIR" ]
  then
    echo "Explicitly specified dart SDK not found at ${DART_SDK_DIR}."
    exit 1
  fi
fi

WEB_UI_DIR="${FLUTTER_DIR}/lib/web_ui"
DART_PATH="$DART_SDK_DIR/bin/dart"

if [[ "$FELT_DEBUG" == "true" || "$FELT_DEBUG" == "1" ]]
then
  FELT_DEBUG_FLAGS="--enable-vm-service --pause-isolates-on-start"
fi

SILENT_LOG=/tmp/felt_pub_get_silent_log.txt
trap "rm -f $SILENT_LOG" EXIT

verbose_on_failure() {
  echo "FAILED with the following output:"
  cat $SILENT_LOG
  exit 1
}

silent_on_success() {
  COMMAND=${1+"$@"}
  $COMMAND > $SILENT_LOG 2>&1 || verbose_on_failure
}

install_deps() {
  # We need to run pub get here before we actually invoke felt.
  echo "Running \`dart pub get\` in 'engine/src/flutter/lib/web_ui'"
  (cd "$WEB_UI_DIR"; silent_on_success $DART_PATH pub get)
}

cd $WEB_UI_DIR
if [[ "$INCREMENTAL" == "0" ]]
then
  install_deps
fi

(cd $WEB_UI_DIR && $DART_SDK_DIR/bin/dart run $FELT_DEBUG_FLAGS dev/felt.dart ${ARGS})