#!/bin/bash

gpg_exists() {
  gpg --version &> /dev/null
  return $?
}

download_and_verify() {
  local file_url="$1"

  if [ -v "$2" ]; then
    local output_file="$2"
  else
    local output_file="${3:-$(basename "$file_url")}"
    local signature_file="$2"
  fi

  if [ -v "$3" ]; then
    local signature_file="$3"
  else
    local signature_file="$output_file.sig"
  fi

  echo
  echo "Downloading from $file_url to $output_file and verifying $signature_file"

  # Download the file
  if ! curl -SfL "$file_url" -o "$output_file"; then
    echo "Error: Failed to download the file from $file_url"
    return 1
  fi

  echo
  sha256sum $output_file

  # Verify
  if gpg_exists; then
    if gpg --verify "$signature_file" "$output_file"; then
      echo "File is valid"
    else
      echo "File is not valid"
      rm "$output_file"
      return 1
    fi
  else
    echo "The file can't be verified because gpg is not installed"
  fi

  return 0
}

unpack() {
  local archive_file=$1
  local target_directory=$2

  echo
  echo "Unpacking..."

  mkdir "$target_directory"
  if tar -C "$target_directory" -xaf "$archive_file"; then
    echo "Unpacked into $target_directory"
  else
    echo "Error unpacking"
    return 1
  fi

  return 0
}

if [ -v "$1" ]; then
  target="$1"
else
  target="$HOME/Qt"
  echo "You did not specify where to extract, so extracting to $target"
  echo "Press enter to proceed, Ctrl+C to abort"
  read
fi

SYSTEM="$(uname) $(uname -p)"
echo "System is $SYSTEM"

if [[ "$SYSTEM" == "Linux x86_64" ]]; then
  if download_and_verify "https://lfs724.b-cdn.net/qt672.tar.zst"; then
    if unpack qt672.tar.zst $target; then
      echo
      echo "Downloaded to $target"
    else
      return 1
    fi
  else
    return 1
  fi

  rm qt672.tar.zst
else
  echo "System is not supported"
  exit 1
fi