#!/bin/bash

# bail on errors and unset variables
set -euo pipefail

SWIFT_VERSION=5.1.3
SWIFT_DIR=swift-$SWIFT_VERSION-RELEASE-ubuntu18.04
SWIFT_FILENAME=$SWIFT_DIR.tar.gz

if [[ $(uname) = "Linux" ]]; then
  if which swift >/dev/null 2>/dev/null && swift --version | grep $SWIFT_VERSION >/dev/null 2>/dev/null; then
    echo "*** swift $SWIFT_VERSION is installed"
  else
    echo "*** installing swift"
    pushd $HOME
    if [[ -e $SWIFT_FILENAME ]]; then
      echo "*** $SWIFT_FILENAME exists, skipping download"
    else
      wget https://swift.org/builds/swift-$SWIFT_VERSION-release/ubuntu1804/swift-$SWIFT_VERSION-RELEASE/$SWIFT_FILENAME
    fi
    if [[ -e $SWIFT_DIR ]]; then
      echo "*** $SWIFT_DIR exists, skipping extraction"
    else
      tar xzf $SWIFT_FILENAME
    fi
    if ! grep $SWIFT_DIR $HOME/.bashrc >/dev/null 2>/dev/null; then
      echo "*** adding $HOME/$SWIFT_DIR/usr/bin to PATH in $HOME/.bashrc"
      echo "export PATH=\"\$HOME/$SWIFT_DIR/usr/bin:\$PATH\"" >> $HOME/.bashrc
    fi
    popd
  fi
fi

echo "*** done"