#!/bin/bash

if (( ${#BASH_SOURCE[@]} == 1 )); then
    echo "This script must be sourced."
    exit 1
fi

if [[ $TRAVIS_PULL_REQUEST == false ]]; then
    export SHOULD_BUILD=all
    return 0
fi

JSON=$(curl -sLf https://api.github.com/repos/$TRAVIS_REPO_SLUG/pulls/$TRAVIS_PULL_REQUEST)
PR_TITLE=$(jq -re '.title' <<< "$JSON")

JSON=$(curl -sLf https://api.github.com/repos/$TRAVIS_REPO_SLUG/pulls/$TRAVIS_PULL_REQUEST/commits)
COMMITS=$(jq -re '.[].sha' <<< "$JSON")

FILES=$(for C in $COMMITS; do JSON=$(curl -sLf https://api.github.com/repos/$TRAVIS_REPO_SLUG/commits/$C); jq -re '.files[].filename' <<< "$JSON"; done)

if [[ $PR_TITLE =~ \[run-systemtest\] ]]; then
  SHOULD_BUILD=systemtest
elif [[ -z $FILES ]]; then
  SHOULD_BUILD=all
elif ! grep -v -E "(\.h|\.hh|\.hxx|\.c|\.cpp|\.cxx)$" <<< "$FILES" &> /dev/null; then
  SHOULD_BUILD=cpp
elif ! grep -v -E "(\.java)$" <<< "$FILES" &> /dev/null; then
  SHOULD_BUILD=java
else
  SHOULD_BUILD=all
fi

export SHOULD_BUILD