#!/usr/bin/env bash
set -euo pipefail

repo_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
unity_editor="${UNITY_EDITOR:-/opt/unity/2018.1.6f1/Editor/Unity}"
output_dir="$repo_dir/Builds/linux"
log_file="$output_dir/build.log"

if [[ ! -x "$unity_editor" ]]; then
    echo "Set UNITY_EDITOR to the Unity 2018.1.6f1 Editor/Unity executable." >&2
    exit 1
fi

mkdir -p "$output_dir"
echo "Building Linux x86_64 player; log: $log_file"

# Unity 2018 on Linux still needs an X server in batch mode.
runner=()
if [[ -z "${DISPLAY:-}" ]]; then
    if ! command -v xvfb-run >/dev/null; then
        echo "Install xvfb and xauth for builds without a display." >&2
        exit 1
    fi
    runner=(xvfb-run -a)
fi

if "${runner[@]}" "$unity_editor" \
    -batchmode -nographics -quit \
    -projectPath "$repo_dir/UnityProject" \
    -buildTarget Linux64 \
    -buildLinux64Player "$output_dir/Simulation.x86_64" \
    -logFile "$log_file"; then
    if [[ ! -x "$output_dir/Simulation.x86_64" ]]; then
        echo "Unity exited without producing a Linux player. See $log_file." >&2
        exit 1
    fi
    echo "Built $output_dir/Simulation.x86_64"
else
    result=$?
    [[ ! -f "$log_file" ]] || tail -n 60 "$log_file" >&2
    exit "$result"
fi