* Writes the report file to [outputDirectory].
     *
     * The file is laid out in such a way as to allow extracting the pure JSON model,
     * see [HtmlReportWriter].
     */
    internal
    fun writeReportFileTo(outputDirectory: File, buildDisplayName: String?, cacheAction: String, requestedTasks: String?, totalProblemCount: Int): File? {
        var reportFile: File?
        modifyState {

        val cacheActionText = cacheAction.summaryText()
        val requestedTasks = startParameter.requestedTasksOrDefault()
        val buildDisplayName = buildName
        val htmlReportFile = report.writeReportFileTo(outputDirectory, buildDisplayName, cacheActionText, requestedTasks, summary.problemCount)
        if (htmlReportFile == null) {
            // there was nothing to report (no problems, no build configuration inputs)