private String purgeLogs()

in client/src/main/java-mvnd/org/mvndaemon/mvnd/client/DefaultClient.java [408:479]
72 lines of code
14 McCabe index (conditional complexity)

    private String purgeLogs() {
        Path storage = parameters.daemonStorage();
        Duration purgeLogPeriod = parameters.purgeLogPeriod();
        if (!Files.isDirectory(storage) || !TimeUtils.isPositive(purgeLogPeriod)) {
            return null;
        }
        String date = DateTimeFormatter.ofPattern("yyyy-MM-dd")
                .withZone(ZoneId.systemDefault())
                .format(Instant.now());
        Path log = storage.resolve("purge-" + date + ".log");
        List<Path> deleted = new ArrayList<>();
        List<Throwable> exceptions = new ArrayList<>();
        FileTime limit = FileTime.from(Instant.now().minus(purgeLogPeriod));
        try (Stream<Path> storagePath = Files.list(storage)) {
            storagePath
                    .filter(p -> p.getFileName().toString().endsWith(LOG_EXTENSION))
                    .filter(p -> !log.equals(p))
                    .filter(p -> {
                        try {
                            FileTime lmt = Files.getLastModifiedTime(p);
                            return lmt.compareTo(limit) < 0;
                        } catch (IOException e) {
                            exceptions.add(e);
                            return false;
                        }
                    })
                    .forEach(p -> {
                        try {
                            Files.delete(p);
                            deleted.add(p);
                        } catch (IOException e) {
                            exceptions.add(e);
                        }
                    });
        } catch (Exception e) {
            exceptions.add(e);
        }
        if (exceptions.isEmpty() && deleted.isEmpty()) {
            return null;
        }
        String logMessage;
        try (PrintWriter w = new PrintWriter(Files.newBufferedWriter(
                log, StandardOpenOption.WRITE, StandardOpenOption.APPEND, StandardOpenOption.CREATE))) {
            w.printf("Purge executed at %s%n", Instant.now().toString());
            if (deleted.isEmpty()) {
                w.printf("No files deleted.%n");
            } else {
                w.printf("Deleted files:%n");
                for (Path p : deleted) {
                    w.printf("    %s%n", p.toString());
                }
            }
            if (!exceptions.isEmpty()) {
                w.printf("%d exception(s) occurred during the purge", exceptions.size());
                for (Throwable t : exceptions) {
                    t.printStackTrace(w);
                }
            }
            char[] buf = new char[80];
            Arrays.fill(buf, '=');
            w.printf("%s%n", new String(buf));
            logMessage = "log available in " + log.toString();
        } catch (IOException e) {
            logMessage = "an exception occurred when writing log to " + log.toString() + ": " + e.toString();
        }
        if (exceptions.isEmpty()) {
            return String.format("Purged %d log files (%s)", deleted.size(), logMessage);
        } else {
            return String.format(
                    "Purged %d log files with %d exceptions (%s)", deleted.size(), exceptions.size(), logMessage);
        }
    }