private String cleanTimestamp()

in flink-cdc-connect/flink-cdc-source-connectors/flink-connector-mysql-cdc/src/main/java/io/debezium/connector/mysql/MySqlDefaultValueConverter.java [407:504]
77 lines of code
20 McCabe index (conditional complexity)

    private String cleanTimestamp(String s) {
        if (s == null) {
            throw new java.lang.IllegalArgumentException("null string");
        }

        s = s.trim();

        // clean first dash
        s = replaceFirstNonNumericSubstring(s, 0, '-');
        // clean second dash
        s = replaceFirstNonNumericSubstring(s, s.indexOf('-') + 1, '-');
        // clean dividing space
        s = replaceFirstNonNumericSubstring(s, s.indexOf('-', s.indexOf('-') + 1) + 1, ' ');
        if (s.indexOf(' ') != -1) {
            // clean first colon
            s = replaceFirstNonNumericSubstring(s, s.indexOf(' ') + 1, ':');
            if (s.indexOf(':') != -1) {
                // clean second colon
                s = replaceFirstNonNumericSubstring(s, s.indexOf(':') + 1, ':');
            }
        }

        final int maxMonth = 12;
        final int maxDay = 31;

        // Parse the date
        int firstDash = s.indexOf('-');
        int secondDash = s.indexOf('-', firstDash + 1);
        int dividingSpace = s.indexOf(' ');

        // Parse the time
        int firstColon = s.indexOf(':', dividingSpace + 1);
        int secondColon = s.indexOf(':', firstColon + 1);
        int period = s.indexOf('.', secondColon + 1);

        int year = 0;
        int month = 0;
        int day = 0;
        int hour = 0;
        int minute = 0;
        int second = 0;

        // Get the date
        int len = s.length();
        boolean parsedDate = false;
        if (firstDash > 0 && secondDash > firstDash) {
            year = Integer.parseInt(s.substring(0, firstDash));
            month = Integer.parseInt(s.substring(firstDash + 1, secondDash));
            if (dividingSpace != -1) {
                day = Integer.parseInt(s.substring(secondDash + 1, dividingSpace));
            } else {
                day = Integer.parseInt(s.substring(secondDash + 1, len));
            }

            if ((month >= 1 && month <= maxMonth) && (day >= 1 && day <= maxDay)) {
                parsedDate = true;
            }
        }
        if (!parsedDate) {
            throw new java.lang.IllegalArgumentException("Cannot parse the date from " + s);
        }

        // Get the time. Hour, minute, second and colons are all optional
        if (dividingSpace != -1 && dividingSpace < len - 1) {
            if (firstColon == -1) {
                hour = Integer.parseInt(s.substring(dividingSpace + 1, len));
            } else {
                hour = Integer.parseInt(s.substring(dividingSpace + 1, firstColon));
                if (firstColon < len - 1) {
                    if (secondColon == -1) {
                        minute = Integer.parseInt(s.substring(firstColon + 1, len));
                    } else {
                        minute = Integer.parseInt(s.substring(firstColon + 1, secondColon));
                        if (secondColon < len - 1) {
                            if (period == -1) {
                                second = Integer.parseInt(s.substring(secondColon + 1, len));
                            } else {
                                second = Integer.parseInt(s.substring(secondColon + 1, period));
                            }
                        }
                    }
                }
            }
        }

        StringBuilder cleanedTimestamp = new StringBuilder();
        cleanedTimestamp =
                cleanedTimestamp.append(
                        String.format(
                                "%04d-%02d-%02d %02d:%02d:%02d",
                                year, month, day, hour, minute, second));

        if (period != -1 && period < len - 1) {
            cleanedTimestamp = cleanedTimestamp.append(".").append(s.substring(period + 1));
        }

        return cleanedTimestamp.toString();
    }