Create filter to format time with a colon

[wi-y]

In this issue: #513 it was reported that the time being returned by a HL7v2 to FHIR liquid template was not in the correct format.

The input time from the HL7v2 message was "0730" and the template was returning a FHIR resource with a time value of "0730". This is technically not a valid time value for FHIR. The FHIR spec states that the format should be in HH:mm:ss format, so the templates technically should be updated to return "07:30:00" in this specific case and in other locations where HL7v2 - 2.8.35.2 Explicit time interval (ST) is used.

In this PR we are creating a new filter which can be used to format the time in the various places where the templates should be formatting the time.

The most common place is in the timeOfDay FHIR element like in this case of ServiceRequest: https://github.com/microsoft/FHIR-Converter/blob/370f5c1964c6e317ba406dad1b057b4399187b92/data/Templates/Hl7v2/Resource/_ServiceRequest.liquid#L533C1-L534C1

Currently the liquid template passes the value from the HL7v2 message to the FHIR output without any formatting. But after this new time formatting filter is rolled out then the templates could be updated to use the filter to format the time correctly.

The templates could be updated as follows to add the formatting filter format_time_with_colon

	{% if type_msg == "ORM" -%}
		{% assign obr_27_2_2_repetitions = OBR_child.27.2.2 | split: "," %}
		{% for entry in obr_27_2_2_repetitions %}
		  "{{ entry | format_time_with_colon }}",
		{% endfor %}
	{% endif -%}

[shabanlushaj]

@wi-y Is it better to ignore (input.Length == 4) to make it more as a general filter because there are cases when time is represented as HHmmssSS e.g. when OBX type(OBX.2.1 ) is time(TM) value(OBX.5.1) has seconds and ms. Also there is inputFormat as filter arg which helps parsing.

[wi-y]

@shabanlushaj agree - it is better to make this more generic for the other HL7v2 times. I've updated the pull request so that the filter is more generic.

Question: Is HHmmssSS supported by HL7v2 for TM time? I was looking at the spec and it seemed to be HHMM[SS[.SSSS]][+/-ZZZZ] with the milliseconds following a decimal. But either way both formats HHmmssff and HHmmss.ff should be supported now.

[shabanlushaj]

@wi-y Whenever it is UTC, timezone can be discarded. I believe same applies for time. It would be nice to have this filter support timezone.

20240107111232-0300 for datetime this is supported by converter (MSH.7 - Date/Time Of Message).

Tried something that might do the work, but we have to ignore check for input length and inputFormat having same length.

var input = "144100.0000+0300";
var inputFormat = "HHmmss.ffffzzzz";
var dt = DateTime.ParseExact(input, inputFormat, CultureInfo.InvariantCulture).TimeOfDay; // might need also an arg for preserve/local/utc output (same as datetime)