FHIR Reference (.NET)

Instructions

In FHIR, resources point at each other with references. A relative literal reference looks like:

Patient/123
Observation/abc-1/_history/4

• ResourceType/id — points at the current version of a resource.
• ResourceType/id/_history/versionId — points at a specific version.

This kata is the offline, deterministic version of Batch-1 Day 4, Assignment 2 (the .NET OpenMRS FHIR facade client): before you can follow a reference to another resource, you must be able to parse and build one.

Implement FhirReference with:

• static FhirReference Parse(string reference) — parse a relative reference.
• string Type — the resource type, e.g. "Patient".
• string Id — the logical id, e.g. "123".
• string Version — the _history version id, or null when unversioned.
• bool IsVersioned — true when a version id is present.
• string Format() — reconstruct the canonical reference string.

Rules

• A valid reference has a non-empty resource type and a non-empty id.
• The type must start with an uppercase letter (FHIR resource types are PascalCase).
• A versioned reference has exactly the segments Type/id/_history/vid, and vid must be non-empty.
• Anything else (null, empty, "Patient", "Patient/", "/123", "Patient/123/foo/4", "Patient/123/_history/") must throw ArgumentException.
• Format() must round-trip: FhirReference.Parse(s).Format() == s for every valid s.