---
title: PolicyDocumentExtensions
summary: API reference for PolicyDocumentExtensions.
status: draft
owner: SAIF Doc Gen
last_reviewed: 2026-09-24
library: SAIF.Services
reference_type: package
---

# PolicyDocumentExtensions

Provides extension methods that convert the internal `PolicyDocument` data model into the `PolicyDocumentModel` view/contract shape consumed by `PolicyDocumentsApiService`, deriving derived flags (invoice/payroll-report detection, packet ID) from the document's description and type fields.

## Purpose
- Converts a single `PolicyDocument` into a `PolicyDocumentModel`, including a nested `DocumentCategory` and derived `IsInvoice`/`IsPayrollReport` flags based on the document's description text.
- Converts a collection of `PolicyDocument` instances into their `PolicyDocumentModel` equivalents in bulk.

## Context
- Namespace: `SAIF.Services.Policies.PolicyDocumentsApi`
- Assembly/package: `SAIF.Services` (packaged inside the `SAIF.SAIFCode.Core` NuGet package).

## Public members
| Member | Signature | Purpose |
| --- | --- | --- |
| ToDocumentModels | `public static IEnumerable<PolicyDocumentModel> ToDocumentModels(this IEnumerable<PolicyDocument> documents)` | Maps each document in the sequence to a `PolicyDocumentModel` via `ToDocumentModel` and returns the resulting collection. |
| ToDocumentModel | `public static PolicyDocumentModel ToDocumentModel(this PolicyDocument document)` | Builds a `PolicyDocumentModel` from the document's ID, packet flag, description, document date, policy-period effective date, and a `DocumentCategory` built from the document type; sets `PacketId` only for packet documents, and flags `IsInvoice`/`IsPayrollReport` by case-insensitive comparison of the description against `"INVOICE"`/`"PAYROLL REPORT"`. |

## Behavioral notes
- `ToDocumentModel` throws `ArgumentNullException` if `document` is `null`.
- `IsInvoice` and `IsPayrollReport` are determined purely by exact (uppercased) string match on `document.Description`, not by a document-type code.*

## Constraints and usage notes
- `PacketId` is populated only when `document.IsPacket` is `true`; non-packet documents get an empty string.

> **Note:** Statements marked with * were inferred from code structure, naming conventions, or
> contextual evidence where direct confirmation was not available in source artifacts. Statements
> marked with ** could not be confirmed; treat as unknown until verified.

## Sources
- `Services/SAIF.Services/Policies/PolicyDocumentsApi/PolicyDocumentsApiService.cs`