> ## Documentation Index
> Fetch the complete documentation index at: https://numadocs.secc.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Conversation Service

> Handles logic related to the `Conversation` model.

Namespace: [Numa.Services](numaservices)<br />
Related Models: [Conversation.cs](../models/conversation)<br />
Related Interfaces: `IConversationService.cs`

## Fields

| Field Name          | Type                             | Description                                                               |
| :------------------ | :------------------------------- | :------------------------------------------------------------------------ |
| `_dbContextFactory` | `IDbContextFactory<NumaContext>` | `DbContextFactory` for instantiating instances of `NumaContext` on-demand |

## Constructor

```csharp theme={null}
public ConversationService( IDbContextFactory<NumaContext> dbContextFactory )
{
    _dbContextFactory = dbContextFactory ?? throw new ArgumentNullException( nameof( dbContextFactory ) );
}
```

## Properties

| Property Name        | Type            | Description                                                          |
| :------------------- | :-------------- | :------------------------------------------------------------------- |
| `ActiveConversation` | `Conversation?` | Object to represent the state of the currently selected conversation |

## Methods

| Method Name                      | Description                                                                            | Parameters        | Return Type                |
| :------------------------------- | :------------------------------------------------------------------------------------- | :---------------- | :------------------------- |
| `GetConversationsByUserIdAsync`  | Gets all conversations available to user in descending order by their `UpdateDatetime` | `string`          | `Task<List<Conversation>>` |
| `SetActiveConversation`          | Sets the `ActiveConversation` property using a `Conversation` object                   | `Conversation`    | `void`                     |
| `SetActiveConversationByIdAsync` | Sets the `ActiveConversation` property using a `Conversation.Id`                       | `string`          | `Task`                     |
| `SetActiveConversationToNull`    | Sets the `ActiveConversation` to `null`                                                |                   | `void`                     |
| `AddConversationAsync`           | Adds a `Conversation` to the Cosmos DB                                                 | `Conversation`    | `Task`                     |
| `UpdateConversationLastMessage`  | Updates the `LastMessage` of a `Conversation` in the Cosmos DB                         | `string`,`string` | `Task`                     |

## IConversationService.cs

```csharp theme={null}
using Numa.Models;

namespace Numa.Interfaces
{
    public interface IConversationService
    {
        Conversation? ActiveConversation { get; }
        Task<List<Conversation>> GetConversationsByUserIdAsync( string userId );
        Task SetActiveConversationByIdAsync( string conversationId );
        void SetActiveConversation( Conversation conversation );
        void SetActiveConversationToNull();
        Task AddConversationAsync( Conversation newConversation );
        Task UpdateConversationLastMessage( string conversationId, string inputMessage );
    }
}
```