### Handle Connection State and QR Code

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Handles connection state updates, displays QR codes for initial pairing, and manages reconnection logic. Ensure you have the QRCoder library installed for QR code generation.

```csharp
using BaileysCSharp.Core.Types;
using BaileysCSharp.Exceptions;
using QRCoder;

private static void OnConnectionUpdate(object? sender, ConnectionState state)
{
    // Display QR code in the terminal on first login
    if (state.QR != null)
    {
        var qrGenerator = new QRCodeGenerator();
        var qrData      = qrGenerator.CreateQrCode(state.QR, QRCodeGenerator.ECCLevel.L);
        var ascii       = new AsciiQRCode(qrData);
        Console.WriteLine(ascii.GetGraphic(1));
        Console.WriteLine("Scan the QR code with WhatsApp on your phone.");
        return;
    }

    if (state.Connection == WAConnectionState.Open)
    {
        Console.WriteLine("Connected to WhatsApp!");
    }

    if (state.Connection == WAConnectionState.Close)
    {
        // Reconnect unless the session was explicitly logged out
        if (state.LastDisconnect?.Error is Boom boom
            && boom.Data?.StatusCode != (int)DisconnectReason.LoggedOut)
        {
            Console.WriteLine($"Disconnected ({boom.Message}), reconnecting …");
            Thread.Sleep(2000);
            socket.MakeSocket();
        }
        else
        {
            Console.WriteLine("Logged out. Delete creds.json and restart to re-pair.");
        }
    }
}
```

--------------------------------

### Create and connect a socket

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Instantiates the full socket stack, handles WebSocket lifecycle events, performs the Noise protocol handshake, and starts the keep-alive thread. This must be called after authentication is configured.

```APIDOC
## Create and connect a socket — `WASocket` / `MakeSocket()`

### Description
Instantiates the full socket stack, wires up all WebSocket lifecycle events, performs the Noise protocol handshake, and starts the keep-alive thread. Must be called after `SocketConfig.Auth` is set.

### Method Signature
`WASocket(SocketConfig config)`
`socket.MakeSocket()`

### Usage Example
```csharp
using BaileysCSharp.Core.Sockets;
using BaileysCSharp.Core.Models;
using BaileysCSharp.Core.Logging;

var config = new SocketConfig
{
    SessionName          = "my-session",
    Logger               = { Level = LogLevel.Info },
    MarkOnlineOnConnect  = true,
    FireInitQueries      = true,   // fetch privacy settings & props on connect
    Auth = new AuthenticationState { Creds = authentication, Keys = keys } // Assuming 'authentication' and 'keys' are already initialized
};

var socket = new WASocket(config);

// Wire up events before connecting
socket.EV.Connection.Update  += OnConnectionUpdate;
socket.EV.Auth.Update        += OnAuthUpdate;
socket.EV.Message.Upsert     += OnMessageUpsert;

// Connect — non-blocking; events arrive asynchronously
socket.MakeSocket();

Console.ReadLine();   // keep the process alive

// Graceful shutdown
socket.Dispose();
```
```

--------------------------------

### Create and Connect WASocket - BaileysCSharp

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Instantiates the full socket stack, wires up WebSocket events, performs the Noise protocol handshake, and starts the keep-alive thread. Must be called after SocketConfig.Auth is set. Events are handled asynchronously.

```csharp
using BaileysCSharp.Core.Sockets;
using BaileysCSharp.Core.Models;
using BaileysCSharp.Core.Logging;

var config = new SocketConfig
{
    SessionName          = "my-session",
    Logger               = { Level = LogLevel.Info },
    MarkOnlineOnConnect  = true,
    FireInitQueries      = true,   // fetch privacy settings & props on connect
    Auth = new AuthenticationState { Creds = authentication, Keys = keys }
};

var socket = new WASocket(config);

// Wire up events before connecting
socket.EV.Connection.Update  += OnConnectionUpdate;
socket.EV.Auth.Update        += OnAuthUpdate;
socket.EV.Message.Upsert     += OnMessageUpsert;

// Connect — non-blocking; events arrive asynchronously
socket.MakeSocket();

Console.ReadLine();   // keep the process alive

// Graceful shutdown
socket.Dispose();
```

--------------------------------

### Manage WhatsApp Newsletters (Channels)

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Perform operations related to WhatsApp Channels, including creation, updating name and description, getting admin count, sending messages, following/unfollowing, muting/unmuting, querying recommendations, and deleting channels.

```csharp
// Create a new channel
var channel = await socket.NewsletterCreate("My Dev Channel");
Console.WriteLine($"Channel ID: {channel.Id}");

// Update name and description
await socket.NewsletterUpdateName(channel.Id, "My Dev Channel – Official");
await socket.NewsletterUpdateDescription(channel.Id, "Daily C# tips and tricks");

// Get admin count
var adminCount = await socket.NewsletterAdminCount(channel.Id);
Console.WriteLine($"Admins: {adminCount}");

// Send a text message to the channel
await socket.SendNewsletterMessage(channel.Id, new NewsletterTextMessage
{
    Text = "Hello, subscribers!"
});

// Follow / unfollow / mute / unmute
await socket.NewsletterFollow(channel.Id);
await socket.NewsletterMute(channel.Id);
await socket.NewsletterUnMute(channel.Id);
await socket.NewsletterUnFollow(channel.Id);

// Query recommended newsletters
var recommended = await socket.QueryRecommendedNewsletters();
foreach (var item in recommended?.Newsletters ?? [])
{
    Console.WriteLine($"{item.ThreadMetadata?.Name}: {item.ThreadMetadata?.SubscriberCount} subscribers");
}

// Delete the channel
await socket.NewsletterDelete(channel.Id);
```

--------------------------------

### Retrieve Profile Picture URL

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Get the CDN URL for a contact's or group's profile picture. Supports fetching both a preview thumbnail and the full-resolution image.

```csharp
using BaileysCSharp.Core.Types;

// Preview thumbnail (default)
var previewUrl = await socket.ProfilePictureUrl("15551234567@s.whatsapp.net");

// Full-resolution image
var fullUrl = await socket.ProfilePictureUrl(
    "15551234567@s.whatsapp.net",
    ProfilePictureUrlType.Image
);

if (fullUrl != null)
{
    var bytes = await new HttpClient().GetByteArrayAsync(fullUrl);
    File.WriteAllBytes("avatar.jpg", bytes);
}
```

--------------------------------

### Initialize Authentication Credentials - BaileysCSharp

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Generates cryptographic material for a new WhatsApp Web session or loads existing credentials. Use this when no persisted credentials exist. A file-backed Signal key store is provided.

```csharp
using BaileysCSharp.Core.Helper;
using BaileysCSharp.Core.Models;
using BaileysCSharp.Core.NoSQL;

var config = new SocketConfig
{
    SessionName = "my-session",       // determines the cache folder name
};

var credsFile = Path.Join(config.CacheRoot, "creds.json");

// Load existing credentials, or create new ones
AuthenticationCreds authentication;
if (File.Exists(credsFile))
{
    authentication = AuthenticationCreds.Deserialize(File.ReadAllText(credsFile));
    Console.WriteLine("Loaded existing credentials");
}
else
{
    authentication = AuthenticationUtils.InitAuthCreds();
    Console.WriteLine("Created fresh credentials – QR scan required");
}

// File-backed Signal key store (session keys, pre-keys, sender keys …)
BaseKeyStore keys = new FileKeyStore(config.CacheRoot);

config.Auth = new AuthenticationState
{
    Creds = authentication,
    Keys  = keys
};
```

--------------------------------

### `FileKeyStore` — file-backed Signal key storage

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Persists Signal pre-keys, session keys, and sender-key state to the local filesystem.

```APIDOC
## FileKeyStore

### Description
Provides a file-backed storage mechanism for Signal protocol keys, including pre-keys, session keys, and sender-key state. Keys are organized into named subdirectories under a specified cache root directory.

### Usage
Instantiate `FileKeyStore` with a path to a writable directory. The socket stack automatically uses this store for key persistence. You can also interact with the store directly to inspect or manually set key values.

### Methods
- `FileKeyStore(string cacheRoot)`: Constructor to initialize the store with a root directory path.
- `Get<T>(string id)`: Retrieves a single key record of type `T` by its ID.
- `Get<T>(IEnumerable<string> ids)`: Retrieves multiple key records of type `T` by a collection of IDs.
- `Set<T>(string id, T value)`: Sets a key record of type `T` with the given ID and value.

### Request Example
```csharp
using BaileysCSharp.Core.NoSQL;

// Instantiate pointing at a writable directory
var store = new FileKeyStore("/var/myapp/session-keys");

// Keys are read/written automatically by the socket stack.
// You can also read them directly for inspection:
var sessionRecord = store.Get<SessionRecord>("15551234567.0");
Console.WriteLine(sessionRecord != null ? "Session exists" : "No session yet");

// Set a value manually (advanced use)
store.Set<SenderKeyRecord>("120363@g.us", senderKeyRecord);

// Retrieve multiple keys in one call
var ids = new List<string> { "15551234567.0", "15559876543.0" };
var sessions = store.Get<SessionRecord>(ids);
Console.WriteLine($"Loaded {sessions.Count} sessions");
```

### Response
- `Get` methods return the requested key records or null/empty collections if not found.
- `Set` methods do not return a value upon successful operation.
```

--------------------------------

### Initialize authentication credentials

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Generates cryptographic material for a new WhatsApp Web session or loads existing credentials. This is a prerequisite for establishing a connection.

```APIDOC
## Initialize authentication credentials — `AuthenticationUtils.InitAuthCreds()`

### Description
Generates all cryptographic material (noise keys, identity key, signed pre-key, registration ID, ADV secret) needed for a fresh WhatsApp Web session. Call this only when no persisted credentials exist; otherwise, deserialize saved credentials from disk.

### Method Signature
`AuthenticationUtils.InitAuthCreds()`

### Usage Example
```csharp
using BaileysCSharp.Core.Helper;
using BaileysCSharp.Core.Models;
using BaileysCSharp.Core.NoSQL;

var config = new SocketConfig
{
    SessionName = "my-session",       // determines the cache folder name
};

var credsFile = Path.Join(config.CacheRoot, "creds.json");

// Load existing credentials, or create new ones
AuthenticationCreds authentication;
if (File.Exists(credsFile))
{
    authentication = AuthenticationCreds.Deserialize(File.ReadAllText(credsFile));
    Console.WriteLine("Loaded existing credentials");
}
else
{
    authentication = AuthenticationUtils.InitAuthCreds();
    Console.WriteLine("Created fresh credentials – QR scan required");
}

// File-backed Signal key store (session keys, pre-keys, sender keys …)
BaseKeyStore keys = new FileKeyStore(config.CacheRoot);

config.Auth = new AuthenticationState
{
    Creds = authentication,
    Keys  = keys
};
```
```

--------------------------------

### File-Backed Signal Key Storage

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Utilize `FileKeyStore` for persisting Signal pre-keys, session keys, and sender-key state to the local filesystem. Keys are organized into subdirectories under a specified cache root. This store is automatically used by the socket stack, but keys can also be read or set manually for inspection or advanced use.

```csharp
using BaileysCSharp.Core.NoSQL;

// Instantiate pointing at a writable directory
var store = new FileKeyStore("/var/myapp/session-keys");

// Keys are read/written automatically by the socket stack.
// You can also read them directly for inspection:
var sessionRecord = store.Get<SessionRecord>("15551234567.0");
Console.WriteLine(sessionRecord != null ? "Session exists" : "No session yet");

// Set a value manually (advanced use)
store.Set<SenderKeyRecord>("120363@g.us", senderKeyRecord);

// Retrieve multiple keys in one call
var ids = new List<string> { "15551234567.0", "15559876543.0" };
var sessions = store.Get<SessionRecord>(ids);
Console.WriteLine($"Loaded {sessions.Count} sessions");
```

--------------------------------

### Send Media Messages (Image, Audio, Video, Document)

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Sends various media types including images, audio (voice notes), videos, and documents. Accepts any readable stream and auto-generates thumbnails. Ensure media files exist at the specified paths.

```csharp
using BaileysCSharp.Core.Models.Sending.Media;

var recipient = "15551234567@s.whatsapp.net";

// --- Image ---
await socket.SendMessage(recipient, new ImageMessageContent
{
    Image   = File.OpenRead("photo.jpg"),
    Caption = "Check out this picture!"
});

// --- Audio (voice note) ---
await socket.SendMessage(recipient, new AudioMessageContent
{
    Audio = File.OpenRead("voice.ogg"),
    Ptt   = true   // true = voice-note UI, false = music player
});

// --- Video (or animated GIF) ---
await socket.SendMessage(recipient, new VideoMessageContent
{
    Video       = File.OpenRead("clip.mp4"),
    Caption     = "Funny clip",
    GifPlayback = false
});

// --- Document ---
await socket.SendMessage(recipient, new DocumentMessageContent
{
    Document = File.OpenRead("report.pdf"),
    FileName  = "Q1-Report.pdf",
    Mimetype  = "application/pdf"
});
```

--------------------------------

### Manage presence and subscribe to updates

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Broadcasts presence status (online, offline, typing, recording) and subscribes to a contact's presence. Also includes an event handler for receiving presence updates.

```csharp
using BaileysCSharp.Core.Types;

// Broadcast typing indicator to a chat
socket.SendPresenceUpdate(WAPresence.Composing, "15551234567@s.whatsapp.net");
// Broadcast recording indicator
socket.SendPresenceUpdate(WAPresence.Recording, "15551234567@s.whatsapp.net");
// Mark yourself as available globally
socket.SendPresenceUpdate(WAPresence.Available);

// Subscribe to a contact's presence (tcToken obtained from contact data)
socket.PresenceSubscribe("15551234567@s.whatsapp.net", tcToken);

// Receive presence events
socket.EV.Pressence.Update += (sender, model) =>
{
    foreach (var (participant, data) in model.Presences)
    {
        Console.WriteLine($"{participant}: {data.LastKnownPresence} (last seen: {data.LastSeen})");
    }
};
```

--------------------------------

### Handle connection state and QR code — EV.Connection.Update

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

This event handler manages the connection state with WhatsApp. It displays a QR code for initial pairing, indicates when the connection is open, and handles disconnections, including automatic reconnection logic.

```APIDOC
## EV.Connection.Update

### Description
Handles the connection state updates from the WhatsApp service. This includes displaying QR codes for pairing, notifying when the connection is open, and managing disconnections with automatic reconnection attempts.

### Event Handler
`OnConnectionUpdate(object? sender, ConnectionState state)`

### Usage
This event is triggered by the `BaileysCSharp` library to inform the application about changes in the connection status.

### Example
```csharp
private static void OnConnectionUpdate(object? sender, ConnectionState state)
{
    // Display QR code in the terminal on first login
    if (state.QR != null)
    {
        // QR code generation and display logic here
        Console.WriteLine("Scan the QR code with WhatsApp on your phone.");
        return;
    }

    if (state.Connection == WAConnectionState.Open)
    {
        Console.WriteLine("Connected to WhatsApp!");
    }

    if (state.Connection == WAConnectionState.Close)
    {
        // Reconnect logic here
        Console.WriteLine("Disconnected, reconnecting …");
        Thread.Sleep(2000);
        socket.MakeSocket();
    }
}
```
```

--------------------------------

### Presence updates

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Broadcast your own presence and subscribe to the presence of any contact using `SendPresenceUpdate`, `PresenceSubscribe`, and `EV.Pressence.Update`.

```APIDOC
## Presence updates — `SendPresenceUpdate` / `PresenceSubscribe` / `EV.Pressence.Update`

### Description
Broadcast your own presence (online/offline/typing/recording) and subscribe to the presence of any contact.

### Methods
- `SendPresenceUpdate`
- `PresenceSubscribe`
- `EV.Pressence.Update` (Event)

### Parameters
#### SendPresenceUpdate
- **presence** (WAPresence) - Required - The presence status to broadcast (e.g., Composing, Recording, Available).
- **toJid** (string) - Optional - The JID of the contact to send the presence update to. If not provided, it's broadcast globally.

#### PresenceSubscribe
- **jid** (string) - Required - The JID of the contact to subscribe to.
- **tcToken** (string) - Required - The tcToken obtained from contact data for subscription.
```

--------------------------------

### Download incoming media

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Decrypts and downloads any media attached to an incoming `WebMessageInfo` using `DownloadMediaMessage`.

```APIDOC
## Download incoming media — `DownloadMediaMessage`

### Description
Decrypts and downloads any media attached to an incoming `WebMessageInfo`. Returns the raw bytes, MIME type, and filename (for documents).

### Method
`DownloadMediaMessage`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
- **msg.Message** (WebMessageInfo) - Required - The message containing the media.
```

--------------------------------

### Persist Credentials

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Saves authentication credentials to a file whenever they are updated. It's crucial to serialize and save immediately to prevent session loss. Use a lock to ensure thread-safe writing.

```csharp
private static void OnAuthUpdate(object? sender, AuthenticationCreds creds)
{
    var path = Path.Join(socket.SocketConfig.CacheRoot, "creds.json");
    // Serialize is thread-safe; use a lock when writing from multiple threads
    lock (locker)
    {
        File.WriteAllText(path, AuthenticationCreds.Serialize(creds));
    }
    Console.WriteLine("Credentials saved.");
}
```

--------------------------------

### Check WhatsApp registration — `OnWhatsApp`

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Verify whether one or more phone numbers have a WhatsApp account before sending.

```APIDOC
## OnWhatsApp

### Description
Verify whether one or more phone numbers have a WhatsApp account before sending.

### Method
`OnWhatsApp`

### Parameters
- `phoneNumbers` (params string[]) - Required - One or more phone numbers to check.

### Request Example
```csharp
var results = await socket.OnWhatsApp("+15551234567", "+447911123456");

foreach (var r in results)
{
    Console.WriteLine($"{r.Jid}: exists={r.Exists}, business={r.IsBusiness}");
}
```

### Response
- `results` (IEnumerable<OnWhatsAppResult>) - A collection of results, each indicating if a number exists on WhatsApp and if it's a business account.
```

--------------------------------

### Group management

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Provides full CRUD operations over WhatsApp groups, including creation, participant management, and settings updates.

```APIDOC
## Group management — `GroupCreate`, `GroupParticipantsUpdate`, `GroupMetaData`, etc.

### Description
Full CRUD over WhatsApp groups: create, update subject/description, manage participants, invite codes, disappearing messages, and admin settings.

### Methods
- `GroupCreate`
- `GroupMetaData`
- `GroupParticipantsUpdate`
- `GroupUpdateSubject`
- `GroupUpdateDescription`
- `GroupToggleEphemeral`
- `GroupInviteCode`
- `GroupAcceptInvite`
- `GroupLeave`

### Parameters
#### GroupCreate
- **subject** (string) - Required - The subject of the group.
- **participants** (List<string>) - Optional - A list of participant JIDs to add initially.

#### GroupMetaData
- **jid** (string) - Required - The JID of the group.

#### GroupParticipantsUpdate
- **jid** (string) - Required - The JID of the group.
- **participants** (List<string>) - Required - A list of participant JIDs to update.
- **action** (ParticipantAction) - Required - The action to perform (Add, Remove, Promote, Demote).

#### GroupUpdateSubject
- **jid** (string) - Required - The JID of the group.
- **subject** (string) - Required - The new subject of the group.

#### GroupUpdateDescription
- **jid** (string) - Required - The JID of the group.
- **description** (string) - Required - The new description of the group.

#### GroupToggleEphemeral
- **jid** (string) - Required - The JID of the group.
- **duration** (int) - Required - The duration in seconds for disappearing messages.

#### GroupInviteCode
- **jid** (string) - Required - The JID of the group.

#### GroupAcceptInvite
- **code** (string) - Required - The invite code of the group.

#### GroupLeave
- **jid** (string) - Required - The JID of the group.
```

--------------------------------

### Group management operations

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Provides full CRUD operations for WhatsApp groups, including creation, metadata fetching, participant updates, subject/description changes, and invite link management.

```csharp
// Create a group with two initial participants
var group = await socket.GroupCreate(
    "Team Alpha",
    ["15551111111@s.whatsapp.net", "15552222222@s.whatsapp.net"]
);
Console.WriteLine($"Group created: {group.ID}");

// Fetch metadata for an existing group
var meta = await socket.GroupMetaData("120363000000000001@g.us");
Console.WriteLine($"Group: {meta.Subject}, members: {meta.Size}");

// Add a participant
await socket.GroupParticipantsUpdate(
    group.ID,
    ["15553333333@s.whatsapp.net"],
    ParticipantAction.Add
);

// Promote to admin
await socket.GroupParticipantsUpdate(group.ID, ["15553333333@s.whatsapp.net"], ParticipantAction.Promote);

// Update subject and description
await socket.GroupUpdateSubject(group.ID, "Team Alpha – Q2");
await socket.GroupUpdateDescription(group.ID, "All things Q2 planning");

// Enable disappearing messages (7 days)
await socket.GroupToggleEphemeral(group.ID, 7 * 24 * 60 * 60);

// Generate and retrieve invite link
var code = await socket.GroupInviteCode(group.ID);
Console.WriteLine($"Invite: https://chat.whatsapp.com/{code}");

// Accept an invite by code
await socket.GroupAcceptInvite(code);

// Leave the group
await socket.GroupLeave(group.ID);
```

--------------------------------

### Check WhatsApp Registration Status

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Verify if one or more phone numbers are registered on WhatsApp before sending messages. The output indicates if the number exists and if it's a business account.

```csharp
var results = await socket.OnWhatsApp("+15551234567", "+447911123456");

foreach (var r in results)
{
    Console.WriteLine($"{r.Jid}: exists={r.Exists}, business={r.IsBusiness}");
}
// Output:
// 15551234567@s.whatsapp.net: exists=True, business=False
// 447911123456@s.whatsapp.net: exists=True, business=True
```

--------------------------------

### Send media messages — SendMessage with media content types

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Enables sending various media types including images, audio, video, and documents. The library handles media uploading and thumbnail generation automatically.

```APIDOC
## SendMessage with Media Content Types

### Description
Sends media messages such as images, audio, video, and documents. The library automatically handles the upload of media to WhatsApp's servers and generates necessary previews or thumbnails.

### Method
`SendMessage(string recipientJid, MediaMessageContent message)`

### Parameters
- **recipientJid** (string) - The WhatsApp JID of the recipient.
- **message** (MediaMessageContent) - An object representing the media message. Specific types include `ImageMessageContent`, `AudioMessageContent`, `VideoMessageContent`, and `DocumentMessageContent`.
  - **ImageMessageContent**:
    - **Image** (Stream) - The image file stream.
    - **Caption** (string) - Optional caption for the image.
  - **AudioMessageContent**:
    - **Audio** (Stream) - The audio file stream.
    - **Ptt** (bool) - Whether to send as a voice note (true) or regular audio (false).
  - **VideoMessageContent**:
    - **Video** (Stream) - The video file stream.
    - **Caption** (string) - Optional caption for the video.
    - **GifPlayback** (bool) - Whether to play as a GIF.
  - **DocumentMessageContent**:
    - **Document** (Stream) - The document file stream.
    - **FileName** (string) - The name of the document file.
    - **Mimetype** (string) - The MIME type of the document.

### Request Example
```csharp
var recipient = "15551234567@s.whatsapp.net";

// Image
await socket.SendMessage(recipient, new ImageMessageContent
{
    Image   = File.OpenRead("photo.jpg"),
    Caption = "Check out this picture!"
});

// Audio (voice note)
await socket.SendMessage(recipient, new AudioMessageContent
{
    Audio = File.OpenRead("voice.ogg"),
    Ptt   = true
});

// Video
await socket.SendMessage(recipient, new VideoMessageContent
{
    Video       = File.OpenRead("clip.mp4"),
    Caption     = "Funny clip",
    GifPlayback = false
});

// Document
await socket.SendMessage(recipient, new DocumentMessageContent
{
    Document = File.OpenRead("report.pdf"),
    FileName  = "Q1-Report.pdf",
    Mimetype  = "application/pdf"
});
```

### Response
- **sent** (MessageSendResult?) - An object containing the key information of the sent message, or null if sending failed.
```

--------------------------------

### Download incoming media messages

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Decrypts and downloads media attached to an incoming message. Handles images, audio, and documents, saving them to files.

```csharp
private static async void OnMessageUpsert(object? sender, MessageEventModel e)
{
    if (e.Type != MessageEventType.Notify) return;   // skip history sync

    foreach (var msg in e.Messages)
    {
        if (msg.Message == null) continue;

        if (msg.Message.ImageMessage != null)
        {
            var media = await socket.DownloadMediaMessage(msg.Message);
            var ext   = MimeTypeUtils.GetExtension(media.MimeType);   // "jpg"
            File.WriteAllBytes($"received_{msg.Key.Id}.{ext}", media.Data);
        }

        if (msg.Message.AudioMessage != null)
        {
            var media = await socket.DownloadMediaMessage(msg.Message);
            File.WriteAllBytes($"audio.{MimeTypeUtils.GetExtension(media.MimeType)}", media.Data);
        }

        if (msg.Message.DocumentMessage != null)
        {
            var media = await socket.DownloadMediaMessage(msg.Message);
            File.WriteAllBytes(media.FileName, media.Data);
        }
    }
}
```

--------------------------------

### Send Contact and Location Messages

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Sends contact cards with details like name, number, and organization, or shares a location pin using latitude and longitude coordinates.

```csharp
using BaileysCSharp.Core.Models.Sending.NonMedia;

var recipient = "15551234567@s.whatsapp.net";

// Contact card
await socket.SendMessage(recipient, new ContactMessageContent
{
    Contact = new ContactShareModel
    {
        FullName      = "Jane Doe",
        ContactNumber = "15559876543",
        Organization  = "Acme Corp"
    }
});

// Location pin (Eiffel Tower)
await socket.SendMessage(recipient, new LocationMessageContent
{
    Location = new Proto.Message.Types.LocationMessage
    {
        DegreesLatitude  = 48.858221,
        DegreesLongitude = 2.294466
    }
});
```

--------------------------------

### Newsletter (Channel) management

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Create, follow, update, and post to WhatsApp Channels (Newsletters).

```APIDOC
## Newsletter Management

### Description
Manage WhatsApp Channels (Newsletters), including creation, updates, posting messages, and subscription actions.

### Methods
- `NewsletterCreate(string name)`: Creates a new channel with the given name.
- `NewsletterUpdateName(string channelId, string name)`: Updates the name of an existing channel.
- `NewsletterUpdateDescription(string channelId, string description)`: Updates the description of an existing channel.
- `NewsletterAdminCount(string channelId)`: Retrieves the number of administrators for a channel.
- `SendNewsletterMessage(string channelId, object message)`: Sends a message to a channel. The message object type depends on the message content (e.g., `NewsletterTextMessage`).
- `NewsletterFollow(string channelId)`: Follows a channel.
- `NewsletterUnFollow(string channelId)`: Unfollows a channel.
- `NewsletterMute(string channelId)`: Mutes notifications for a channel.
- `NewsletterUnMute(string channelId)`: Unmutes notifications for a channel.
- `QueryRecommendedNewsletters()`: Retrieves a list of recommended newsletters.
- `NewsletterDelete(string channelId)`: Deletes a channel.

### Request Example
```csharp
// Create a new channel
var channel = await socket.NewsletterCreate("My Dev Channel");
Console.WriteLine($"Channel ID: {channel.Id}");

// Update name and description
await socket.NewsletterUpdateName(channel.Id, "My Dev Channel – Official");
await socket.NewsletterUpdateDescription(channel.Id, "Daily C# tips and tricks");

// Get admin count
var adminCount = await socket.NewsletterAdminCount(channel.Id);
Console.WriteLine($"Admins: {adminCount}");

// Send a text message to the channel
await socket.SendNewsletterMessage(channel.Id, new NewsletterTextMessage
{
    Text = "Hello, subscribers!"
});

// Follow / unfollow / mute / unmute
await socket.NewsletterFollow(channel.Id);
await socket.NewsletterMute(channel.Id);
await socket.NewsletterUnMute(channel.Id);
await socket.NewsletterUnFollow(channel.Id);

// Query recommended newsletters
var recommended = await socket.QueryRecommendedNewsletters();
foreach (var item in recommended?.Newsletters ?? [])
{
    Console.WriteLine($"{item.ThreadMetadata?.Name}: {item.ThreadMetadata?.SubscriberCount} subscribers");
}

// Delete the channel
await socket.NewsletterDelete(channel.Id);
```

### Response
Responses vary depending on the method called. For example, `NewsletterCreate` returns a `Channel` object, while `NewsletterAdminCount` returns an integer.
```

--------------------------------

### Send a text message — SendMessage with TextMessageContent

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Allows sending plain text messages to individual users or groups. It supports message quoting (replies) and mentions by specifying participant JIDs.

```APIDOC
## SendMessage with TextMessageContent

### Description
Sends a plain text message to a specified recipient (user or group). This method supports replying to existing messages by including `ContextInfo` and mentioning participants in group chats.

### Method
`SendMessage(string recipientJid, TextMessageContent message)`

### Parameters
- **recipientJid** (string) - The WhatsApp JID of the recipient (e.g., "15551234567@s.whatsapp.net" or "120363000000000001@g.us").
- **message** (TextMessageContent) - An object containing the text content and optional context for the message.
  - **Text** (string) - The content of the message.
  - **Mentions** (List<string>) - Optional. A list of JIDs to mention in the message.
  - **ContextInfo** (Proto.ContextInfo) - Optional. Information for quoting a previous message.

### Request Example
```csharp
// Plain text
var sent = await socket.SendMessage(
    "15551234567@s.whatsapp.net",
    new TextMessageContent { Text = "Hello from BaileysCSharp!" }
);

// Reply (quote) an existing message
var reply = await socket.SendMessage(
    "15551234567@s.whatsapp.net",
    new TextMessageContent
    {
        Text        = "This is a reply",
        ContextInfo = new Proto.ContextInfo { QuotedMessage = originalMsg.Message }
    }
);

// Mention participants in a group
var mention = await socket.SendMessage(
    "120363000000000001@g.us",
    new TextMessageContent
    {
        Text     = "Hey @15551234567, check this out!",
        Mentions = ["15551234567@s.whatsapp.net"]
    }
);
```

### Response
- **sent** (MessageSendResult?) - An object containing the key information of the sent message, or null if sending failed.
```

--------------------------------

### Persist credentials — EV.Auth.Update

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

This event fires whenever the authentication credentials are changed. It is crucial for saving the session state to prevent data loss, especially after successful pairing or updates to pre-key information.

```APIDOC
## EV.Auth.Update

### Description
Fired whenever the credential object is mutated. This event is essential for persisting session data, ensuring that the application can resume without re-authentication.

### Event Handler
`OnAuthUpdate(object? sender, AuthenticationCreds creds)`

### Usage
Implement this handler to serialize and save the `AuthenticationCreds` object to a persistent storage, such as a file.

### Example
```csharp
private static void OnAuthUpdate(object? sender, AuthenticationCreds creds)
{
    var path = Path.Join(socket.SocketConfig.CacheRoot, "creds.json");
    // Serialize is thread-safe; use a lock when writing from multiple threads
    lock (locker)
    {
        File.WriteAllText(path, AuthenticationCreds.Serialize(creds));
    }
    Console.WriteLine("Credentials saved.");
}
```
```

--------------------------------

### Send contact and location messages

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Provides functionality to send contact cards (vCards) and geographical location pins.

```APIDOC
## Send Contact and Location Messages

### Description
Sends contact information as a vCard or shares a specific geographical location via a map pin.

### Method
`SendMessage(string recipientJid, MessageContent message)`

### Parameters
- **recipientJid** (string) - The WhatsApp JID of the recipient.
- **message** (MessageContent) - An object representing the message content. This can be either `ContactMessageContent` or `LocationMessageContent`.
  - **ContactMessageContent**:
    - **Contact** (ContactShareModel) - An object containing the contact details.
      - **FullName** (string) - The full name of the contact.
      - **ContactNumber** (string) - The phone number of the contact.
      - **Organization** (string) - Optional organization name.
  - **LocationMessageContent**:
    - **Location** (Proto.Message.Types.LocationMessage) - An object containing location coordinates.
      - **DegreesLatitude** (double) - The latitude in degrees.
      - **DegreesLongitude** (double) - The longitude in degrees.

### Request Example
```csharp
var recipient = "15551234567@s.whatsapp.net";

// Contact card
await socket.SendMessage(recipient, new ContactMessageContent
{
    Contact = new ContactShareModel
    {
        FullName      = "Jane Doe",
        ContactNumber = "15559876543",
        Organization  = "Acme Corp"
    }
});

// Location pin (Eiffel Tower)
await socket.SendMessage(recipient, new LocationMessageContent
{
    Location = new Proto.Message.Types.LocationMessage
    {
        DegreesLatitude  = 48.858221,
        DegreesLongitude = 2.294466
    }
});
```

### Response
- **sent** (MessageSendResult?) - An object containing the key information of the sent message, or null if sending failed.
```

--------------------------------

### React to a message

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Sends or removes an emoji reaction on any existing message using `SendMessage` with `ReactMessageContent`.

```APIDOC
## React to a message — `SendMessage` with `ReactMessageContent`

### Description
Sends or removes an emoji reaction on any existing message.

### Method
`SendMessage`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
- **msg.Key.RemoteJid** (string) - Required - The remote JID of the chat.
- **ReactMessageContent** (object) - Required - Content for the reaction.
  - **Key** (MessageKey) - Required - The key of the message to react to.
  - **ReactText** (string) - Required - The emoji reaction text. An empty string removes the reaction.
```

--------------------------------

### React to a message with emoji

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Sends or removes an emoji reaction on any existing message. Use an empty string for ReactText to remove a reaction.

```csharp
using BaileysCSharp.Core.Models.Sending.NonMedia;

// Add a heart reaction
await socket.SendMessage(
    msg.Key.RemoteJid,
    new ReactMessageContent
    {
        Key       = msg.Key,
        ReactText = "❤️"         // empty string removes the reaction
    }
);
```

--------------------------------

### Privacy settings

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Programmatically update all WhatsApp privacy controls including last seen, profile picture, read receipts, and online status.

```APIDOC
## Privacy settings — `UpdateLastSeenPrivacy`, `UpdateOnlinePrivacy`, `UpdateProfilePicturePrivacy`, etc.

### Description
Programmatically update all WhatsApp privacy controls.

### Methods
- `UpdateLastSeenPrivacy`
- `UpdateProfilePicturePrivacy`
- `UpdateReadReceiptsPrivacy`
- `UpdateOnlinePrivacy`
- `UpdateDefaultDisappearingMode`

### Parameters
#### UpdateLastSeenPrivacy
- **value** (WAPrivacyValue) - Required - The privacy setting for last seen (e.g., All, Contacts, MyContacts, None).

#### UpdateProfilePicturePrivacy
- **value** (WAPrivacyValue) - Required - The privacy setting for profile picture.

#### UpdateReadReceiptsPrivacy
- **value** (WAReadReceiptsValue) - Required - The privacy setting for read receipts (e.g., All, Contacts, None).

#### UpdateOnlinePrivacy
- **value** (WAPrivacyOnlineValue) - Required - The privacy setting for online status (e.g., Match_Last_Seen, Everyone, Close_Friends, Close_Friends_Except, Contacts, Contacts_Except, None).

#### UpdateDefaultDisappearingMode
- **duration** (int) - Required - The default duration in seconds for disappearing messages in new chats.
```

--------------------------------

### Profile picture URL — `ProfilePictureUrl`

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Retrieve the CDN URL of a contact's or group's profile picture.

```APIDOC
## ProfilePictureUrl

### Description
Retrieve the CDN URL of a contact's or group's profile picture.

### Method
`ProfilePictureUrl`

### Parameters
- `jid` (string) - Required - The JID of the contact or group.
- `type` (ProfilePictureUrlType) - Optional - The type of picture to retrieve (Thumbnail or Image). Defaults to Thumbnail.

### Request Example
```csharp
// Preview thumbnail (default)
var previewUrl = await socket.ProfilePictureUrl("15551234567@s.whatsapp.net");

// Full-resolution image
var fullUrl = await socket.ProfilePictureUrl(
    "15551234567@s.whatsapp.net",
    ProfilePictureUrlType.Image
);

if (fullUrl != null)
{
    var bytes = await new HttpClient().GetByteArrayAsync(fullUrl);
    File.WriteAllBytes("avatar.jpg", bytes);
}
```

### Response
- `url` (string) - The CDN URL of the profile picture, or null if not found.
```

--------------------------------

### Update WhatsApp privacy settings

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Programmatically updates various WhatsApp privacy controls, including last seen, profile picture visibility, read receipts, online status, and default disappearing message timer.

```csharp
using BaileysCSharp.Core.Types;

// "Last seen" visible only to contacts
socket.UpdateLastSeenPrivacy(WAPrivacyValue.Contacts);

// Profile picture visible to everyone
socket.UpdateProfilePicturePrivacy(WAPrivacyValue.All);

// Read receipts off
socket.UpdateReadReceiptsPrivacy(WAReadReceiptsValue.None);

// Online status hidden from everyone
socket.UpdateOnlinePrivacy(WAPrivacyOnlineValue.Match_Last_Seen);

// Default disappearing message timer for new chats (24 hours)
await socket.UpdateDefaultDisappearingMode(24 * 60 * 60);
```

--------------------------------

### Send Text Message

Source: https://context7.com/whiskeysockets/baileyscsharp/llms.txt

Sends plain text messages to a recipient. Supports replying to existing messages by quoting them and mentioning participants in group chats.

```csharp
using BaileysCSharp.Core.Models.Sending.NonMedia;

// Plain text
var sent = await socket.SendMessage(
    "15551234567@s.whatsapp.net",
    new TextMessageContent { Text = "Hello from BaileysCSharp!" }
);
Console.WriteLine($"Sent message id: {sent?.Key.Id}");

// Reply (quote) an existing message
var reply = await socket.SendMessage(
    "15551234567@s.whatsapp.net",
    new TextMessageContent
    {
        Text        = "This is a reply",
        ContextInfo = new Proto.ContextInfo { QuotedMessage = originalMsg.Message }
    }
);

// Mention participants in a group
var mention = await socket.SendMessage(
    "120363000000000001@g.us",
    new TextMessageContent
    {
        Text     = "Hey @15551234567, check this out!",
        Mentions = ["15551234567@s.whatsapp.net"]
    }
);
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.