# Telegram Binding

The Telegram binding allows sending and receiving messages to and from Telegram clients (https://telegram.org), by using the Telegram Bot API.

# Prerequisites

As described in the Telegram Bot API (https://core.telegram.org/bots#6-botfather), this is the manual procedure needed in order to get the necessary information.

1. Create a new Bot and get the Token

- On a Telegram client open a chat with BotFather.
- Send `/newbot` to BotFather and fill in all the needed information. The authentication token that is given will be needed in the next steps.

2. Create the destination chat

- Open a chat with your new Bot and send any message to it. The next step will not work unless you send a message to your bot first.

3. Get the chatID

- Open a browser and invoke `https://api.telegram.org/bot<token>/getUpdates` (where `<token>` is the authentication token previously obtained)
- Look at the JSON result to find the value of `id`: that's the chatID.

Note that if using a Telegram group chat, the group chatIDs are prefixed with a dash that must be included in the config (e.g. `-22334455`).
If this does not work for you (the JSON response may be empty), or you want to send to *more* than one recipient (= another chatID), the alternative is to contact (= open a chat with) a Telegram bot to respond with the chatID.
There's a number of them such as `@myidbot` or `@chatid_echo_bot` - open a chat, eventually tap `/start` and it will return the chatID you're looking for.
Another option is `@getidsbot` which gives you much more information.
Note bots may work or not at any time so eventually you need to try another one.

4. Test the bot

- Open this URL in your web browser, replacing <token> with the authentication token and <chatId> with the chatId:
- `https://api.telegram.org/bot<token>/sendMessage?chat_id=<chatId>&text=testing`
- Your Telegram-bot should send you a message with the text: `testing`

**Notice:** By default your bot will only receive messages that either start with the '/' symbol or mention the bot by username (or if you talk to it directly). 
However, if you add your bot to a group you must either talk to BotFather and send the command "/setprivacy" and then disable it or you give admin rights to your bot in that group. 
Otherwise you will not be able to receive those messages.

## Supported Things

**telegramBot** - A Telegram Bot that can send and receive messages.

The Telegram binding supports the following things which originate from the last message sent to the Telegram bot:

* message text or URL
* message date
* full name of sender (first name + last name)
* username of sender
* chat id (used to identify the chat of the last message)
* reply id (used to identify an answer from a user of a previously sent message by the binding)

Please note that the binding channels cannot be used to send messages.
In order to send a message, an action must be used instead.

## Thing Configuration

**telegramBot** parameters:

| Property | Default | Required | Description |
|-|-|-|-|
| `chatIds` | | Yes | A list of chatIds that are entered one per line in the UI, or are comma separated values when using textual config. |
| `botToken` | | Yes | Authentication token that looks like 1122334455:AABBCCDDEEFFGG1122334455667788 |
| `parseMode` |  None   | No | Support for formatted messages, values: Markdown or HTML. |
| `proxyHost` |  None   | No | Proxy host for telegram binding. |
| `proxyPort` |  None   | No | Proxy port for telegram binding. |
| `proxyType` |  SOCKS5 | No | Type of proxy server for telegram binding (SOCKS5 or HTTP). |
| `longPollingTime` | 25 | No | Timespan in seconds for long polling the telegram API. |

By default chat ids are bi-directionally, i.e. they can send and receive messages.
They can be prefixed with an access modifier:

- `<` restricts the chat to send only, i.e. this chat id can send messages to openHAB, but will never receive a notification.
- `>` restricts the chat to receive only, i.e. this chat id will receive all notifications, but messages from this chat id will be discarded. 

To use the reply function, chat ids need to be bi-directional.

telegram.thing (no proxy):

```
Thing telegram:telegramBot:Telegram_Bot [ chatIds="ID", botToken="TOKEN" ]
```

telegram.thing (multiple chat ids, one bi-directional chat (ID1), one outbound-only (ID2)):

```
Thing telegram:telegramBot:Telegram_Bot [ chatIds="ID1",">ID2", botToken="TOKEN" ]
```

telegram.thing (markdown format):

```
Thing telegram:telegramBot:Telegram_Bot [ chatIds="ID", botToken="TOKEN", parseMode ="Markdown" ]
```

telegram.thing (SOCKS5 proxy server is used): 

```
Thing telegram:telegramBot:Telegram_Bot [ chatIds="ID", botToken="TOKEN", proxyHost="HOST", proxyPort="PORT", proxyType="TYPE" ]
```

or HTTP proxy server

```
Thing telegram:telegramBot:Telegram_Bot [ chatIds="ID", botToken="TOKEN", proxyHost="localhost", proxyPort="8123", proxyType="HTTP" ]
```

## Channels

| Channel Type ID                      | Item Type | Description                                                     |
|--------------------------------------|-----------|-----------------------------------------------------------------|
| lastMessageText                      | String    | The last received message                                       |
| lastMessageURL                       | String    | The URL of the last received message content                    |
| lastMessageDate                      | DateTime  | The date of the last received message (UTC)                     |
| lastMessageName                      | String    | The full name of the sender of the last received message        |
| lastMessageUsername                  | String    | The username of the sender of the last received message         |
| chatId                               | String    | The id of the chat of the last received message                 |
| replyId                              | String    | The id of the reply which was passed to sendTelegram() as replyId argument. This id can be used to have an unambiguous assignment of the users reply to the message which was sent by the bot             |

All channels are read-only.
Either `lastMessageText` or `lastMessageURL` are populated for a given message.
If the message did contain text, the content is written to `lastMessageText`.
If the message did contain an audio, photo, video or voice, the URL to retrieve that content can be found in `lastMessageURL`. 

## Rule Actions

This binding includes a number of rule actions, which allow the sending of Telegram messages from within rules.

```
val telegramAction = getActions("telegram","telegram:telegramBot:<uid>")
```

where uid is the Thing UID of the Telegram thing (not the chat id!).

Once this action instance is retrieved, you can invoke the `sendTelegram' method on it:

```
telegramAction.sendTelegram("Hello world!")
```

The following actions are supported.
Each of the actions returns true on success or false on failure.

### Actions to send messages to all configured chats

These actions will send a message to all chat ids configured for this bot.

| Action                     | Description  |
|----------------------------|--------------|
| sendTelegram(String message) | Sends a message. |
| sendTelegram(String format, Object... args)          | Sends a formatted message (See https://docs.oracle.com/javase/8/docs/api/java/util/Formatter.html for more information).
| sendTelegramQuery(String message, String replyId, String... buttons) | Sends a question to the user that can be answered via the defined buttons. The replyId can be freely choosen and is sent back with the answer. Then, the id is required to identify what question has been answered (e.g. in case of multiple open questions). The final result looks like this: ![Telegram Inline Keyboard](doc/queryExample.png). |
| sendTelegramAnswer(String replyId, String message) | Sends a message after the user has answered a question. You should *always* call this method after you received an answer. It will remove buttons from the specific question and will also stop the progress bar displayed at the client side. If no message is necessary, just pass `null` here. |
| sendTelegramPhoto(String photoURL, String caption) | Sends a picture. Can be one of the URL formats, see the Note below, or a base64 encoded image (simple base64 data or data URI scheme). |
| sendTelegramPhoto(String photoURL, String caption, String username, String password) | Sends a picture which is downloaded from a username/password protected http/https address. |
| sendTelegramAnimation(String animationURL, String caption) | Send animation files either GIF or H.264/MPEG-4 AVC video without sound. |
| sendTelegramVideo(String videoURL, String caption) | Send MP4 video files up to 50MB. |

**Note:** In actions that require a file URL, the following formats are acceptable:

+ http://foo.com/bar.jpg
+ https://foo.com/bar.jpg
+ file://c:\\foo\\bar.jpg
+ c:\\foo\\bar.jpg
+ /etc/openhab/html/bar.jpg

### Actions to send messages to a particular chat

Just put the chat id (must be a long value!) followed by an "L" as the first argument to one of the above mentioned APIs:

```
telegramAction.sendTelegram(1234567L, "Hello world!")
```

## Full Example

### Send a text message to telegram chat

telegram.rules

```java
rule "Send telegram with Fixed Message"
when
   Item Foo changed
then
   val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")
   telegramAction.sendTelegram("item Foo changed")
end
```

### Send a text message with a formatted message

telegram.rules

```java
rule "Send telegram with Formatted Message"
when
   Item Foo changed
then
   val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")
   telegramAction.sendTelegram("item Foo changed to %s and number is %.1f", Foo.state.toString, 23.56)
end
```

### Send an image to telegram chat

`http`, `https`, and `file` are the only protocols allowed or a base64 encoded image.

telegram.rules

```java
rule "Send telegram with image and caption from image accessible by url"
when
    Item Light_GF_Living_Table changed
then
    val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")
    telegramAction.sendTelegramPhoto("http://www.openhab.org/assets/images/openhab-logo-top.png",
        "sent from openHAB")
end
```

telegram.rules

```java
rule "Send telegram with image without caption from image accessible by url"
when
    Item Light_GF_Living_Table changed
then
    val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")
    telegramAction.sendTelegramPhoto("http://www.openhab.org/assets/images/openhab-logo-top.png",
        null)
end
```

telegram.rules

```java
rule "Send telegram with image from password protected http source"
when
    Item Light_GF_Living_Table changed
then
    val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")
    telegramAction.sendTelegramPhoto("http://192.168.1.5/doorcam/picture.jpg", "Door Camera", "user", "mypassword")
end
```

To send a base64 jpeg or png image:

telegram.rules

```java
rule "Send telegram with base64 image and caption"
when
    Item Light_GF_Living_Table changed
then
    val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")
    // image as base64 string
    var String base64Image = "iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAMAAACdt4HsAAAAS1BMVEUAAABAQEA9QUc7P0Y0OD88QEY+QUhmaW7c3N3w8PBlaG0+QUjb29w5PUU3O0G+vsigoas6P0WfoKo4O0I9QUdkZ2w9Qkg+QkkkSUnT3FKbAAAAGXRSTlMACJbx//CV9v//9pT/7Ur//+z/SfD2kpMHrnfDaAAAAGhJREFUeAHt1bUBAzAMRFGZmcL7LxpOalN5r/evLIlgGwBgXMhxSjP64sa6cdYH+hLWzYiKvqSbI4kQeEt5PlBealsMFIkAAgi8HNriOLcjduLTafWwBB9n3p8v/+Ma1Mxxvd4IAGCzB4xDPuBRkEZiAAAAAElFTkSuQmCC"
    telegramAction.sendTelegramPhoto(base64Image, "battery of motion sensor is empty")
    
    // image as base64 string in data URI scheme
    var String base64ImageDataURI = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAMAAACdt4HsAAAAS1BMVEUAAABAQEA9QUc7P0Y0OD88QEY+QUhmaW7c3N3w8PBlaG0+QUjb29w5PUU3O0G+vsigoas6P0WfoKo4O0I9QUdkZ2w9Qkg+QkkkSUnT3FKbAAAAGXRSTlMACJbx//CV9v//9pT/7Ur//+z/SfD2kpMHrnfDaAAAAGhJREFUeAHt1bUBAzAMRFGZmcL7LxpOalN5r/evLIlgGwBgXMhxSjP64sa6cdYH+hLWzYiKvqSbI4kQeEt5PlBealsMFIkAAgi8HNriOLcjduLTafWwBB9n3p8v/+Ma1Mxxvd4IAGCzB4xDPuBRkEZiAAAAAElFTkSuQmCC"
    telegramAction.sendTelegramPhoto(base64ImageDataURI, "battery of motion sensor is empty")    
end
```

To send an image that resides on the local computer file system:

telegram.rules

```java
rule "Send telegram with local image and caption"
when
    Item Light_GF_Living_Table changed
then
    val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")
    telegramAction.sendTelegramPhoto("file://C:/mypicture.jpg", "sent from openHAB")
end
```

To send an image based on an Image Item:

telegram.rules

```java
rule "Send telegram with Image Item image and caption"
when
    Item Webcam_Image changed
then
    val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")
    telegramAction.sendTelegramPhoto(Webcam_Image.state.toFullString, "sent from openHAB")
end
```

To receive a message and react on that:

telegram.items

```php
String telegramMessage "Telegram Message" { channel = "telegram:telegramBot:2b155b22:lastMessageText" }
```

telegram.rules

```java
rule "Receive telegram"
when
    Item telegramMessage received update "lights off"
then
    gLights.sendCommand(OFF)
end
```

To send a question with two alternatives and a reply from the bot:

telegram.items

```php
String telegramReplyId "Telegram Reply Id" { channel = "telegram:telegramBot:2b155b22:replyId" }
```

telegram.rules

```java
rule "Send telegram with question"
when
    Item Presence changed to OFF
then
    val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")
    telegramAction.sendTelegramQuery("No one is at home, but some lights are still on. Do you want me to turn off the lights?", "Reply_Lights", "Yes", "No")
end


rule "Reply handler for lights"
when
    Item telegramReplyId received update Reply_Lights
then
    val telegramAction = getActions("telegram","telegram:telegramBot:2b155b22")

    if (telegramMessage.state.toString == "Yes")
    {
        gLights.sendCommand(OFF)
        telegramAction.sendTelegramAnswer(telegramReplyId.state.toString, "Ok, lights are *off* now.") 
    }
    else
    {
        telegramAction.sendTelegramAnswer(telegramReplyId.state.toString, "Ok, I'll leave them *on*.")
    }
end
```