# Telegram Bot Calendar

## telegram-bot-calendar

## Overview

This package is for creating calendar UI in telegram bot messages. Easy to use comes with built-in tools to create calendar UI with ease.

![Demo Calendar](https://github.com/AyushAgrawal25/telegram-bot-calendar/blob/HEAD/images/demo.png "Demo Calendar")

## Installation

```bash
npm install telegram-bot-calendar
```

## Initialization

### For JS

```JS
const calendar = require('telegram-bot-calendar');
```

### For TS

```typescript
import calendar from 'telegram-bot-calendar';
```

## Getting first date of the month

This function will provide the `Date` object for the first date of the provided date's month.

```JS
const todaysDate = Date.now();

const firstDate = calendar.getFirstDate(todaysDate);
```

## Creating UI

This function will provide the JSON object, which needs to be passed with the message body while calling the send message API.

```JS
const todaysDate = Date.now();

const calendarUI = calendar.getUI(todaysDate);
```

Calling the send message API of Telegram bot with calendar UI.

```JS
const todaysDate = Date.now();

const calendarUI = calendar.getUI(todaysDate);

const sendMsgURL = `https://api.telegram.org/bot${process.env.telegramToken}/sendMessage`;

await axios.post(sendMsgURL,
    {
        chat_id: chat_id,
        text: "Telegram Bot Calendar",
        reply_markup: calendarUI
    }
)
```

## Handling callbacks

The callback needs to be handled with command type. The `type` object specifies the type of command provided by the user using the calendar.
It can be either a date or command for next month's or the previous month's calendar.

```JS
const callbackData = data.callback_query.data;

const commandData = calendar.getCommandData(data.callback_query.data);
```

`commandData` is an object consisting of two properties:

1. `type`: it specifies the type of command passed by the user. It can be one of the seven listed below command types.

    - `providedDate` : This will be returned when the user clicks on the button displaying a valid date.  In this case, the `data` object will consist of the date in the format `month/date/year`.

    - `nextMonth` : This will be returned when the clicks on the `Next Month` button. It is an indication to display the next month. `data` object, in this case, will consist of the first date of the displaying month.

    - `prevMonth` : This will be returned when the clicks on the `Previous Month` button. It is an indication to display to the previous month. `data` object in this case will consist of the first date of the displaying month.

    - `currMonth` : This will be returned when the user clicks on the button displaying the calendar's current month or demanded month.

    - `day` : This will be returned when the user clicks on the button displaying one of the seven days of the week.

    - `dash` : This will be returned when the user clicks on the button displaying one of the empty buttons which are displaying as dash or hyphen '-'.

    - `notCalendarCommand` : This will be returned when the callback data provided to the getCommandData function is not a calendar command or not a `telegram-bot-calendar`'s generated callback data.

2. `data`: it provides the information it can be either `null` or have some value depending upon the type. This will consist of a valid date in case of :

    - `nextMonth`

    - `prevMonth`

    - `providedDate`

    This will be `null` in case of :

    - `day`

    - `currMonth`

    - `dash`

    - `notCalendarCommand`

    The date will provided in the format `month/date/year`.
    Eg. 2/19/2022

## Creating next month's calendar

To create then next month's calendar, first date of the next month is required which can be easily generated using the `getNextMonthFirstDate`.

```JS
const nextMonth = calendar.getNextMonthFirstDate(currDate);

const calendarUI = calendar.getUI(nextMonth);
```

In this way you can create next month's calendar UI. The `currDate` can be the date provided by callback with `nextMonth` command type.

## Creating previous months calendar

To create then previous month's calendar, first date of the previous month is required which can be easily generated using the `getPrevMonthFirstDate`.

```JS
const prevMonth = calendar.getPrevMonthFirstDate(currDate);

const calendarUI = calendar.getUI(prevMonth);
```

In this way you can create previous month's calendar UI. The `currDate` can be the date provided by callback with `prevMonth` command type.

## Additional

If you want to delete the previously shown calendar you can use the telegram's delete message API.

```JS
const chat_id = data.callback_query.from.id;
const message_id = data.callback_query.message.message_id;

const deleteMsgURL = `https://api.telegram.org/bot${process.env.telegramToken}/deleteMessage`;

await axios.post(deleteMsgURL,
    {
        chat_id: chat_id,
        message_id: message_id
    }
)
```