1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

// This example demonstrates how to deal with messages and callback queries
// within a single dialogue.
//
// # Example
// ```
// - /start
// - Let's start! What's your full name?
// - John Doe
// - Select a product:
//   [Apple, Banana, Orange, Potato]
// - <A user selects "Banana">
// - John Doe, product 'Banana' has been purchased successfully!
// ```

use teloxide::{
    dispatching::{dialogue, dialogue::InMemStorage, UpdateHandler},
    prelude::*,
    types::{InlineKeyboardButton, InlineKeyboardMarkup},
    utils::command::BotCommands,
};

type MyDialogue = Dialogue<State, InMemStorage<State>>;
type HandlerResult = Result<(), Box<dyn std::error::Error + Send + Sync>>;

#[derive(Clone, Default)]
pub enum State {
    #[default]
    Start,
    ReceiveFullName,
    ReceiveProductChoice {
        full_name: String,
    },
}

#[derive(BotCommands, Clone)]
#[command(rename_rule = "lowercase", description = "These commands are supported:")]
enum Command {
    #[command(description = "display this text.")]
    Help,
    #[command(description = "start the purchase procedure.")]
    Start,
    #[command(description = "cancel the purchase procedure.")]
    Cancel,
}

#[tokio::main]
async fn main() {
    pretty_env_logger::init();
    log::info!("Starting purchase bot...");

    let bot = Bot::from_env();

    Dispatcher::builder(bot, schema())
        .dependencies(dptree::deps![InMemStorage::<State>::new()])
        .enable_ctrlc_handler()
        .build()
        .dispatch()
        .await;
}

fn schema() -> UpdateHandler<Box<dyn std::error::Error + Send + Sync + 'static>> {
    use dptree::case;

    let command_handler = teloxide::filter_command::<Command, _>()
        .branch(
            case![State::Start]
                .branch(case![Command::Help].endpoint(help))
                .branch(case![Command::Start].endpoint(start)),
        )
        .branch(case![Command::Cancel].endpoint(cancel));

    let message_handler = Update::filter_message()
        .branch(command_handler)
        .branch(case![State::ReceiveFullName].endpoint(receive_full_name))
        .branch(dptree::endpoint(invalid_state));

    let callback_query_handler = Update::filter_callback_query().branch(
        case![State::ReceiveProductChoice { full_name }].endpoint(receive_product_selection),
    );

    dialogue::enter::<Update, InMemStorage<State>, State, _>()
        .branch(message_handler)
        .branch(callback_query_handler)
}

async fn start(bot: Bot, dialogue: MyDialogue, msg: Message) -> HandlerResult {
    bot.send_message(msg.chat.id, "Let's start! What's your full name?").await?;
    dialogue.update(State::ReceiveFullName).await?;
    Ok(())
}

async fn help(bot: Bot, msg: Message) -> HandlerResult {
    bot.send_message(msg.chat.id, Command::descriptions().to_string()).await?;
    Ok(())
}

async fn cancel(bot: Bot, dialogue: MyDialogue, msg: Message) -> HandlerResult {
    bot.send_message(msg.chat.id, "Cancelling the dialogue.").await?;
    dialogue.exit().await?;
    Ok(())
}

async fn invalid_state(bot: Bot, msg: Message) -> HandlerResult {
    bot.send_message(msg.chat.id, "Unable to handle the message. Type /help to see the usage.")
        .await?;
    Ok(())
}

async fn receive_full_name(bot: Bot, dialogue: MyDialogue, msg: Message) -> HandlerResult {
    match msg.text().map(ToOwned::to_owned) {
        Some(full_name) => {
            let products = ["Apple", "Banana", "Orange", "Potato"]
                .map(|product| InlineKeyboardButton::callback(product, product));

            bot.send_message(msg.chat.id, "Select a product:")
                .reply_markup(InlineKeyboardMarkup::new([products]))
                .await?;
            dialogue.update(State::ReceiveProductChoice { full_name }).await?;
        }
        None => {
            bot.send_message(msg.chat.id, "Please, send me your full name.").await?;
        }
    }

    Ok(())
}

async fn receive_product_selection(
    bot: Bot,
    dialogue: MyDialogue,
    full_name: String, // Available from `State::ReceiveProductChoice`.
    q: CallbackQuery,
) -> HandlerResult {
    if let Some(product) = &q.data {
        bot.send_message(
            dialogue.chat_id(),
            format!("{full_name}, product '{product}' has been purchased successfully!"),
        )
        .await?;
        dialogue.exit().await?;
    }

    Ok(())
}