extern crate serde; // 1.0.78
#[macro_use]
extern crate serde_derive; // 1.0.78
extern crate serde_json; // 1.0.27

use std::collections::BTreeMap;

static DEFAULT: &'static str = r###"{
    "value": 0,
    "eventType": "default",
    "payload": {
        "text": "it's text!",
        "number": 23,
        "map": {
            "key": "value"
        },
        "list": [0, 1, 2]
    }
}"###;

#[derive(Debug,Deserialize)]
pub struct Event {
    value: u64,
    payload: EventPayload,
}

#[derive(Debug,Deserialize)]
#[serde(tag="eventType", content="payload")]
pub enum EventPayload {
    #[serde(rename="default")]
    Default(DefaultEventPayload),
}

#[derive(Debug,Deserialize)]
pub struct DefaultEventPayload {
    text: String,
    number: u64,
    #[serde(default)]
    map: BTreeMap<String, String>,
    #[serde(default)]
    list: Vec<u64>
}

fn main() {
    let value: Event = serde_json::from_str(&DEFAULT).unwrap();
    println!("{:?}", value);
}