use anyhow::Result;
use serde_derive::{Serialize, Deserialize};

#[derive(Serialize, Deserialize, Debug)]
#[serde(tag = "type", content = "settings", rename_all = "lowercase")]
pub enum TypeWithSettings {
    Foo(
        #[serde(default, skip_serializing_if = "is_default")]
        FooSettings
    ),
    Bar(
        #[serde(default, skip_serializing_if = "is_default")]
        BarSettings
    ),
}

#[derive(Serialize, Deserialize, Debug, Default, PartialEq)]
pub struct FooSettings {
    value: String,
}

#[derive(Serialize, Deserialize, Debug, Default, PartialEq)]
pub struct BarSettings {
    value: u32,
}

fn main() {
    println!("calling de():");
    if let Err(e) = de() {
        println!("Error: {:?}", e);
    }

    println!("calling ser():");
    if let Err(e) = ser() {
        println!("Error: {:?}", e);
    }
}

fn de() -> Result<()> {
    let json = r#"
    {
        "type": "foo"
    }"#;
    let settings: TypeWithSettings = serde_json::from_str(json)?;
    println!("{:?}", settings);
    Ok(())
}

fn ser() -> Result<()> {
    let settings = TypeWithSettings::Foo(FooSettings::default());
    println!("{}", serde_json::to_string_pretty(&settings)?);
    Ok(())
}

pub fn is_default<T: Default + PartialEq>(t: &T) -> bool {
    t == &T::default()
}