tera 0.2.0

use std::collections::BTreeMap;

use serde::ser::Serialize;
use serde_json::value::{Value, to_value};

pub type TemplateContext = BTreeMap<String, Value>;

#[derive(Debug, Clone)]
pub struct Context {
    data: BTreeMap<String, Value>,
}

impl Context {
    pub fn new() -> Context {
        Context {
            data: BTreeMap::new()
        }
    }

    pub fn add<T: Serialize>(&mut self, key: &str, d: &T) {
        self.data.insert(key.to_owned(), to_value(d));
    }

    pub fn as_json(&self) -> Value {
        to_value(&self.data)
    }
}

impl Default for Context {
    fn default() -> Context {
        Context::new()
    }
}

pub trait ValueRender {
    fn render(&self) -> String;
}
// Needed to render variables
// From handlebars-rust
impl ValueRender for Value {
    fn render(&self) -> String {
        match *self {
            Value::String(ref s) => s.clone(),
            Value::I64(i) => i.to_string(),
            Value::U64(i) => i.to_string(),
            Value::F64(f) => f.to_string(),
            Value::Bool(i) => i.to_string(),
            Value::Null => "".to_owned(),
            Value::Array(ref a) => {
                let mut buf = String::new();
                buf.push('[');
                for i in a.iter() {
                    buf.push_str(i.render().as_ref());
                    buf.push_str(", ");
                }
                buf.push(']');
                buf
            },
            Value::Object(_) => "[object]".to_owned()
        }
    }
}


pub trait ValueNumber {
    fn to_number(&self) -> Result<f32, ()>;
}
// Needed for all the maths
// Convert everything to f32, seems like a terrible idea
impl ValueNumber for Value {
    fn to_number(&self) -> Result<f32, ()> {
        match *self {
            Value::I64(i) => Ok(i as f32),
            Value::U64(i) => Ok(i as f32),
            Value::F64(f) => Ok(f as f32),
            _ => Err(())
        }
    }
}

// From handlebars-rust
pub trait ValueTruthy {
    fn is_truthy(&self) -> bool;
}

impl ValueTruthy for Value {
    fn is_truthy(&self) -> bool {
        match *self {
            Value::I64(i) => i != 0,
            Value::U64(i) => i != 0,
            Value::F64(i) => i != 0.0 || !i.is_nan(),
            Value::Bool(ref i) => *i,
            Value::Null => false,
            Value::String(ref i) => !i.is_empty(),
            Value::Array(ref i) => !i.is_empty(),
            Value::Object(ref i) => !i.is_empty()
        }
    }
}