use std::ops::Deref;
use serde::{Deserialize, Serialize, de::DeserializeOwned};
#[derive(Debug, Serialize, Deserialize)]
pub struct FrontMatter<T> {
pub content: String,
#[serde(flatten)]
pub data: Option<T>,
}
impl<T> FrontMatter<T> {
pub fn new(data: Option<T>, content: String) -> Self {
Self { data, content }
}
pub fn new_empty(data: Option<T>) -> Self {
Self::new(data, String::new())
}
}
impl<T> FrontMatter<T>
where
T: DeserializeOwned,
{
pub fn parse(input: String) -> eyre::Result<Self> {
if input.starts_with("---\n")
&& let Some((frontmatter, content)) = input[3..].split_once("\n---\n")
{
let data = serde_yaml_ng::from_str(frontmatter)?;
return Ok(Self {
content: content.to_string(),
data,
});
}
Ok(Self {
content: input,
data: None,
})
}
}
impl<T> FrontMatter<T>
where
T: Serialize,
{
pub fn format(&self) -> eyre::Result<String> {
let mut output = String::new();
if let Some(data) = &self.data {
output.push_str("---\n");
output.push_str(&serde_yaml_ng::to_string(data)?);
output.push_str("---\n\n");
}
output.push_str(&self.content);
if !output.ends_with('\n') {
output.push('\n');
}
Ok(output)
}
}
#[derive(Debug, Serialize, Deserialize)]
pub struct FrontMatterRequired<T>(FrontMatter<T>);
impl<T> FrontMatterRequired<T> {
pub fn new(data: T, content: String) -> Self {
Self(FrontMatter::new(Some(data), content))
}
pub fn new_empty(data: T) -> Self {
Self(FrontMatter::new_empty(Some(data)))
}
pub fn data(&self) -> &T {
self.0.data.as_ref().expect("missing front matter data")
}
pub fn data_mut(&mut self) -> &mut T {
self.0.data.as_mut().expect("missing front matter data")
}
pub fn content_mut(&mut self) -> &mut String {
&mut self.0.content
}
}
impl<T> FrontMatterRequired<T>
where
T: DeserializeOwned,
{
pub fn parse(input: String) -> eyre::Result<Self> {
let fm = FrontMatter::parse(input)?;
if fm.data.is_none() {
eyre::bail!("missing frontmatter!");
}
Ok(Self(fm))
}
}
impl<T> Deref for FrontMatterRequired<T> {
type Target = FrontMatter<T>;
fn deref(&self) -> &Self::Target {
&self.0
}
}