#[derive(Debug)]
pub enum Token<'a> {
    TextElement(TextElement<'a>),
    Paragraph(Paragraph<'a>),
}

impl<'a> Into<Token<'a>> for TextElement<'a> {
    fn into(self) -> Token<'a> {
        Token::TextElement(self)
    }
}

impl<'a> Into<Token<'a>> for Paragraph<'a> {
    fn into(self) -> Token<'a> {
        Token::Paragraph(self)
    }
}

#[derive(Debug)]
pub enum TextElement<'a> {
    Span(Span<'a>),
    Space(Space<'a>),
    LineBreak(LineBreak<'a>),
    Symbol(Symbol<'a>),
    Bold(Bold<'a>),
    Link(Link<'a>),
}

#[derive(Debug)]
pub struct Span<'a> {
    pub contents: &'a str,
}

#[derive(Debug)]
pub struct Space<'a> {
    pub contents: &'a str,
}

#[derive(Debug)]
pub struct LineBreak<'a> {
    pub contents: &'a str,
}

#[derive(Debug)]
pub struct Symbol<'a> {
    pub contents: &'a str,
}

#[derive(Debug)]
pub struct BlankLine<'a> {
    pub contents: &'a str,
}

#[derive(Debug)]
pub struct Sequence<'a> {
    pub contents: &'a str,
}

#[derive(Debug)]
pub struct Bold<'a> {
    pub contents: &'a str,
}

#[derive(Debug)]
pub struct Link<'a> {
    pub contents: &'a str,
}

#[derive(Debug)]
pub struct Paragraph<'a> {
    pub contents: Vec<TextElement<'a>>,
    pub paragraph_end: &'a str,
}

pub trait Source<'a> {
    fn get_source(&'a self) -> &'a str;
}

impl<'a> Source<'a> for TextElement<'a> {
    fn get_source(&'a self) -> &'a str {
        match self {
            TextElement::Span(elem) => elem.contents,
            TextElement::Space(elem) => elem.contents,
            TextElement::LineBreak(elem) => elem.contents,
            TextElement::Symbol(elem) => elem.contents,
            TextElement::Bold(elem) => elem.contents,
            TextElement::Link(elem) => elem.contents,
        }
    }
}

impl<'a> Source<'a> for Paragraph<'a> {
    fn get_source(&'a self) -> &'a str {
        if self.contents.is_empty() {
            return self.paragraph_end;
        }
        // TODO: Is there a better way to do this? At a minimum I should be checking that the pointers are contiguous instead of blindly adding their lengths but maybe theres a good way in nom to get both the recognize() value and the parsed values so we can just store a &str to the source.
        let start = self.contents[0].get_source().as_ptr();
        let len = self
            .contents
            .iter()
            .map(|text_element| text_element.get_source().len())
            .sum::<usize>()
            + self.paragraph_end.len();
        let full_source = unsafe {
            let slice = std::slice::from_raw_parts(start, len);
            std::str::from_utf8(slice)
                .expect("A token should always be made with valid utf-8 source material.")
        };
        full_source
    }
}