use color_eyre::Result;
use pulldown_cmark::Event;
use pulldown_cmark::Tag;
use pulldown_cmark::{Options, Parser};

use crate::hilighting;

pub fn render_markdown_to_html(markdown: &str) -> Result<String> {
    let options = Options::all();
    let mut content_html = String::new();
    let parser = Parser::new_ext(markdown, options);

    let mut code_block = false;
    let mut code_lang = None;
    let mut code_accumulator = String::new();
    let mut events = Vec::new();
    for event in parser {
        match event {
            Event::Text(text) => {
                if code_block {
                    code_accumulator.push_str(&text);
                }
                else {
                    events.push(Event::Text(text));
                }
            }
            Event::Start(Tag::CodeBlock(kind)) => {
                code_block = true;
                if let pulldown_cmark::CodeBlockKind::Fenced(lang) = kind {
                    code_lang = Some(lang);
                }
            }
            Event::End(Tag::CodeBlock(_)) => {
                code_block = false;

                let lang = code_lang.take().unwrap_or("".into());
                let res = hilighting::hilight(&code_accumulator, &lang).unwrap();

                events.push(Event::Html(res.into()));

                code_accumulator.clear();
            }
            _ => events.push(event),
        }
    }

    events.retain(|e| match e {
        Event::Text(t) | Event::Html(t) => !t.is_empty(),
        _ => true,
    });

    pulldown_cmark::html::push_html(&mut content_html, events.into_iter());

    Ok(content_html)
}