use crate::syntax_highlight::syntax_highlight;

use super::parser::{Block, Span};

pub fn span_to_html(ss: Vec<Span>) -> String {
    let mut out = String::new();
    for s in ss {
        out += match s {
            Span::Break => format!("<br/>"),
            Span::Text(t) => escape(&t),
            Span::Code(c) => format!("<code>{}</code>", escape(&c)),
            Span::Link(text, url) => {
                format!("<a href=\"{}\">{}</a>", escape(&url), escape(&text))
            }
            Span::Image(_, _) => todo!(),
            Span::Emphasis(c) => format!("<i>{}</i>", span_to_html(c)),
            Span::Strong(c) => format!("<b>{}</b>", span_to_html(c)),
            Span::Latex(s) => fix_katex(
                &katex::render_with_opts(&s, &katex::OptsBuilder::default().build().unwrap())
                    .unwrap(),
            ),
        }
        .as_str()
    }
    out
}
pub fn blocks_to_html(blocks: Vec<Block>) -> String {
    let mut out = String::new();
    for e in blocks {
        out += match e {
            Block::Header(level, text) => {
                format!("<h{level}>{}</h{level}>", span_to_html(text))
            }
            Block::Paragraph(p) => format!("<p>{}</p>", span_to_html(p)),
            Block::Blockquote(q) => format!("<quote>{}</quote>", blocks_to_html(q)),
            Block::CodeBlock(syntax, content) => {
                if let Some(s) = &syntax {
                    format!("<pre>{}</pre>", syntax_highlight(s, &content))
                } else {
                    format!("<pre>{}</pre>", escape(&content))
                }
            }
            Block::OrderedList(els) => format!(
                "<ol>{}</ol>",
                els.into_iter()
                    .map(|e| format!("<li>{}</li>", blocks_to_html(e)))
                    .collect::<Vec<_>>()
                    .join("")
            ),
            Block::UnorderedList(els) => {
                format!(
                    "<ul>{}</ul>",
                    els.into_iter()
                        .map(|e| format!("<li>{}</li>", blocks_to_html(e)))
                        .collect::<Vec<_>>()
                        .join("")
                )
            }
            Block::Raw(r) => r,
            Block::Hr => format!("<hr/>"),
            Block::LatexBlock(s) => fix_katex(
                &katex::render_with_opts(
                    &s,
                    &katex::OptsBuilder::default()
                        .display_mode(true)
                        .build()
                        .unwrap(),
                )
                .unwrap(),
            ),
        }
        .as_str();
    }
    out
}

pub fn escape(text: &str) -> String {
    text.replace("&", "&amp;")
        .replace("<", "&lt;")
        .replace(">", "&gt;")
        .replace("'", "&#8217;")
        .replace("\"", "&quot;")
}

// TODO this is *really* bad fix
fn fix_katex<'a>(s: &str) -> String {
    let e = s.find("<span class=\"katex-html\"").unwrap();
    s[0..e].replace(
        "<mspace linebreak=\"newline\"></mspace>",
        "</mrow></semantics></math><math xmlns=\"http://www.w3.org/1998/Math/MathML\" display=\"block\"><semantics><mrow>",
    )
}