//! Plain-text serialization of a Document for inspection and assertions.

use we_dom::{Document, NodeData, NodeId};

/// Dump the document tree as indented text. Useful as a "what does the parser
/// think this page is" snapshot for regression tests.
pub fn dump(doc: &Document) -> String {
    let mut out = String::new();
    walk(doc, doc.root(), 0, &mut out);
    out
}

fn walk(doc: &Document, node: NodeId, depth: usize, out: &mut String) {
    for _ in 0..depth {
        out.push_str("  ");
    }
    match doc.node_data(node) {
        NodeData::Document => out.push_str("#document\n"),
        NodeData::DocumentFragment => out.push_str("#document-fragment\n"),
        NodeData::Element { tag_name, .. } => {
            out.push('<');
            out.push_str(tag_name.as_str());
            if let Some(attrs) = doc.attributes(node) {
                for a in attrs {
                    out.push(' ');
                    out.push_str(a.name.as_str());
                    out.push_str("=\"");
                    for c in a.value.chars() {
                        match c {
                            '"' => out.push_str("&quot;"),
                            '\n' => out.push_str("\\n"),
                            _ => out.push(c),
                        }
                    }
                    out.push('"');
                }
            }
            out.push_str(">\n");
            // Descend into a declarative shadow root, if present, so shadow
            // content appears in the dump (it is not a light-DOM child).
            if let Some(root) = doc.shadow_root(node) {
                for _ in 0..depth + 1 {
                    out.push_str("  ");
                }
                out.push_str("#shadow-root\n");
                for child in doc.children(root) {
                    walk(doc, child, depth + 2, out);
                }
            }
        }
        NodeData::Text { data } => {
            let trimmed = data.trim();
            if !trimmed.is_empty() {
                out.push('"');
                for c in trimmed.chars().take(120) {
                    match c {
                        '"' => out.push_str("\\\""),
                        '\n' => out.push_str("\\n"),
                        _ => out.push(c),
                    }
                }
                if trimmed.chars().count() > 120 {
                    out.push('…');
                }
                out.push('"');
                out.push('\n');
            } else {
                out.push_str("(whitespace)\n");
            }
        }
        NodeData::Comment { data } => {
            out.push_str("<!--");
            out.push_str(data);
            out.push_str("-->\n");
        }
    }
    for child in doc.children(node) {
        walk(doc, child, depth + 1, out);
    }
}