//! AST element extraction and assertion helpers
//!
//! This module provides utilities for making assertions about AST content.
//! For extracting elements, use the query APIs directly on the root session:
//!   - doc.root.iter_paragraphs_recursive().next()
//!   - doc.root.iter_sessions_recursive().next()
//!   - doc.root.find_paragraphs(|p| ...)
//!     etc.

use crate::lex::ast::traits::Container;
use crate::lex::ast::{ContentItem, Document, Paragraph};

// ===== Assertion helpers =====

/// Check if a paragraph's text starts with the given string
pub fn paragraph_text_starts_with(paragraph: &Paragraph, expected: &str) -> bool {
    paragraph.text().starts_with(expected)
}

/// Check if a paragraph's text contains the given string
pub fn paragraph_text_contains(paragraph: &Paragraph, expected: &str) -> bool {
    paragraph.text().contains(expected)
}

// ===== Document comparison utilities =====

/// Check if two documents have matching AST structure
pub fn documents_match(doc1: &Document, doc2: &Document) -> bool {
    doc1.root.children.len() == doc2.root.children.len()
        && doc1
            .root
            .children
            .iter()
            .zip(doc2.root.children.iter())
            .all(|(item1, item2)| content_items_match(item1, item2))
}

/// Check if two content items match (recursive)
pub fn content_items_match(item1: &ContentItem, item2: &ContentItem) -> bool {
    use ContentItem::*;
    match (item1, item2) {
        (Paragraph(p1), Paragraph(p2)) => p1.lines.len() == p2.lines.len(),
        (Session(s1), Session(s2)) => {
            s1.label() == s2.label()
                && s1.children().len() == s2.children().len()
                && s1
                    .children()
                    .iter()
                    .zip(s2.children().iter())
                    .all(|(c1, c2)| content_items_match(c1, c2))
        }
        (List(l1), List(l2)) => l1.items.len() == l2.items.len(),
        (Definition(d1), Definition(d2)) => {
            d1.label() == d2.label() && d1.children().len() == d2.children().len()
        }
        (Annotation(a1), Annotation(a2)) => a1.children().len() == a2.children().len(),
        (VerbatimBlock(v1), VerbatimBlock(v2)) => v1.children.len() == v2.children.len(),
        _ => false, // Different types don't match
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::lex::testing::lexplore::loader::*;

    #[test]
    fn test_query_api_usage() {
        let doc = Lexplore::paragraph(1).parse().unwrap();

        // Use query API directly
        let paragraph = doc.root.iter_paragraphs_recursive().next();
        assert!(paragraph.is_some());
    }

    #[test]
    fn test_paragraph_assertions() {
        let doc = Lexplore::paragraph(1).parse().unwrap();

        // Use query API directly
        let paragraph = doc.root.iter_paragraphs_recursive().next().unwrap();

        assert!(paragraph_text_starts_with(paragraph, "This is a simple"));
    }
}
