kreuzberg 4.8.4

//! Native table detection using the pdf_oxide backend.
//!
//! Uses pdf_oxide's built-in `extract_tables_with_config` API with strict mode
//! to detect tables with high precision, replacing the heuristic word-based
//! approach that caused false positives on paragraph text.

use super::OxideDocument;
use crate::pdf::error::{PdfError, Result};
use crate::types::{BoundingBox, Table};

/// Extract tables from all pages using pdf_oxide's native table detection.
///
/// Uses `TableDetectionConfig::strict()` to reduce false positives from
/// paragraph text being misidentified as tables.
///
/// # Arguments
///
/// * `doc` - Mutable reference to the oxide document
///
/// # Returns
///
/// A `Vec<Table>` containing all detected tables with cells, markdown, and bounding boxes.
pub(crate) fn extract_tables_native(doc: &mut OxideDocument) -> Result<Vec<Table>> {
    let page_count = doc
        .doc
        .page_count()
        .map_err(|e| PdfError::MetadataExtractionFailed(format!("pdf_oxide: failed to get page count: {e}")))?;

    let config = pdf_oxide::structure::spatial_table_detector::TableDetectionConfig::strict();
    let mut all_tables = Vec::new();

    for page_idx in 0..page_count {
        let extracted = match doc.doc.extract_tables_with_config(page_idx, config.clone()) {
            Ok(tables) => tables,
            Err(e) => {
                tracing::debug!(page = page_idx, "pdf_oxide extract_tables failed: {e}");
                continue;
            }
        };

        let page_number = page_idx + 1; // Kreuzberg uses 1-indexed page numbers

        for extracted_table in extracted {
            if extracted_table.rows.is_empty() || extracted_table.col_count == 0 {
                continue;
            }

            let (cells, markdown) = convert_extracted_table(&extracted_table);

            // Skip tables that produced no meaningful content
            if cells.is_empty() || markdown.trim().is_empty() {
                continue;
            }

            let bounding_box = extracted_table.bbox.map(|rect| BoundingBox {
                x0: rect.x as f64,
                y0: rect.y as f64,
                x1: (rect.x + rect.width) as f64,
                y1: (rect.y + rect.height) as f64,
            });

            all_tables.push(Table {
                cells,
                markdown,
                page_number,
                bounding_box,
            });
        }
    }

    Ok(all_tables)
}

/// Convert a pdf_oxide `ExtractedTable` to kreuzberg's cell grid and markdown.
///
/// Maps rows/cells from the native table structure to a 2D `Vec<Vec<String>>`
/// grid and builds a markdown representation with proper header separators.
fn convert_extracted_table(
    table: &pdf_oxide::structure::table_extractor::ExtractedTable,
) -> (Vec<Vec<String>>, String) {
    let mut cells: Vec<Vec<String>> = Vec::with_capacity(table.rows.len());
    let mut markdown = String::new();
    let mut found_header = false;

    for (row_idx, row) in table.rows.iter().enumerate() {
        let row_cells: Vec<String> = row.cells.iter().map(|cell| cell.text.trim().to_string()).collect();

        // Build markdown row
        markdown.push('|');
        for cell in &row_cells {
            markdown.push(' ');
            markdown.push_str(cell);
            markdown.push_str(" |");
        }
        markdown.push('\n');

        // Insert header separator after the first header row
        if row.is_header && !found_header {
            found_header = true;
            markdown.push('|');
            for _ in &row_cells {
                markdown.push_str(" --- |");
            }
            markdown.push('\n');
        } else if row_idx == 0 && !found_header {
            // If no explicit header, treat first row as header for markdown formatting
            found_header = true;
            markdown.push('|');
            for _ in &row_cells {
                markdown.push_str(" --- |");
            }
            markdown.push('\n');
        }

        cells.push(row_cells);
    }

    (cells, markdown)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_convert_extracted_table_basic() {
        use pdf_oxide::structure::table_extractor::{ExtractedTable, TableCell, TableRow};

        let table = ExtractedTable {
            rows: vec![
                TableRow {
                    cells: vec![
                        TableCell {
                            text: "Name".to_string(),
                            colspan: 1,
                            rowspan: 1,
                            mcids: vec![],
                            bbox: None,
                            is_header: true,
                        },
                        TableCell {
                            text: "Age".to_string(),
                            colspan: 1,
                            rowspan: 1,
                            mcids: vec![],
                            bbox: None,
                            is_header: true,
                        },
                    ],
                    is_header: true,
                },
                TableRow {
                    cells: vec![
                        TableCell {
                            text: "Alice".to_string(),
                            colspan: 1,
                            rowspan: 1,
                            mcids: vec![],
                            bbox: None,
                            is_header: false,
                        },
                        TableCell {
                            text: "30".to_string(),
                            colspan: 1,
                            rowspan: 1,
                            mcids: vec![],
                            bbox: None,
                            is_header: false,
                        },
                    ],
                    is_header: false,
                },
            ],
            has_header: true,
            col_count: 2,
            bbox: None,
        };

        let (cells, markdown) = convert_extracted_table(&table);
        assert_eq!(cells.len(), 2);
        assert_eq!(cells[0], vec!["Name", "Age"]);
        assert_eq!(cells[1], vec!["Alice", "30"]);
        assert!(markdown.contains("| Name | Age |"));
        assert!(markdown.contains("| --- | --- |"));
        assert!(markdown.contains("| Alice | 30 |"));
    }

    #[test]
    fn test_convert_extracted_table_no_header() {
        use pdf_oxide::structure::table_extractor::{ExtractedTable, TableCell, TableRow};

        let table = ExtractedTable {
            rows: vec![
                TableRow {
                    cells: vec![TableCell {
                        text: "A".to_string(),
                        colspan: 1,
                        rowspan: 1,
                        mcids: vec![],
                        bbox: None,
                        is_header: false,
                    }],
                    is_header: false,
                },
                TableRow {
                    cells: vec![TableCell {
                        text: "B".to_string(),
                        colspan: 1,
                        rowspan: 1,
                        mcids: vec![],
                        bbox: None,
                        is_header: false,
                    }],
                    is_header: false,
                },
            ],
            has_header: false,
            col_count: 1,
            bbox: None,
        };

        let (cells, markdown) = convert_extracted_table(&table);
        assert_eq!(cells.len(), 2);
        // Even without explicit header, first row gets separator for valid markdown
        assert!(markdown.contains("| --- |"));
    }

    #[test]
    fn test_convert_extracted_table_empty() {
        use pdf_oxide::structure::table_extractor::ExtractedTable;

        let table = ExtractedTable {
            rows: vec![],
            has_header: false,
            col_count: 0,
            bbox: None,
        };

        let (cells, markdown) = convert_extracted_table(&table);
        assert!(cells.is_empty());
        assert!(markdown.is_empty());
    }
}