jw-hwp-core 0.1.0

use crate::container::Container;
use crate::doc_info;
use crate::error::{Error, Location, WarningCode, WarningCollector};
use crate::model::{HwpDocument, ParagraphDetail, Section};
use crate::record::{
    Record, RecordIter, HWPTAG_CTRL_HEADER, HWPTAG_EQEDIT, HWPTAG_LIST_HEADER,
    HWPTAG_PARA_CHAR_SHAPE, HWPTAG_PARA_HEADER, HWPTAG_PARA_TEXT, HWPTAG_SHAPE_COMPONENT_PICTURE,
    HWPTAG_TABLE,
};
use crate::structure::{classify, make_preview, NodeKind, StructureNode};
use crate::summary;
use crate::table::{parse_cell_list_header, parse_table_payload, Cell, Table, TableProps};
use crate::text::decode_para_text;
use std::path::Path;

pub fn read_document(path: &Path) -> Result<HwpDocument, Error> {
    let mut container = Container::open(path)?;
    let v = container.header.version;
    let version = format!("{}.{}.{}.{}", v.major, v.minor, v.build, v.revision);

    let mut warnings = WarningCollector::default();
    let metadata = summary::read(&mut container).unwrap_or_default();
    let properties = doc_info::read(&mut container).unwrap_or_default();
    let shapes = doc_info::read_shape_tables(&mut container).unwrap_or_default();
    let assets = doc_info::read_asset_catalog(&mut container).unwrap_or_default();

    let mut sections = Vec::new();
    let names = container.section_names();
    for (section_index, name) in names.iter().enumerate() {
        let bytes = container.read_section(name)?;
        sections.push(read_section(section_index, &bytes, &mut warnings));
    }
    Ok(HwpDocument {
        version,
        metadata,
        properties,
        shapes,
        sections,
        assets,
        warnings: warnings.take(),
    })
}

struct ParaBuilder {
    text: String,
    ctrl_id: Option<[u8; 4]>,
    kind: NodeKind,
    para_shape_id: u32,
    runs: Vec<(u32, u32)>,
    footnotes_collected: Vec<crate::model::FootnoteBody>,
    equation_script: Option<String>,
    image_refs: Vec<crate::model::ImageRef>,
}

impl ParaBuilder {
    fn new() -> Self {
        Self {
            text: String::new(),
            ctrl_id: None,
            kind: NodeKind::Paragraph,
            para_shape_id: 0,
            runs: Vec::new(),
            footnotes_collected: Vec::new(),
            equation_script: None,
            image_refs: Vec::new(),
        }
    }
}

fn finalize_para(
    b: ParaBuilder,
    para_index: usize,
    section_index: usize,
) -> (String, StructureNode, ParagraphDetail) {
    let node = StructureNode {
        id: format!("{}:{}", section_index, para_index),
        kind: b.kind,
        preview: make_preview(&b.text),
        ctrl_id: b.ctrl_id.map(|c| String::from_utf8_lossy(&c).into_owned()),
    };
    let detail = ParagraphDetail {
        text: b.text.clone(),
        para_shape_id: b.para_shape_id,
        runs: b.runs,
        footnotes: b.footnotes_collected,
        equation: b.equation_script,
        image_refs: b.image_refs,
    };
    (b.text, node, detail)
}

fn read_section(index: usize, bytes: &[u8], warnings: &mut WarningCollector) -> Section {
    let mut paragraphs: Vec<String> = Vec::new();
    let mut paragraph_details: Vec<ParagraphDetail> = Vec::new();
    let mut structure: Vec<StructureNode> = Vec::new();
    let mut tables: Vec<Table> = Vec::new();
    let mut current: Option<ParaBuilder> = None;

    let mut iter = RecordIter::new(bytes);

    while let Some(rec_res) = iter.next() {
        let rec = match rec_res {
            Ok(r) => r,
            Err(e) => {
                warnings.push(
                    WarningCode::TruncatedRecord,
                    e.to_string(),
                    Some(Location {
                        section: Some(index),
                        ..Default::default()
                    }),
                );
                break;
            }
        };
        let Record { header, payload } = rec;

        match header.tag_id {
            HWPTAG_PARA_HEADER => {
                if let Some(b) = current.take() {
                    let pi = paragraphs.len();
                    let (t, n, d) = finalize_para(b, pi, index);
                    paragraphs.push(t);
                    structure.push(n);
                    paragraph_details.push(d);
                }
                let mut pb = ParaBuilder::new();
                if payload.len() >= 10 {
                    pb.para_shape_id =
                        u16::from_le_bytes(payload[8..10].try_into().unwrap()) as u32;
                }
                current = Some(pb);
            }
            HWPTAG_PARA_CHAR_SHAPE => {
                if let Some(b) = current.as_mut() {
                    let n = payload.len() / 8;
                    for i in 0..n {
                        let off = i * 8;
                        let pos = u32::from_le_bytes(payload[off..off + 4].try_into().unwrap());
                        let cid = u32::from_le_bytes(payload[off + 4..off + 8].try_into().unwrap());
                        b.runs.push((pos, cid));
                    }
                }
            }
            HWPTAG_PARA_TEXT => {
                let text = decode_para_text(payload);
                match current.as_mut() {
                    Some(b) => b.text.push_str(&text),
                    None => {
                        let pi = paragraphs.len();
                        structure.push(StructureNode {
                            id: format!("{}:{}", index, pi),
                            kind: NodeKind::Paragraph,
                            preview: make_preview(&text),
                            ctrl_id: None,
                        });
                        paragraphs.push(text);
                    }
                }
            }
            HWPTAG_CTRL_HEADER => {
                if payload.len() >= 4 {
                    let word = u32::from_le_bytes(payload[..4].try_into().unwrap());
                    let ascii = word.to_be_bytes();
                    if let Some(b) = current.as_mut() {
                        if b.ctrl_id.is_none() {
                            b.ctrl_id = Some(ascii);
                            b.kind = classify(ascii);
                        }
                    }
                    match &ascii {
                        b"tbl " => {
                            match consume_table(index, paragraphs.len(), &mut iter, warnings) {
                                Some(table) => tables.push(table),
                                None => {
                                    warnings.push(
                                        WarningCode::UnsupportedContent,
                                        "table parse aborted".to_string(),
                                        Some(Location {
                                            section: Some(index),
                                            paragraph: Some(paragraphs.len()),
                                            ..Default::default()
                                        }),
                                    );
                                }
                            }
                        }
                        b"%fn " | b"%en " => {
                            let kind = if &ascii == b"%fn " {
                                "footnote"
                            } else {
                                "endnote"
                            };
                            let paragraphs_collected =
                                consume_list_body(&mut iter, warnings, index);
                            if let Some(b) = current.as_mut() {
                                b.footnotes_collected.push(crate::model::FootnoteBody {
                                    kind: kind.into(),
                                    text: paragraphs_collected.join("\n"),
                                });
                            }
                        }
                        b"eqed" => {
                            let saved = iter.offset();
                            if let Some(Ok(rec)) = iter.next() {
                                if rec.header.tag_id == HWPTAG_EQEDIT && rec.payload.len() >= 6 {
                                    let p = rec.payload;
                                    let script_len =
                                        u16::from_le_bytes(p[4..6].try_into().unwrap()) as usize;
                                    let nbytes = script_len * 2;
                                    if 6 + nbytes <= p.len() {
                                        let mut units = Vec::with_capacity(script_len);
                                        for i in 0..script_len {
                                            units.push(u16::from_le_bytes(
                                                p[6 + i * 2..8 + i * 2].try_into().unwrap(),
                                            ));
                                        }
                                        let s = String::from_utf16_lossy(&units);
                                        if let Some(b) = current.as_mut() {
                                            b.equation_script = Some(s);
                                        }
                                    }
                                } else {
                                    iter.set_offset(saved);
                                }
                            }
                        }
                        b"gso " => {
                            // Walk nested shape records until we hit the next peer
                            // CTRL_HEADER, outer PARA_HEADER, or the outer PARA_TEXT;
                            // capture the first HWPTAG_SHAPE_COMPONENT_PICTURE's
                            // bin_data_id (u16 at payload offset 0).
                            let mut bin_id: Option<u16> = None;
                            loop {
                                let saved = iter.offset();
                                let Some(rec_res) = iter.next() else { break };
                                let rec = match rec_res {
                                    Ok(r) => r,
                                    Err(_) => break,
                                };
                                if rec.header.tag_id == HWPTAG_PARA_HEADER
                                    || rec.header.tag_id == HWPTAG_CTRL_HEADER
                                    || rec.header.tag_id == HWPTAG_PARA_TEXT
                                    || rec.header.tag_id == HWPTAG_PARA_CHAR_SHAPE
                                {
                                    iter.set_offset(saved);
                                    break;
                                }
                                if rec.header.tag_id == HWPTAG_SHAPE_COMPONENT_PICTURE
                                    && rec.payload.len() >= 2
                                    && bin_id.is_none()
                                {
                                    bin_id = Some(u16::from_le_bytes(
                                        rec.payload[0..2].try_into().unwrap(),
                                    ));
                                }
                            }
                            if let Some(b) = current.as_mut() {
                                b.image_refs.push(crate::model::ImageRef {
                                    bin_id: bin_id.unwrap_or(0),
                                });
                            }
                        }
                        _ => {}
                    }
                }
            }
            other => {
                warnings.push(
                    WarningCode::UnknownRecordTag,
                    format!(
                        "tag=0x{:03X} level={} size={}",
                        other, header.level, header.size
                    ),
                    Some(Location {
                        section: Some(index),
                        paragraph: Some(paragraphs.len()),
                        ..Default::default()
                    }),
                );
            }
        }
    }
    if let Some(b) = current.take() {
        let pi = paragraphs.len();
        let (t, n, d) = finalize_para(b, pi, index);
        paragraphs.push(t);
        structure.push(n);
        paragraph_details.push(d);
    }
    Section {
        index,
        paragraphs,
        paragraph_details,
        structure,
        tables,
    }
}

fn consume_table(
    section_index: usize,
    para_index: usize,
    iter: &mut RecordIter<'_>,
    warnings: &mut WarningCollector,
) -> Option<Table> {
    let tbl_rec = next_record(iter, warnings, section_index)?;
    if tbl_rec.header.tag_id != HWPTAG_TABLE {
        warnings.push(
            WarningCode::UnsupportedContent,
            format!("expected HWPTAG_TABLE, got 0x{:03X}", tbl_rec.header.tag_id),
            Some(Location {
                section: Some(section_index),
                paragraph: Some(para_index),
                ..Default::default()
            }),
        );
        return None;
    }
    let TableProps { rows, cols } = match parse_table_payload(tbl_rec.payload) {
        Ok(tp) => tp,
        Err(e) => {
            warnings.push(
                WarningCode::UnsupportedContent,
                e.to_string(),
                Some(Location {
                    section: Some(section_index),
                    paragraph: Some(para_index),
                    ..Default::default()
                }),
            );
            return None;
        }
    };

    let mut cells_grid: Vec<Vec<Option<Cell>>> = (0..rows)
        .map(|_| (0..cols).map(|_| None).collect())
        .collect();
    let expected_cells = rows as usize * cols as usize;
    let mut seen_cells = 0usize;
    while seen_cells < expected_cells {
        let lh = next_record(iter, warnings, section_index)?;
        if lh.header.tag_id != HWPTAG_LIST_HEADER {
            // Record inside table body that isn't a cell header — skip silently.
            continue;
        }
        let ch = match parse_cell_list_header(lh.payload) {
            Ok(c) => c,
            Err(e) => {
                warnings.push(
                    WarningCode::UnsupportedContent,
                    e.to_string(),
                    Some(Location {
                        section: Some(section_index),
                        paragraph: Some(para_index),
                        ..Default::default()
                    }),
                );
                return None;
            }
        };
        let para_count = ch.para_count.max(0) as usize;
        let (paragraphs, text) = consume_cell_paragraphs(iter, para_count, warnings, section_index);
        if (ch.row as usize) < cells_grid.len() && (ch.col as usize) < cols as usize {
            cells_grid[ch.row as usize][ch.col as usize] = Some(Cell {
                col: ch.col,
                row: ch.row,
                col_span: ch.col_span,
                row_span: ch.row_span,
                text,
                paragraphs,
            });
        }
        seen_cells += 1;
    }
    Some(Table {
        id: format!("{}:{}", section_index, para_index),
        rows,
        cols,
        caption: None,
        cells: cells_grid,
    })
}

fn next_record<'a>(
    iter: &mut RecordIter<'a>,
    warnings: &mut WarningCollector,
    section_index: usize,
) -> Option<Record<'a>> {
    match iter.next()? {
        Ok(r) => Some(r),
        Err(e) => {
            warnings.push(
                WarningCode::TruncatedRecord,
                e.to_string(),
                Some(Location {
                    section: Some(section_index),
                    ..Default::default()
                }),
            );
            None
        }
    }
}

fn consume_list_body(
    iter: &mut RecordIter<'_>,
    _warnings: &mut WarningCollector,
    _section_index: usize,
) -> Vec<String> {
    // Next record MUST be HWPTAG_LIST_HEADER — peek+skip.
    let saved = iter.offset();
    let Some(rec_res) = iter.next() else {
        iter.set_offset(saved);
        return Vec::new();
    };
    let rec = match rec_res {
        Ok(r) => r,
        Err(_) => {
            iter.set_offset(saved);
            return Vec::new();
        }
    };
    if rec.header.tag_id != HWPTAG_LIST_HEADER {
        iter.set_offset(saved);
        return Vec::new();
    }
    // para_count is first i16 of LIST_HEADER payload.
    let para_count = if rec.payload.len() >= 2 {
        i16::from_le_bytes(rec.payload[0..2].try_into().unwrap()).max(0) as usize
    } else {
        0
    };
    // Collect only records at the inner level. Inner paragraphs have level >=
    // LIST_HEADER.level; anything at a lower level belongs to the outer scope.
    let inner_min_level = rec.header.level;
    let mut collected: Vec<String> = Vec::with_capacity(para_count);
    let mut current: Option<String> = None;
    let mut seen_headers = 0usize;
    loop {
        if seen_headers >= para_count && current.is_none() {
            break;
        }
        let saved = iter.offset();
        let Some(rec_res) = iter.next() else { break };
        let rec = match rec_res {
            Ok(r) => r,
            Err(_) => break,
        };
        if rec.header.level < inner_min_level {
            // Record belongs to an outer scope — rewind and exit.
            iter.set_offset(saved);
            if let Some(p) = current.take() {
                collected.push(p);
            }
            break;
        }
        match rec.header.tag_id {
            HWPTAG_PARA_HEADER => {
                if let Some(p) = current.take() {
                    collected.push(p);
                }
                if seen_headers >= para_count {
                    iter.set_offset(saved);
                    break;
                }
                current = Some(String::new());
                seen_headers += 1;
            }
            HWPTAG_PARA_TEXT => {
                let t = decode_para_text(rec.payload);
                if let Some(buf) = current.as_mut() {
                    buf.push_str(&t);
                } else {
                    collected.push(t);
                }
            }
            HWPTAG_LIST_HEADER => {
                iter.set_offset(saved);
                if let Some(p) = current.take() {
                    collected.push(p);
                }
                break;
            }
            _ => {}
        }
    }
    if let Some(p) = current.take() {
        collected.push(p);
    }
    collected
}

fn consume_cell_paragraphs(
    iter: &mut RecordIter<'_>,
    para_count: usize,
    warnings: &mut WarningCollector,
    section_index: usize,
) -> (Vec<String>, String) {
    let mut collected: Vec<String> = Vec::with_capacity(para_count);
    let mut current: Option<String> = None;
    let mut seen_headers = 0usize;
    loop {
        if seen_headers >= para_count && current.is_none() {
            break;
        }
        let saved = iter.offset();
        let Some(rec_res) = iter.next() else { break };
        let rec = match rec_res {
            Ok(r) => r,
            Err(e) => {
                warnings.push(
                    WarningCode::TruncatedRecord,
                    e.to_string(),
                    Some(Location {
                        section: Some(section_index),
                        ..Default::default()
                    }),
                );
                break;
            }
        };
        match rec.header.tag_id {
            HWPTAG_PARA_HEADER => {
                if seen_headers >= para_count {
                    // next cell/sibling starts here — rewind so caller sees it.
                    iter.set_offset(saved);
                    if let Some(p) = current.take() {
                        collected.push(p);
                    }
                    break;
                }
                if let Some(p) = current.take() {
                    collected.push(p);
                }
                current = Some(String::new());
                seen_headers += 1;
            }
            HWPTAG_PARA_TEXT => {
                let t = decode_para_text(rec.payload);
                if let Some(buf) = current.as_mut() {
                    buf.push_str(&t);
                } else {
                    collected.push(t);
                }
            }
            HWPTAG_LIST_HEADER => {
                // Next cell's header — rewind and exit.
                iter.set_offset(saved);
                if let Some(p) = current.take() {
                    collected.push(p);
                }
                break;
            }
            _ => {}
        }
    }
    if let Some(p) = current.take() {
        collected.push(p);
    }
    let text = collected.join("\n");
    (collected, text)
}

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

    fn encode_header(tag: u16, level: u16, size: u32) -> Vec<u8> {
        let word = (tag as u32 & 0x3FF) | ((level as u32 & 0x3FF) << 10) | (size.min(0xFFF) << 20);
        let mut v = word.to_le_bytes().to_vec();
        if size >= 0xFFF {
            v.extend_from_slice(&size.to_le_bytes());
        }
        v
    }
    fn le_utf16(s: &str) -> Vec<u8> {
        s.encode_utf16().flat_map(|u| u.to_le_bytes()).collect()
    }

    fn build_table_props_payload(rows: u16, cols: u16) -> Vec<u8> {
        let mut p = Vec::new();
        p.extend_from_slice(&0u32.to_le_bytes());
        p.extend_from_slice(&rows.to_le_bytes());
        p.extend_from_slice(&cols.to_le_bytes());
        p.extend_from_slice(&0u16.to_le_bytes());
        p.extend_from_slice(&[0u8; 8]);
        for _ in 0..rows {
            p.extend_from_slice(&1000u16.to_le_bytes());
        }
        p.extend_from_slice(&0u16.to_le_bytes());
        p.extend_from_slice(&0u16.to_le_bytes()); // zones=0
        p
    }

    fn build_cell_list_header_payload(para_count: i16, col: u16, row: u16) -> Vec<u8> {
        let mut p = Vec::new();
        p.extend_from_slice(&para_count.to_le_bytes());
        p.extend_from_slice(&[0u8; 4]); // props
        p.extend_from_slice(&[0u8; 2]); // unknown/list_id
        p.extend_from_slice(&col.to_le_bytes());
        p.extend_from_slice(&row.to_le_bytes());
        p.extend_from_slice(&1u16.to_le_bytes()); // col_span
        p.extend_from_slice(&1u16.to_le_bytes()); // row_span
        p.extend_from_slice(&[0u8; 18]); // width+height+margins+border_fill
        p
    }

    #[test]
    fn classifies_paragraph_with_table_ctrl() {
        let mut buf = Vec::new();
        buf.extend(encode_header(HWPTAG_PARA_HEADER, 0, 0));
        let t = le_utf16("before");
        buf.extend(encode_header(HWPTAG_PARA_TEXT, 1, t.len() as u32));
        buf.extend(&t);
        buf.extend(encode_header(HWPTAG_PARA_HEADER, 0, 0));
        buf.extend(encode_header(HWPTAG_CTRL_HEADER, 1, 4));
        buf.extend_from_slice(&[0x20, 0x6C, 0x62, 0x74]); // LE u32 encoding of "tbl "
        let t2 = le_utf16("caption");
        buf.extend(encode_header(HWPTAG_PARA_TEXT, 1, t2.len() as u32));
        buf.extend(&t2);

        let mut w = WarningCollector::default();
        let s = read_section(0, &buf, &mut w);
        assert_eq!(s.paragraphs.len(), 2);
        assert_eq!(s.structure.len(), 2);
        assert_eq!(s.structure[0].kind, NodeKind::Paragraph);
        assert_eq!(s.structure[1].kind, NodeKind::Table);
        assert_eq!(s.structure[1].ctrl_id.as_deref(), Some("tbl "));
        assert_eq!(s.structure[1].id, "0:1");
    }

    #[test]
    fn structure_ids_are_stable() {
        let mut buf = Vec::new();
        for _ in 0..3 {
            buf.extend(encode_header(HWPTAG_PARA_HEADER, 0, 0));
            let t = le_utf16("x");
            buf.extend(encode_header(HWPTAG_PARA_TEXT, 1, t.len() as u32));
            buf.extend(&t);
        }
        let mut w = WarningCollector::default();
        let s = read_section(2, &buf, &mut w);
        assert_eq!(
            s.structure
                .iter()
                .map(|n| n.id.as_str())
                .collect::<Vec<_>>(),
            ["2:0", "2:1", "2:2"]
        );
    }

    #[test]
    fn captures_para_shape_id_and_char_shape_runs() {
        let mut buf = Vec::new();
        // PARA_HEADER with para_shape_ref at offset 8..10 = 7
        let mut ph = vec![0u8; 22];
        ph[8..10].copy_from_slice(&7u16.to_le_bytes());
        buf.extend(encode_header(HWPTAG_PARA_HEADER, 0, ph.len() as u32));
        buf.extend(&ph);
        let t = le_utf16("hello");
        buf.extend(encode_header(HWPTAG_PARA_TEXT, 1, t.len() as u32));
        buf.extend(&t);
        // PARA_CHAR_SHAPE with two boundaries
        let mut pcs = Vec::new();
        pcs.extend_from_slice(&0u32.to_le_bytes());
        pcs.extend_from_slice(&3u32.to_le_bytes());
        pcs.extend_from_slice(&2u32.to_le_bytes());
        pcs.extend_from_slice(&5u32.to_le_bytes());
        buf.extend(encode_header(HWPTAG_PARA_CHAR_SHAPE, 1, pcs.len() as u32));
        buf.extend(&pcs);

        let mut w = WarningCollector::default();
        let s = read_section(0, &buf, &mut w);
        assert_eq!(s.paragraph_details.len(), 1);
        assert_eq!(s.paragraph_details[0].para_shape_id, 7);
        assert_eq!(s.paragraph_details[0].runs, vec![(0, 3), (2, 5)]);
        assert_eq!(s.paragraph_details[0].text, "hello");
    }

    #[test]
    fn captures_footnote_body() {
        let mut buf = Vec::new();
        // Outer PARA_HEADER
        buf.extend(encode_header(HWPTAG_PARA_HEADER, 0, 0));
        // CTRL_HEADER "%fn " — LE bytes = [0x20, 0x6E, 0x66, 0x25]
        buf.extend(encode_header(HWPTAG_CTRL_HEADER, 1, 4));
        buf.extend_from_slice(&[0x20, 0x6E, 0x66, 0x25]);
        // LIST_HEADER: para_count=1 (i16) + padding.
        let mut lh = Vec::new();
        lh.extend_from_slice(&1i16.to_le_bytes());
        lh.extend_from_slice(&[0u8; 30]);
        buf.extend(encode_header(HWPTAG_LIST_HEADER, 2, lh.len() as u32));
        buf.extend(&lh);
        // Inner (footnote) paragraph
        buf.extend(encode_header(HWPTAG_PARA_HEADER, 2, 0));
        let t_inner = le_utf16("nota bene");
        buf.extend(encode_header(HWPTAG_PARA_TEXT, 2, t_inner.len() as u32));
        buf.extend(&t_inner);
        // Outer PARA_TEXT
        let t_outer = le_utf16("see below");
        buf.extend(encode_header(HWPTAG_PARA_TEXT, 1, t_outer.len() as u32));
        buf.extend(&t_outer);

        let mut w = WarningCollector::default();
        let s = read_section(0, &buf, &mut w);
        assert_eq!(s.paragraphs.len(), 1);
        assert_eq!(s.paragraphs[0], "see below");
        assert_eq!(s.paragraph_details[0].footnotes.len(), 1);
        assert_eq!(s.paragraph_details[0].footnotes[0].kind, "footnote");
        assert_eq!(s.paragraph_details[0].footnotes[0].text, "nota bene");
    }

    #[test]
    fn captures_equation_script() {
        let mut buf = Vec::new();
        buf.extend(encode_header(HWPTAG_PARA_HEADER, 0, 0));
        buf.extend(encode_header(HWPTAG_CTRL_HEADER, 1, 4));
        // MAKE_4CHID("eqed") as LE bytes: ['d','e','q','e'].
        buf.extend_from_slice(b"deqe");
        // equation_edit payload: 4 bytes props, 2 bytes len, utf-16 LE script "x=1".
        let script: Vec<u16> = "x=1".encode_utf16().collect();
        let mut pl = vec![0u8; 4];
        pl.extend_from_slice(&(script.len() as u16).to_le_bytes());
        for u in &script {
            pl.extend_from_slice(&u.to_le_bytes());
        }
        buf.extend(encode_header(HWPTAG_EQEDIT, 2, pl.len() as u32));
        buf.extend(&pl);
        let t = le_utf16("see eqn");
        buf.extend(encode_header(HWPTAG_PARA_TEXT, 1, t.len() as u32));
        buf.extend(&t);

        let mut w = WarningCollector::default();
        let s = read_section(0, &buf, &mut w);
        assert_eq!(s.paragraph_details.len(), 1);
        assert_eq!(s.paragraph_details[0].equation.as_deref(), Some("x=1"));
        assert_eq!(s.paragraphs[0], "see eqn");
    }

    #[test]
    fn captures_image_bin_id() {
        let mut buf = Vec::new();
        buf.extend(encode_header(HWPTAG_PARA_HEADER, 0, 0));
        buf.extend(encode_header(HWPTAG_CTRL_HEADER, 1, 4));
        // MAKE_4CHID("gso ") as LE bytes: [0x20, 'o', 's', 'g'] = [0x20, 0x6F, 0x73, 0x67].
        buf.extend_from_slice(&[0x20, 0x6F, 0x73, 0x67]);
        // HWPTAG_SHAPE_COMPONENT_PICTURE with bin_id=7 at payload offset 0.
        let mut pic = vec![0u8; 20];
        pic[0..2].copy_from_slice(&7u16.to_le_bytes());
        buf.extend(encode_header(
            HWPTAG_SHAPE_COMPONENT_PICTURE,
            2,
            pic.len() as u32,
        ));
        buf.extend(&pic);
        let t = le_utf16("image below");
        buf.extend(encode_header(HWPTAG_PARA_TEXT, 1, t.len() as u32));
        buf.extend(&t);

        let mut w = WarningCollector::default();
        let s = read_section(0, &buf, &mut w);
        assert_eq!(s.paragraph_details.len(), 1);
        assert_eq!(s.paragraph_details[0].image_refs.len(), 1);
        assert_eq!(s.paragraph_details[0].image_refs[0].bin_id, 7);
        assert_eq!(s.paragraphs[0], "image below");
    }

    #[test]
    fn assembles_single_cell_table() {
        let mut buf = Vec::new();
        // outer paragraph containing the table
        buf.extend(encode_header(HWPTAG_PARA_HEADER, 0, 0));
        // CTRL_HEADER "tbl " — bytes on disk are LE u32 of MAKE_4CHID
        buf.extend(encode_header(HWPTAG_CTRL_HEADER, 1, 4));
        buf.extend_from_slice(&[0x20, 0x6C, 0x62, 0x74]);
        // HWPTAG_TABLE (1×1, no zones): 24 bytes payload
        let tbl = build_table_props_payload(1, 1);
        buf.extend(encode_header(HWPTAG_TABLE, 2, tbl.len() as u32));
        buf.extend(&tbl);
        // cell 0,0 LIST_HEADER: 32 bytes payload
        let ch = build_cell_list_header_payload(1, 0, 0);
        buf.extend(encode_header(HWPTAG_LIST_HEADER, 2, ch.len() as u32));
        buf.extend(&ch);
        // cell paragraph
        buf.extend(encode_header(HWPTAG_PARA_HEADER, 2, 0));
        let t = le_utf16("cell A");
        buf.extend(encode_header(HWPTAG_PARA_TEXT, 2, t.len() as u32));
        buf.extend(&t);

        let mut w = WarningCollector::default();
        let s = read_section(0, &buf, &mut w);
        assert_eq!(s.tables.len(), 1);
        let tbl = &s.tables[0];
        assert_eq!((tbl.rows, tbl.cols), (1, 1));
        let cell = tbl.cells[0][0].as_ref().unwrap();
        assert_eq!(cell.text, "cell A");
    }
}