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use super::common::{
classify_prose, html_metadata, parse_html_blocks, remove_comments, split_at_sentences,
ChunkRecordInput, ContentType, HtmlBlockType, MAX_CHUNK_CHARS, MIN_CHUNK_CHARS,
};
// ── Prose helpers ─────────────────────────────────────────────────────────────
fn flush_prose(
chunks: &mut Vec<ChunkRecordInput>,
heading: &Option<String>,
parts: &mut Vec<String>,
len: &mut usize,
) {
if parts.is_empty() {
return;
}
let content = parts.join("\n").trim().to_string();
parts.clear();
*len = 0;
if content.is_empty() {
return;
}
chunks.push(ChunkRecordInput {
content_type: classify_prose(&content),
content,
metadata: html_metadata(heading.clone()),
});
}
fn merge_short_prose(chunks: Vec<ChunkRecordInput>, min_chars: usize) -> Vec<ChunkRecordInput> {
let soft_max = MAX_CHUNK_CHARS + min_chars;
let mut result: Vec<ChunkRecordInput> = Vec::new();
for chunk in chunks {
let is_prose = matches!(
chunk.content_type,
ContentType::PlainParagraph
| ContentType::ShortDisconnectedParagraph
| ContentType::LongSingleParagraph
);
if is_prose && chunk.content.len() < min_chars {
if let Some(prev) = result.last_mut() {
let prev_prose = matches!(
prev.content_type,
ContentType::PlainParagraph
| ContentType::ShortDisconnectedParagraph
| ContentType::LongSingleParagraph
);
if prev_prose && prev.content.len() + chunk.content.len() < soft_max {
prev.content = format!("{}\n{}", prev.content, chunk.content)
.trim()
.to_string();
prev.content_type = classify_prose(&prev.content);
continue;
}
}
}
result.push(chunk);
}
result
}
// ── Core build function ───────────────────────────────────────────────────────
pub fn build_chunks_from_html_bytes(bytes: &[u8]) -> Result<Vec<ChunkRecordInput>, String> {
let text = super::encoding::decode_html(bytes);
// Empty input is not a failure. A blank or whitespace-only document parsed
// perfectly well; it simply has nothing to chunk, so it returns `[]` like
// docx/ppt/xlsx always have (TECH_DEBT T6). Reserving errors for genuine
// parse failures is also what lets `epub::extract` stop swallowing them.
if text.trim().is_empty() {
return Ok(Vec::new());
}
let blocks = parse_html_blocks(&remove_comments(&text));
let mut chunks = Vec::new();
let mut current_heading: Option<String> = None;
let mut prose_parts: Vec<String> = Vec::new();
let mut prose_len = 0usize;
for block in blocks {
match block.block_type {
HtmlBlockType::Heading => {
flush_prose(
&mut chunks,
¤t_heading,
&mut prose_parts,
&mut prose_len,
);
current_heading = Some(block.content.clone());
chunks.push(ChunkRecordInput {
content_type: ContentType::HeadingSection,
content: block.content,
metadata: html_metadata(None),
});
}
HtmlBlockType::Code => {
flush_prose(
&mut chunks,
¤t_heading,
&mut prose_parts,
&mut prose_len,
);
chunks.push(ChunkRecordInput {
content_type: ContentType::CodeBlock,
content: block.content,
metadata: html_metadata(current_heading.clone()),
});
}
HtmlBlockType::Table => {
flush_prose(
&mut chunks,
¤t_heading,
&mut prose_parts,
&mut prose_len,
);
chunks.push(ChunkRecordInput {
content_type: ContentType::Table,
content: block.content,
metadata: html_metadata(current_heading.clone()),
});
}
HtmlBlockType::List => {
flush_prose(
&mut chunks,
¤t_heading,
&mut prose_parts,
&mut prose_len,
);
if !block.content.is_empty() {
chunks.push(ChunkRecordInput {
content_type: ContentType::BulletNumberedList,
content: block.content,
metadata: html_metadata(current_heading.clone()),
});
}
}
HtmlBlockType::Paragraph => {
if block.content.is_empty() {
continue;
}
let parts = if block.content.len() > MAX_CHUNK_CHARS {
split_at_sentences(&block.content, MAX_CHUNK_CHARS)
} else {
vec![block.content]
};
for part in parts {
let add = part.len() + 1;
if prose_len + add > MAX_CHUNK_CHARS && !prose_parts.is_empty() {
flush_prose(
&mut chunks,
¤t_heading,
&mut prose_parts,
&mut prose_len,
);
}
prose_len += add;
prose_parts.push(part);
}
}
}
}
flush_prose(
&mut chunks,
¤t_heading,
&mut prose_parts,
&mut prose_len,
);
let chunks = merge_short_prose(chunks, MIN_CHUNK_CHARS);
// A document that parsed cleanly but holds no extractable text is EMPTY,
// not broken: return an empty list rather than an error. Raising here
// conflated "nothing to chunk" with "could not read this file", and it was
// inconsistent — docx/ppt/xlsx already returned `[]` for the same condition
// while txt/html/md raised (TECH_DEBT T6). Structural invalidity still
// errors: a PPTX with no slides, or a PDF with no text layer, both raise a
// typed error carrying a remedy.
Ok(chunks)
}