import type { Block } from './types';
const isBlankLine = (line: string): boolean => line.trim().length === 0;
const isFencedCodeDelimiter = (line: string): boolean => /^\s*```/.test(line);
const isHeading = (line: string): boolean => /^\s*#{1,6}\s+/.test(line);
const isFrontmatterDelimiter = (line: string): boolean =>
/^\s*---\s*$/.test(line);
const trimTrailingNewlines = (text: string): string =>
text.replace(/\n+$/g, '\n');
export const segmentDocument = (text: string): Block[] => {
const lines = text.split('\n');
const blocks: Block[] = [];
let index = 0;
let insideCodeBlock = false;
// Buffers
let currentSectionLines: string[] = [];
let currentSectionStartLine = 1;
const flushCurrentSection = (endIndex: number) => {
if (currentSectionLines.length > 0) {
// Filter out leading blank lines from the block content to keep it clean,
// but strictly speaking, we just want to ensure non-empty content.
const rawContent = currentSectionLines.join('\n');
if (rawContent.trim().length > 0) {
blocks.push({
type: 'paragraph', // Generic type
content: `${trimTrailingNewlines(rawContent)}\n`,
lineStart: currentSectionStartLine,
lineEnd: endIndex,
});
}
currentSectionLines = [];
}
};
while (index < lines.length) {
const currentLine = lines[index];
// 1. Handle Frontmatter (Must be at start of file)
if (blocks.length === 0 && isFrontmatterDelimiter(currentLine)) {
const startLine = index + 1;
const contentLines: string[] = [currentLine];
index++;
while (index < lines.length && !isFrontmatterDelimiter(lines[index])) {
contentLines.push(lines[index]);
index++;
}
if (index < lines.length && isFrontmatterDelimiter(lines[index])) {
contentLines.push(lines[index]);
index++;
}
blocks.push({
type: 'paragraph',
content: `${trimTrailingNewlines(contentLines.join('\n'))}\n`,
lineStart: startLine,
lineEnd: index,
});
continue;
}
// 2. Track Code Blocks (Headers inside code blocks are ignored)
if (isFencedCodeDelimiter(currentLine)) {
insideCodeBlock = !insideCodeBlock;
}
const isHeader = !insideCodeBlock && isHeading(currentLine);
// 3. Split on Headers
if (isHeader) {
// If we have accumulated content, flush it as the previous block
if (currentSectionLines.length > 0) {
flushCurrentSection(index);
}
// Start a new section with this header
currentSectionStartLine = index + 1;
currentSectionLines = [currentLine];
} else {
// Accumulate content
if (currentSectionLines.length === 0 && !isBlankLine(currentLine)) {
currentSectionStartLine = index + 1;
}
currentSectionLines.push(currentLine);
}
index++;
}
// Flush remaining content
flushCurrentSection(index);
return blocks;
};
