/**
* Utility for processing note content, extracting frontmatter, and generating statistics
*/
export interface NoteFrontmatter {
[key: string]: any;
}
export interface NoteStatistics {
wordCount: number;
characterCount: number;
headingCount: number;
headings: string[];
}
export interface NotePreview {
mode: 'preview';
frontmatter: NoteFrontmatter | null;
preview: string;
statistics: NoteStatistics;
}
export interface NoteFullContent {
mode: 'full';
content: string;
}
export class NoteContentProcessor {
private static readonly PREVIEW_LENGTH = 200;
private static readonly FRONTMATTER_REGEX = /^---\r?\n([\s\S]*?)\r?\n---\r?\n?/;
private static readonly HEADING_REGEX = /^(#{1,6})\s+(.+)$/gm;
/**
* Extract frontmatter from markdown content
*/
static extractFrontmatter(content: string): { frontmatter: NoteFrontmatter | null; contentWithoutFrontmatter: string } {
const match = content.match(this.FRONTMATTER_REGEX);
if (!match) {
return { frontmatter: null, contentWithoutFrontmatter: content };
}
const frontmatterYaml = match[1];
let contentWithoutFrontmatter = content.substring(match[0].length);
// Remove leading newline if present
if (contentWithoutFrontmatter.startsWith('\n')) {
contentWithoutFrontmatter = contentWithoutFrontmatter.substring(1);
}
try {
// Simple YAML parsing for basic frontmatter
// This handles common cases but isn't a full YAML parser
const frontmatter = this.parseSimpleYaml(frontmatterYaml);
return { frontmatter, contentWithoutFrontmatter };
} catch (error) {
// If YAML parsing fails, return null frontmatter but still remove the frontmatter section
return { frontmatter: null, contentWithoutFrontmatter };
}
}
/**
* Simple YAML parser for basic frontmatter (handles most common cases)
*/
private static parseSimpleYaml(yamlString: string): NoteFrontmatter {
const result: NoteFrontmatter = {};
const lines = yamlString.split('\n');
// Handle empty frontmatter
if (lines.every(line => !line.trim() || line.trim().startsWith('#'))) {
return result;
}
for (const line of lines) {
const trimmedLine = line.trim();
if (!trimmedLine || trimmedLine.startsWith('#')) continue;
const colonIndex = trimmedLine.indexOf(':');
if (colonIndex === -1) continue;
const key = trimmedLine.substring(0, colonIndex).trim();
let value = trimmedLine.substring(colonIndex + 1).trim();
// Handle quoted strings
if ((value.startsWith('"') && value.endsWith('"')) ||
(value.startsWith("'") && value.endsWith("'"))) {
value = value.slice(1, -1);
}
// Handle arrays [item1, item2]
else if (value.startsWith('[') && value.endsWith(']')) {
const arrayContent = value.slice(1, -1);
result[key] = arrayContent.split(',').map(item => item.trim());
continue;
}
// Handle booleans
else if (value === 'true') {
result[key] = true;
continue;
}
else if (value === 'false') {
result[key] = false;
continue;
}
// Handle numbers
else if (!isNaN(Number(value)) && value !== '') {
result[key] = Number(value);
continue;
}
// Validate basic malformed YAML
if (value.startsWith('"') && !value.endsWith('"')) {
throw new Error('Malformed quoted string');
}
if (value.startsWith('[') && !value.endsWith(']')) {
throw new Error('Malformed array');
}
result[key] = value;
}
return result;
}
/**
* Generate statistics for note content
*/
static generateStatistics(content: string): NoteStatistics {
// Count words (split by whitespace, filter empty strings)
const words = content.split(/\s+/).filter(word => word.length > 0);
const wordCount = words.length;
// Count characters (excluding frontmatter for content without frontmatter)
const characterCount = content.length;
// Extract headings
const headings: string[] = [];
let match;
const headingRegex = new RegExp(this.HEADING_REGEX);
while ((match = headingRegex.exec(content)) !== null) {
headings.push(match[2].trim());
}
return {
wordCount,
characterCount,
headingCount: headings.length,
headings
};
}
/**
* Create preview version of content (first N characters without frontmatter)
*/
static createPreview(contentWithoutFrontmatter: string, length: number = this.PREVIEW_LENGTH): string {
if (contentWithoutFrontmatter.length <= length) {
return contentWithoutFrontmatter;
}
return contentWithoutFrontmatter.substring(0, length);
}
/**
* Process note content and return preview mode response
*/
static processForPreview(fullContent: string): NotePreview {
const { frontmatter, contentWithoutFrontmatter } = this.extractFrontmatter(fullContent);
const preview = this.createPreview(contentWithoutFrontmatter);
const statistics = this.generateStatistics(contentWithoutFrontmatter);
return {
mode: 'preview',
frontmatter,
preview,
statistics
};
}
/**
* Process note content and return full mode response
*/
static processForFull(fullContent: string): NoteFullContent {
return {
mode: 'full',
content: fullContent
};
}
}
