/**
* File attachment service for reading and formatting file contents
*/
import { existsSync } from 'node:fs';
import { readFile } from 'node:fs/promises';
import { extname } from 'node:path';
interface FileAttachment {
path: string;
start_line?: number | undefined;
end_line?: number | undefined;
description?: string | undefined;
}
interface FormattedFileResult {
success: boolean;
path: string;
content: string;
error?: string | undefined;
}
export class FileAttachmentService {
/**
* Format multiple file attachments into a markdown section
*/
async formatAttachments(attachments: FileAttachment[]): Promise<string> {
if (!attachments || attachments.length === 0) {
return '';
}
const results = await Promise.all(
attachments.map((attachment) => this.formatSingleFile(attachment))
);
// Build the attachments section
let output = '\n\n---\n\n# 📎 ATTACHED FILES\n\n';
output += `*${results.length} file${results.length > 1 ? 's' : ''} attached for context*\n\n`;
for (const result of results) {
output += result.content;
output += '\n\n';
}
return output;
}
/**
* Format a single file attachment
*/
private async formatSingleFile(attachment: FileAttachment): Promise<FormattedFileResult> {
const { path, start_line, end_line, description } = attachment;
// Check if file exists
if (!existsSync(path)) {
return {
success: false,
path,
content: `## ❌ ${path}\n\n**FILE NOT FOUND**\n${description ? `\n*Description:* ${description}\n` : ''}`,
error: 'File not found',
};
}
try {
// Read file content
const content = await readFile(path, 'utf-8');
const lines = content.split('\n');
const language = this.detectLanguage(path);
// Validate line ranges
const validatedRange = this.validateLineRange(start_line, end_line, lines.length);
if (!validatedRange.valid) {
return {
success: false,
path,
content: `## ⚠️ ${path}\n\n**INVALID LINE RANGE**: ${validatedRange.error}\n${description ? `\n*Description:* ${description}\n` : ''}`,
error: validatedRange.error,
};
}
// Extract relevant lines
const startIdx = validatedRange.start - 1;
const endIdx = validatedRange.end - 1;
const selectedLines = lines.slice(startIdx, endIdx + 1);
// Build formatted output
let formatted = `## 📄 ${path}\n\n`;
// Add metadata
const isPartial = start_line !== undefined || end_line !== undefined;
formatted += `**Language:** ${language} | `;
formatted += `**Lines:** ${isPartial ? `${validatedRange.start}-${validatedRange.end}` : lines.length} | `;
formatted += `**Size:** ${(content.length / 1024).toFixed(2)} KB\n`;
if (description) {
formatted += `\n*${description}*\n`;
}
formatted += '\n';
// Add file content with line numbers
formatted += this.formatCodeBlock(selectedLines, language, startIdx);
return {
success: true,
path,
content: formatted,
};
} catch (error) {
return {
success: false,
path,
content: `## ❌ ${path}\n\n**ERROR READING FILE**: ${error instanceof Error ? error.message : String(error)}\n${description ? `\n*Description:* ${description}\n` : ''}`,
error: error instanceof Error ? error.message : String(error),
};
}
}
/**
* Format code block with line numbers and smart truncation
*/
private formatCodeBlock(lines: string[], language: string, startIdx: number): string {
let output = `\`\`\`${language.toLowerCase()}\n`;
// Smart truncation for very large files (keep first 500 lines + last 100 lines)
if (lines.length > 600) {
// First 500 lines
const firstLines = lines.slice(0, 500);
firstLines.forEach((line, idx) => {
const lineNumber = startIdx + idx + 1;
output += `${lineNumber.toString().padStart(4, ' ')}: ${line}\n`;
});
// Truncation marker
output += `\n... [${lines.length - 600} lines truncated for brevity] ...\n\n`;
// Last 100 lines
const lastLines = lines.slice(-100);
lastLines.forEach((line, idx) => {
const lineNumber = startIdx + lines.length - 100 + idx + 1;
output += `${lineNumber.toString().padStart(4, ' ')}: ${line}\n`;
});
} else {
// Show all lines with numbers
lines.forEach((line, idx) => {
const lineNumber = startIdx + idx + 1;
output += `${lineNumber.toString().padStart(4, ' ')}: ${line}\n`;
});
}
output += '```';
return output;
}
/**
* Validate line range and return corrected values
*/
private validateLineRange(
start_line: number | undefined,
end_line: number | undefined,
totalLines: number
): { valid: boolean; start: number; end: number; error?: string } {
// No range specified - return full file
if (start_line === undefined && end_line === undefined) {
return { valid: true, start: 1, end: totalLines };
}
// Only start_line specified
if (start_line !== undefined && end_line === undefined) {
if (start_line < 1 || start_line > totalLines) {
return {
valid: false,
start: 1,
end: totalLines,
error: `start_line ${start_line} out of range (1-${totalLines})`,
};
}
return { valid: true, start: start_line, end: totalLines };
}
// Only end_line specified
if (start_line === undefined && end_line !== undefined) {
if (end_line < 1 || end_line > totalLines) {
return {
valid: false,
start: 1,
end: totalLines,
error: `end_line ${end_line} out of range (1-${totalLines})`,
};
}
return { valid: true, start: 1, end: end_line };
}
// Both specified
if (start_line !== undefined && end_line !== undefined) {
if (start_line < 1 || start_line > totalLines) {
return {
valid: false,
start: 1,
end: totalLines,
error: `start_line ${start_line} out of range (1-${totalLines})`,
};
}
if (end_line < 1 || end_line > totalLines) {
return {
valid: false,
start: 1,
end: totalLines,
error: `end_line ${end_line} out of range (1-${totalLines})`,
};
}
if (start_line > end_line) {
return {
valid: false,
start: 1,
end: totalLines,
error: `start_line ${start_line} cannot be greater than end_line ${end_line}`,
};
}
return { valid: true, start: start_line, end: end_line };
}
return { valid: true, start: 1, end: totalLines };
}
private detectLanguage(filePath: string): string {
const ext = extname(filePath).toLowerCase();
const map: Record<string, string> = {
'.js': 'javascript', '.jsx': 'javascript', '.mjs': 'javascript',
'.ts': 'typescript', '.tsx': 'typescript',
'.py': 'python', '.go': 'go', '.rs': 'rust', '.rb': 'ruby',
'.java': 'java', '.c': 'c', '.cpp': 'cpp', '.h': 'c',
'.json': 'json', '.yaml': 'yaml', '.yml': 'yaml', '.toml': 'toml',
'.md': 'markdown', '.html': 'html', '.css': 'css', '.sql': 'sql',
'.sh': 'bash', '.xml': 'xml',
};
if (filePath.endsWith('Dockerfile')) return 'dockerfile';
return map[ext] || 'text';
}
}
