import * as path from "path"
// @ts-ignore-next-line
import pdf from "pdf-parse/lib/pdf-parse"
import mammoth from "mammoth"
import fs from "fs/promises"
import { isBinaryFile } from "isbinaryfile"

export async function extractTextFromFile(filePath: string): Promise<string> {
	try {
		await fs.access(filePath)
	} catch (error) {
		throw new Error(`File not found: ${filePath}`)
	}
	const fileExtension = path.extname(filePath).toLowerCase()
	switch (fileExtension) {
		case ".pdf":
			return extractTextFromPDF(filePath)
		case ".docx":
			return extractTextFromDOCX(filePath)
		case ".ipynb":
			return extractTextFromIPYNB(filePath)
		default:
			const isBinary = await isBinaryFile(filePath).catch(() => false)
			if (!isBinary) {
				return addLineNumbers(await fs.readFile(filePath, "utf8"))
			} else {
				throw new Error(`Cannot read text for file type: ${fileExtension}`)
			}
	}
}

async function extractTextFromPDF(filePath: string): Promise<string> {
	const dataBuffer = await fs.readFile(filePath)
	const data = await pdf(dataBuffer)
	return addLineNumbers(data.text)
}

async function extractTextFromDOCX(filePath: string): Promise<string> {
	const result = await mammoth.extractRawText({ path: filePath })
	return addLineNumbers(result.value)
}

async function extractTextFromIPYNB(filePath: string): Promise<string> {
	const data = await fs.readFile(filePath, "utf8")
	const notebook = JSON.parse(data)
	let extractedText = ""

	for (const cell of notebook.cells) {
		if ((cell.cell_type === "markdown" || cell.cell_type === "code") && cell.source) {
			extractedText += cell.source.join("\n") + "\n"
		}
	}

	return addLineNumbers(extractedText)
}

export function addLineNumbers(content: string, startLine: number = 1): string {
	const lines = content.split('\n')
	const maxLineNumberWidth = String(startLine + lines.length - 1).length
	return lines
		.map((line, index) => {
			const lineNumber = String(startLine + index).padStart(maxLineNumberWidth, ' ')
			return `${lineNumber} | ${line}`
		}).join('\n')
}
// Checks if every line in the content has line numbers prefixed (e.g., "1 | content" or "123 | content")
// Line numbers must be followed by a single pipe character (not double pipes)
export function everyLineHasLineNumbers(content: string): boolean {
	const lines = content.split(/\r?\n/)
	return lines.length > 0 && lines.every(line => /^\s*\d+\s+\|(?!\|)/.test(line))
}

// Strips line numbers from content while preserving the actual content
// Handles formats like "1 | content", " 12 | content", "123 | content"
// Preserves content that naturally starts with pipe characters
export function stripLineNumbers(content: string): string {
	// Split into lines to handle each line individually
	const lines = content.split(/\r?\n/)
	
	// Process each line
	const processedLines = lines.map(line => {
		// Match line number pattern and capture everything after the pipe
		const match = line.match(/^\s*\d+\s+\|(?!\|)\s?(.*)$/)
		return match ? match[1] : line
	})
	
	// Join back with original line endings
	const lineEnding = content.includes('\r\n') ? '\r\n' : '\n'
	return processedLines.join(lineEnding)
}