package pdfprocessor

import (
	"crypto/md5"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
)

func DownloadPDF(url string, saveDir string) (string, string, error) {
	resp, err := http.Get(url)
	if err != nil {
		return "", "", fmt.Errorf("downloading PDF: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", "", fmt.Errorf("download failed with status: %d", resp.StatusCode)
	}

	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", "", fmt.Errorf("reading PDF data: %w", err)
	}

	hash := fmt.Sprintf("%x", md5.Sum(data))
	filename := fmt.Sprintf("%s.pdf", hash)
	filepath := filepath.Join(saveDir, filename)

	if err := os.WriteFile(filepath, data, 0644); err != nil {
		return "", "", fmt.Errorf("saving PDF: %w", err)
	}

	return filepath, hash, nil
}

func ComputeMD5(filePath string) (string, error) {
	f, err := os.Open(filePath)
	if err != nil {
		return "", err
	}
	defer f.Close()

	h := md5.New()
	if _, err := io.Copy(h, f); err != nil {
		return "", err
	}
	return fmt.Sprintf("%x", h.Sum(nil)), nil
}