main.go

package main

import (
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"

	"github.com/pdfcpu/pdfcpu/pkg/api"
)

var formatRegex = regexp.MustCompile(`_(A\d+|Letter|Legal)_(\d+)`)

type FileFormatCount struct {
	File   string
	Format string
	Count  int
}

func main() {
	folder := "/Users/johannes/Monte Cloud/05 Veranstaltungen/01 Fasentsonntag/2025/Preislisten/PDF"
	files, err := os.ReadDir(folder)
	if err != nil {
		fmt.Println("Error reading directory:", err)
		return
	}

	// Map to store format to file associations
	formatMap := make(map[string][]string)

	for _, file := range files {
		if file.IsDir() || !strings.HasSuffix(file.Name(), ".pdf") {
			continue
		}
		formats := extractFormats(file.Name())
		if len(formats) == 0 {
			fmt.Println("Skipping file with no format info:", file.Name())
			continue
		}
		for _, f := range formats {
			for i := 0; i < f.Count; i++ {
				formatMap[f.Format] = append(formatMap[f.Format], filepath.Join(folder, file.Name()))
			}
		}
	}

	// Merge PDFs by format
	for format, pdfFiles := range formatMap {
		sort.Strings(pdfFiles) // Sorting ensures consistent order
		outputFile := filepath.Join(folder, fmt.Sprintf("merged_%s.pdf", format))
		fmt.Println("Merging PDFs for", format, "into", outputFile)
		err := mergePDFs(pdfFiles, outputFile)
		if err != nil {
			fmt.Println("Error merging PDFs for", format, ":", err)
		}
	}
}

func extractFormats(filename string) []FileFormatCount {
	matches := formatRegex.FindAllStringSubmatch(filename, -1)
	if matches == nil {
		return nil
	}

	var results []FileFormatCount
	for _, match := range matches {
		count := 1
		fmt.Sscanf(match[2], "%d", &count)
		results = append(results, FileFormatCount{
			File:   filename,
			Format: match[1],
			Count:  count,
		})
	}
	return results
}

func mergePDFs(inputFiles []string, outputFile string) error {
	return api.MergeCreateFile(inputFiles, outputFile, false, nil)
}