feat: initialer Commit des csv2excel CLI-Tools

Go-CLI-Tool zum Konvertieren von CSV-Dateien in Excel (.xlsx),
mit Mage-Build-System und Architektur-Dokumentation.

.gitignore

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+dist/
+.beads/export-state/
+.bv/

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+`csv2excel` is a Go CLI tool that converts one or more CSV files into a single Excel (.xlsx) file, placing each CSV as a separate worksheet.
+
+## Build
+
+This project uses [Mage](https://magefile.org/) (`magefiles/` — eigenes Go-Modul).
+
+```bash
+mage Build         # aktuelles OS (auto)
+mage BuildWindows  # dist/csv2excel.exe
+mage BuildLinux    # dist/csv2excel
+mage Install       # nach $GOBIN
+mage Clean         # dist/ entfernen
+```
+
+Ohne Mage: `go build -o dist/csv2excel.exe .`
+
+## Weiterführende Dokumentation
+
+- **Architektur & Dependencies:** Siehe `docs/architecture.md`

docs/architecture.md

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+# Architecture
+
+## Overview
+
+Single-file tool — entire application logic lives in `main.go`.
+
+- **`main()`**: Parses flags (`-sep`, `-enc`, `-o`), iterates over input CSV files, creates one Excel sheet per file using the filename (without extension) as the sheet name, writes all rows, saves the output `.xlsx`.
+- **`detectDelimiter()`**: Auto-detects the CSV delimiter by counting `;`, `,`, and `\t` occurrences in the first line. Falls back to `;` on error.
+
+Key behaviors:
+- Sheet names are truncated to 31 characters (Excel limit)
+- Encoding `windows1252` wraps the file reader with a Windows-1252 decoder
+- `csvReader.LazyQuotes = true` for tolerance with malformed CSV files
+- The first sheet renames "Sheet1"; subsequent sheets are created fresh
+
+## Version Injection
+
+Version info is injected at build time via ldflags from git tags:
+- `internal/version.Version` — from `git describe --tags --always`
+- `internal/version.Commit` — from `git rev-parse --short HEAD`
+- `internal/version.BuildDate` — from `date -u`
+
+## Dependencies
+
+- `github.com/xuri/excelize/v2` — Excel file creation/manipulation
+- `golang.org/x/text` — Character encoding (Windows-1252 support)

go.mod

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+module code.beautifulmachines.dev/jakoubek/csv2excel
+
+go 1.25.0
+
+require (
+	github.com/richardlehane/mscfb v1.0.6 // indirect
+	github.com/richardlehane/msoleps v1.0.6 // indirect
+	github.com/tiendc/go-deepcopy v1.7.2 // indirect
+	github.com/xuri/efp v0.0.1 // indirect
+	github.com/xuri/excelize/v2 v2.10.1 // indirect
+	github.com/xuri/nfp v0.0.2-0.20250530014748-2ddeb826f9a9 // indirect
+	golang.org/x/crypto v0.48.0 // indirect
+	golang.org/x/net v0.50.0 // indirect
+	golang.org/x/text v0.34.0 // indirect
+)

go.sum

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+github.com/richardlehane/mscfb v1.0.6 h1:eN3bvvZCp00bs7Zf52bxNwAx5lJDBK1tCuH19qq5aC8=
+github.com/richardlehane/mscfb v1.0.6/go.mod h1:pe0+IUIc0AHh0+teNzBlJCtSyZdFOGgV4ZK9bsoV+Jo=
+github.com/richardlehane/msoleps v1.0.6 h1:9BvkpjvD+iUBalUY4esMwv6uBkfOip/Lzvd93jvR9gg=
+github.com/richardlehane/msoleps v1.0.6/go.mod h1:BWev5JBpU9Ko2WAgmZEuiz4/u3ZYTKbjLycmwiWUfWg=
+github.com/tiendc/go-deepcopy v1.7.2 h1:Ut2yYR7W9tWjTQitganoIue4UGxZwCcJy3orjrrIj44=
+github.com/tiendc/go-deepcopy v1.7.2/go.mod h1:4bKjNC2r7boYOkD2IOuZpYjmlDdzjbpTRyCx+goBCJQ=
+github.com/xuri/efp v0.0.1 h1:fws5Rv3myXyYni8uwj2qKjVaRP30PdjeYe2Y6FDsCL8=
+github.com/xuri/efp v0.0.1/go.mod h1:ybY/Jr0T0GTCnYjKqmdwxyxn2BQf2RcQIIvex5QldPI=
+github.com/xuri/excelize/v2 v2.10.1 h1:V62UlqopMqha3kOpnlHy2CcRVw1V8E63jFoWUmMzxN0=
+github.com/xuri/excelize/v2 v2.10.1/go.mod h1:iG5tARpgaEeIhTqt3/fgXCGoBRt4hNXgCp3tfXKoOIc=
+github.com/xuri/nfp v0.0.2-0.20250530014748-2ddeb826f9a9 h1:+C0TIdyyYmzadGaL/HBLbf3WdLgC29pgyhTjAT/0nuE=
+github.com/xuri/nfp v0.0.2-0.20250530014748-2ddeb826f9a9/go.mod h1:WwHg+CVyzlv/TX9xqBFXEZAuxOPxn2k1GNHwG41IIUQ=
+golang.org/x/crypto v0.48.0 h1:/VRzVqiRSggnhY7gNRxPauEQ5Drw9haKdM0jqfcCFts=
+golang.org/x/crypto v0.48.0/go.mod h1:r0kV5h3qnFPlQnBSrULhlsRfryS2pmewsg+XfMgkVos=
+golang.org/x/net v0.50.0 h1:ucWh9eiCGyDR3vtzso0WMQinm2Dnt8cFMuQa9K33J60=
+golang.org/x/net v0.50.0/go.mod h1:UgoSli3F/pBgdJBHCTc+tp3gmrU4XswgGRgtnwWTfyM=
+golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
+golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=

internal/version/version.go

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+package version
+
+var (
+	Version   = "dev"
+	Commit    = "none"
+	BuildDate = "unknown"
+)

magefiles/go.mod

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+module csv2excel/magefile
+
+go 1.25.0
+
+require github.com/magefile/mage v1.15.0 // indirect

magefiles/go.sum

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+github.com/magefile/mage v1.15.0 h1:BvGheCMAsG3bWUDbZ8AyXXpCNwU9u5CB6sM+HNb9HYg=
+github.com/magefile/mage v1.15.0/go.mod h1:z5UZb/iS3GoOSn0JgWuiw7dxlurVYTu+/jHXqQg881A=

magefiles/magefile.go

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+//go:build mage
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"github.com/magefile/mage/mg"
+	"github.com/magefile/mage/sh"
+)
+
+const binaryName = "csv2excel"
+
+func ldflags() (string, error) {
+	version, err := sh.Output("git", "describe", "--tags", "--always")
+	if err != nil {
+		version = "dev"
+	}
+	commit, err := sh.Output("git", "rev-parse", "--short", "HEAD")
+	if err != nil {
+		commit = "none"
+	}
+	buildDate, err := sh.Output("date", "-u", "+%Y-%m-%dT%H:%M:%SZ")
+	if err != nil {
+		buildDate = "unknown"
+	}
+	return fmt.Sprintf(
+		`-X csv2excel/internal/version.Version=%s -X csv2excel/internal/version.Commit=%s -X csv2excel/internal/version.BuildDate=%s`,
+		version, commit, buildDate,
+	), nil
+}
+
+// Build builds the binary for the current platform.
+func Build() error {
+	switch runtime.GOOS {
+	case "windows":
+		return BuildWindows()
+	default:
+		return BuildLinux()
+	}
+}
+
+// BuildLinux builds a static binary for Linux amd64.
+func BuildLinux() error {
+	mg.Deps(ensureDistDir)
+	flags, err := ldflags()
+	if err != nil {
+		return err
+	}
+	out := filepath.Join("dist", binaryName)
+	env := map[string]string{
+		"GOOS":        "linux",
+		"GOARCH":      "amd64",
+		"CGO_ENABLED": "0",
+	}
+	return sh.RunWithV(env, "go", "build", "-ldflags", flags, "-o", out, ".")
+}
+
+// BuildWindows builds a binary for Windows amd64.
+func BuildWindows() error {
+	mg.Deps(ensureDistDir)
+	flags, err := ldflags()
+	if err != nil {
+		return err
+	}
+	out := filepath.Join("dist", binaryName+".exe")
+	env := map[string]string{
+		"GOOS":        "windows",
+		"GOARCH":      "amd64",
+		"CGO_ENABLED": "0",
+	}
+	return sh.RunWithV(env, "go", "build", "-ldflags", flags, "-o", out, ".")
+}
+
+// Install installs the binary to $GOBIN or $GOPATH/bin.
+func Install() error {
+	fmt.Println("Installing", binaryName, "...")
+	flags, err := ldflags()
+	if err != nil {
+		return err
+	}
+	err = sh.RunV("go", "install", "-ldflags", flags, ".")
+	if err != nil {
+		return err
+	}
+	fmt.Println("Done.")
+	return nil
+}
+
+// Clean removes the dist/ directory.
+func Clean() error {
+	return sh.Rm("dist")
+}
+
+func ensureDistDir() error {
+	return os.MkdirAll("dist", 0o755)
+}

main.go

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+package main
+
+import (
+	"encoding/csv"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/xuri/excelize/v2"
+	"golang.org/x/text/encoding/charmap"
+	"golang.org/x/text/transform"
+)
+
+func main() {
+	sep := flag.String("sep", "auto", "Trennzeichen: auto, ',', ';', '\\t'")
+	enc := flag.String("enc", "utf8", "Encoding: utf8, windows1252")
+	out := flag.String("o", "output.xlsx", "Ausgabedatei")
+	flag.Parse()
+
+	files := flag.Args()
+	if len(files) == 0 {
+		fmt.Fprintln(os.Stderr, "Verwendung: csv2xlsx [flags] datei1.csv datei2.csv ...")
+		os.Exit(1)
+	}
+
+	fmt.Println(sep)
+	fmt.Println(enc)
+	fmt.Println(out)
+
+	xlsx := excelize.NewFile()
+	firstSheet := true
+
+	for _, path := range files {
+
+		sheetName := strings.TrimSuffix(filepath.Base(path), filepath.Ext(path))
+		// Excelize: max 31 Zeichen, keine Sonderzeichen
+		if len(sheetName) > 31 {
+			sheetName = sheetName[:31]
+		}
+
+		f, err := os.Open(path)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Fehler beim Öffnen %s: %v\n", path, err)
+			continue
+		}
+		defer f.Close()
+
+		var reader io.Reader = f
+		if *enc == "windows1252" {
+			reader = transform.NewReader(f, charmap.Windows1252.NewDecoder())
+		}
+
+		delimiter := detectDelimiter(path, *sep)
+
+		csvReader := csv.NewReader(reader)
+		csvReader.Comma = delimiter
+		csvReader.LazyQuotes = true // tolerant bei kaputten CSV-Dateien
+
+		if firstSheet {
+			xlsx.SetSheetName("Sheet1", sheetName)
+			firstSheet = false
+		} else {
+			xlsx.NewSheet(sheetName)
+		}
+
+		row := 1
+		for {
+			record, err := csvReader.Read()
+			if err == io.EOF {
+				break
+			}
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Warnung Zeile %d in %s: %v\n", row, path, err)
+				continue
+			}
+			for col, val := range record {
+				cell, _ := excelize.CoordinatesToCellName(col+1, row)
+				xlsx.SetCellValue(sheetName, cell, val)
+			}
+			row++
+		}
+		fmt.Printf("✓ %s → Reiter \"%s\" (%d Zeilen)\n", path, sheetName, row-1)
+	}
+
+	if err := xlsx.SaveAs(*out); err != nil {
+		fmt.Fprintf(os.Stderr, "Fehler beim Speichern: %v\n", err)
+		os.Exit(1)
+	}
+	fmt.Printf("✅ Gespeichert: %s\n", *out)
+
+}
+
+func detectDelimiter(path, hint string) rune {
+	switch hint {
+	case ";":
+		return ';'
+	case "\t":
+		return '\t'
+	case ",":
+		return ','
+	}
+	// auto-detect: erste Zeile lesen und zählen
+	f, err := os.Open(path)
+	if err != nil {
+		return ';'
+	}
+	defer f.Close()
+	buf := make([]byte, 4096)
+	n, _ := f.Read(buf)
+	line := string(buf[:n])
+	if idx := strings.Index(line, "\n"); idx > 0 {
+		line = line[:idx]
+	}
+	sc := strings.Count(line, ";")
+	cc := strings.Count(line, ",")
+	tc := strings.Count(line, "\t")
+	if tc >= sc && tc >= cc {
+		return '\t'
+	}
+	if sc >= cc {
+		return ';'
+	}
+	return ','
+}