iotlcm/internal/service/export_xlsx.go

package service

import (
	"archive/zip"
	"bytes"
	"encoding/xml"
	"fmt"
	"strconv"
	"strings"
)

func exportInboundCardsXLSX(cards []SIMCard) ([]byte, error) {
	var buf bytes.Buffer
	zw := zip.NewWriter(&buf)
	files := map[string]string{
		"[Content_Types].xml":        contentTypesXML,
		"_rels/.rels":                rootRelsXML,
		"xl/workbook.xml":            workbookXML,
		"xl/_rels/workbook.xml.rels": workbookRelsXML,
		"xl/sharedStrings.xml":       sharedStringsXML(),
		"xl/styles.xml":              stylesXML,
		"xl/worksheets/sheet1.xml":   sheetXML(cards),
	}
	for _, name := range []string{"[Content_Types].xml", "_rels/.rels", "xl/workbook.xml", "xl/_rels/workbook.xml.rels", "xl/sharedStrings.xml", "xl/styles.xml", "xl/worksheets/sheet1.xml"} {
		w, err := zw.Create(name)
		if err != nil {
			return nil, err
		}
		if _, err := w.Write([]byte(files[name])); err != nil {
			return nil, err
		}
	}
	if err := zw.Close(); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

func sheetXML(cards []SIMCard) string {
	var b strings.Builder
	b.WriteString(`<?xml version="1.0" encoding="UTF-8" standalone="yes"?>`)
	b.WriteString(`<worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">`)
	b.WriteString(`<dimension ref="A1:R`)
	b.WriteString(strconv.Itoa(len(cards) + 1))
	b.WriteString(`"/><sheetViews><sheetView tabSelected="true" workbookViewId="0"/></sheetViews>`)
	b.WriteString(`<sheetFormatPr defaultRowHeight="15"/><cols><col min="1" max="18" width="9.140625" style="1"/></cols><sheetData>`)
	writeSharedStringRow(&b, 1, len(inboundExportHeaders))
	for i, card := range cards {
		row := inboundExportRow(card)
		values := make([]string, 0, len(inboundExportColumns))
		for _, column := range inboundExportColumns {
			values = append(values, row[column.Key])
		}
		writeSheetRow(&b, i+2, values)
	}
	b.WriteString(`</sheetData></worksheet>`)
	return b.String()
}

func writeSharedStringRow(b *strings.Builder, rowNum, count int) {
	b.WriteString(`<row r="`)
	b.WriteString(strconv.Itoa(rowNum))
	b.WriteString(`">`)
	for i := 0; i < count; i++ {
		ref := fmt.Sprintf("%s%d", columnName(i+1), rowNum)
		b.WriteString(`<c r="`)
		b.WriteString(ref)
		b.WriteString(`" s="1" t="s"><v>`)
		b.WriteString(strconv.Itoa(i))
		b.WriteString(`</v></c>`)
	}
	b.WriteString(`</row>`)
}

func writeSheetRow(b *strings.Builder, rowNum int, values []string) {
	b.WriteString(`<row r="`)
	b.WriteString(strconv.Itoa(rowNum))
	b.WriteString(`">`)
	for i, value := range values {
		ref := fmt.Sprintf("%s%d", columnName(i+1), rowNum)
		b.WriteString(`<c r="`)
		b.WriteString(ref)
		b.WriteString(`" s="1" t="inlineStr"><is><t>`)
		b.WriteString(xmlEscape(value))
		b.WriteString(`</t></is></c>`)
	}
	b.WriteString(`</row>`)
}

func sharedStringsXML() string {
	var b strings.Builder
	b.WriteString(`<?xml version="1.0" encoding="UTF-8" standalone="yes"?>`)
	b.WriteString(`<sst xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" count="`)
	b.WriteString(strconv.Itoa(len(inboundExportHeaders)))
	b.WriteString(`" uniqueCount="`)
	b.WriteString(strconv.Itoa(len(inboundExportHeaders)))
	b.WriteString(`">`)
	for _, header := range inboundExportHeaders {
		b.WriteString(`<si><t>`)
		b.WriteString(xmlEscape(header))
		b.WriteString(`</t></si>`)
	}
	b.WriteString(`</sst>`)
	return b.String()
}

func columnName(index int) string {
	var out []byte
	for index > 0 {
		index--
		out = append([]byte{byte('A' + index%26)}, out...)
		index /= 26
	}
	return string(out)
}

func xmlEscape(value string) string {
	var b strings.Builder
	_ = xml.EscapeText(&b, []byte(value))
	return b.String()
}

const contentTypesXML = `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">
  <Default Extension="rels" ContentType="application/vnd.openxmlformats-package.relationships+xml"/>
  <Default Extension="xml" ContentType="application/xml"/>
  <Override PartName="/xl/workbook.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml"/>
  <Override PartName="/xl/worksheets/sheet1.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml"/>
  <Override PartName="/xl/sharedStrings.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.sharedStrings+xml"/>
  <Override PartName="/xl/styles.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.styles+xml"/>
</Types>`

const rootRelsXML = `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">
  <Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="xl/workbook.xml"/>
</Relationships>`

const workbookXML = `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<workbook xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships">
  <sheets>
    <sheet name="Sheet1" sheetId="1" r:id="rId1"/>
  </sheets>
</workbook>`

const workbookRelsXML = `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">
  <Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet" Target="worksheets/sheet1.xml"/>
  <Relationship Id="rId2" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles" Target="styles.xml"/>
  <Relationship Id="rId3" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/sharedStrings" Target="sharedStrings.xml"/>
</Relationships>`

const stylesXML = `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<styleSheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">
  <fonts count="1"><font><sz val="11"/><color theme="1"/><name val="Calibri"/><family val="2"/></font></fonts>
  <fills count="2"><fill><patternFill patternType="none"/></fill><fill><patternFill patternType="gray125"/></fill></fills>
  <borders count="1"><border><left/><right/><top/><bottom/><diagonal/></border></borders>
  <cellStyleXfs count="1"><xf numFmtId="0" fontId="0" fillId="0" borderId="0"/></cellStyleXfs>
  <cellXfs count="2"><xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0"/><xf numFmtId="49" fontId="0" fillId="0" borderId="0" xfId="0" applyNumberFormat="1"/></cellXfs>
  <cellStyles count="1"><cellStyle name="Normal" xfId="0" builtinId="0"/></cellStyles>
  <dxfs count="0"/><tableStyles count="0" defaultPivotStyle="PivotStyleLight16" defaultTableStyle="TableStyleMedium2"/>
</styleSheet>`