initial commit

Author: asonnleitner

.gitignore

@@ -0,0 +1,35 @@
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+.idea/**/contentModel.xml
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+.idea/**/gradle.xml
+.idea/**/libraries
+cmake-build-*/
+.idea/**/mongoSettings.xml
+*.iws
+out/
+.idea_modules/
+atlassian-ide-plugin.xml
+.idea/replstate.xml
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+.idea/httpRequests
+.idea/caches/build_file_checksums.ser
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+*.test
+*.out

.idea/.gitignore

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+module github.com/asonnleitner/qr-payment
+
+go 1.17

.idea/codeStyles/Project.xml

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+package iban
+
+import (
+	"fmt"
+	"github.com/asonnleitner/qr-payment/utils"
+	"regexp"
+	"strings"
+)
+
+const (
+	errInvalidAccountNumber    = "Invalid account number"
+	errCountryCodeNotSupported = "Country code not supported"
+)
+
+var (
+	czechBankAccountPattern = regexp.MustCompile(`^([0-9]{2,6}-)?([0-9]{2,10}/)([0-9]{4})$`)
+	lettersPattern          = regexp.MustCompile(`[A-Z]`)
+)
+
+func ParseAccount(account, country string) string {
+	var pattern *regexp.Regexp
+	country = strings.ToUpper(country)
+	account = strings.Replace(account, " ", "", -1)
+
+	switch country {
+	case "CZ":
+		pattern = czechBankAccountPattern
+	default:
+		panic(errCountryCodeNotSupported)
+	}
+
+	prefix, number, bankCode := splitAccount(account, pattern)
+
+	return convertToIBAN(country, prefix, number, bankCode)
+}
+
+func convertToIBAN(country, prefix, number, bankCode string) string {
+	var bban string
+
+	if country == "CZ" {
+		bban = bankCode + prefix + number
+	} else {
+		panic(errCountryCodeNotSupported)
+	}
+
+	checksum := calculateChecksum(country, bban)
+
+	return fmt.Sprintf("%s%s%s", country, checksum, bban)
+}
+
+func calculateChecksum(country, bban string) string {
+	bban = bban + country + "00"
+
+	return fmt.Sprintf("%02d", 98-utils.Modulo(
+		replaceLetters(bban), 97,
+	))
+}
+
+func splitAccount(account string, pattern *regexp.Regexp) (prefix, number, bankCode string) {
+	account = strings.TrimSpace(account)
+
+	if !strings.Contains(account, "-") {
+		account = "00-" + account
+	}
+
+	if len(account) < 10 || len(account) > 22 {
+		panic(errInvalidAccountNumber)
+	}
+
+	parts := pattern.FindStringSubmatch(account)
+
+	prefix = utils.Padding(
+		strings.Replace(parts[1], "-", "", -1), 6, "0", utils.PaddingLeft,
+	)
+	number = utils.Padding(
+		strings.Replace(parts[2], "/", "", -1), 10, "0", utils.PaddingLeft,
+	)
+	bankCode = parts[3]
+	return
+}
+
+func replaceLetters(iban string) string {
+	letters := lettersPattern.FindAllString(iban, -1)
+
+	for i := 0; i < len(letters); i++ {
+		iban = strings.Replace(iban, letters[i], fmt.Sprintf("%d", letters[i][0]-'A'+10), -1)
+	}
+
+	return iban
+}

.idea/codeStyles/codeStyleConfig.xml

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+package main
+
+import (
+	"fmt"
+	"github.com/asonnleitner/qr-payment/iban"
+)
+
+func main() {
+	IBAN := iban.ParseAccount("2171532/0800", "CZ")
+
+	fmt.Println(IBAN)
+}

.idea/misc.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="Go" enabled="true" />
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/modules.xml

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+package utils
+
+import "strings"
+
+const PaddingLeft = "left"
+const PaddingRight = "right"
+
+func Padding(input string, length int, char string, direction string) string {
+	if len(input) >= length {
+		return input
+	}
+
+	if direction == "left" {
+		return strings.Repeat(char, length-len(input)) + input
+	} else if direction == "right" {
+		return input + strings.Repeat(char, length-len(input))
+	} else {
+		return input
+	}
+}
+
+func Modulo(dividend string, divisor int) int {
+	var remainder int
+
+	for i := 0; i < len(dividend); i++ {
+		remainder = (remainder*10 + int(dividend[i]-'0')) % divisor
+	}
+
+	return remainder
+}