From 53cae5ebe67adb8ee7f4011efbc3432527bde800 Mon Sep 17 00:00:00 2001
From: Fred Boniface <fred@fjla.uk>
Date: Fri, 1 Sep 2023 19:08:59 +0100
Subject: [PATCH] Init

---
 go.mod                 |  3 ++
 validation/charsets.go | 11 ++++++
 validation/rules.go    | 89 ++++++++++++++++++++++++++++++++++++++++++
 validation/validate.go | 28 +++++++++++++
 4 files changed, 131 insertions(+)
 create mode 100644 go.mod
 create mode 100644 validation/charsets.go
 create mode 100644 validation/rules.go
 create mode 100644 validation/validate.go

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..a82281d
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.fjla.uk/fred.boniface/barcodes
+
+go 1.19
diff --git a/validation/charsets.go b/validation/charsets.go
new file mode 100644
index 0000000..6dd485b
--- /dev/null
+++ b/validation/charsets.go
@@ -0,0 +1,11 @@
+package validation
+
+import "regexp"
+
+var (
+	ASCII    = regexp.MustCompile(`^[\x00-\x7F]+$`)
+	ANY      = regexp.MustCompile(`.`)
+	CODE39   = regexp.MustCompile(`^[0-9A-Z\-\.\ $%*+/]+$`)
+	NUMERAL  = regexp.MustCompile(`^[0-9]+$`)
+	ISO88591 = regexp.MustCompile(`^[\x00-\xFF]+$`)
+)
diff --git a/validation/rules.go b/validation/rules.go
new file mode 100644
index 0000000..48e99b7
--- /dev/null
+++ b/validation/rules.go
@@ -0,0 +1,89 @@
+package validation
+
+import "regexp"
+
+// This needs to be a map of structs
+
+type rule struct {
+	minLength uint64
+	maxLength uint64
+	charset   regexp.Regexp
+	divisible uint8
+}
+
+var aztec = rule{
+	minLength: 1,
+	maxLength: 3067,
+	charset:   *ANY,
+	divisible: 1,
+}
+
+var code39 = rule{
+	minLength: 1,
+	maxLength: 80,
+	charset:   *CODE39,
+	divisible: 1,
+}
+
+var code128 = rule{
+	minLength: 1,
+	maxLength: 80,
+	charset:   *ASCII,
+	divisible: 1,
+}
+
+var datamatrix = rule{
+	minLength: 1,
+	maxLength: 2335,
+	charset:   *ANY,
+	divisible: 1,
+}
+
+var ean8 = rule{
+	minLength: 7,
+	maxLength: 7,
+	charset:   *NUMERAL,
+	divisible: 1,
+}
+
+var ean13 = rule{
+	minLength: 12,
+	maxLength: 12,
+	charset:   *NUMERAL,
+	divisible: 1,
+}
+
+var ean14 = rule{
+	minLength: 2,
+	maxLength: 80,
+	charset:   *NUMERAL,
+	divisible: 2,
+}
+
+var pdf417 = rule{
+	minLength: 1,
+	maxLength: 1100,
+	charset:   *ANY,
+	divisible: 1,
+}
+
+var pzn7 = rule{
+	minLength: 7,
+	maxLength: 7,
+	charset:   *NUMERAL,
+	divisible: 1,
+}
+
+var qr = rule{
+	minLength: 1,
+	maxLength: 4296,
+	charset:   *ISO88591,
+	divisible: 1,
+}
+
+var upca = rule{
+	minLength: 11,
+	maxLength: 11,
+	charset:   *NUMERAL,
+	divisible: 1,
+}
diff --git a/validation/validate.go b/validation/validate.go
new file mode 100644
index 0000000..ca73a82
--- /dev/null
+++ b/validation/validate.go
@@ -0,0 +1,28 @@
+package validation
+
+import "fmt"
+
+func Validate(input string, format string) bool {
+	rule, exists := barcodeRules[format]
+	if !exists {
+		fmt.Printf("Error: No rule found for format '%s'\n", format)
+		return false
+	}
+
+	if uint64(len(input)) < rule.minLength || uint64(len(input)) > rule.maxLength {
+		fmt.Printf("Validation Error: Length must be between %d and %d\n", rule.minLength, rule.maxLength)
+		return false
+	}
+
+	if !rule.charset.MatchString(input) {
+		fmt.Println("Validation Error: Contains illegal characters")
+		return false
+	}
+
+	if uint64(len(input))%uint64(rule.divisible) != 0 {
+		fmt.Printf("Validation Error: Length must be a multiple of %d", rule.divisible)
+		return false
+	}
+
+	return true
+}