feat: add BVK exchange library

validation.go

@@ -0,0 +1,88 @@
+package mila
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"unicode/utf8"
+)
+
+type Config struct {
+	MaxRouteLen    int
+	MaxTextLen     int
+	MaxTemplateLen int
+}
+
+func DefaultConfig() Config {
+	return Config{
+		MaxRouteLen:    3,
+		MaxTextLen:     200,
+		MaxTemplateLen: 200,
+	}
+}
+
+type ValidationError struct {
+	Field string `json:"field"`
+	Msg   string `json:"message"`
+}
+
+func (e ValidationError) Error() string {
+	return fmt.Sprintf("%s: %s", e.Field, e.Msg)
+}
+
+func Validate(cfg Config, state ContentState) error {
+	cfg = normalizeConfig(cfg)
+
+	state.Route = strings.TrimSpace(state.Route)
+	state.Template = strings.TrimSpace(state.Template)
+
+	if state.Route == "" {
+		return ValidationError{Field: "route", Msg: "is required"}
+	}
+	if runeLen(state.Route) > cfg.MaxRouteLen {
+		return ValidationError{Field: "route", Msg: fmt.Sprintf("must be at most %d characters", cfg.MaxRouteLen)}
+	}
+	if !utf8.ValidString(state.Route) {
+		return ValidationError{Field: "route", Msg: "must be valid UTF-8"}
+	}
+	if !utf8.ValidString(state.Text) {
+		return ValidationError{Field: "str", Msg: "must be valid UTF-8"}
+	}
+	if runeLen(state.Text) > cfg.MaxTextLen {
+		return ValidationError{Field: "str", Msg: fmt.Sprintf("must be at most %d characters", cfg.MaxTextLen)}
+	}
+	if state.Template == "" {
+		return ValidationError{Field: "tpl_name", Msg: "is required"}
+	}
+	if !utf8.ValidString(state.Template) {
+		return ValidationError{Field: "tpl_name", Msg: "must be valid UTF-8"}
+	}
+	if runeLen(state.Template) > cfg.MaxTemplateLen {
+		return ValidationError{Field: "tpl_name", Msg: fmt.Sprintf("must be at most %d characters", cfg.MaxTemplateLen)}
+	}
+
+	return nil
+}
+
+func IsValidationError(err error) bool {
+	var target ValidationError
+	return errors.As(err, &target)
+}
+
+func normalizeConfig(cfg Config) Config {
+	def := DefaultConfig()
+	if cfg.MaxRouteLen <= 0 {
+		cfg.MaxRouteLen = def.MaxRouteLen
+	}
+	if cfg.MaxTextLen <= 0 {
+		cfg.MaxTextLen = def.MaxTextLen
+	}
+	if cfg.MaxTemplateLen <= 0 {
+		cfg.MaxTemplateLen = def.MaxTemplateLen
+	}
+	return cfg
+}
+
+func runeLen(s string) int {
+	return utf8.RuneCountInString(s)
+}