refactored for maintainability

internal/validation/validation.go

@@ -0,0 +1,93 @@
+// Package validation provides utilities for parsing and validating request data
+package validation
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"git.haelnorr.com/h/golib/hws"
+	"git.haelnorr.com/h/oslstats/internal/notify"
+	"git.haelnorr.com/h/oslstats/internal/throw"
+	"git.haelnorr.com/h/timefmt"
+)
+
+type ValidationRule struct {
+	Condition bool   // Condition on which to fail validation
+	Title     string // Title for warning message
+	Message   string // Warning message
+}
+
+// Getter abstracts getting values from either form or query
+type Getter interface {
+	Get(key string) string
+	AddCheck(check *ValidationRule)
+	String(key string) *StringField
+	Int(key string) *IntField
+	Time(key string, format *timefmt.Format) *TimeField
+	ValidateChecks() []*ValidationRule
+	Validate() bool
+	ValidateAndNotify(s *hws.Server, w http.ResponseWriter, r *http.Request) bool
+	ValidateAndError(s *hws.Server, w http.ResponseWriter, r *http.Request) bool
+
+	getChecks() []*ValidationRule
+}
+type Field struct {
+	Key      string
+	optional bool
+	getter   Getter
+}
+
+func newField(key string, g Getter) Field {
+	return Field{
+		Key:    key,
+		getter: g,
+	}
+}
+
+func newFailedCheck(title, message string) *ValidationRule {
+	return &ValidationRule{
+		Condition: true,
+		Title:     title,
+		Message:   message,
+	}
+}
+
+func validate(g Getter) []*ValidationRule {
+	failed := []*ValidationRule{}
+	for _, check := range g.getChecks() {
+		if check != nil && check.Condition {
+			failed = append(failed, check)
+		}
+	}
+	return failed
+}
+
+func validateAndNotify(
+	s *hws.Server,
+	w http.ResponseWriter,
+	r *http.Request,
+	g Getter,
+) bool {
+	failedChecks := g.ValidateChecks()
+	for _, check := range failedChecks {
+		notify.Warn(s, w, r, check.Title, check.Message, nil)
+	}
+	return len(failedChecks) == 0
+}
+
+func validateAndError(
+	s *hws.Server,
+	w http.ResponseWriter,
+	r *http.Request,
+	g Getter,
+) bool {
+	failedChecks := g.ValidateChecks()
+	var err error
+	for _, check := range failedChecks {
+		err_ := fmt.Errorf("%s: %s", check.Title, check.Message)
+		err = errors.Join(err, err_)
+	}
+	throw.BadRequest(s, w, r, "Invalid form data", err)
+	return len(failedChecks) == 0
+}