From f617a78c6c7f8f6ffce9e4a0ddeaafd4422bf51a Mon Sep 17 00:00:00 2001
From: Nikolai Papin <nikolai@weirdcat.ru>
Date: Mon, 24 Nov 2025 22:15:01 +0300
Subject: [PATCH] feat: link validator

---
 src/cmd/main.go                             |  2 +
 src/internal/linkvalidator/linkvalidator.go | 88 +++++++++++++++++++++
 src/internal/validator/validator.go         | 20 -----
 3 files changed, 90 insertions(+), 20 deletions(-)
 create mode 100644 src/internal/linkvalidator/linkvalidator.go
 delete mode 100644 src/internal/validator/validator.go

diff --git a/src/cmd/main.go b/src/cmd/main.go
index e4e9f34..1bf2699 100644
--- a/src/cmd/main.go
+++ b/src/cmd/main.go
@@ -21,6 +21,7 @@ package main
 
 import (
 	"git.weirdcat.su/weirdcat/auto-attendance/internal/config"
+	"git.weirdcat.su/weirdcat/auto-attendance/internal/linkvalidator"
 	"git.weirdcat.su/weirdcat/auto-attendance/internal/logger"
 	"go.uber.org/fx"
 )
@@ -30,6 +31,7 @@ func main() {
 		fx.Provide(
 			config.NewConfig,
 			logger.NewLogger,
+			linkvalidator.NewLinkValidator,
 		),
 		fx.Invoke(func(log *logger.Logger) {
 			log.Info("Starting application...");
diff --git a/src/internal/linkvalidator/linkvalidator.go b/src/internal/linkvalidator/linkvalidator.go
new file mode 100644
index 0000000..b4e8173
--- /dev/null
+++ b/src/internal/linkvalidator/linkvalidator.go
@@ -0,0 +1,88 @@
+// Copyright (c) 2025 Nikolai Papin
+//
+// This file is part of the Auto Attendance app that looks for
+// self-attend QR-codes during lectures and opens their URLs in your
+// browser.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+// the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package linkvalidator
+
+import (
+	"net/url"
+	"strings"
+
+	"git.weirdcat.su/weirdcat/auto-attendance/internal/config"
+	"git.weirdcat.su/weirdcat/auto-attendance/internal/logger"
+)
+
+type LinkValidator interface {
+	ValidateLink(string) (token string, ok bool)
+}
+
+type linkValidatorImpl struct {
+	config *config.Config
+	log    *logger.Logger
+}
+
+// ValidateLink implements LinkValidator.
+func (v *linkValidatorImpl) ValidateLink(rawURL string) (token string, ok bool) {
+	if rawURL == "" {
+		v.log.Debug("Empty URL provided for validation")
+		return "", false
+	}
+
+	parsedURL, err := url.Parse(rawURL)
+	if err != nil {
+		v.log.Debug("Failed to parse URL", "url", rawURL, "error", err)
+		return "", false
+	}
+
+	if v.config.Communication.QrUrl != "" {
+		expectedURL, err := url.Parse(v.config.Communication.QrUrl)
+		if err == nil {
+			if parsedURL.Scheme != expectedURL.Scheme || 
+			   parsedURL.Host != expectedURL.Host || 
+			   parsedURL.Path != expectedURL.Path {
+				v.log.Debug("URL doesn't match configured QR URL pattern", 
+					"url", rawURL, "expected", v.config.Communication.QrUrl)
+				return "", false
+			}
+		}
+	}
+
+	if v.config.Communication.ApiSelfApproveMethod != "" {
+		if !strings.Contains(parsedURL.Path, v.config.Communication.ApiSelfApproveMethod) {
+			v.log.Debug("URL doesn't contain expected API method", 
+				"url", parsedURL.Path, "expected", v.config.Communication.ApiSelfApproveMethod)
+			return "", false
+		}
+	}
+
+	token = parsedURL.Query().Get("token")
+	if token == "" {
+		v.log.Debug("URL missing token parameter", "url", rawURL)
+		return "", false
+	}
+
+	v.log.Debug("URL validation successful", "url", rawURL)
+	return token, true
+}
+
+func NewLinkValidator(config *config.Config, log *logger.Logger) LinkValidator {
+	return &linkValidatorImpl{
+		config: config,
+		log:    log,
+	}
+}
diff --git a/src/internal/validator/validator.go b/src/internal/validator/validator.go
deleted file mode 100644
index e72b1ee..0000000
--- a/src/internal/validator/validator.go
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright (c) 2025 Nikolai Papin
-//
-// This file is part of the Auto Attendance app that looks for
-// self-attend QR-codes during lectures and opens their URLs in your 
-// browser.
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
-// the GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-package validator