1 files changed, 496 insertions, 0 deletions
diff --git a/internal/html_test.go b/internal/html_test.go
new file mode 100644
index 0000000..b22eea4
--- /dev/null
+++ b/internal/html_test.go
@@ -0,0 +1,496 @@
+package internal
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+// TestHtmlStatusBadge tests the htmlStatusBadge function.
+func TestHtmlStatusBadge(t *testing.T) {
+	tests := []struct {
+		status   nagiosCode
+		expected string
+	}{
+		{nagiosOk, `<span class="OK">OK</span>`},
+		{nagiosWarning, `<span class="WARNING">WARNING</span>`},
+		{nagiosCritical, `<span class="CRITICAL">CRITICAL</span>`},
+		{nagiosUnknown, `<span class="UNKNOWN">UNKNOWN</span>`},
+	}
+
+	for _, tt := range tests {
+		result := htmlStatusBadge(tt.status)
+		if result != tt.expected {
+			t.Errorf("htmlStatusBadge(%v) = %q, want %q", tt.status, result, tt.expected)
+		}
+	}
+}
+
+// TestHtmlHeader tests the htmlHeader function.
+func TestHtmlHeader(t *testing.T) {
+	subject := "GOGIOS Report [C:1 W:2 U:3 S:4 OK:5]"
+	result := htmlHeader(subject, 1, 2, 3, 4, 5)
+
+	// Check that the header contains expected elements
+	expectedElements := []string{
+		"<!DOCTYPE html>",
+		`<html lang="en">`,
+		"<head>",
+		`<meta charset="UTF-8">`,
+		`<meta name="viewport"`,
+		"<title>",
+		subject,
+		`<meta http-equiv="refresh" content="300">`,
+		"<style>",
+		".CRITICAL { color: #dc3545; }",
+		".WARNING { color: #ff8c00; }",
+		"Gogios Status Report",
+		"C:1 W:2 U:3 S:4 OK:5",
+		"Last Updated:",
+	}
+
+	for _, elem := range expectedElements {
+		if !strings.Contains(result, elem) {
+			t.Errorf("htmlHeader() missing expected element: %q", elem)
+		}
+	}
+}
+
+// TestHtmlFooter tests the htmlFooter function.
+func TestHtmlFooter(t *testing.T) {
+	result := htmlFooter()
+
+	expectedElements := []string{
+		"Generated by Gogios at",
+		"</div>",
+		"</body>",
+		"</html>",
+	}
+
+	for _, elem := range expectedElements {
+		if !strings.Contains(result, elem) {
+			t.Errorf("htmlFooter() missing expected element: %q", elem)
+		}
+	}
+}
+
+// TestHtmlReportBy tests the htmlReportBy method with various filters.
+func TestHtmlReportBy(t *testing.T) {
+	now := time.Now().Unix()
+	staleEpoch := now - 7200 // 2 hours ago
+
+	s := state{
+		staleEpoch: staleEpoch,
+		checks: map[string]checkState{
+			"check1": {
+				Status:     nagiosCritical,
+				PrevStatus: nagiosOk,
+				Epoch:      now,
+				output:     "Service is down",
+			},
+			"check2": {
+				Status:     nagiosWarning,
+				PrevStatus: nagiosWarning,
+				Epoch:      now,
+				output:     "High load",
+			},
+			"check3": {
+				Status:     nagiosOk,
+				PrevStatus: nagiosOk,
+				Epoch:      staleEpoch - 100, // stale
+				output:     "All good",
+			},
+		},
+	}
+
+	// Test critical filter
+	var sb strings.Builder
+	count := s.htmlReportBy(&sb, false, false, func(cs checkState) bool {
+		return cs.Status == nagiosCritical
+	})
+
+	if count != 1 {
+		t.Errorf("htmlReportBy(critical filter) count = %d, want 1", count)
+	}
+
+	result := sb.String()
+	if !strings.Contains(result, "check1") {
+		t.Error("htmlReportBy(critical filter) missing check1")
+	}
+	if !strings.Contains(result, "Service is down") {
+		t.Error("htmlReportBy(critical filter) missing output text")
+	}
+	if !strings.Contains(result, "CRITICAL") {
+		t.Error("htmlReportBy(critical filter) missing CRITICAL status")
+	}
+
+	// Test status change filter
+	sb.Reset()
+	count = s.htmlReportBy(&sb, true, false, func(cs checkState) bool {
+		return cs.Status == nagiosCritical && cs.changed()
+	})
+
+	if count != 1 {
+		t.Errorf("htmlReportBy(changed filter) count = %d, want 1", count)
+	}
+
+	result = sb.String()
+	if !strings.Contains(result, "→") {
+		t.Error("htmlReportBy(changed filter) missing status change arrow")
+	}
+	if !strings.Contains(result, "OK") {
+		t.Error("htmlReportBy(changed filter) missing previous OK status")
+	}
+}
+
+// TestHtmlReportChanged tests the htmlReportChanged method.
+func TestHtmlReportChanged(t *testing.T) {
+	now := time.Now().Unix()
+
+	s := state{
+		staleEpoch: now - 3600,
+		checks: map[string]checkState{
+			"check1": {
+				Status:     nagiosCritical,
+				PrevStatus: nagiosOk,
+				Epoch:      now,
+				output:     "Service failed",
+			},
+			"check2": {
+				Status:     nagiosOk,
+				PrevStatus: nagiosOk,
+				Epoch:      now,
+				output:     "Still OK",
+			},
+		},
+	}
+
+	var sb strings.Builder
+	changed := s.htmlReportChanged(&sb)
+
+	if !changed {
+		t.Error("htmlReportChanged() returned false, want true")
+	}
+
+	result := sb.String()
+	if !strings.Contains(result, "check1") {
+		t.Error("htmlReportChanged() missing changed check")
+	}
+	if strings.Contains(result, "check2") {
+		t.Error("htmlReportChanged() should not include unchanged check")
+	}
+}
+
+// TestHtmlReport tests the complete HTML report generation.
+func TestHtmlReport(t *testing.T) {
+	now := time.Now().Unix()
+	staleEpoch := now - 3600
+
+	s := state{
+		staleEpoch: staleEpoch,
+		checks: map[string]checkState{
+			"critical_check": {
+				Status:     nagiosCritical,
+				PrevStatus: nagiosOk,
+				Epoch:      now,
+				output:     "Service is down",
+			},
+			"warning_check": {
+				Status:     nagiosWarning,
+				PrevStatus: nagiosWarning,
+				Epoch:      now,
+				output:     "High CPU usage",
+			},
+			"ok_check": {
+				Status:     nagiosOk,
+				PrevStatus: nagiosOk,
+				Epoch:      now,
+				output:     "Everything fine",
+			},
+			"stale_check": {
+				Status:     nagiosOk,
+				PrevStatus: nagiosOk,
+				Epoch:      staleEpoch - 100,
+				output:     "Not updated recently",
+			},
+		},
+	}
+
+	subject := "GOGIOS Report [C:1 W:1 U:0 S:1 OK:2]"
+	result := s.htmlReport(subject)
+
+	// Check that all major sections are present
+	expectedSections := []string{
+		"<!DOCTYPE html>",
+		"Gogios Status Report",
+		"Alerts with status changed",
+		"Unhandled alerts",
+		"Stale alerts",
+		"Generated by Gogios",
+		"</html>",
+	}
+
+	for _, section := range expectedSections {
+		if !strings.Contains(result, section) {
+			t.Errorf("htmlReport() missing section: %q", section)
+		}
+	}
+
+	// Check that check names appear
+	if !strings.Contains(result, "critical_check") {
+		t.Error("htmlReport() missing critical_check")
+	}
+	if !strings.Contains(result, "warning_check") {
+		t.Error("htmlReport() missing warning_check")
+	}
+
+	// Check status summary
+	if !strings.Contains(result, "C:1 W:1 U:0 S:1 OK:2") {
+		t.Error("htmlReport() missing correct status summary")
+	}
+}
+
+// TestHtmlEscaping tests that HTML special characters are properly escaped.
+func TestHtmlEscaping(t *testing.T) {
+	now := time.Now().Unix()
+
+	s := state{
+		staleEpoch: now - 3600,
+		checks: map[string]checkState{
+			"<script>alert('xss')</script>": {
+				Status:     nagiosCritical,
+				PrevStatus: nagiosOk,
+				Epoch:      now,
+				output:     "Output with <tags> & \"quotes\"",
+			},
+		},
+	}
+
+	var sb strings.Builder
+	s.htmlReportBy(&sb, false, false, func(cs checkState) bool {
+		return cs.Status == nagiosCritical
+	})
+
+	result := sb.String()
+
+	// Check that HTML is escaped
+	if strings.Contains(result, "<script>") {
+		t.Error("htmlReportBy() did not escape <script> tag in check name")
+	}
+	if !strings.Contains(result, "&lt;script&gt;") {
+		t.Error("htmlReportBy() missing escaped <script> tag")
+	}
+	if strings.Contains(result, "<tags>") && !strings.Contains(result, "&lt;tags&gt;") {
+		t.Error("htmlReportBy() did not escape <tags> in output")
+	}
+}
+
+// TestPersistHTMLReport tests the file creation and atomic write.
+func TestPersistHTMLReport(t *testing.T) {
+	// Create a temporary directory for testing
+	tmpDir := t.TempDir()
+	htmlFile := filepath.Join(tmpDir, "subdir", "status.html")
+
+	conf := config{
+		HTMLStatusFile: htmlFile,
+	}
+
+	now := time.Now().Unix()
+	s := state{
+		staleEpoch: now - 3600,
+		checks: map[string]checkState{
+			"test_check": {
+				Status:     nagiosCritical,
+				PrevStatus: nagiosOk,
+				Epoch:      now,
+				output:     "Test output",
+			},
+		},
+	}
+
+	subject := "GOGIOS Report [C:1 W:0 U:0 S:0 OK:0]"
+
+	// Test that the function creates the directory and file
+	err := persistHTMLReport(s, subject, conf)
+	if err != nil {
+		t.Fatalf("persistHTMLReport() error = %v", err)
+	}
+
+	// Check that the file was created
+	if _, err := os.Stat(htmlFile); os.IsNotExist(err) {
+		t.Error("persistHTMLReport() did not create the HTML file")
+	}
+
+	// Check that the temp file was removed
+	tmpFile := htmlFile + ".tmp"
+	if _, err := os.Stat(tmpFile); !os.IsNotExist(err) {
+		t.Error("persistHTMLReport() did not clean up temporary file")
+	}
+
+	// Read and verify the content
+	content, err := os.ReadFile(htmlFile)
+	if err != nil {
+		t.Fatalf("Failed to read HTML file: %v", err)
+	}
+
+	contentStr := string(content)
+	if !strings.Contains(contentStr, "<!DOCTYPE html>") {
+		t.Error("HTML file missing DOCTYPE declaration")
+	}
+	if !strings.Contains(contentStr, "test_check") {
+		t.Error("HTML file missing test check")
+	}
+	if !strings.Contains(contentStr, "Test output") {
+		t.Error("HTML file missing check output")
+	}
+	if !strings.Contains(contentStr, "C:1 W:0 U:0 S:0 OK:0") {
+		t.Error("HTML file missing status summary")
+	}
+}
+
+// TestFederatedChecks tests HTML generation for federated checks.
+func TestFederatedChecks(t *testing.T) {
+	now := time.Now().Unix()
+
+	s := state{
+		staleEpoch: now - 3600,
+		checks: map[string]checkState{
+			"remote_check": {
+				Status:        nagiosCritical,
+				PrevStatus:    nagiosOk,
+				Epoch:         now,
+				output:        "Remote service down",
+				federatedFrom: "remote.example.com",
+			},
+		},
+	}
+
+	var sb strings.Builder
+	s.htmlReportBy(&sb, false, false, func(cs checkState) bool {
+		return cs.Status == nagiosCritical
+	})
+
+	result := sb.String()
+
+	if !strings.Contains(result, "federated from") {
+		t.Error("htmlReportBy() missing federated indicator")
+	}
+	if !strings.Contains(result, "remote.example.com") {
+		t.Error("htmlReportBy() missing federated hostname")
+	}
+}
+
+// TestW3CCompliance tests that generated HTML meets W3C HTML5 standards.
+func TestW3CCompliance(t *testing.T) {
+	now := time.Now().Unix()
+
+	s := state{
+		staleEpoch: now - 3600,
+		checks: map[string]checkState{
+			"test_check": {
+				Status:     nagiosCritical,
+				PrevStatus: nagiosOk,
+				Epoch:      now,
+				output:     "Test output",
+			},
+		},
+	}
+
+	subject := "GOGIOS Report [C:1 W:0 U:0 S:0 OK:0]"
+	html := s.htmlReport(subject)
+
+	// W3C HTML5 Required Elements
+	requiredElements := map[string]string{
+		"DOCTYPE":           "<!DOCTYPE html>",
+		"html with lang":    `<html lang="en">`,
+		"charset meta":      `<meta charset="UTF-8">`,
+		"viewport meta":     `<meta name="viewport"`,
+		"title":             "<title>",
+		"closing html":      "</html>",
+		"closing head":      "</head>",
+		"closing body":      "</body>",
+		"proper html close": "</html>",
+	}
+
+	for name, elem := range requiredElements {
+		if !strings.Contains(html, elem) {
+			t.Errorf("W3C compliance check failed: missing %s (%q)", name, elem)
+		}
+	}
+
+	// Check that DOCTYPE is at the very beginning
+	if !strings.HasPrefix(html, "<!DOCTYPE html>") {
+		t.Error("W3C compliance: DOCTYPE must be the first line")
+	}
+
+	// Check proper tag nesting (basic validation)
+	htmlTagStart := strings.Index(html, "<html")
+	htmlTagEnd := strings.LastIndex(html, "</html>")
+	if htmlTagStart == -1 || htmlTagEnd == -1 {
+		t.Error("W3C compliance: missing <html> or </html> tag")
+	}
+	if htmlTagStart > htmlTagEnd {
+		t.Error("W3C compliance: </html> appears before <html>")
+	}
+
+	headStart := strings.Index(html, "<head>")
+	headEnd := strings.Index(html, "</head>")
+	if headStart == -1 || headEnd == -1 {
+		t.Error("W3C compliance: missing <head> or </head> tag")
+	}
+	if headStart > headEnd {
+		t.Error("W3C compliance: </head> appears before <head>")
+	}
+
+	bodyStart := strings.Index(html, "<body>")
+	bodyEnd := strings.LastIndex(html, "</body>")
+	if bodyStart == -1 || bodyEnd == -1 {
+		t.Error("W3C compliance: missing <body> or </body> tag")
+	}
+	if bodyStart > bodyEnd {
+		t.Error("W3C compliance: </body> appears before <body>")
+	}
+
+	// Head should come before body
+	if headEnd > bodyStart {
+		t.Error("W3C compliance: <head> section should be closed before <body> starts")
+	}
+
+	// Check for proper character encoding in meta tag
+	if !strings.Contains(html, `charset="UTF-8"`) {
+		t.Error("W3C compliance: charset should be UTF-8")
+	}
+
+	// Verify no common HTML errors
+	commonErrors := []string{
+		"<<",     // Double tag opening
+		">>",     // Double tag closing
+		"< ",     // Space after tag opening
+		" >",     // Space before tag closing (in tag name)
+		"<//>",   // Malformed closing tag
+		"</ >",   // Empty closing tag
+		"< >",    // Empty tag
+	}
+
+	for _, err := range commonErrors {
+		if strings.Contains(html, err) {
+			t.Errorf("W3C compliance: found malformed HTML pattern: %q", err)
+		}
+	}
+
+	// Verify all div tags are properly closed
+	divOpen := strings.Count(html, "<div")
+	divClose := strings.Count(html, "</div>")
+	if divOpen != divClose {
+		t.Errorf("W3C compliance: mismatched div tags (open: %d, close: %d)", divOpen, divClose)
+	}
+
+	// Verify all span tags are properly closed
+	spanOpen := strings.Count(html, "<span")
+	spanClose := strings.Count(html, "</span>")
+	if spanOpen != spanClose {
+		t.Errorf("W3C compliance: mismatched span tags (open: %d, close: %d)", spanOpen, spanClose)
+	}
+}