Feat: Perfect privacy support (#606)

internal/updater/providers/perfectprivacy/citytoserver.go

@@ -0,0 +1,45 @@
+package perfectprivacy
+
+import (
+	"net"
+
+	"github.com/qdm12/gluetun/internal/models"
+)
+
+type cityToServer map[string]models.PerfectprivacyServer
+
+func (cts cityToServer) add(city string, ips []net.IP) {
+	server, ok := cts[city]
+	if !ok {
+		server.City = city
+		server.IPs = ips
+		server.TCP = true
+		server.UDP = true
+	} else {
+		// Do not insert duplicate IP addresses
+		existingIPs := make(map[string]struct{}, len(server.IPs))
+		for _, ip := range server.IPs {
+			existingIPs[ip.String()] = struct{}{}
+		}
+
+		for _, ip := range ips {
+			ipString := ip.String()
+			_, ok := existingIPs[ipString]
+			if ok {
+				continue
+			}
+			existingIPs[ipString] = struct{}{}
+			server.IPs = append(server.IPs, ip)
+		}
+	}
+
+	cts[city] = server
+}
+
+func (cts cityToServer) toServersSlice() (servers []models.PerfectprivacyServer) {
+	servers = make([]models.PerfectprivacyServer, 0, len(cts))
+	for _, server := range cts {
+		servers = append(servers, server)
+	}
+	return servers
+}