Refactor (#174)

- Goal was to simplify main.go complexity
- Use common structures and interfaces for all vpn providers
- Moved files around
- Removed some alias models

internal/models/selection.go

@@ -0,0 +1,100 @@
+package models
+
+import (
+	"fmt"
+	"net"
+	"strings"
+)
+
+// ProviderSettings contains settings specific to a VPN provider
+type ProviderSettings struct {
+	Name               VPNProvider
+	ServerSelection    ServerSelection
+	ExtraConfigOptions ExtraConfigOptions
+	PortForwarding     PortForwarding
+}
+
+type ServerSelection struct {
+	// Common
+	Protocol NetworkProtocol
+	TargetIP net.IP
+
+	// Cyberghost, PIA, Surfshark, Windscribe
+	Region string
+
+	// Cyberghost
+	Group string
+
+	// Mullvad
+	Country string
+	City    string
+	ISP     string
+	Owned   bool
+
+	// Mullvad, Windscribe
+	CustomPort uint16
+
+	// PIA
+	EncryptionPreset string
+}
+
+type ExtraConfigOptions struct {
+	ClientKey        string // Cyberghost
+	EncryptionPreset string // PIA
+}
+
+// PortForwarding contains settings for port forwarding
+type PortForwarding struct {
+	Enabled  bool
+	Filepath Filepath
+}
+
+func (p *PortForwarding) String() string {
+	if p.Enabled {
+		return fmt.Sprintf("on, saved in %s", p.Filepath)
+	}
+	return "off"
+}
+
+func (p *ProviderSettings) String() string {
+	settingsList := []string{
+		fmt.Sprintf("%s settings:", strings.Title(string(p.Name))),
+		"Network protocol: " + string(p.ServerSelection.Protocol),
+	}
+	switch strings.ToLower(string(p.Name)) {
+	case "private internet access":
+		settingsList = []string{
+			"Region: " + p.ServerSelection.Region,
+			"Encryption preset: " + p.ExtraConfigOptions.EncryptionPreset,
+			"Port forwarding: " + p.PortForwarding.String(),
+		}
+	case "mullvad":
+		settingsList = []string{
+			"Country: " + p.ServerSelection.Country,
+			"City: " + p.ServerSelection.City,
+			"ISP: " + p.ServerSelection.ISP,
+			"Custom port: " + string(p.ServerSelection.CustomPort),
+		}
+	case "windscribe":
+		settingsList = []string{
+			"Region: " + p.ServerSelection.Region,
+			"Custom port: " + string(p.ServerSelection.CustomPort),
+		}
+	case "surfshark":
+		settingsList = []string{
+			"Region: " + p.ServerSelection.Region,
+		}
+	case "cyberghost":
+		settingsList = []string{
+			"ClientKey: [redacted]",
+			"Group: " + p.ServerSelection.Group,
+			"Region: " + p.ServerSelection.Region,
+		}
+	}
+	if p.ServerSelection.TargetIP != nil {
+		settingsList = append(settingsList,
+			"Target IP address: "+string(p.ServerSelection.TargetIP),
+		)
+	}
+	return strings.Join(settingsList, "\n |--")
+}