expressvpn wip

internal/provider/expressvpn/updater/candidates.go

@@ -0,0 +1,146 @@
+package updater
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/qdm12/gluetun/internal/models"
+)
+
+// generateCandidateHostnames generates multiple hostname candidates for a given location
+// by trying different slug variations, number suffixes, and country aliases.
+func generateCandidateHostnames(server models.Server) (hostnames []string, err error) {
+	country := strings.ToLower(server.Country)
+	city := strings.ToLower(server.City)
+
+	if strings.Contains(country, " (via ") {
+		destinationEndIndex := strings.Index(country, " (via ")
+		destination := strings.TrimSpace(country[:destinationEndIndex])
+		destination = strings.ReplaceAll(destination, " ", "")
+
+		sourceEndIndex := strings.Index(country[destinationEndIndex:], ")")
+		if sourceEndIndex == -1 {
+			return nil, fmt.Errorf("invalid location format, missing closing parenthesis for source: %q", country)
+		}
+		source := strings.TrimSpace(country[destinationEndIndex+len(" (via ") : destinationEndIndex+sourceEndIndex])
+		source = strings.ReplaceAll(source, " ", "")
+
+		sourceAliases := countryNameToAliases(source)
+		sources := make([]string, 0, 1+len(sourceAliases))
+		sources = append(sources, source)
+		sources = append(sources, sourceAliases...)
+		destinationAliases := countryNameToAliases(destination)
+		destinations := make([]string, 0, 1+len(destinationAliases))
+		destinations = append(destinations, destination)
+		destinations = append(destinations, destinationAliases...)
+
+		slugs := make([]string, 0, (1+len(sourceAliases))*(1+len(destinationAliases)))
+		for _, destination := range destinations {
+			for _, source := range sources {
+				slugs = append(slugs, destination+"-"+source)
+			}
+		}
+
+		if city != "" {
+			return nil, fmt.Errorf("city %q should be empty for multi-hop country: %s", city, country)
+		}
+
+		return makeNumberedCandidates(slugs, server.Number), nil
+	}
+
+	countrySlug := strings.ReplaceAll(strings.TrimSpace(country), " ", "")
+	countrySlugAliases := countryNameToAliases(countrySlug)
+	countrySlugs := make([]string, 0, 1+len(countrySlugAliases))
+	countrySlugs = append(countrySlugs, countrySlug)
+	countrySlugs = append(countrySlugs, countrySlugAliases...)
+
+	var citySlugs []string
+	if city != "" {
+		if strings.Contains(city, " ") {
+			citySlugs = append(citySlugs, strings.ReplaceAll(city, " ", ""))
+			citySlugs = append(citySlugs, strings.ReplaceAll(city, " ", "-"))
+		} else {
+			citySlugs = append(citySlugs, city)
+		}
+	}
+
+	var slugs []string
+	if len(citySlugs) == 0 {
+		slugs = countrySlugs
+	} else {
+		slugs = make([]string, 0, len(countrySlugs)*len(citySlugs))
+		for _, countrySlug := range countrySlugs {
+			for _, citySlug := range citySlugs {
+				slugs = append(slugs, countrySlug+"-"+citySlug)
+			}
+		}
+	}
+
+	return makeNumberedCandidates(slugs, server.Number), nil
+}
+
+func makeNumberedCandidates(baseSlugs []string, serverNumber uint16) (candidates []string) {
+	numbersToTry := []uint16{1, 2, 3, 4, 5}
+	if serverNumber > 0 {
+		numbersToTry = []uint16{serverNumber}
+	}
+	const candidateVariationsPerNumber = 2                                           // slugN and slug-N
+	candidateVariationsPerBase := 1 + len(numbersToTry)*candidateVariationsPerNumber // base + (slugN and slug-N for each number)
+	candidates = make([]string, 0, len(baseSlugs)*candidateVariationsPerBase)
+	for _, base := range baseSlugs {
+		candidates = append(candidates, base+hostnameSuffix)
+		for _, number := range numbersToTry {
+			candidates = append(candidates,
+				base+fmt.Sprintf("%d-ca-version-2.expressnetw.com", number),
+				base+fmt.Sprintf("-%d-ca-version-2.expressnetw.com", number))
+		}
+	}
+	return candidates
+}
+
+// hostnameSuffix is appended to all ExpressVPN hostnames.
+const hostnameSuffix = "-ca-version-2.expressnetw.com"
+
+// countryNameToAliases maps common country names to alternative names used in hostnames.
+func countryNameToAliases(country string) (aliases []string) {
+	switch country {
+	case "usa":
+		return []string{"us"}
+	case "uk":
+		return []string{"gb"}
+	case "netherlands":
+		return []string{"nl"}
+	case "switzerland":
+		return []string{"ch"}
+	case "japan":
+		return []string{"jp"}
+	case "sweden":
+		return []string{"se"}
+	case "norway":
+		return []string{"no"}
+	case "denmark":
+		return []string{"dk"}
+	case "finland":
+		return []string{"fi"}
+	case "portugal":
+		return []string{"pt"}
+	case "spain":
+		return []string{"es"}
+	case "germany":
+		return []string{"de"}
+	case "italy":
+		return []string{"it"}
+	case "australia":
+		return []string{"au"}
+	case "singapore":
+		return []string{"sg"}
+	case "taiwan":
+		return []string{"tw"}
+	case "southkorea":
+		return []string{"kr"}
+	case "northmacedonia":
+		return []string{"macedonia"}
+	default:
+		return nil
+	}
+}