platform: modularize api/gui, add docs-tests-web foundation, and refresh root config

selective-vpn-api/app/dnscfg/mode.go

@@ -0,0 +1,136 @@
+package dnscfg
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func NormalizeResolverMode(mode string, viaSmartDNS bool, directMode string, smartDNSMode string, hybridWildcardMode string) string {
+	switch strings.ToLower(strings.TrimSpace(mode)) {
+	case strings.ToLower(strings.TrimSpace(directMode)):
+		return directMode
+	case strings.ToLower(strings.TrimSpace(smartDNSMode)):
+		return hybridWildcardMode
+	case strings.ToLower(strings.TrimSpace(hybridWildcardMode)), "hybrid":
+		return hybridWildcardMode
+	default:
+		if viaSmartDNS {
+			return hybridWildcardMode
+		}
+		return directMode
+	}
+}
+
+func SmartDNSForced(envRaw string) bool {
+	switch strings.TrimSpace(strings.ToLower(envRaw)) {
+	case "1", "true", "yes", "on":
+		return true
+	default:
+		return false
+	}
+}
+
+type ModeState struct {
+	ViaSmartDNS  bool   `json:"via_smartdns"`
+	SmartDNSAddr string `json:"smartdns_addr"`
+	Mode         string `json:"mode"`
+}
+
+type ModeConfig struct {
+	Path                  string
+	DirectMode            string
+	DefaultSmartDNSAddr   string
+	NormalizeResolverMode func(mode string, viaSmartDNS bool) string
+	NormalizeSmartDNSAddr func(raw string) string
+}
+
+func LoadMode(cfg ModeConfig) (ModeState, bool) {
+	mode := ModeState{
+		ViaSmartDNS:  false,
+		SmartDNSAddr: strings.TrimSpace(cfg.DefaultSmartDNSAddr),
+		Mode:         strings.TrimSpace(cfg.DirectMode),
+	}
+	needPersist := false
+
+	data, err := os.ReadFile(strings.TrimSpace(cfg.Path))
+	switch {
+	case err == nil:
+		var stored ModeState
+		if err := json.Unmarshal(data, &stored); err == nil {
+			normalized, changed := normalizeModeState(stored, cfg)
+			mode = normalized
+			if strings.TrimSpace(stored.Mode) == "" || stored.ViaSmartDNS != normalized.ViaSmartDNS || changed {
+				needPersist = true
+			}
+		} else {
+			needPersist = true
+		}
+	case os.IsNotExist(err):
+		needPersist = true
+	}
+
+	normalized, changed := normalizeModeState(mode, cfg)
+	mode = normalized
+	if changed {
+		needPersist = true
+	}
+	return mode, needPersist
+}
+
+func SaveMode(cfg ModeConfig, mode ModeState) error {
+	normalized, _ := normalizeModeState(mode, cfg)
+	path := strings.TrimSpace(cfg.Path)
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		return err
+	}
+	tmp := path + ".tmp"
+	b, err := json.MarshalIndent(normalized, "", "  ")
+	if err != nil {
+		return err
+	}
+	if err := os.WriteFile(tmp, b, 0o644); err != nil {
+		return err
+	}
+	return os.Rename(tmp, path)
+}
+
+func normalizeModeState(mode ModeState, cfg ModeConfig) (ModeState, bool) {
+	changed := false
+	prevMode := mode.Mode
+	mode.Mode = normalizeResolverMode(cfg, mode.Mode, mode.ViaSmartDNS)
+	if mode.Mode != prevMode {
+		changed = true
+	}
+
+	viaSmartDNS := mode.Mode != strings.TrimSpace(cfg.DirectMode)
+	if mode.ViaSmartDNS != viaSmartDNS {
+		mode.ViaSmartDNS = viaSmartDNS
+		changed = true
+	}
+
+	prevAddr := mode.SmartDNSAddr
+	mode.SmartDNSAddr = normalizeSmartDNSAddr(cfg, mode.SmartDNSAddr)
+	if mode.SmartDNSAddr == "" {
+		mode.SmartDNSAddr = strings.TrimSpace(cfg.DefaultSmartDNSAddr)
+	}
+	if mode.SmartDNSAddr != prevAddr {
+		changed = true
+	}
+	return mode, changed
+}
+
+func normalizeResolverMode(cfg ModeConfig, mode string, viaSmartDNS bool) string {
+	if cfg.NormalizeResolverMode == nil {
+		return strings.TrimSpace(mode)
+	}
+	return strings.TrimSpace(cfg.NormalizeResolverMode(mode, viaSmartDNS))
+}
+
+func normalizeSmartDNSAddr(cfg ModeConfig, raw string) string {
+	if cfg.NormalizeSmartDNSAddr == nil {
+		return strings.TrimSpace(raw)
+	}
+	return strings.TrimSpace(cfg.NormalizeSmartDNSAddr(raw))
+}