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

selective-vpn-api/app/watchers_state_files.go

@@ -0,0 +1,109 @@
+package app
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/json"
+	"os"
+	"time"
+)
+
+// ---------------------------------------------------------------------
+// status file watcher
+// ---------------------------------------------------------------------
+
+func watchStatusFile(ctx context.Context, every time.Duration) {
+	var last [32]byte
+	have := false
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(every):
+		}
+
+		data, err := os.ReadFile(statusFilePath)
+		if err != nil {
+			continue
+		}
+		h := sha256.Sum256(data)
+		if have && h == last {
+			continue
+		}
+		last = h
+		have = true
+
+		var st Status
+		if err := json.Unmarshal(data, &st); err != nil {
+			events.push("status_error", map[string]any{"error": err.Error()})
+			continue
+		}
+		events.push("status_changed", st)
+	}
+}
+
+// ---------------------------------------------------------------------
+// login file watcher
+// ---------------------------------------------------------------------
+
+func watchLoginFile(ctx context.Context, every time.Duration) {
+	var last [32]byte
+	have := false
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(every):
+		}
+
+		data, err := os.ReadFile(loginStatePath)
+		if err != nil {
+			continue
+		}
+		h := sha256.Sum256(data)
+		if have && h == last {
+			continue
+		}
+		last = h
+		have = true
+
+		var st VPNLoginState
+		if err := json.Unmarshal(data, &st); err != nil {
+			events.push("login_state_error", map[string]any{"error": err.Error()})
+			continue
+		}
+		events.push("login_state_changed", st)
+	}
+}
+
+// ---------------------------------------------------------------------
+// generic file watcher
+// ---------------------------------------------------------------------
+
+func watchFileChange(ctx context.Context, path string, kind string, mode string, every time.Duration) {
+	var lastMod time.Time
+	var lastSize int64 = -1
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(every):
+		}
+
+		info, err := os.Stat(path)
+		if err != nil {
+			continue
+		}
+		if info.ModTime() == lastMod && info.Size() == lastSize {
+			continue
+		}
+		lastMod = info.ModTime()
+		lastSize = info.Size()
+		events.push(kind, map[string]any{
+			"path":  path,
+			"mode":  mode,
+			"size":  info.Size(),
+			"mtime": info.ModTime().UTC().Format(time.RFC3339Nano),
+		})
+	}
+}