Print notice if password recovery email is not set

This was requested by the Winlink Development Team.

Resolves la5nta#442

main.go

@@ -377,10 +377,10 @@ func main() {
 			if config.VersionReportingDisabled {
 				return
 			}
-
-			for { // Check every 6 hours, but it won't post more frequent than 24h.
-				postVersionUpdate() // Ignore errors
-				time.Sleep(6 * time.Hour)
+			for {
+				postVersionUpdate()                  // 24 hour hold on success
+				checkPasswordRecoveryEmailIsSet(ctx) // 14 day hold on success
+				time.Sleep(6 * time.Hour)            // Retry every 6 hours
 			}
 		}()
 	}

winlink_api.go

@@ -0,0 +1,137 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"time"
+
+	"github.com/la5nta/pat/internal/buildinfo"
+	"github.com/la5nta/pat/internal/cmsapi"
+	"github.com/la5nta/pat/internal/debug"
+	"github.com/la5nta/pat/internal/directories"
+)
+
+// doIfElapsed implements a per-callsign rate limited function.
+func doIfElapsed(name string, t time.Duration, fn func() error) error {
+	filePath := filepath.Join(directories.StateDir(), "."+name+"_"+fOptions.MyCall+".json")
+	file, err := os.OpenFile(filePath, os.O_RDWR|os.O_CREATE, 0o600)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	var lastUpdated time.Time
+	json.NewDecoder(file).Decode(&lastUpdated)
+	if since := time.Since(lastUpdated); since < t {
+		debug.Printf("Skipping %q (last run: %s ago)", name, since.Truncate(time.Minute))
+		return nil
+	}
+
+	if err := fn(); err != nil {
+		return err
+	}
+
+	file.Truncate(0)
+	file.Seek(0, 0)
+	return json.NewEncoder(file).Encode(time.Now())
+}
+
+func postVersionUpdate() {
+	const interval = 24 * time.Hour
+	err := doIfElapsed("version_report", interval, func() error {
+		debug.Printf("Posting version update...")
+		// WDT do not want us to post version reports for callsigns without a registered account
+		if exists, err := accountExists(fOptions.MyCall); err != nil {
+			return err
+		} else if !exists {
+			return fmt.Errorf("account does not exist")
+		}
+		return cmsapi.VersionAdd{
+			Callsign: fOptions.MyCall,
+			Program:  buildinfo.AppName,
+			Version:  buildinfo.Version,
+			Comments: fmt.Sprintf("%s - %s/%s", buildinfo.GitRev, runtime.GOOS, runtime.GOARCH),
+		}.Post()
+	})
+	if err != nil {
+		debug.Printf("Failed to post version update: %v", err)
+	}
+}
+
+func checkPasswordRecoveryEmailIsSet(ctx context.Context) {
+	const interval = 14 * 24 * time.Hour
+	err := doIfElapsed("pw_recovery_email_check", interval, func() error {
+		debug.Printf("Checking if winlink.org password recovery email is set...")
+		set, err := passwordRecoveryEmailSet(ctx)
+		if err != nil {
+			return err
+		}
+		debug.Printf("Password recovery email set: %t", set)
+		if set {
+			return nil
+		}
+		fmt.Println("")
+		fmt.Println("WINLINK NOTICE: Password recovery email is not set for your Winlink account. It is highly recommended to do so.")
+		fmt.Println("Run `" + os.Args[0] + " account --help` for help setting your recovery address. You can also manage your account settings at https://winlink.org/.")
+		fmt.Println("")
+		return nil
+	})
+	if err != nil {
+		debug.Printf("Failed to check if password recovery email is set: %v", err)
+	}
+}
+
+func passwordRecoveryEmailSet(ctx context.Context) (bool, error) {
+	if config.SecureLoginPassword == "" {
+		return false, fmt.Errorf("missing password")
+	}
+	switch exists, err := accountExists(fOptions.MyCall); {
+	case err != nil:
+		return false, fmt.Errorf("error checking if account exist: %w", err)
+	case !exists:
+		return false, fmt.Errorf("account does not exist")
+	}
+	email, err := cmsapi.PasswordRecoveryEmailGet(ctx, fOptions.MyCall, config.SecureLoginPassword)
+	return email != "", err
+}
+
+func accountExists(callsign string) (bool, error) {
+	var cache struct {
+		Expires       time.Time
+		AccountExists bool
+	}
+
+	fileName := fmt.Sprintf(".cached_account_check_%s.json", callsign)
+	filePath := filepath.Join(directories.StateDir(), fileName)
+	f, err := os.OpenFile(filePath, os.O_RDWR|os.O_CREATE, 0o600)
+	if err != nil {
+		return false, err
+	}
+	json.NewDecoder(f).Decode(&cache)
+	if time.Since(cache.Expires) < 0 {
+		return cache.AccountExists, nil
+	}
+	defer func() {
+		f.Truncate(0)
+		f.Seek(0, 0)
+		json.NewEncoder(f).Encode(cache)
+	}()
+
+	debug.Printf("Checking if account exists...")
+	exists, err := cmsapi.AccountExists(callsign)
+	debug.Printf("Account exists: %t (%v)", exists, err)
+	if !exists || err != nil {
+		// Let's try again in 48 hours
+		cache.Expires = time.Now().Add(48 * time.Hour)
+		return false, err
+	}
+
+	// Keep this response for a month. It will probably not change.
+	cache.Expires = time.Now().Add(30 * 24 * time.Hour)
+	cache.AccountExists = exists
+	return exists, err
+}