fix: address code review findings

internal/cache/preferences.go

@@ -105,7 +105,7 @@ func (p *Preferences) AddSavedCity(ctx context.Context, userID, cityCode, cityNa
 		Date:    "",
 		Request: "",
 	}
-	if err := p.store.Set(ctx, cacheKey, data, CityTTL); err != nil {
+	if err := p.store.Set(ctx, cacheKey, data, PreferenceTTL); err != nil {
 		return err
 	}
 
@@ -148,7 +148,7 @@ func (p *Preferences) RemoveSavedCity(ctx context.Context, userID, cityCode stri
 		return err
 	}
 
-	return p.store.Set(ctx, key, data, CityTTL)
+	return p.store.Set(ctx, key, data, PreferenceTTL)
 }
 
 // GetSearchHistory returns the user's search history.
@@ -217,7 +217,7 @@ func (p *Preferences) AddSearchHistory(ctx context.Context, userID, fromCity, to
 		return err
 	}
 
-	if err := p.store.Set(ctx, key, data, CityTTL); err != nil {
+	if err := p.store.Set(ctx, key, data, PreferenceTTL); err != nil {
 		return err
 	}
 
@@ -260,7 +260,7 @@ func (p *Preferences) RemoveOldSearchHistory(ctx context.Context, userID string,
 		return err
 	}
 
-	if err := p.store.Set(ctx, key, data, CityTTL); err != nil {
+	if err := p.store.Set(ctx, key, data, PreferenceTTL); err != nil {
 		return err
 	}
 

internal/cache/store.go

@@ -147,6 +147,9 @@ const (
 
 	// SearchFarTermTTL is the time-to-live for search results with far-term dates (7 days).
 	SearchFarTermTTL = 7 * 24 * time.Hour
+
+	// PreferenceTTL is the time-to-live for user preferences (7 days).
+	PreferenceTTL = 7 * 24 * time.Hour
 )
 
 // GetCityKey returns the cache key for a city code.

internal/routing/graph.go

@@ -808,6 +808,8 @@ func (g *Graph) ApplyMCT(itinerary *Itinerary, mctBase int) *Itinerary {
 	adjustedLegs := make([]RouteLeg, len(itinerary.Legs))
 	copy(adjustedLegs, itinerary.Legs)
 
+	totalMCT := 0
+
 	for i := 1; i < len(adjustedLegs); i++ {
 		prevLeg := &adjustedLegs[i-1]
 		currLeg := &adjustedLegs[i]
@@ -828,9 +830,36 @@ func (g *Graph) ApplyMCT(itinerary *Itinerary, mctBase int) *Itinerary {
 		}
 
 		// Add the MCT to the total duration (as waiting time at transfer)
-		itinerary.TotalDuration += mct
+		totalMCT += mct
 	}
 
+	// Update leg durations to include MCT for transfer legs
+	for i := 1; i < len(adjustedLegs); i++ {
+		prevLeg := &adjustedLegs[i-1]
+		currLeg := &adjustedLegs[i]
+
+		// Determine MCT based on node types and transfer kinds
+		mct := mctBase
+
+		// Reduce MCT for city hub transfers (the transfer point node is a city)
+		// The transfer point is the destination of the previous leg / start of current leg
+		transferPoint := prevLeg.To // = currLeg.From
+		if transferPoint.Type == NodeTypeCity {
+			mct = mctBase / 2 // 30 min -> 15 min for city hub transfers
+		}
+
+		// Increase MCT for mode changes (different transport types)
+		if prevLeg.Transport != currLeg.Transport {
+			mct = mctBase + 600 // 30 min + 10 min for mode change
+		}
+
+		// Add MCT to the current leg's duration (transfer wait time)
+		adjustedLegs[i].Duration += mct
+	}
+
+	// Update total duration
+	itinerary.TotalDuration += totalMCT
+
 	// Recalculate leg structure with proper transfer timing
 	itinerary.Legs = adjustedLegs
 	return itinerary
@@ -894,14 +923,25 @@ func (g *Graph) FindRoutesPareto(originID, destID string, opts SearchOptions, cl
 	var allItineraries []*Itinerary
 
 	// Search with different max transfer limits to find diverse routes
-	for maxTransfers := 0; maxTransfers <= opts.MaxTransfers; maxTransfers++ {
+	if opts.MaxTransfers < 0 {
+		// No limit on transfers - use a reasonable default
 		optsCopy := opts
-		optsCopy.MaxTransfers = maxTransfers
+		optsCopy.MaxTransfers = 5
 
 		result := g.FindRoute(originID, destID, optsCopy, closedStations, neighbors)
 		if result != nil && result.TotalDuration > 0 {
 			allItineraries = append(allItineraries, result)
 		}
+	} else {
+		for maxTransfers := 0; maxTransfers <= opts.MaxTransfers; maxTransfers++ {
+			optsCopy := opts
+			optsCopy.MaxTransfers = maxTransfers
+
+			result := g.FindRoute(originID, destID, optsCopy, closedStations, neighbors)
+			if result != nil && result.TotalDuration > 0 {
+				allItineraries = append(allItineraries, result)
+			}
+		}
 	}
 
 	// Sort according to the specified RankingMode
@@ -1089,9 +1129,9 @@ func (g *Graph) checkRouteForChanges(itinerary *Itinerary) bool {
 
 // rescheduleRoute performs a re-search for the route with updated graph data.
 // This is called when significant changes are detected in the route legs.
-func (g *Graph) rescheduleRoute(originID, destID string, opts SearchOptions) *Itinerary {
+func (g *Graph) rescheduleRoute(originID, destID string, opts SearchOptions, closedStations map[string]bool, neighbors map[string][]storage.StationNeighbor) *Itinerary {
 	// Re-run the search with the same options to get an updated route
-	result := g.FindRoute(originID, destID, opts, nil, nil)
+	result := g.FindRoute(originID, destID, opts, closedStations, neighbors)
 	if result != nil {
 		result.LastChecked = time.Now().Unix()
 		result.NeedsReSearch = false
@@ -1102,9 +1142,9 @@ func (g *Graph) rescheduleRoute(originID, destID string, opts SearchOptions) *It
 
 // CheckAndRescheduleRoute checks a route for changes and returns an updated route if needed.
 // This is the main entry point for flight change notification logic.
-func (g *Graph) CheckAndRescheduleRoute(itinerary *Itinerary, originID, destID string, opts SearchOptions) *Itinerary {
+func (g *Graph) CheckAndRescheduleRoute(itinerary *Itinerary, originID, destID string, opts SearchOptions, closedStations map[string]bool, neighbors map[string][]storage.StationNeighbor) *Itinerary {
 	if g.checkRouteForChanges(itinerary) {
-		return g.rescheduleRoute(originID, destID, opts)
+		return g.rescheduleRoute(originID, destID, opts, closedStations, neighbors)
 	}
 	return itinerary
 }

internal/routing/graph_test.go

@@ -388,7 +388,7 @@ func TestRouteReSearchOnChange(t *testing.T) {
 
 	// Since LastChecked is 2 hours ago (> 3600s ago), the recent-check skip won't apply
 	// and checkRouteForChanges will run full evaluation
-	checked := graph.CheckAndRescheduleRoute(itinerary, "s1", "s3", SearchOptions{MaxTransfers: 5})
+	checked := graph.CheckAndRescheduleRoute(itinerary, "s1", "s3", SearchOptions{MaxTransfers: 5}, nil, nil)
 
 	t.Logf("Initial - NeedsReSearch: %v, ReSearchReason: %s", itinerary.NeedsReSearch, itinerary.ReSearchReason)
 	t.Logf("Initial - checked route ID: %s, NeedsReSearch: %v", checked.ID, checked.NeedsReSearch)
@@ -414,7 +414,7 @@ func TestRouteReSearchOnChange(t *testing.T) {
 	}
 
 	// Re-check for changes after simulating cancellation
-	checked2 := graph.CheckAndRescheduleRoute(itinerary, "s1", "s3", SearchOptions{MaxTransfers: 5})
+	checked2 := graph.CheckAndRescheduleRoute(itinerary, "s1", "s3", SearchOptions{MaxTransfers: 5}, nil, nil)
 	t.Logf("After cancellation - NeedsReSearch: %v, ReSearchReason: %s", checked2.NeedsReSearch, checked2.ReSearchReason)
 	t.Logf("After cancellation - route ID: %s", checked2.ID)
 
@@ -451,7 +451,7 @@ func TestRouteReSearchOnChange(t *testing.T) {
 	}
 
 	// Re-check for major delay
-	checked3 := graph.CheckAndRescheduleRoute(itinerary2, "s1", "s3", SearchOptions{MaxTransfers: 5})
+	checked3 := graph.CheckAndRescheduleRoute(itinerary2, "s1", "s3", SearchOptions{MaxTransfers: 5}, nil, nil)
 	t.Logf("After major delay - NeedsReSearch: %v, ReSearchReason: %s", checked3.NeedsReSearch, checked3.ReSearchReason)
 	t.Logf("After major delay - route ID: %s", checked3.ID)
 

internal/yandex/client.go

@@ -15,6 +15,9 @@ import (
 	"trip-planner/internal/metrics"
 )
 
+// rng is a seeded random number generator for jitter calculations.
+var rng = rand.New(rand.NewSource(time.Now().UnixNano()))
+
 // Client represents a Yandex Schedules API client with rate limiting,
 // circuit breaking, and retry capabilities.
 type Client struct {
@@ -421,6 +424,5 @@ func applyJitter(backoff time.Duration) time.Duration {
 }
 
 func randFloat64() float64 {
-	// Use math/rand with a seed based on function call index for variability
-	return rand.Float64()
+	return rng.Float64()
 }