fix: address code review findings

internal/cache/store.go

@@ -222,17 +222,16 @@ func (c *CacheAside) GetSearch(ctx context.Context, key *CacheKey, fetch func()
 
 	// Try cache first
 	data, err := c.store.Get(ctx, key)
-	if err == nil && data != nil {
+	if err != nil {
+		return nil, err
+	}
+	if data != nil {
 		c.metrics.RecordCacheHit("search") // cache hit
 		return data, nil
 	}
 
 	// Cache miss: fetch from backend
-	if errors.Is(err, redis.Nil) {
-		c.metrics.RecordCacheMiss("search") // record search cache miss
-	} else if err != nil {
-		return nil, err
-	}
+	c.metrics.RecordCacheMiss("search") // record search cache miss
 
 	// Fetch from backend
 	data, err = fetch()

internal/routing/graph.go

@@ -418,7 +418,7 @@ func (g *Graph) FindRoute(originID, destID string, opts SearchOptions, closedSta
 			newDurationWithMCT := newDuration + transferTime
 
 			// Check if we've visited this node with fewer transfers
-			visKey := current.nodeID
+			visKey := nextNode.ID
 			if existingTransfers, ok := visited[visKey]; ok {
 				if current.transfers+1 > existingTransfers {
 					// Already visited this node with fewer transfers, skip
@@ -880,7 +880,7 @@ type SearchResult struct {
 // route in all three metrics simultaneously. Routes are sorted according to the RankingMode
 // in SearchOptions: "fastest" (default, by duration), "fewest_transfers" (by transfers),
 // or "cheapest" (by cost).
-func (g *Graph) FindRoutesPareto(originID, destID string, opts SearchOptions) []*Itinerary {
+func (g *Graph) FindRoutesPareto(originID, destID string, opts SearchOptions, closedStations map[string]bool, neighbors map[string][]storage.StationNeighbor) []*Itinerary {
 	// Run multiple searches with different strategies to find diverse routes
 	var allItineraries []*Itinerary
 
@@ -889,7 +889,7 @@ func (g *Graph) FindRoutesPareto(originID, destID string, opts SearchOptions) []
 		optsCopy := opts
 		optsCopy.MaxTransfers = maxTransfers
 
-		result := g.FindRoute(originID, destID, optsCopy, nil, nil)
+		result := g.FindRoute(originID, destID, optsCopy, closedStations, neighbors)
 		if result != nil && result.TotalDuration > 0 {
 			allItineraries = append(allItineraries, result)
 		}

internal/routing/graph_test.go

@@ -1,9 +1,11 @@
 package routing
 
 import (
-	"time"
 	"fmt"
 	"testing"
+	"time"
+
+	"trip-planner/internal/storage"
 )
 
 func TestFindRouteMaxTransfers(t *testing.T) {
@@ -40,7 +42,9 @@ func TestFindRouteMaxTransfers(t *testing.T) {
 
 	// Test with MaxTransfers=0: should only find the direct route (0 transfers)
 	opts0 := SearchOptions{MaxTransfers: 0}
-	results0 := graph.FindRoutesPareto("s1", "s6", opts0)
+	closedStations0 := make(map[string]bool)
+	neighborsMap0 := make(map[string][]storage.StationNeighbor)
+	results0 := graph.FindRoutesPareto("s1", "s6", opts0, closedStations0, neighborsMap0)
 	t.Logf("MaxTransfers=0: found %d route(s)", len(results0))
 	for _, r := range results0 {
 		t.Logf("  Route: duration=%d, transfers=%d", r.TotalDuration, r.TotalTransfers)
@@ -60,7 +64,9 @@ func TestFindRouteMaxTransfers(t *testing.T) {
 
 	// Test with MaxTransfers=1: should find direct route + 1-transfer route if any
 	opts1 := SearchOptions{MaxTransfers: 1}
-	results1 := graph.FindRoutesPareto("s1", "s6", opts1)
+	closedStations1 := make(map[string]bool)
+	neighborsMap1 := make(map[string][]storage.StationNeighbor)
+	results1 := graph.FindRoutesPareto("s1", "s6", opts1, closedStations1, neighborsMap1)
 	t.Logf("MaxTransfers=1: found %d route(s)", len(results1))
 	for _, r := range results1 {
 		t.Logf("  Route: duration=%d, transfers=%d", r.TotalDuration, r.TotalTransfers)
@@ -74,7 +80,9 @@ func TestFindRouteMaxTransfers(t *testing.T) {
 
 	// Test with MaxTransfers=2: should find more routes
 	opts2 := SearchOptions{MaxTransfers: 2}
-	results2 := graph.FindRoutesPareto("s1", "s6", opts2)
+	closedStations2 := make(map[string]bool)
+	neighborsMap2 := make(map[string][]storage.StationNeighbor)
+	results2 := graph.FindRoutesPareto("s1", "s6", opts2, closedStations2, neighborsMap2)
 	t.Logf("MaxTransfers=2: found %d route(s)", len(results2))
 	for _, r := range results2 {
 		t.Logf("  Route: duration=%d, transfers=%d", r.TotalDuration, r.TotalTransfers)
@@ -163,7 +171,9 @@ func TestParetoFrontGeneration(t *testing.T) {
 
 	t.Run("fastest mode (default) sorts by duration", func(t *testing.T) {
 		opts := SearchOptions{MaxTransfers: 3}
-		results := graph.FindRoutesPareto("s1", "s8", opts)
+		closedStations := make(map[string]bool)
+		neighborsMap := make(map[string][]storage.StationNeighbor)
+		results := graph.FindRoutesPareto("s1", "s8", opts, closedStations, neighborsMap)
 
 		// Should find at least some Pareto-optimal routes
 		if len(results) == 0 {
@@ -199,7 +209,9 @@ func TestParetoFrontGeneration(t *testing.T) {
 
 	t.Run("fewest_transfers mode sorts by transfers first", func(t *testing.T) {
 		opts := SearchOptions{MaxTransfers: 3, RankingMode: "fewest_transfers"}
-		results := graph.FindRoutesPareto("s1", "s8", opts)
+		closedStations := make(map[string]bool)
+		neighborsMap := make(map[string][]storage.StationNeighbor)
+		results := graph.FindRoutesPareto("s1", "s8", opts, closedStations, neighborsMap)
 
 		if len(results) == 0 {
 			t.Fatal("expected at least one Pareto-optimal route with fewest_transfers mode")
@@ -230,7 +242,9 @@ func TestParetoFrontGeneration(t *testing.T) {
 
 	t.Run("cheapest mode sorts by cost first", func(t *testing.T) {
 		opts := SearchOptions{MaxTransfers: 3, RankingMode: "cheapest"}
-		results := graph.FindRoutesPareto("s1", "s8", opts)
+		closedStations := make(map[string]bool)
+		neighborsMap := make(map[string][]storage.StationNeighbor)
+		results := graph.FindRoutesPareto("s1", "s8", opts, closedStations, neighborsMap)
 
 		if len(results) == 0 {
 			t.Fatal("expected at least one Pareto-optimal route with cheapest mode")

internal/yandex/client.go

@@ -7,6 +7,7 @@ import (
 	"math/rand"
 	"net/http"
 	"net/url"
+	"strings"
 	"sync"
 	"time"
 
@@ -269,8 +270,17 @@ func isRetryableError(err error) bool {
 	if err == nil {
 		return false
 	}
-	// Network-level errors are retryable
-	return true
+	// Check for HTTP status codes that are retryable (5xx errors)
+	apiErr, ok := err.(*APIError)
+	if ok {
+		return apiErr.Code >= 500 && apiErr.Code < 600
+	}
+	// Check for network errors
+	errStr := err.Error()
+	return strings.Contains(errStr, "timeout") ||
+		strings.Contains(errStr, "connection refused") ||
+		strings.Contains(errStr, "dial tcp") ||
+		strings.Contains(errStr, "context deadline exceeded")
 }
 
 // buildURL constructs a Yandex API URL with query parameters.