package store

import (
	"testing"
	"time"

	"git.flowmade.one/flowmade-one/aether"
)

func TestSaveSnapshot_PersistsCorrectly(t *testing.T) {
	store := NewInMemoryEventStore()

	snapshot := &aether.ActorSnapshot{
		ActorID: "actor-123",
		Version: 10,
		State: map[string]interface{}{
			"balance": 100.50,
			"status":  "active",
		},
		Timestamp: time.Date(2026, 1, 9, 12, 0, 0, 0, time.UTC),
	}

	err := store.SaveSnapshot(snapshot)
	if err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	// Verify snapshot was persisted by retrieving it
	retrieved, err := store.GetLatestSnapshot("actor-123")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if retrieved == nil {
		t.Fatal("expected snapshot to be persisted, got nil")
	}

	if retrieved.ActorID != snapshot.ActorID {
		t.Errorf("ActorID mismatch: got %q, want %q", retrieved.ActorID, snapshot.ActorID)
	}
	if retrieved.Version != snapshot.Version {
		t.Errorf("Version mismatch: got %d, want %d", retrieved.Version, snapshot.Version)
	}
	if retrieved.State["balance"] != snapshot.State["balance"] {
		t.Errorf("State.balance mismatch: got %v, want %v", retrieved.State["balance"], snapshot.State["balance"])
	}
	if retrieved.State["status"] != snapshot.State["status"] {
		t.Errorf("State.status mismatch: got %v, want %v", retrieved.State["status"], snapshot.State["status"])
	}
	if !retrieved.Timestamp.Equal(snapshot.Timestamp) {
		t.Errorf("Timestamp mismatch: got %v, want %v", retrieved.Timestamp, snapshot.Timestamp)
	}
}

func TestSaveSnapshot_MultipleSnapshots(t *testing.T) {
	store := NewInMemoryEventStore()

	// Save multiple snapshots for the same actor
	for i := 1; i <= 5; i++ {
		snapshot := &aether.ActorSnapshot{
			ActorID: "actor-multi",
			Version: int64(i * 10),
			State: map[string]interface{}{
				"iteration": i,
			},
			Timestamp: time.Now(),
		}
		if err := store.SaveSnapshot(snapshot); err != nil {
			t.Fatalf("SaveSnapshot failed for version %d: %v", i*10, err)
		}
	}

	// Verify all snapshots were saved by checking the latest
	retrieved, err := store.GetLatestSnapshot("actor-multi")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if retrieved.Version != 50 {
		t.Errorf("expected latest version 50, got %d", retrieved.Version)
	}
}

func TestGetLatestSnapshot_ReturnsMostRecent(t *testing.T) {
	store := NewInMemoryEventStore()

	// Save snapshots in non-sequential order to test version comparison
	versions := []int64{5, 15, 10, 25, 20}
	for _, v := range versions {
		snapshot := &aether.ActorSnapshot{
			ActorID: "actor-latest",
			Version: v,
			State: map[string]interface{}{
				"version": v,
			},
			Timestamp: time.Now(),
		}
		if err := store.SaveSnapshot(snapshot); err != nil {
			t.Fatalf("SaveSnapshot failed for version %d: %v", v, err)
		}
	}

	latest, err := store.GetLatestSnapshot("actor-latest")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if latest == nil {
		t.Fatal("expected snapshot, got nil")
	}

	if latest.Version != 25 {
		t.Errorf("expected latest version 25, got %d", latest.Version)
	}

	// Verify the state matches the snapshot with version 25
	if latest.State["version"].(int64) != 25 {
		t.Errorf("expected state.version to be 25, got %v", latest.State["version"])
	}
}

func TestGetLatestSnapshot_NoSnapshotExists(t *testing.T) {
	store := NewInMemoryEventStore()

	// Query for a non-existent actor
	snapshot, err := store.GetLatestSnapshot("non-existent-actor")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if snapshot != nil {
		t.Errorf("expected nil for non-existent actor, got %+v", snapshot)
	}
}

func TestGetLatestSnapshot_EmptyActorID(t *testing.T) {
	store := NewInMemoryEventStore()

	// Save a snapshot with empty actor ID
	snapshot := &aether.ActorSnapshot{
		ActorID: "",
		Version: 1,
		State:   map[string]interface{}{},
		Timestamp: time.Now(),
	}
	if err := store.SaveSnapshot(snapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	// Retrieve with empty actor ID
	retrieved, err := store.GetLatestSnapshot("")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if retrieved == nil {
		t.Fatal("expected snapshot with empty actorID, got nil")
	}
}

func TestSnapshotVersioning_RespectedAcrossActors(t *testing.T) {
	store := NewInMemoryEventStore()

	// Save snapshots for different actors
	actors := []string{"actor-a", "actor-b", "actor-c"}
	for i, actorID := range actors {
		snapshot := &aether.ActorSnapshot{
			ActorID: actorID,
			Version: int64((i + 1) * 100), // Different versions per actor
			State: map[string]interface{}{
				"actor": actorID,
			},
			Timestamp: time.Now(),
		}
		if err := store.SaveSnapshot(snapshot); err != nil {
			t.Fatalf("SaveSnapshot failed for %s: %v", actorID, err)
		}
	}

	// Verify each actor has their own snapshot with correct version
	for i, actorID := range actors {
		snapshot, err := store.GetLatestSnapshot(actorID)
		if err != nil {
			t.Fatalf("GetLatestSnapshot failed for %s: %v", actorID, err)
		}

		expectedVersion := int64((i + 1) * 100)
		if snapshot.Version != expectedVersion {
			t.Errorf("actor %s: expected version %d, got %d", actorID, expectedVersion, snapshot.Version)
		}
	}
}

func TestSnapshotVersioning_LowerVersionAfterHigher(t *testing.T) {
	store := NewInMemoryEventStore()

	// Save a high version first
	highSnapshot := &aether.ActorSnapshot{
		ActorID: "actor-order",
		Version: 100,
		State: map[string]interface{}{
			"marker": "high",
		},
		Timestamp: time.Now(),
	}
	if err := store.SaveSnapshot(highSnapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	// Save a lower version after
	lowSnapshot := &aether.ActorSnapshot{
		ActorID: "actor-order",
		Version: 50,
		State: map[string]interface{}{
			"marker": "low",
		},
		Timestamp: time.Now(),
	}
	if err := store.SaveSnapshot(lowSnapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	// GetLatestSnapshot should return the higher version (100), not the most recently saved
	latest, err := store.GetLatestSnapshot("actor-order")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if latest.Version != 100 {
		t.Errorf("expected version 100, got %d", latest.Version)
	}
	if latest.State["marker"] != "high" {
		t.Errorf("expected marker 'high', got %v", latest.State["marker"])
	}
}

func TestSnapshotDataIntegrity_ComplexState(t *testing.T) {
	store := NewInMemoryEventStore()

	complexState := map[string]interface{}{
		"string":  "hello",
		"integer": 42,
		"float":   3.14159,
		"boolean": true,
		"null":    nil,
		"array":   []interface{}{"a", "b", "c"},
		"nested": map[string]interface{}{
			"level1": map[string]interface{}{
				"level2": "deep value",
			},
		},
	}

	snapshot := &aether.ActorSnapshot{
		ActorID:   "actor-complex",
		Version:   1,
		State:     complexState,
		Timestamp: time.Now(),
	}

	if err := store.SaveSnapshot(snapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	retrieved, err := store.GetLatestSnapshot("actor-complex")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	// Verify all fields
	if retrieved.State["string"] != "hello" {
		t.Errorf("string mismatch: got %v", retrieved.State["string"])
	}
	if retrieved.State["integer"] != 42 {
		t.Errorf("integer mismatch: got %v", retrieved.State["integer"])
	}
	if retrieved.State["float"] != 3.14159 {
		t.Errorf("float mismatch: got %v", retrieved.State["float"])
	}
	if retrieved.State["boolean"] != true {
		t.Errorf("boolean mismatch: got %v", retrieved.State["boolean"])
	}
	if retrieved.State["null"] != nil {
		t.Errorf("null mismatch: got %v", retrieved.State["null"])
	}

	// Verify array
	arr, ok := retrieved.State["array"].([]interface{})
	if !ok {
		t.Fatal("array is not []interface{}")
	}
	if len(arr) != 3 || arr[0] != "a" || arr[1] != "b" || arr[2] != "c" {
		t.Errorf("array mismatch: got %v", arr)
	}

	// Verify nested structure
	nested, ok := retrieved.State["nested"].(map[string]interface{})
	if !ok {
		t.Fatal("nested is not map[string]interface{}")
	}
	level1, ok := nested["level1"].(map[string]interface{})
	if !ok {
		t.Fatal("level1 is not map[string]interface{}")
	}
	if level1["level2"] != "deep value" {
		t.Errorf("nested value mismatch: got %v", level1["level2"])
	}
}

func TestSnapshotDataIntegrity_SpecialCharacters(t *testing.T) {
	store := NewInMemoryEventStore()

	specialState := map[string]interface{}{
		"unicode":    "Hello, \u4e16\u754c!",
		"emoji":      "\U0001F600\U0001F680",
		"newlines":   "line1\nline2\r\nline3",
		"tabs":       "col1\tcol2",
		"quotes":     `"double" and 'single'`,
		"backslash":  `path\to\file`,
	}

	snapshot := &aether.ActorSnapshot{
		ActorID:   "actor-special",
		Version:   1,
		State:     specialState,
		Timestamp: time.Now(),
	}

	if err := store.SaveSnapshot(snapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	retrieved, err := store.GetLatestSnapshot("actor-special")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	for key, expected := range specialState {
		if retrieved.State[key] != expected {
			t.Errorf("State[%q] mismatch: got %q, want %q", key, retrieved.State[key], expected)
		}
	}
}

func TestSnapshotDataIntegrity_EmptyState(t *testing.T) {
	store := NewInMemoryEventStore()

	snapshot := &aether.ActorSnapshot{
		ActorID:   "actor-empty",
		Version:   1,
		State:     map[string]interface{}{},
		Timestamp: time.Now(),
	}

	if err := store.SaveSnapshot(snapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	retrieved, err := store.GetLatestSnapshot("actor-empty")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if len(retrieved.State) != 0 {
		t.Errorf("expected empty state, got %v", retrieved.State)
	}
}

func TestSnapshotDataIntegrity_NilState(t *testing.T) {
	store := NewInMemoryEventStore()

	snapshot := &aether.ActorSnapshot{
		ActorID:   "actor-nil",
		Version:   1,
		State:     nil,
		Timestamp: time.Now(),
	}

	if err := store.SaveSnapshot(snapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	retrieved, err := store.GetLatestSnapshot("actor-nil")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if retrieved.State != nil {
		t.Errorf("expected nil state, got %v", retrieved.State)
	}
}

func TestSnapshotDataIntegrity_LargeState(t *testing.T) {
	store := NewInMemoryEventStore()

	// Create a large state with many entries
	largeState := make(map[string]interface{})
	for i := 0; i < 1000; i++ {
		largeState[string(rune('a'+i%26))+string(rune('0'+i%10))] = i
	}

	snapshot := &aether.ActorSnapshot{
		ActorID:   "actor-large",
		Version:   1,
		State:     largeState,
		Timestamp: time.Now(),
	}

	if err := store.SaveSnapshot(snapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	retrieved, err := store.GetLatestSnapshot("actor-large")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if len(retrieved.State) != len(largeState) {
		t.Errorf("state size mismatch: got %d, want %d", len(retrieved.State), len(largeState))
	}
}

func TestSnapshotDataIntegrity_TimestampPreserved(t *testing.T) {
	store := NewInMemoryEventStore()

	// Test various timestamps
	timestamps := []time.Time{
		time.Date(2026, 1, 9, 12, 0, 0, 0, time.UTC),
		time.Date(2020, 6, 15, 23, 59, 59, 999999999, time.UTC),
		time.Time{}, // Zero time
	}

	for i, ts := range timestamps {
		actorID := "actor-ts-" + string(rune('a'+i))
		snapshot := &aether.ActorSnapshot{
			ActorID:   actorID,
			Version:   1,
			State:     map[string]interface{}{},
			Timestamp: ts,
		}

		if err := store.SaveSnapshot(snapshot); err != nil {
			t.Fatalf("SaveSnapshot failed: %v", err)
		}

		retrieved, err := store.GetLatestSnapshot(actorID)
		if err != nil {
			t.Fatalf("GetLatestSnapshot failed: %v", err)
		}

		if !retrieved.Timestamp.Equal(ts) {
			t.Errorf("timestamp %d mismatch: got %v, want %v", i, retrieved.Timestamp, ts)
		}
	}
}

func TestSnapshotVersioning_ZeroVersion(t *testing.T) {
	store := NewInMemoryEventStore()

	snapshot := &aether.ActorSnapshot{
		ActorID:   "actor-zero-version",
		Version:   0,
		State:     map[string]interface{}{"initial": true},
		Timestamp: time.Now(),
	}

	if err := store.SaveSnapshot(snapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	retrieved, err := store.GetLatestSnapshot("actor-zero-version")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if retrieved.Version != 0 {
		t.Errorf("expected version 0, got %d", retrieved.Version)
	}
}

func TestSnapshotVersioning_LargeVersion(t *testing.T) {
	store := NewInMemoryEventStore()

	largeVersion := int64(9223372036854775807) // MaxInt64

	snapshot := &aether.ActorSnapshot{
		ActorID:   "actor-large-version",
		Version:   largeVersion,
		State:     map[string]interface{}{"maxed": true},
		Timestamp: time.Now(),
	}

	if err := store.SaveSnapshot(snapshot); err != nil {
		t.Fatalf("SaveSnapshot failed: %v", err)
	}

	retrieved, err := store.GetLatestSnapshot("actor-large-version")
	if err != nil {
		t.Fatalf("GetLatestSnapshot failed: %v", err)
	}

	if retrieved.Version != largeVersion {
		t.Errorf("expected version %d, got %d", largeVersion, retrieved.Version)
	}
}

func TestSnapshotStore_ImplementsInterface(t *testing.T) {
	// Verify InMemoryEventStore implements SnapshotStore interface
	var _ aether.SnapshotStore = (*InMemoryEventStore)(nil)
}