package ucca

import (
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
)

func TestSearchCollection_UsesCorrectCollection(t *testing.T) {
	// Track which collection was requested
	var requestedURL string

	// Mock Ollama (embedding)
	ollamaMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		json.NewEncoder(w).Encode(ollamaEmbeddingResponse{
			Embedding: make([]float64, 1024),
		})
	}))
	defer ollamaMock.Close()

	// Mock Qdrant
	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestedURL = r.URL.Path
		json.NewEncoder(w).Encode(qdrantSearchResponse{
			Result: []qdrantSearchHit{},
		})
	}))
	defer qdrantMock.Close()

	// Parse qdrant mock host/port
	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		ollamaURL:        ollamaMock.URL,
		embeddingModel:   "bge-m3",
		collection:       "bp_compliance_ce",
		textIndexEnsured: make(map[string]bool),
		hybridEnabled:    false, // dense-only for this test
		httpClient:       http.DefaultClient,
	}

	// Test with explicit collection
	_, err := client.SearchCollection(context.Background(), "bp_compliance_recht", "test query", nil, 3)
	if err != nil {
		t.Fatalf("SearchCollection failed: %v", err)
	}

	if !strings.Contains(requestedURL, "/collections/bp_compliance_recht/") {
		t.Errorf("Expected collection bp_compliance_recht in URL, got: %s", requestedURL)
	}
}

func TestSearchCollection_FallbackDefault(t *testing.T) {
	var requestedURL string

	ollamaMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		json.NewEncoder(w).Encode(ollamaEmbeddingResponse{
			Embedding: make([]float64, 1024),
		})
	}))
	defer ollamaMock.Close()

	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestedURL = r.URL.Path
		json.NewEncoder(w).Encode(qdrantSearchResponse{
			Result: []qdrantSearchHit{},
		})
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		ollamaURL:        ollamaMock.URL,
		embeddingModel:   "bge-m3",
		collection:       "bp_compliance_ce",
		textIndexEnsured: make(map[string]bool),
		hybridEnabled:    false,
		httpClient:       http.DefaultClient,
	}

	// Test with empty collection (should fall back to default)
	_, err := client.SearchCollection(context.Background(), "", "test query", nil, 3)
	if err != nil {
		t.Fatalf("SearchCollection failed: %v", err)
	}

	if !strings.Contains(requestedURL, "/collections/bp_compliance_ce/") {
		t.Errorf("Expected default collection bp_compliance_ce in URL, got: %s", requestedURL)
	}
}

func TestScrollChunks_ReturnsChunksAndNextOffset(t *testing.T) {
	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if !strings.Contains(r.URL.Path, "/points/scroll") {
			t.Errorf("Expected scroll endpoint, got: %s", r.URL.Path)
		}

		// Decode request to verify fields
		var reqBody map[string]interface{}
		json.NewDecoder(r.Body).Decode(&reqBody)

		if reqBody["with_vectors"] != false {
			t.Error("Expected with_vectors=false")
		}
		if reqBody["with_payload"] != true {
			t.Error("Expected with_payload=true")
		}

		resp := map[string]interface{}{
			"result": map[string]interface{}{
				"points": []map[string]interface{}{
					{
						"id": "abc-123",
						"payload": map[string]interface{}{
							"text":             "Artikel 35 DSGVO",
							"regulation_code":  "eu_2016_679",
							"regulation_name":  "DSGVO",
							"regulation_short": "DSGVO",
							"category":         "regulation",
							"article":          "Art. 35",
							"paragraph":        "1",
							"source_url":       "https://example.com/dsgvo",
						},
					},
					{
						"id": "def-456",
						"payload": map[string]interface{}{
							"chunk_text":         "AI Act Titel III",
							"regulation_id":      "eu_2024_1689",
							"regulation_name_de": "KI-Verordnung",
							"regulation_short":   "AI Act",
							"category":           "regulation",
							"source":             "https://example.com/ai-act",
						},
					},
				},
				"next_page_offset": "def-456",
			},
		}
		json.NewEncoder(w).Encode(resp)
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		textIndexEnsured: make(map[string]bool),
		httpClient:       http.DefaultClient,
	}

	chunks, nextOffset, err := client.ScrollChunks(context.Background(), "bp_compliance_ce", "", 100)
	if err != nil {
		t.Fatalf("ScrollChunks failed: %v", err)
	}

	if len(chunks) != 2 {
		t.Fatalf("Expected 2 chunks, got %d", len(chunks))
	}

	// First chunk uses direct field names
	if chunks[0].ID != "abc-123" {
		t.Errorf("Expected ID abc-123, got %s", chunks[0].ID)
	}
	if chunks[0].Text != "Artikel 35 DSGVO" {
		t.Errorf("Expected text 'Artikel 35 DSGVO', got '%s'", chunks[0].Text)
	}
	if chunks[0].RegulationCode != "eu_2016_679" {
		t.Errorf("Expected regulation_code eu_2016_679, got %s", chunks[0].RegulationCode)
	}
	if chunks[0].Article != "Art. 35" {
		t.Errorf("Expected article 'Art. 35', got '%s'", chunks[0].Article)
	}

	// Second chunk uses fallback field names (chunk_text, regulation_id, etc.)
	if chunks[1].Text != "AI Act Titel III" {
		t.Errorf("Expected fallback text 'AI Act Titel III', got '%s'", chunks[1].Text)
	}
	if chunks[1].RegulationCode != "eu_2024_1689" {
		t.Errorf("Expected fallback regulation_code eu_2024_1689, got '%s'", chunks[1].RegulationCode)
	}
	if chunks[1].RegulationName != "KI-Verordnung" {
		t.Errorf("Expected fallback regulation_name 'KI-Verordnung', got '%s'", chunks[1].RegulationName)
	}

	if nextOffset != "def-456" {
		t.Errorf("Expected next_offset 'def-456', got '%s'", nextOffset)
	}
}

func TestScrollChunks_EmptyCollection_ReturnsEmpty(t *testing.T) {
	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		resp := map[string]interface{}{
			"result": map[string]interface{}{
				"points":           []interface{}{},
				"next_page_offset": nil,
			},
		}
		json.NewEncoder(w).Encode(resp)
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		textIndexEnsured: make(map[string]bool),
		httpClient:       http.DefaultClient,
	}

	chunks, nextOffset, err := client.ScrollChunks(context.Background(), "bp_compliance_ce", "", 100)
	if err != nil {
		t.Fatalf("ScrollChunks failed: %v", err)
	}

	if len(chunks) != 0 {
		t.Errorf("Expected 0 chunks, got %d", len(chunks))
	}

	if nextOffset != "" {
		t.Errorf("Expected empty next_offset, got '%s'", nextOffset)
	}
}

func TestScrollChunks_WithOffset_SendsOffset(t *testing.T) {
	var receivedBody map[string]interface{}

	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		json.NewDecoder(r.Body).Decode(&receivedBody)
		resp := map[string]interface{}{
			"result": map[string]interface{}{
				"points":           []interface{}{},
				"next_page_offset": nil,
			},
		}
		json.NewEncoder(w).Encode(resp)
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		textIndexEnsured: make(map[string]bool),
		httpClient:       http.DefaultClient,
	}

	_, _, err := client.ScrollChunks(context.Background(), "bp_compliance_ce", "some-offset-id", 50)
	if err != nil {
		t.Fatalf("ScrollChunks failed: %v", err)
	}

	if receivedBody["offset"] != "some-offset-id" {
		t.Errorf("Expected offset 'some-offset-id', got '%v'", receivedBody["offset"])
	}
	if receivedBody["limit"] != float64(50) {
		t.Errorf("Expected limit 50, got %v", receivedBody["limit"])
	}
}

func TestScrollChunks_SendsAPIKey(t *testing.T) {
	var receivedAPIKey string

	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		receivedAPIKey = r.Header.Get("api-key")
		resp := map[string]interface{}{
			"result": map[string]interface{}{
				"points":           []interface{}{},
				"next_page_offset": nil,
			},
		}
		json.NewEncoder(w).Encode(resp)
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		qdrantAPIKey:     "test-api-key-123",
		textIndexEnsured: make(map[string]bool),
		httpClient:       http.DefaultClient,
	}

	_, _, err := client.ScrollChunks(context.Background(), "bp_compliance_ce", "", 10)
	if err != nil {
		t.Fatalf("ScrollChunks failed: %v", err)
	}

	if receivedAPIKey != "test-api-key-123" {
		t.Errorf("Expected api-key 'test-api-key-123', got '%s'", receivedAPIKey)
	}
}

func TestSearch_StillWorks(t *testing.T) {
	var requestedURL string

	ollamaMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		json.NewEncoder(w).Encode(ollamaEmbeddingResponse{
			Embedding: make([]float64, 1024),
		})
	}))
	defer ollamaMock.Close()

	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestedURL = r.URL.Path
		json.NewEncoder(w).Encode(qdrantSearchResponse{
			Result: []qdrantSearchHit{
				{
					ID:    "1",
					Score: 0.95,
					Payload: map[string]interface{}{
						"chunk_text":         "Test content",
						"regulation_id":      "eu_2016_679",
						"regulation_name_de": "DSGVO",
						"regulation_short":   "DSGVO",
						"category":           "regulation",
						"source":             "https://example.com",
					},
				},
			},
		})
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		ollamaURL:        ollamaMock.URL,
		embeddingModel:   "bge-m3",
		collection:       "bp_compliance_ce",
		textIndexEnsured: make(map[string]bool),
		hybridEnabled:    false,
		httpClient:       http.DefaultClient,
	}

	results, err := client.Search(context.Background(), "DSGVO Art. 35", nil, 5)
	if err != nil {
		t.Fatalf("Search failed: %v", err)
	}

	if len(results) != 1 {
		t.Fatalf("Expected 1 result, got %d", len(results))
	}

	if results[0].RegulationCode != "eu_2016_679" {
		t.Errorf("Expected regulation_code eu_2016_679, got %s", results[0].RegulationCode)
	}

	if !strings.Contains(requestedURL, "/collections/bp_compliance_ce/") {
		t.Errorf("Expected default collection in URL, got: %s", requestedURL)
	}
}

// --- Hybrid Search Tests ---

func TestHybridSearch_UsesQueryAPI(t *testing.T) {
	var requestedPaths []string

	ollamaMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		json.NewEncoder(w).Encode(ollamaEmbeddingResponse{
			Embedding: make([]float64, 1024),
		})
	}))
	defer ollamaMock.Close()

	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestedPaths = append(requestedPaths, r.URL.Path)

		if strings.Contains(r.URL.Path, "/index") {
			// Text index creation — return OK
			w.WriteHeader(http.StatusOK)
			w.Write([]byte(`{"result":{"operation_id":1,"status":"completed"}}`))
			return
		}

		if strings.Contains(r.URL.Path, "/points/query") {
			// Verify the query request body has prefetch + fusion
			var reqBody map[string]interface{}
			json.NewDecoder(r.Body).Decode(&reqBody)

			if _, ok := reqBody["prefetch"]; !ok {
				t.Error("Query request missing 'prefetch' field")
			}
			queryField, ok := reqBody["query"].(map[string]interface{})
			if !ok || queryField["fusion"] != "rrf" {
				t.Error("Query request missing 'query.fusion=rrf'")
			}

			json.NewEncoder(w).Encode(qdrantQueryResponse{
				Result: []qdrantSearchHit{
					{
						ID:    "1",
						Score: 0.88,
						Payload: map[string]interface{}{
							"chunk_text":         "Hybrid result",
							"regulation_id":      "eu_2016_679",
							"regulation_name_de": "DSGVO",
							"regulation_short":   "DSGVO",
							"category":           "regulation",
							"source":             "https://example.com",
						},
					},
				},
			})
			return
		}

		// Fallback: should not reach dense search
		t.Error("Unexpected dense search call when hybrid succeeded")
		json.NewEncoder(w).Encode(qdrantSearchResponse{Result: []qdrantSearchHit{}})
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		ollamaURL:        ollamaMock.URL,
		embeddingModel:   "bge-m3",
		collection:       "bp_compliance_ce",
		textIndexEnsured: make(map[string]bool),
		hybridEnabled:    true,
		httpClient:       http.DefaultClient,
	}

	results, err := client.Search(context.Background(), "DSGVO Art. 35", nil, 5)
	if err != nil {
		t.Fatalf("Hybrid search failed: %v", err)
	}

	if len(results) != 1 {
		t.Fatalf("Expected 1 result, got %d", len(results))
	}
	if results[0].Text != "Hybrid result" {
		t.Errorf("Expected 'Hybrid result', got '%s'", results[0].Text)
	}

	// Verify text index was created
	hasIndex := false
	hasQuery := false
	for _, p := range requestedPaths {
		if strings.Contains(p, "/index") {
			hasIndex = true
		}
		if strings.Contains(p, "/points/query") {
			hasQuery = true
		}
	}
	if !hasIndex {
		t.Error("Expected text index creation call")
	}
	if !hasQuery {
		t.Error("Expected Query API call")
	}
}

func TestHybridSearch_FallbackToDense(t *testing.T) {
	var requestedPaths []string

	ollamaMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		json.NewEncoder(w).Encode(ollamaEmbeddingResponse{
			Embedding: make([]float64, 1024),
		})
	}))
	defer ollamaMock.Close()

	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestedPaths = append(requestedPaths, r.URL.Path)

		if strings.Contains(r.URL.Path, "/index") {
			// Simulate text index failure (old Qdrant version)
			w.WriteHeader(http.StatusBadRequest)
			w.Write([]byte(`{"status":{"error":"not supported"}}`))
			return
		}

		if strings.Contains(r.URL.Path, "/points/search") {
			// Dense fallback
			json.NewEncoder(w).Encode(qdrantSearchResponse{
				Result: []qdrantSearchHit{
					{
						ID:    "2",
						Score: 0.90,
						Payload: map[string]interface{}{
							"chunk_text":         "Dense fallback result",
							"regulation_id":      "eu_2016_679",
							"regulation_name_de": "DSGVO",
							"regulation_short":   "DSGVO",
							"category":           "regulation",
							"source":             "https://example.com",
						},
					},
				},
			})
			return
		}

		w.WriteHeader(http.StatusInternalServerError)
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		ollamaURL:        ollamaMock.URL,
		embeddingModel:   "bge-m3",
		collection:       "bp_compliance_ce",
		textIndexEnsured: make(map[string]bool),
		hybridEnabled:    true,
		httpClient:       http.DefaultClient,
	}

	results, err := client.Search(context.Background(), "test query", nil, 5)
	if err != nil {
		t.Fatalf("Fallback search failed: %v", err)
	}

	if len(results) != 1 {
		t.Fatalf("Expected 1 result, got %d", len(results))
	}
	if results[0].Text != "Dense fallback result" {
		t.Errorf("Expected 'Dense fallback result', got '%s'", results[0].Text)
	}

	// Verify it fell back to dense search
	hasDense := false
	for _, p := range requestedPaths {
		if strings.Contains(p, "/points/search") {
			hasDense = true
		}
	}
	if !hasDense {
		t.Error("Expected fallback to dense /points/search")
	}
}

func TestEnsureTextIndex_OnlyCalledOnce(t *testing.T) {
	callCount := 0

	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if strings.Contains(r.URL.Path, "/index") {
			callCount++
			w.WriteHeader(http.StatusOK)
			w.Write([]byte(`{"result":{"operation_id":1,"status":"completed"}}`))
			return
		}
		w.WriteHeader(http.StatusOK)
		w.Write([]byte(`{"result":[]}`))
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		textIndexEnsured: make(map[string]bool),
		httpClient:       http.DefaultClient,
	}

	ctx := context.Background()
	_ = client.ensureTextIndex(ctx, "test_collection")
	_ = client.ensureTextIndex(ctx, "test_collection")
	_ = client.ensureTextIndex(ctx, "test_collection")

	if callCount != 1 {
		t.Errorf("Expected ensureTextIndex to call Qdrant exactly once, called %d times", callCount)
	}
}

func TestHybridDisabled_UsesDenseOnly(t *testing.T) {
	var requestedPaths []string

	ollamaMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		json.NewEncoder(w).Encode(ollamaEmbeddingResponse{
			Embedding: make([]float64, 1024),
		})
	}))
	defer ollamaMock.Close()

	qdrantMock := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestedPaths = append(requestedPaths, r.URL.Path)
		json.NewEncoder(w).Encode(qdrantSearchResponse{
			Result: []qdrantSearchHit{},
		})
	}))
	defer qdrantMock.Close()

	client := &LegalRAGClient{
		qdrantURL:        qdrantMock.URL,
		ollamaURL:        ollamaMock.URL,
		embeddingModel:   "bge-m3",
		collection:       "bp_compliance_ce",
		textIndexEnsured: make(map[string]bool),
		hybridEnabled:    false,
		httpClient:       http.DefaultClient,
	}

	_, err := client.Search(context.Background(), "test", nil, 5)
	if err != nil {
		t.Fatalf("Search failed: %v", err)
	}

	for _, p := range requestedPaths {
		if strings.Contains(p, "/points/query") {
			t.Error("Query API should not be called when hybrid is disabled")
		}
		if strings.Contains(p, "/index") {
			t.Error("Text index should not be created when hybrid is disabled")
		}
	}
}