package service

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"net/http/httptest"
	"testing"

	"github.com/gochat/gochat/internal/llm"
	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

func setupCopilotConfigServiceTest(t *testing.T) (*CopilotConfigService, *gorm.DB, *llm.ProviderManager) {
	t.Helper()
	db, err := gorm.Open(sqlite.Open("file:"+t.Name()+"?mode=memory&cache=shared"), &gorm.Config{})
	require.NoError(t, err)
	require.NoError(t, db.AutoMigrate(&model.InstallationConfig{}))
	manager := llm.NewProviderManager()
	svc := NewCopilotConfigService(repository.NewInstallationConfigRepo(db), manager)
	return svc, db, manager
}

func float64Ptr(v float64) *float64 { return &v }

func testCopilotInput(baseURL string) CopilotProviderConfigInput {
	return CopilotProviderConfigInput{
		Chat: CopilotChatConfigInput{
			Provider:           "openai_compatible",
			BaseURL:            baseURL,
			Model:              "custom-model",
			CopilotSecretInput: CopilotSecretInput{APIKey: "secret-api-key"},
		},
		Embedding: CopilotEmbeddingConfigInput{
			Mode:       llm.EmbeddingModeReuseChat,
			Provider:   "openai_compatible",
			BaseURL:    baseURL,
			Model:      "custom-embedding",
			Dimensions: 3,
		},
		Generation: CopilotGenerationConfigInput{Temperature: float64Ptr(0.4), MaxTokens: intPtr(800)},
		Request:    CopilotRequestConfigInput{TimeoutSeconds: intPtr(30), MaxRetries: intPtr(0)},
	}
}

func TestCopilotConfigServiceDefaultsToUnconfigured(t *testing.T) {
	svc, _, _ := setupCopilotConfigServiceTest(t)
	payload, err := svc.Get(context.Background())
	require.NoError(t, err)
	assert.Equal(t, "openai", payload.Chat.Provider)
	assert.Equal(t, "gpt-4o-mini", payload.Chat.Model)
	assert.False(t, payload.Configured)
}

func TestCopilotConfigServiceSavesPlaintextKeysAndConfiguresManager(t *testing.T) {
	svc, db, manager := setupCopilotConfigServiceTest(t)
	payload, err := svc.Update(context.Background(), testCopilotInput("https://llm.example.com/v1/"))
	require.NoError(t, err)
	assert.True(t, payload.Configured)
	assert.Equal(t, "sec****-key", payload.Chat.APIKey.Masked)

	var stored model.InstallationConfig
	require.NoError(t, db.Where("name = ?", copilotChatAPIKeyConfigKey).First(&stored).Error)
	assert.Equal(t, "secret-api-key", stored.Value)

	snapshot, configured := manager.Snapshot()
	assert.True(t, configured)
	assert.Equal(t, "custom-model", snapshot.ChatModel)
	assert.Equal(t, "https://llm.example.com/v1", snapshot.ChatBaseURL)
	assert.Equal(t, 0, snapshot.MaxRetries)
}

func TestCopilotConfigServiceClearsActiveProvider(t *testing.T) {
	svc, _, manager := setupCopilotConfigServiceTest(t)
	_, err := svc.Update(context.Background(), testCopilotInput("https://llm.example.com/v1"))
	require.NoError(t, err)

	input := testCopilotInput("https://llm.example.com/v1")
	input.Chat.APIKey = ""
	input.Chat.ClearAPIKey = true
	payload, err := svc.Update(context.Background(), input)
	require.NoError(t, err)
	assert.False(t, payload.Configured)
	_, configured := manager.Snapshot()
	assert.False(t, configured)
}

func TestCopilotConfigServiceRejectsAnthropicWithoutSeparateEmbedding(t *testing.T) {
	svc, _, _ := setupCopilotConfigServiceTest(t)
	input := testCopilotInput("https://api.anthropic.com")
	input.Chat.Provider = "anthropic"
	_, err := svc.Update(context.Background(), input)
	require.ErrorContains(t, err, "separate embedding provider")
}

func TestCopilotConfigServiceRejectsCredentialsInBaseURL(t *testing.T) {
	svc, _, _ := setupCopilotConfigServiceTest(t)
	input := testCopilotInput("https://user:secret@llm.example.com/v1")
	_, err := svc.Update(context.Background(), input)
	require.ErrorContains(t, err, "must not contain credentials")
}

func TestCopilotConfigServiceTestsChatAndEmbeddingWithoutChangingSavedConfig(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		switch r.URL.Path {
		case "/chat/completions":
			var req llm.ChatRequest
			require.NoError(t, json.NewDecoder(r.Body).Decode(&req))
			_, _ = w.Write([]byte(`{"id":"chat-1","choices":[{"message":{"role":"assistant","content":"OK"},"finish_reason":"stop"}]}`))
		case "/embeddings":
			_, _ = w.Write([]byte(`{"data":[{"index":0,"embedding":[0.1,0.2,0.3]}],"model":"custom-embedding"}`))
		default:
			http.NotFound(w, r)
		}
	}))
	defer server.Close()

	svc, _, _ := setupCopilotConfigServiceTest(t)
	input := testCopilotInput(server.URL)
	health, err := svc.Test(context.Background(), input)
	require.NoError(t, err)
	assert.True(t, health.Chat.OK)
	assert.True(t, health.Embedding.OK)

	payload, err := svc.Get(context.Background())
	require.NoError(t, err)
	assert.False(t, payload.Configured, "testing candidate settings must not persist them")
}

func TestNormalizeCopilotProviderErrorDoesNotExposeProviderResponse(t *testing.T) {
	providerErr := fmt.Errorf("chat completion: %w", &llm.APIError{
		StatusCode: http.StatusInternalServerError,
		Message:    "complete provider response containing sk-secret-value",
	})

	normalized := normalizeCopilotProviderError(providerErr)
	assert.Equal(t, "provider request failed", normalized)
	assert.NotContains(t, normalized, "sk-secret-value")
	assert.Equal(t, "provider response format is incompatible", normalizeCopilotProviderError(
		fmt.Errorf("unmarshal chat response: invalid character"),
	))
}