package v1

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

	"github.com/gin-gonic/gin"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/suite"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"

	"github.com/gochat/gochat/internal/channel"
	"github.com/gochat/gochat/internal/llm"
	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
	"github.com/gochat/gochat/internal/service"
)

// --- Mock LLM Provider for message handler tests ---
// Named separately to avoid conflict with mockLLMProvider in captain_task_service_test.go

type mockMsgHandlerLLMProvider struct {
	chatResponse *llm.ChatResponse
	chatError    error
}

func (m *mockMsgHandlerLLMProvider) ChatCompletion(ctx context.Context, req llm.ChatRequest) (*llm.ChatResponse, error) {
	if m.chatError != nil {
		return nil, m.chatError
	}
	return m.chatResponse, nil
}

func (m *mockMsgHandlerLLMProvider) CreateEmbedding(ctx context.Context, req llm.EmbeddingRequest) (*llm.EmbeddingResponse, error) {
	return &llm.EmbeddingResponse{}, nil
}

func (m *mockMsgHandlerLLMProvider) ChatCompletionStream(ctx context.Context, req llm.ChatRequest, onChunk func(llm.StreamChunk) error) error {
	return nil
}

// --- Message Handler Test Suite --- (CRUD, Retry, Translate)

type MessageHandlerTestSuite struct {
	suite.Suite
	router      *gin.Engine
	handler     *MessageHandler
	db          *gorm.DB
	testAccount *model.Account
	testInbox   *model.Inbox
	testContact *model.Contact
	testConv    *model.Conversation
	testMessage *model.Message
	mockLLM     *mockMsgHandlerLLMProvider
	dispatcher  *channel.Dispatcher
}

func (s *MessageHandlerTestSuite) SetupSuite() {
	gin.SetMode(gin.TestMode)

	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Silent),
	})
	s.Require().NoError(err)
	s.db = db

	// AutoMigrate all required models
	err = db.AutoMigrate(
		&model.Account{},
		&model.Inbox{},
		&model.Contact{},
		&model.ContactInbox{},
		&model.Conversation{},
		&model.ConversationParticipant{},
		&model.Message{},
		&model.InboxMember{},
	)
	s.Require().NoError(err)

// Wire up repos, services, handlers
	msgRepo := repository.NewMessageRepo(db)
	s.dispatcher = channel.NewDispatcher()
	s.mockLLM = &mockMsgHandlerLLMProvider{
		chatResponse: &llm.ChatResponse{
			Choices: []llm.ChatChoice{
				{
					Message: llm.ChatMessage{Role: "assistant", Content: "Bonjour le monde"},
				},
			},
		},
	}
	msgSvc := service.NewMessageService(msgRepo, s.dispatcher, s.mockLLM)
	s.handler = NewMessageHandler(msgSvc)

	// Setup router with all message routes
	r := gin.New()
	r.RedirectTrailingSlash = false
	s.router = r

	// Auth middleware: inject user_id into context for all message routes
	r.Use(func(c *gin.Context) {
		c.Set("user_id", uint(1))
		c.Next()
	})

	accountGroup := r.Group("/api/v1/accounts/:account_id")
	{
		conversations := accountGroup.Group("/conversations")
		{
			msgs := conversations.Group("/:conversation_id/messages")
			{
				msgs.GET("/", s.handler.List)
				msgs.POST("/", s.handler.Create)
				msgs.GET("/:message_id", s.handler.Get)
				msgs.PATCH("/:message_id", s.handler.Update)
				msgs.DELETE("/:message_id", s.handler.Delete)
				msgs.POST("/:message_id/retry", s.handler.Retry)
				msgs.POST("/:message_id/translate", s.handler.Translate)
			}
		}
	}
}

func (s *MessageHandlerTestSuite) TearDownSuite() {
	if s.db != nil {
		sqlDB, _ := s.db.DB()
		sqlDB.Close()
	}
}

func (s *MessageHandlerTestSuite) SetupTest() {
	// Seed data for each test
	account := &model.Account{Name: "MsgHandlerTestAccount", Locale: "en", Active: true}
	s.Require().NoError(s.db.Create(account).Error)
	s.testAccount = account

	inbox := &model.Inbox{AccountID: account.ID, Name: "MsgHandlerTestInbox", ChannelType: "web_widget", ChannelID: 1}
	s.Require().NoError(s.db.Create(inbox).Error)
	s.testInbox = inbox

	contact := &model.Contact{AccountID: account.ID, Name: "MsgHandlerTestContact"}
	s.Require().NoError(s.db.Create(contact).Error)
	s.testContact = contact

	conv := &model.Conversation{
		AccountID:   account.ID,
		InboxID:     inbox.ID,
		ContactID:   contact.ID,
		Status:      string(model.ConversationStatusOpen),
		Priority:    string(model.ConversationPriorityMedium),
		ChannelType: "web_widget",
		Channel:     "web_widget",
	}
	s.Require().NoError(s.db.Create(conv).Error)
	s.testConv = conv

	msg := &model.Message{
		ConversationID: conv.ID,
		AccountID:      account.ID,
		InboxID:        inbox.ID,
		Content:        "Hello world",
		ContentType:    "text",
		MessageType:    "outgoing",
		SenderType:     "user",
	}
	s.Require().NoError(s.db.Create(msg).Error)
	s.testMessage = msg

// Reset mock LLM to default success response
	s.mockLLM.chatResponse = &llm.ChatResponse{
		Choices: []llm.ChatChoice{
			{
				Message: llm.ChatMessage{Role: "assistant", Content: "Bonjour le monde"},
			},
		},
	}
	s.mockLLM.chatError = nil
}

func (s *MessageHandlerTestSuite) TearDownTest() {
	s.db.Exec("DELETE FROM messages")
	s.db.Exec("DELETE FROM conversation_participants")
	s.db.Exec("DELETE FROM conversations")
	s.db.Exec("DELETE FROM contact_inboxes")
	s.db.Exec("DELETE FROM contacts")
	s.db.Exec("DELETE FROM inbox_members")
	s.db.Exec("DELETE FROM inboxes")
	s.db.Exec("DELETE FROM accounts")
}

func TestMessageHandlerTestSuite(t *testing.T) {
	suite.Run(t, new(MessageHandlerTestSuite))
}

// --- Helper for building message list URL --- 

func msgListURL(accountID, convID uint) string {
	return fmt.Sprintf("/api/v1/accounts/%d/conversations/%d/messages/", accountID, convID)
}

func msgDetailURL(accountID, convID, msgID uint) string {
	return fmt.Sprintf("/api/v1/accounts/%d/conversations/%d/messages/%d", accountID, convID, msgID)
}

func msgRetryURL(accountID, convID, msgID uint) string {
	return fmt.Sprintf("/api/v1/accounts/%d/conversations/%d/messages/%d/retry", accountID, convID, msgID)
}

func msgTranslateURL(accountID, convID, msgID uint) string {
	return fmt.Sprintf("/api/v1/accounts/%d/conversations/%d/messages/%d/translate", accountID, convID, msgID)
}

// --- List Tests --- 

func (s *MessageHandlerTestSuite) TestList_Success() {
	w := httptest.NewRecorder()
	url := msgListURL(s.testAccount.ID, s.testConv.ID)
	req, _ := http.NewRequest("GET", url, nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusOK, w.Code)
	var resp map[string]interface{}
	json.Unmarshal(w.Body.Bytes(), &resp)
	assert.True(s.T(), resp["success"].(bool))
	data, ok := resp["data"].([]interface{})
	assert.True(s.T(), ok)
	assert.GreaterOrEqual(s.T(), len(data), 1)
}

func (s *MessageHandlerTestSuite) TestList_Empty() {
	// Delete seeded messages to test empty list
	s.db.Exec("DELETE FROM messages")

	w := httptest.NewRecorder()
	url := msgListURL(s.testAccount.ID, s.testConv.ID)
	req, _ := http.NewRequest("GET", url, nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusOK, w.Code)
	var resp map[string]interface{}
	json.Unmarshal(w.Body.Bytes(), &resp)
	data, ok := resp["data"].([]interface{})
	assert.True(s.T(), ok)
	assert.Equal(s.T(), 0, len(data))
}

func (s *MessageHandlerTestSuite) TestList_InvalidConversationID() {
	w := httptest.NewRecorder()
	req, _ := http.NewRequest("GET", "/api/v1/accounts/1/conversations/abc/messages/", nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

// --- Create Tests --- 

func (s *MessageHandlerTestSuite) TestCreate_Success() {
	payload := map[string]interface{}{
		"content":      "New message",
		"content_type": "text",
		"message_type": "outgoing",
		"private":      false,
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	url := msgListURL(s.testAccount.ID, s.testConv.ID)
	req, _ := http.NewRequest("POST", url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusCreated, w.Code)
	var resp map[string]interface{}
	json.Unmarshal(w.Body.Bytes(), &resp)
	assert.True(s.T(), resp["success"].(bool))
	data := resp["data"].(map[string]interface{})
	assert.NotNil(s.T(), data["id"])
	assert.Equal(s.T(), "New message", data["content"])
}

func (s *MessageHandlerTestSuite) TestCreate_MissingContent() {
	payload := map[string]interface{}{
		"content_type": "text",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	url := msgListURL(s.testAccount.ID, s.testConv.ID)
	req, _ := http.NewRequest("POST", url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

func (s *MessageHandlerTestSuite) TestCreate_InvalidConversationID() {
	payload := map[string]interface{}{
		"content":      "Test",
		"content_type": "text",
		"message_type": "outgoing",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	req, _ := http.NewRequest("POST", "/api/v1/accounts/1/conversations/abc/messages/", bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

// --- Get Tests --- 

func (s *MessageHandlerTestSuite) TestGet_Success() {
	w := httptest.NewRecorder()
	url := msgDetailURL(s.testAccount.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("GET", url, nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusOK, w.Code)
	var resp map[string]interface{}
	json.Unmarshal(w.Body.Bytes(), &resp)
	assert.True(s.T(), resp["success"].(bool))
	data := resp["data"].(map[string]interface{})
	assert.Equal(s.T(), float64(s.testMessage.ID), data["id"])
	assert.Equal(s.T(), "Hello world", data["content"])
}

func (s *MessageHandlerTestSuite) TestGet_NotFound() {
	w := httptest.NewRecorder()
	url := msgDetailURL(s.testAccount.ID, s.testConv.ID, 999)
	req, _ := http.NewRequest("GET", url, nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusNotFound, w.Code)
}

func (s *MessageHandlerTestSuite) TestGet_InvalidID() {
	w := httptest.NewRecorder()
	req, _ := http.NewRequest("GET", "/api/v1/accounts/1/conversations/1/messages/abc", nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

// --- Update Tests --- 

func (s *MessageHandlerTestSuite) TestUpdate_Success() {
	payload := map[string]interface{}{
		"content": "Updated content",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	url := msgDetailURL(s.testAccount.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("PATCH", url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusOK, w.Code)
	var resp map[string]interface{}
	json.Unmarshal(w.Body.Bytes(), &resp)
	assert.True(s.T(), resp["success"].(bool))
	data := resp["data"].(map[string]interface{})
	assert.Equal(s.T(), "Updated content", data["content"])
}

func (s *MessageHandlerTestSuite) TestUpdate_NotFound() {
	payload := map[string]interface{}{
		"content": "Updated content",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	url := msgDetailURL(s.testAccount.ID, s.testConv.ID, 999)
	req, _ := http.NewRequest("PATCH", url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusNotFound, w.Code)
}

// --- Delete Tests --- 

func (s *MessageHandlerTestSuite) TestDelete_Success() {
	w := httptest.NewRecorder()
	url := msgDetailURL(s.testAccount.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("DELETE", url, nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusNoContent, w.Code)
}

func (s *MessageHandlerTestSuite) TestDelete_NotFound() {
	w := httptest.NewRecorder()
	url := msgDetailURL(s.testAccount.ID, s.testConv.ID, 999)
	req, _ := http.NewRequest("DELETE", url, nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusNotFound, w.Code)
}

// --- Retry Tests --- 

func (s *MessageHandlerTestSuite) TestRetry_Success() {
	w := httptest.NewRecorder()
	url := msgRetryURL(s.testAccount.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("POST", url, nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusOK, w.Code)
	var resp map[string]interface{}
	json.Unmarshal(w.Body.Bytes(), &resp)
	assert.True(s.T(), resp["success"].(bool))
	data := resp["data"].(map[string]interface{})
	assert.Equal(s.T(), float64(s.testMessage.ID), data["id"])
}

func (s *MessageHandlerTestSuite) TestRetry_InvalidAccountID() {
	w := httptest.NewRecorder()
	req, _ := http.NewRequest("POST", "/api/v1/accounts/abc/conversations/1/messages/1/retry", nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

func (s *MessageHandlerTestSuite) TestRetry_InvalidMessageID() {
	w := httptest.NewRecorder()
	req, _ := http.NewRequest("POST", "/api/v1/accounts/1/conversations/1/messages/abc/retry", nil)
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

func (s *MessageHandlerTestSuite) TestRetry_NotFound() {
	w := httptest.NewRecorder()
	url := msgRetryURL(s.testAccount.ID, s.testConv.ID, 999)
	req, _ := http.NewRequest("POST", url, nil)
	s.router.ServeHTTP(w, req)

	// Service returns "not found" error → handleServiceError → 404
	assert.Equal(s.T(), http.StatusNotFound, w.Code)
}

func (s *MessageHandlerTestSuite) TestRetry_AccountMismatch() {
	// Create a second account with its own conversation
	account2 := &model.Account{Name: "OtherAccount", Locale: "en", Active: true}
	s.Require().NoError(s.db.Create(account2).Error)

	// Try to retry message from account 1 using account 2 context
	w := httptest.NewRecorder()
	url := msgRetryURL(account2.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("POST", url, nil)
	s.router.ServeHTTP(w, req)

	// The service's FindByAccountAndID won't find the message under account 2 → "not found" → 404
	assert.Equal(s.T(), http.StatusNotFound, w.Code)
}

// --- Translate Tests --- 

func (s *MessageHandlerTestSuite) TestTranslate_Success() {
	payload := map[string]interface{}{
		"target_language": "fr",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	url := msgTranslateURL(s.testAccount.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("POST", url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusOK, w.Code)
	var resp map[string]interface{}
	json.Unmarshal(w.Body.Bytes(), &resp)
	assert.True(s.T(), resp["success"].(bool))
	data := resp["data"].(map[string]interface{})
	assert.Equal(s.T(), "Bonjour le monde", data["translated_content"])
	assert.Equal(s.T(), "Hello world", data["original_content"])
	assert.Equal(s.T(), "fr", data["target_language"])
}

func (s *MessageHandlerTestSuite) TestTranslate_EmptyTargetLanguage() {
	payload := map[string]interface{}{
		"target_language": "",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	url := msgTranslateURL(s.testAccount.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("POST", url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	// Validation fails: "required" → handleServiceError → 400
	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

func (s *MessageHandlerTestSuite) TestTranslate_MissingBody() {
	w := httptest.NewRecorder()
	url := msgTranslateURL(s.testAccount.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("POST", url, nil)
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	// ShouldBindJSON fails → 400
	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

func (s *MessageHandlerTestSuite) TestTranslate_InvalidAccountID() {
	payload := map[string]interface{}{
		"target_language": "fr",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	req, _ := http.NewRequest("POST", "/api/v1/accounts/abc/conversations/1/messages/1/translate", bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

func (s *MessageHandlerTestSuite) TestTranslate_InvalidMessageID() {
	payload := map[string]interface{}{
		"target_language": "fr",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	req, _ := http.NewRequest("POST", "/api/v1/accounts/1/conversations/1/messages/abc/translate", bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	assert.Equal(s.T(), http.StatusBadRequest, w.Code)
}

func (s *MessageHandlerTestSuite) TestTranslate_NotFound() {
	payload := map[string]interface{}{
		"target_language": "fr",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	url := msgTranslateURL(s.testAccount.ID, s.testConv.ID, 999)
	req, _ := http.NewRequest("POST", url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	// Service returns "not found" → 404
	assert.Equal(s.T(), http.StatusNotFound, w.Code)
}

func (s *MessageHandlerTestSuite) TestTranslate_LLMError() {
	// Set LLM to return error
	s.mockLLM.chatError = fmt.Errorf("LLM service unavailable")

	payload := map[string]interface{}{
		"target_language": "fr",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	url := msgTranslateURL(s.testAccount.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("POST", url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	// LLM error → service wraps it → handleServiceError → 500 (no "not found"/"invalid"/"validation"/"required" keywords)
	assert.Equal(s.T(), http.StatusUnprocessableEntity, w.Code)
}

func (s *MessageHandlerTestSuite) TestTranslate_EmptyChoices() {
// Set LLM to return response with no choices
	s.mockLLM.chatResponse = &llm.ChatResponse{
		Choices: []llm.ChatChoice{},
	}

	payload := map[string]interface{}{
		"target_language": "fr",
	}
	body, _ := json.Marshal(payload)

	w := httptest.NewRecorder()
	url := msgTranslateURL(s.testAccount.ID, s.testConv.ID, s.testMessage.ID)
	req, _ := http.NewRequest("POST", url, bytes.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	s.router.ServeHTTP(w, req)

	// Empty choices → translated_content is empty string → still returns 200 OK
	assert.Equal(s.T(), http.StatusOK, w.Code)
	var resp map[string]interface{}
	json.Unmarshal(w.Body.Bytes(), &resp)
	assert.True(s.T(), resp["success"].(bool))
	data := resp["data"].(map[string]interface{})
	assert.Equal(s.T(), "", data["translated_content"])
	assert.Equal(s.T(), "Hello world", data["original_content"])
}

// --- DirectUpload Handler Tests (upload_handler_test.go extension) ---
// These test DirectUpload endpoint validation independently using nil service pattern.

func TestDirectUploadHandler_NoFile(t *testing.T) {
	// Create handler with nil service — we only test validation before service call
	h := &UploadHandler{svc: nil}
	gin.SetMode(gin.TestMode)
	r := gin.New()
	widget := r.Group("/widget")
	widget.POST("/direct_uploads", h.DirectUpload)

	req, _ := http.NewRequest("POST", "/widget/direct_uploads", nil)
	req.Header.Set("Content-Type", "application/json")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusBadRequest, w.Code)
}

func TestDirectUploadHandler_InvalidContentType(t *testing.T) {
	h := &UploadHandler{svc: nil}
	gin.SetMode(gin.TestMode)
	r := gin.New()
	widget := r.Group("/widget")
	widget.POST("/direct_uploads", h.DirectUpload)

	req, _ := http.NewRequest("POST", "/widget/direct_uploads", bytes.NewReader([]byte("not multipart")))
	req.Header.Set("Content-Type", "text/plain")
	w := httptest.NewRecorder()
	r.ServeHTTP(w, req)

	assert.Equal(t, http.StatusBadRequest, w.Code)
}