package service

import (
	"bytes"
	"context"
	"encoding/csv"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"strconv"
	"strings"
	"time"

	"gorm.io/datatypes"
	"gorm.io/gorm"

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
	"github.com/gochat/gochat/internal/search"
	applogger "github.com/gochat/gochat/pkg/logger"
	pkgvalidator "github.com/gochat/gochat/pkg/validator"
)

// ContactService implements business logic for Contact operations.
// Reference: Chatwoot app/controllers/api/v1/contacts_controller.rb
type ContactService struct {
	repo            *repository.ContactRepo
	contactInboxSvc *ContactInboxService
	noteRepo        *repository.NoteRepo
	searchIndexer   SearchIndexer
	searchReader    ContactSearchReader
	exportMailer    ContactExportMailer
}

// NewContactService creates a new Contact service.
func NewContactService(repo *repository.ContactRepo, contactInboxSvc *ContactInboxService, noteRepo *repository.NoteRepo) *ContactService {
	return &ContactService{repo: repo, contactInboxSvc: contactInboxSvc, noteRepo: noteRepo}
}

func (s *ContactService) SetSearchIndexer(indexer SearchIndexer) {
	s.searchIndexer = indexer
}

func (s *ContactService) SetSearchReader(reader ContactSearchReader) {
	s.searchReader = reader
}

func (s *ContactService) SetContactExportMailer(mailer ContactExportMailer) {
	s.exportMailer = mailer
}

func (s *ContactService) indexContact(ctx context.Context, contact *model.Contact) {
	if s.searchIndexer != nil {
		logSearchIndexError("contact", contact.ID, s.searchIndexer.IndexContact(ctx, contact))
	}
}

func (s *ContactService) deleteContactIndex(ctx context.Context, accountID uint, id uint) {
	if s.searchIndexer != nil {
		logSearchIndexError("contact", id, s.searchIndexer.DeleteContact(ctx, accountID, id))
	}
}

// Ready reports whether the service has the dependencies required for DB-backed operations.
func (s *ContactService) Ready() bool {
	return s != nil && s.repo != nil
}

func (s *ContactService) DB() *gorm.DB {
	if s == nil || s.repo == nil {
		return nil
	}
	return s.repo.DB()
}

// ListByAccount retrieves all contacts for an account with optional sort.
func (s *ContactService) ListByAccount(ctx context.Context, accountID uint, offset, limit int, sort string, labels ...[]string) ([]model.Contact, int64, error) {
	return s.repo.FindByAccount(ctx, accountID, offset, limit, sort, labels...)
}

// Search searches contacts by name, email, phone, or identifier with optional sort.
func (s *ContactService) Search(ctx context.Context, accountID uint, query string, offset, limit int, sort string, searchMode search.SearchMode, labels ...[]string) ([]model.Contact, int64, error) {
	if query == "" {
		return s.repo.FindByAccount(ctx, accountID, offset, limit, sort, labels...)
	}
	if s.searchReader != nil {
		filter := serviceSearchFilter(offset, limit, sort, searchMode, search.ResultTypeContact)
		filter.Labels = firstServiceContactLabelFilter(labels)
		results, total, err := s.searchReader.SearchContacts(ctx, accountID, query, filter)
		if err != nil {
			return nil, 0, err
		}
		contacts, err := s.contactsFromSearchResults(ctx, accountID, results)
		if err != nil {
			return nil, 0, err
		}
		return contacts, total, nil
	}
	return s.repo.Search(ctx, accountID, query, offset, limit, sort, searchMode, labels...)
}

func (s *ContactService) contactsFromSearchResults(ctx context.Context, accountID uint, results []search.SearchResult) ([]model.Contact, error) {
	contacts := make([]model.Contact, 0, len(results))
	for _, result := range results {
		if result.ID == 0 || result.AccountID != accountID {
			continue
		}
		contact, err := s.repo.FindByAccountAndID(ctx, accountID, result.ID)
		if err != nil {
			continue
		}
		contacts = append(contacts, *contact)
	}
	return contacts, nil
}

func firstServiceContactLabelFilter(filters [][]string) []string {
	if len(filters) == 0 {
		return nil
	}
	return normalizeContactServiceLabels(filters[0])
}

// GetByID retrieves a single contact.
func (s *ContactService) GetByID(ctx context.Context, id uint) (*model.Contact, error) {
	return s.repo.FindByID(ctx, id)
}

// GetByAccountAndID retrieves a contact scoped to an account.
func (s *ContactService) GetByAccountAndID(ctx context.Context, accountID, id uint) (*model.Contact, error) {
	return s.repo.FindByAccountAndID(ctx, accountID, id)
}

// ListContactInboxes retrieves all contact_inboxes for a contact.
func (s *ContactService) ListContactInboxes(ctx context.Context, contactID uint) ([]model.ContactInbox, error) {
	return s.contactInboxSvc.ListByContact(ctx, contactID)
}

// CreateContactRequest is the DTO for creating a contact.
// Reference: Chatwoot app/controllers/api/v1/contacts_controller.rb#create
// When inbox_id is provided, a ContactInbox record is auto-created (Chatwoot pattern).
type CreateContactRequest struct {
	Name                 string         `json:"name" validate:"required,min=1"`
	Email                string         `json:"email,omitempty" validate:"omitempty,email"`
	Phone                string         `json:"phone,omitempty"`
	Identifier           string         `json:"identifier,omitempty"`
	AvatarURL            string         `json:"avatar_url,omitempty"`
	InboxID              *uint          `json:"inbox_id,omitempty"`
	SourceID             string         `json:"source_id,omitempty"`
	AdditionalAttributes *model.JSONMap `json:"additional_attributes,omitempty"`
	CustomAttributes     *model.JSONMap `json:"custom_attributes,omitempty"`
	ContactType          string         `json:"contact_type,omitempty"`
	MiddleName           string         `json:"middle_name,omitempty"`
	LastName             string         `json:"last_name,omitempty"`
	CountryCode          string         `json:"country_code,omitempty"`
	Location             string         `json:"location,omitempty"`
	CompanyID            *uint          `json:"company_id,omitempty"`
}

// Create creates a new contact and optionally auto-creates a ContactInbox when inbox_id is provided.
// Reference: Chatwoot contacts_controller#create — auto-creates ContactInbox for channel source.
func (s *ContactService) Create(ctx context.Context, accountID uint, req CreateContactRequest) (*model.Contact, error) {
	if err := pkgvalidator.ValidateStruct(req); err != nil {
		return nil, err
	}

	contact := &model.Contact{
		AccountID:   accountID,
		Name:        req.Name,
		Email:       req.Email,
		PhoneNumber: req.Phone,
		Identifier:  req.Identifier,
		AvatarURL:   req.AvatarURL,
		MiddleName:  req.MiddleName,
		LastName:    req.LastName,
		CountryCode: req.CountryCode,
		Location:    req.Location,
		ContactType: req.ContactType,
		SourceID:    req.SourceID,
		CompanyID:   req.CompanyID,
	}

	if req.AdditionalAttributes != nil {
		contact.AdditionalAttributes = mergeContactJSON(contact.AdditionalAttributes, model.ToDatatypesJSON(req.AdditionalAttributes))
	}
	if req.CustomAttributes != nil {
		contact.CustomAttributes = mergeContactJSON(contact.CustomAttributes, model.ToDatatypesJSON(req.CustomAttributes))
	}

	if err := s.repo.Create(ctx, contact); err != nil {
		applogger.L().Errorf("Failed to create contact: %v", err)
		return nil, err
	}
	s.indexContact(ctx, contact)

	// Auto-create ContactInbox when inbox_id is provided (Chatwoot pattern)
	if req.InboxID != nil && *req.InboxID > 0 {
		sourceID := req.SourceID
		if sourceID == "" {
			sourceID = contact.Email // fallback: use email as source_id
		}
		ciReq := CreateContactInboxRequest{
			ContactID: contact.ID,
			InboxID:   *req.InboxID,
			SourceID:  sourceID,
		}
		if _, err := s.contactInboxSvc.Create(ctx, ciReq); err != nil {
			applogger.L().Errorf("Failed to auto-create ContactInbox for contact %d: %v", contact.ID, err)
			// Non-blocking: contact is created, but ContactInbox creation failed
		}
	}

	return contact, nil
}

// UpdateContactRequest is the DTO for updating a contact.
type UpdateContactRequest struct {
	Name                 string         `json:"name,omitempty" validate:"omitempty,min=1"`
	Email                string         `json:"email,omitempty" validate:"omitempty,email"`
	Phone                string         `json:"phone,omitempty"`
	Identifier           string         `json:"identifier,omitempty"`
	AvatarURL            string         `json:"avatar_url,omitempty"`
	MiddleName           string         `json:"middle_name,omitempty"`
	LastName             string         `json:"last_name,omitempty"`
	CountryCode          string         `json:"country_code,omitempty"`
	Location             string         `json:"location,omitempty"`
	ContactType          string         `json:"contact_type,omitempty"`
	AdditionalAttributes *model.JSONMap `json:"additional_attributes,omitempty"`
	CustomAttributes     *model.JSONMap `json:"custom_attributes,omitempty"`
	CompanyID            *uint          `json:"company_id,omitempty"`
}

// Update modifies an existing contact.
func (s *ContactService) Update(ctx context.Context, accountID, id uint, req UpdateContactRequest) (*model.Contact, error) {
	if err := pkgvalidator.ValidateStruct(req); err != nil {
		return nil, err
	}

	contact, err := s.repo.FindByAccountAndID(ctx, accountID, id)
	if err != nil {
		return nil, err
	}

	if req.Name != "" {
		contact.Name = req.Name
	}
	if req.Email != "" {
		contact.Email = req.Email
	}
	if req.Phone != "" {
		contact.PhoneNumber = req.Phone
	}
	if req.Identifier != "" {
		contact.Identifier = req.Identifier
	}
	if req.AvatarURL != "" {
		contact.AvatarURL = req.AvatarURL
	}
	if req.MiddleName != "" {
		contact.MiddleName = req.MiddleName
	}
	if req.LastName != "" {
		contact.LastName = req.LastName
	}
	if req.CountryCode != "" {
		contact.CountryCode = req.CountryCode
	}
	if req.Location != "" {
		contact.Location = req.Location
	}
	if req.ContactType != "" {
		contact.ContactType = req.ContactType
	}
	if req.AdditionalAttributes != nil {
		contact.AdditionalAttributes = model.ToDatatypesJSON(req.AdditionalAttributes)
	}
	if req.CustomAttributes != nil {
		contact.CustomAttributes = model.ToDatatypesJSON(req.CustomAttributes)
	}
	if req.CompanyID != nil {
		contact.CompanyID = req.CompanyID
	}

	if err := s.repo.Update(ctx, contact); err != nil {
		return nil, err
	}
	s.indexContact(ctx, contact)
	return contact, nil
}

// Delete soft-deletes a contact.
func (s *ContactService) Delete(ctx context.Context, accountID, id uint) error {
	contact, err := s.repo.FindByAccountAndID(ctx, accountID, id)
	if err != nil {
		return err
	}
	if err := s.repo.Delete(ctx, contact.ID); err != nil {
		return err
	}
	s.deleteContactIndex(ctx, accountID, contact.ID)
	return nil
}

// CreateNoteRequest is the DTO for creating a contact note.
type CreateNoteRequest struct {
	Content string `json:"content" validate:"required,min=1"`
}

// ListNotes retrieves notes for a contact.
// Reference: Chatwoot app/controllers/api/v1/contacts/notes_controller.rb #index
func (s *ContactService) ListNotes(ctx context.Context, accountID, contactID uint) ([]model.Note, error) {
	// Verify contact belongs to account
	_, err := s.repo.FindByAccountAndID(ctx, accountID, contactID)
	if err != nil {
		return nil, errors.New("contact not found")
	}
	return s.noteRepo.FindByContact(ctx, accountID, contactID)
}

// CreateNote creates a note for a contact.
// Reference: Chatwoot app/controllers/api/v1/contacts/notes_controller.rb #create
func (s *ContactService) CreateNote(ctx context.Context, accountID, contactID, userID uint, req CreateNoteRequest) (*model.Note, error) {
	if err := pkgvalidator.ValidateStruct(req); err != nil {
		return nil, err
	}
	// Verify contact belongs to account
	_, err := s.repo.FindByAccountAndID(ctx, accountID, contactID)
	if err != nil {
		return nil, errors.New("contact not found")
	}
	note := &model.Note{
		Content:   req.Content,
		AccountID: accountID,
		ContactID: contactID,
		UserID:    &userID,
	}
	if err := s.noteRepo.Create(ctx, note); err != nil {
		return nil, err
	}
	if s.repo != nil && s.repo.DB() != nil {
		_ = s.repo.DB().WithContext(ctx).Preload("User").First(note, note.ID).Error
	}
	return note, nil
}

// GetNote retrieves a single note scoped to account and contact.
func (s *ContactService) GetNote(ctx context.Context, accountID, contactID, noteID uint) (*model.Note, error) {
	if s == nil || s.noteRepo == nil {
		return nil, errors.New("contact service not ready")
	}
	return s.noteRepo.GetByIDContext(ctx, accountID, contactID, noteID)
}

// UpdateNote updates a note scoped to account and contact.
func (s *ContactService) UpdateNote(ctx context.Context, accountID, contactID, noteID uint, req CreateNoteRequest) (*model.Note, error) {
	if err := pkgvalidator.ValidateStruct(req); err != nil {
		return nil, err
	}
	note, err := s.noteRepo.GetByIDContext(ctx, accountID, contactID, noteID)
	if err != nil {
		return nil, err
	}
	note.Content = req.Content
	return s.noteRepo.Update(note)
}

// DeleteNote removes a note scoped to account and contact.
func (s *ContactService) DeleteNote(ctx context.Context, accountID, contactID, noteID uint) error {
	if s == nil || s.noteRepo == nil {
		return errors.New("contact service not ready")
	}
	if _, err := s.noteRepo.GetByIDContext(ctx, accountID, contactID, noteID); err != nil {
		return err
	}
	return s.noteRepo.DeleteContext(ctx, accountID, contactID, noteID)
}

// ListActive retrieves contacts with recent activity for an account.
// GET /api/v1/accounts/:id/contacts/active
// Reference: Chatwoot contacts#active
func (s *ContactService) ListActive(ctx context.Context, accountID uint, offset, limit int, sort string) ([]model.Contact, int64, error) {
	return s.repo.FindActive(ctx, accountID, offset, limit, sort)
}

// ExportCSV writes all contacts for an account as CSV.
// GET /api/v1/accounts/:id/contacts/export
// Reference: Chatwoot contacts#export
func (s *ContactService) ExportCSV(ctx context.Context, accountID uint, w io.Writer) error {
	csvData, _, err := s.GenerateContactExportCSV(ctx, accountID, ContactExportRequest{})
	if err != nil {
		return err
	}
	_, err = w.Write(csvData)
	return nil
}

// ImportCSVResult holds the result of a CSV import operation.
type ImportCSVResult struct {
	Imported int `json:"imported"`
	Skipped  int `json:"skipped"`
	Failed   int `json:"failed"`
}

type ContactExportRequest struct {
	ColumnNames []string                       `json:"column_names"`
	Payload     []ContactExportFilterCondition `json:"payload"`
	Label       string                         `json:"label"`
}

type ContactExportFilterCondition struct {
	AttributeKey string `json:"attribute_key"`
	FilterType   string `json:"filter_type"`
	Operator     string `json:"operator"`
	Values       []any  `json:"values"`
}

func (s *ContactService) ExportContacts(ctx context.Context, accountID, userID uint, req ContactExportRequest) (*model.ContactExport, error) {
	if !s.Ready() {
		return nil, errors.New("contact service not ready")
	}

	var account model.Account
	if err := s.repo.DB().WithContext(ctx).First(&account, accountID).Error; err != nil {
		return nil, err
	}

	var userIDPtr *uint
	if userID != 0 {
		userIDPtr = &userID
	}
	columnsJSON, _ := json.Marshal(req.ColumnNames)
	filterJSON, _ := json.Marshal(map[string]any{"payload": req.Payload, "label": req.Label})
	export := &model.ContactExport{
		AccountID:    accountID,
		UserID:       userIDPtr,
		Status:       string(model.DataImportStatusPending),
		FileName:     contactExportFilename(account),
		ContentType:  "text/csv",
		ColumnNames:  columnsJSON,
		FilterParams: filterJSON,
	}
	if err := s.repo.DB().WithContext(ctx).Create(export).Error; err != nil {
		return nil, err
	}
	if err := s.repo.DB().WithContext(ctx).Model(export).Update("status", string(model.DataImportStatusProcessing)).Error; err != nil {
		return nil, err
	}

	csvData, rowCount, err := s.GenerateContactExportCSV(ctx, accountID, req)
	if err != nil {
		s.repo.DB().WithContext(ctx).Model(export).Updates(map[string]any{
			"status": string(model.DataImportStatusFailed),
			"error":  err.Error(),
		})
		return export, err
	}

	completedAt := time.Now()
	export.FileURL = fmt.Sprintf("/api/v1/accounts/%d/contacts/export/%d/download", accountID, export.ID)
	updates := map[string]any{
		"status":       string(model.DataImportStatusCompleted),
		"csv_data":     csvData,
		"row_count":    rowCount,
		"file_url":     export.FileURL,
		"completed_at": completedAt,
	}
	if err := s.repo.DB().WithContext(ctx).Model(export).Updates(updates).Error; err != nil {
		return nil, err
	}
	if err := s.repo.DB().WithContext(ctx).First(export, export.ID).Error; err != nil {
		return nil, err
	}
	if err := s.createContactExportNotification(ctx, export); err != nil {
		applogger.L().Warnf("contact export notification failed: %v", err)
	}
	if err := s.sendContactExportEmail(ctx, &account, export); err != nil {
		applogger.L().Warnf("contact export email failed: %v", err)
	}
	return export, nil
}

func (s *ContactService) sendContactExportEmail(ctx context.Context, account *model.Account, export *model.ContactExport) error {
	if s.exportMailer == nil || export == nil || export.UserID == nil || *export.UserID == 0 {
		return nil
	}
	var user model.User
	if err := s.repo.DB().WithContext(ctx).Where("id = ?", *export.UserID).First(&user).Error; err != nil {
		return err
	}
	return s.exportMailer.SendContactExportComplete(ctx, account, &user, export)
}

func (s *ContactService) GenerateContactExportCSV(ctx context.Context, accountID uint, req ContactExportRequest) ([]byte, int, error) {
	params := contactExportFilterParams(req)
	contacts, err := s.repo.FindForExport(ctx, accountID, params)
	if err != nil {
		return nil, 0, fmt.Errorf("failed to fetch contacts for export: %w", err)
	}

	headers := validContactExportHeaders(req.ColumnNames)
	labelsByContactID := map[uint][]string{}
	if containsString(headers, "labels") {
		ids := make([]uint, 0, len(contacts))
		for _, contact := range contacts {
			ids = append(ids, contact.ID)
		}
		labelsByContactID, err = s.repo.ContactLabelsByContactIDs(ctx, accountID, ids)
		if err != nil {
			return nil, 0, fmt.Errorf("failed to fetch contact labels for export: %w", err)
		}
	}

	var body bytes.Buffer
	body.Write([]byte{0xEF, 0xBB, 0xBF})
	csvWriter := csv.NewWriter(&body)
	if err := csvWriter.Write(headers); err != nil {
		return nil, 0, fmt.Errorf("failed to write CSV header: %w", err)
	}
	for _, contact := range contacts {
		row := make([]string, 0, len(headers))
		for _, header := range headers {
			row = append(row, contactExportValue(contact, header, labelsByContactID[contact.ID]))
		}
		if err := csvWriter.Write(row); err != nil {
			return nil, 0, fmt.Errorf("failed to write CSV row: %w", err)
		}
	}
	csvWriter.Flush()
	if err := csvWriter.Error(); err != nil {
		return nil, 0, fmt.Errorf("CSV flush error: %w", err)
	}
	return body.Bytes(), len(contacts), nil
}

func (s *ContactService) GetContactExport(ctx context.Context, accountID, exportID uint) (*model.ContactExport, error) {
	var export model.ContactExport
	err := s.repo.DB().WithContext(ctx).Where("account_id = ? AND id = ?", accountID, exportID).First(&export).Error
	if err != nil {
		return nil, err
	}
	return &export, nil
}

func contactExportFilename(account model.Account) string {
	name := strings.TrimSpace(account.Name)
	if name == "" {
		name = "account"
	}
	name = strings.NewReplacer("/", "_", "\\", "_", " ", "_").Replace(name)
	return fmt.Sprintf("%s_%d_contacts.csv", name, account.ID)
}

func contactExportFilterParams(req ContactExportRequest) repository.ContactFilterParams {
	params := repository.ContactFilterParams{}
	if strings.TrimSpace(req.Label) != "" {
		params.Labels = strings.TrimSpace(req.Label)
	}
	for _, condition := range req.Payload {
		if len(condition.Values) == 0 {
			continue
		}
		value := strings.TrimSpace(contactExportFilterValue(condition.Values[0]))
		switch strings.TrimSpace(condition.AttributeKey) {
		case "contact_type":
			params.ContactType = value
		case "source_id", "contact_source":
			params.ContactSource = value
		case "status":
			params.Status = value
		case "labels", "label_list":
			params.Labels = strings.Join(contactExportFilterValues(condition.Values), ",")
		case "inbox_id":
			if n, err := strconv.ParseUint(value, 10, 32); err == nil && n != 0 {
				inboxID := uint(n)
				params.InboxID = &inboxID
			}
		case "updated_within":
			if n, err := strconv.Atoi(value); err == nil && n > 0 {
				params.UpdatedWithin = &n
			}
		}
	}
	return params
}

func contactExportFilterValue(value any) string {
	switch v := value.(type) {
	case string:
		return v
	case float64:
		return strconv.FormatFloat(v, 'f', -1, 64)
	case int:
		return strconv.Itoa(v)
	case uint:
		return strconv.FormatUint(uint64(v), 10)
	case json.Number:
		return v.String()
	default:
		return fmt.Sprint(v)
	}
}

func contactExportFilterValues(values []any) []string {
	result := make([]string, 0, len(values))
	for _, value := range values {
		text := strings.TrimSpace(contactExportFilterValue(value))
		if text != "" {
			result = append(result, text)
		}
	}
	return result
}

func validContactExportHeaders(columnNames []string) []string {
	requested := columnNames
	if len(requested) == 0 {
		requested = []string{"id", "name", "email", "phone_number", "labels"}
	}
	allowed := map[string]struct{}{
		"id": {}, "name": {}, "middle_name": {}, "last_name": {}, "email": {}, "phone_number": {},
		"identifier": {}, "country_code": {}, "location": {}, "contact_type": {}, "blocked": {},
		"source_id": {}, "company_id": {}, "last_activity_at": {}, "created_at": {}, "updated_at": {}, "labels": {},
	}
	seen := map[string]struct{}{}
	headers := make([]string, 0, len(requested))
	for _, header := range requested {
		header = strings.TrimSpace(header)
		if header == "" {
			continue
		}
		if _, ok := allowed[header]; !ok {
			continue
		}
		if _, ok := seen[header]; ok {
			continue
		}
		seen[header] = struct{}{}
		headers = append(headers, header)
	}
	return headers
}

func contactExportValue(contact model.Contact, header string, labels []string) string {
	switch header {
	case "id":
		return strconv.FormatUint(uint64(contact.ID), 10)
	case "name":
		return contact.Name
	case "middle_name":
		return contact.MiddleName
	case "last_name":
		return contact.LastName
	case "email":
		return contact.Email
	case "phone_number":
		return contact.PhoneNumber
	case "identifier":
		return contact.Identifier
	case "country_code":
		return contact.CountryCode
	case "location":
		return contact.Location
	case "contact_type":
		return contact.ContactType
	case "blocked":
		return strconv.FormatBool(contact.Blocked)
	case "source_id":
		return contact.SourceID
	case "company_id":
		if contact.CompanyID == nil {
			return ""
		}
		return strconv.FormatUint(uint64(*contact.CompanyID), 10)
	case "last_activity_at":
		if contact.LastActivityAt == nil {
			return ""
		}
		return strconv.FormatInt(*contact.LastActivityAt, 10)
	case "created_at":
		return contact.CreatedAt.Format(time.RFC3339)
	case "updated_at":
		return contact.UpdatedAt.Format(time.RFC3339)
	case "labels":
		return strings.Join(labels, ",")
	default:
		return ""
	}
}

func containsString(values []string, needle string) bool {
	for _, value := range values {
		if value == needle {
			return true
		}
	}
	return false
}

func (s *ContactService) createContactExportNotification(ctx context.Context, export *model.ContactExport) error {
	if export.UserID == nil || *export.UserID == 0 {
		return nil
	}
	attrs, _ := json.Marshal(map[string]any{
		"file_url":  export.FileURL,
		"file_name": export.FileName,
		"row_count": export.RowCount,
	})
	notification := &model.Notification{
		AccountID:            &export.AccountID,
		UserID:               *export.UserID,
		NotificationType:     "contacts_export_complete",
		PrimaryActorType:     "ContactExport",
		PrimaryActorID:       export.ID,
		EmailEnabled:         true,
		AdditionalAttributes: attrs,
	}
	return s.repo.DB().WithContext(ctx).Create(notification).Error
}

func (s *ContactService) ImportContacts(ctx context.Context, accountID, userID uint, r io.Reader) (*model.DataImport, error) {
	if !s.Ready() {
		return nil, errors.New("contact service not ready")
	}
	var userIDPtr *uint
	if userID != 0 {
		userIDPtr = &userID
	}
	dataImport := &model.DataImport{AccountID: accountID, UserID: userIDPtr, DataType: "contacts", Status: string(model.DataImportStatusPending)}
	if err := s.repo.DB().WithContext(ctx).Create(dataImport).Error; err != nil {
		return nil, err
	}
	if err := s.repo.DB().WithContext(ctx).Model(dataImport).Update("status", string(model.DataImportStatusProcessing)).Error; err != nil {
		return nil, err
	}

	result, err := s.ImportCSV(ctx, accountID, r)
	if err != nil {
		s.repo.DB().WithContext(ctx).Model(dataImport).Updates(map[string]any{
			"status":            string(model.DataImportStatusFailed),
			"processing_errors": err.Error(),
		})
		return dataImport, err
	}
	updates := map[string]any{
		"status":            string(model.DataImportStatusCompleted),
		"processed_records": result.Imported,
		"failed_records":    result.Failed,
		"total_records":     result.Imported + result.Skipped + result.Failed,
	}
	if err := s.repo.DB().WithContext(ctx).Model(dataImport).Updates(updates).Error; err != nil {
		return nil, err
	}
	if err := s.repo.DB().WithContext(ctx).First(dataImport, dataImport.ID).Error; err != nil {
		return nil, err
	}
	return dataImport, nil
}

// ImportCSV reads contacts from a CSV reader and creates them.
// POST /api/v1/accounts/:id/contacts/import
// Reference: Chatwoot contacts#import
func (s *ContactService) ImportCSV(ctx context.Context, accountID uint, r io.Reader) (*ImportCSVResult, error) {
	csvReader := csv.NewReader(r)

	// Read header row
	header, err := csvReader.Read()
	if err != nil {
		return nil, fmt.Errorf("failed to read CSV header: %w", err)
	}

	// Build column index map
	colIndex := make(map[string]int)
	for i, col := range header {
		colIndex[col] = i
	}

	result := &ImportCSVResult{}
	for {
		row, err := csvReader.Read()
		if err == io.EOF {
			break
		}
		if err != nil {
			result.Failed++
			continue
		}

		contact := &model.Contact{AccountID: accountID}
		customAttributes := map[string]any{}
		var labels []string

		if idx, ok := colIndex["name"]; ok && idx < len(row) {
			contact.Name = row[idx]
		}
		if idx, ok := colIndex["email"]; ok && idx < len(row) {
			contact.Email = row[idx]
		}
		if idx, ok := colIndex["phone_number"]; ok && idx < len(row) {
			contact.PhoneNumber = formatImportPhone(row[idx])
		}
		if idx, ok := colIndex["identifier"]; ok && idx < len(row) {
			contact.Identifier = row[idx]
		}
		if idx, ok := colIndex["country_code"]; ok && idx < len(row) {
			contact.CountryCode = row[idx]
		}
		if idx, ok := colIndex["location"]; ok && idx < len(row) {
			contact.Location = row[idx]
		}
		if idx, ok := colIndex["city"]; ok && idx < len(row) && row[idx] != "" {
			contact.Location = row[idx]
		}
		if idx, ok := colIndex["company_name"]; ok && idx < len(row) && row[idx] != "" {
			customAttributes["company_name"] = row[idx]
		}
		if idx, ok := colIndex["contact_type"]; ok && idx < len(row) {
			contact.ContactType = row[idx]
		}
		if idx, ok := colIndex["labels"]; ok && idx < len(row) {
			labels = splitImportLabels(row[idx])
		}
		labels, invalidLabels, err := s.resolveApprovedImportLabels(ctx, accountID, labels)
		if err != nil {
			return nil, err
		}
		if len(invalidLabels) > 0 {
			applogger.L().Warnf("Skipping imported contact row with unknown labels: %s", strings.Join(invalidLabels, ", "))
			result.Failed++
			continue
		}
		known := map[string]struct{}{"name": {}, "email": {}, "phone_number": {}, "identifier": {}, "country_code": {}, "location": {}, "city": {}, "company_name": {}, "contact_type": {}, "labels": {}}
		for i, col := range header {
			col = strings.TrimSpace(col)
			if col == "" || i >= len(row) {
				continue
			}
			if _, ok := known[col]; ok || row[i] == "" {
				continue
			}
			customAttributes[col] = row[i]
		}

		existing := s.findImportContact(ctx, accountID, contact)
		if existing != nil {
			mergeImportContact(existing, contact, customAttributes)
			if err := s.repo.Update(ctx, existing); err != nil {
				applogger.L().Errorf("Failed to update imported contact row: %v", err)
				result.Failed++
				continue
			}
			if err := s.updateImportedLabels(ctx, accountID, existing.ID, labels); err != nil {
				applogger.L().Errorf("Failed to update imported contact labels: %v", err)
				result.Failed++
				continue
			}
			result.Imported++
			continue
		}

		contact.CustomAttributes = jsonFromMap(customAttributes)
		contact.AdditionalAttributes = datatypes.JSON("{}")

		if err := s.repo.Create(ctx, contact); err != nil {
			applogger.L().Errorf("Failed to import contact row: %v", err)
			result.Failed++
			continue
		}
		if err := s.updateImportedLabels(ctx, accountID, contact.ID, labels); err != nil {
			applogger.L().Errorf("Failed to update imported contact labels: %v", err)
			result.Failed++
			continue
		}
		result.Imported++
	}

	return result, nil
}

func (s *ContactService) resolveApprovedImportLabels(ctx context.Context, accountID uint, labels []string) ([]string, []string, error) {
	if len(labels) == 0 {
		return nil, nil, nil
	}
	approved := map[string]string{}
	var tags []model.Tag
	if err := s.repo.DB().WithContext(ctx).Where("account_id = ?", accountID).Find(&tags).Error; err != nil {
		return nil, nil, err
	}
	for _, tag := range tags {
		approved[strings.ToLower(strings.TrimSpace(tag.Name))] = tag.Name
	}

	seen := map[string]struct{}{}
	resolved := make([]string, 0, len(labels))
	invalid := make([]string, 0)
	for _, label := range labels {
		label = strings.TrimSpace(label)
		if label == "" {
			continue
		}
		key := strings.ToLower(label)
		canonical, ok := approved[key]
		if !ok {
			if _, exists := seen["invalid:"+key]; !exists {
				invalid = append(invalid, key)
				seen["invalid:"+key] = struct{}{}
			}
			continue
		}
		if _, exists := seen[key]; exists {
			continue
		}
		seen[key] = struct{}{}
		resolved = append(resolved, canonical)
	}
	return resolved, invalid, nil
}

func (s *ContactService) findImportContact(ctx context.Context, accountID uint, contact *model.Contact) *model.Contact {
	if contact.Identifier != "" {
		if existing, err := s.repo.FindByIdentifier(ctx, accountID, contact.Identifier); err == nil {
			return existing
		}
	}
	if contact.Email != "" {
		if existing, err := s.repo.FindByEmail(ctx, accountID, contact.Email); err == nil {
			return existing
		}
	}
	if contact.PhoneNumber != "" {
		var existing model.Contact
		if err := s.repo.DB().WithContext(ctx).Where("account_id = ? AND phone_number = ?", accountID, contact.PhoneNumber).First(&existing).Error; err == nil {
			return &existing
		}
	}
	return nil
}

func mergeImportContact(existing *model.Contact, incoming *model.Contact, customAttributes map[string]any) {
	if incoming.Identifier != "" {
		existing.Identifier = incoming.Identifier
	}
	if incoming.Email != "" {
		existing.Email = incoming.Email
	}
	if incoming.PhoneNumber != "" {
		existing.PhoneNumber = incoming.PhoneNumber
	}
	if incoming.Name != "" {
		existing.Name = incoming.Name
	}
	if incoming.CountryCode != "" {
		existing.CountryCode = incoming.CountryCode
	}
	if incoming.Location != "" {
		existing.Location = incoming.Location
	}
	if incoming.ContactType != "" {
		existing.ContactType = incoming.ContactType
	}
	merged := map[string]any{}
	if len(existing.CustomAttributes) > 0 {
		_ = json.Unmarshal(existing.CustomAttributes, &merged)
	}
	for key, value := range customAttributes {
		merged[key] = value
	}
	existing.CustomAttributes = jsonFromMap(merged)
}

func jsonFromMap(values map[string]any) datatypes.JSON {
	if len(values) == 0 {
		return datatypes.JSON("{}")
	}
	bytes, _ := json.Marshal(values)
	return datatypes.JSON(bytes)
}

func formatImportPhone(phone string) string {
	phone = strings.TrimSpace(phone)
	if phone == "" || strings.HasPrefix(phone, "+") {
		return phone
	}
	return "+" + phone
}

func splitImportLabels(raw string) []string {
	parts := strings.Split(raw, ",")
	labels := make([]string, 0, len(parts))
	for _, part := range parts {
		part = strings.TrimSpace(part)
		if part != "" {
			labels = append(labels, part)
		}
	}
	return labels
}

func (s *ContactService) updateImportedLabels(ctx context.Context, accountID, contactID uint, labels []string) error {
	if len(labels) == 0 {
		return nil
	}
	_, err := s.UpdateLabels(ctx, accountID, contactID, labels)
	return err
}

// Filter retrieves contacts matching advanced filter criteria.
// POST /api/v1/accounts/:id/contacts/filter
// Reference: Chatwoot ContactFilterService#perform — filters by contact_type, source,
// assignee, inbox, labels, status, and applies sort order with pagination.
func (s *ContactService) Filter(ctx context.Context, accountID uint, params repository.ContactFilterParams, offset, limit int) ([]model.Contact, int64, error) {
	return s.repo.Filter(ctx, accountID, params, offset, limit)
}

// DeleteCustomAttributes removes all custom attributes from a contact.
// DELETE /api/v1/accounts/:id/contacts/:contact_id/custom_attributes
// Reference: Chatwoot contacts#destroy_custom_attributes
func (s *ContactService) DeleteCustomAttributes(ctx context.Context, accountID, contactID uint) error {
	// Verify contact belongs to account
	contact, err := s.repo.FindByAccountAndID(ctx, accountID, contactID)
	if err != nil {
		return errors.New("contact not found")
	}
	return s.repo.DeleteCustomAttributes(ctx, contact.ID)
}

func (s *ContactService) DestroyCustomAttributes(ctx context.Context, accountID, contactID uint, keys []string) (*model.Contact, error) {
	contact, err := s.repo.FindByAccountAndID(ctx, accountID, contactID)
	if err != nil {
		return nil, errors.New("contact not found")
	}
	attrs := map[string]any{}
	if len(contact.CustomAttributes) > 0 {
		_ = json.Unmarshal(contact.CustomAttributes, &attrs)
	}
	for _, key := range keys {
		delete(attrs, key)
	}
	bytes, _ := json.Marshal(attrs)
	contact.CustomAttributes = datatypes.JSON(bytes)
	if err := s.repo.Update(ctx, contact); err != nil {
		return nil, err
	}
	s.indexContact(ctx, contact)
	return contact, nil
}

func (s *ContactService) DeleteAvatar(ctx context.Context, accountID, contactID uint) (*model.Contact, error) {
	contact, err := s.repo.FindByAccountAndID(ctx, accountID, contactID)
	if err != nil {
		return nil, errors.New("contact not found")
	}
	contact.AvatarURL = ""
	if err := s.repo.Update(ctx, contact); err != nil {
		return nil, err
	}
	s.indexContact(ctx, contact)
	return contact, nil
}

func (s *ContactService) GetLabels(ctx context.Context, accountID, contactID uint) ([]string, error) {
	if _, err := s.repo.FindByAccountAndID(ctx, accountID, contactID); err != nil {
		return nil, errors.New("contact not found")
	}
	var rows []struct{ Name string }
	err := s.DB().WithContext(ctx).Table("contact_labels").
		Select("tags.name").
		Joins("JOIN tags ON tags.id = contact_labels.tag_id").
		Where("contact_labels.account_id = ? AND contact_labels.contact_id = ? AND tags.deleted_at IS NULL", accountID, contactID).
		Order("contact_labels.created_at ASC, tags.name ASC").
		Scan(&rows).Error
	if err != nil {
		return nil, err
	}
	labels := make([]string, 0, len(rows))
	for _, row := range rows {
		labels = append(labels, row.Name)
	}
	return labels, nil
}

func (s *ContactService) UpdateLabels(ctx context.Context, accountID, contactID uint, labels []string) ([]string, error) {
	if _, err := s.repo.FindByAccountAndID(ctx, accountID, contactID); err != nil {
		return nil, errors.New("contact not found")
	}
	normalized := normalizeContactServiceLabels(labels)
	err := s.DB().WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("account_id = ? AND contact_id = ?", accountID, contactID).Delete(&model.ContactLabel{}).Error; err != nil {
			return err
		}
		for _, label := range normalized {
			tag := model.Tag{AccountID: accountID, Name: label}
			if err := tx.Where("account_id = ? AND name = ?", accountID, label).FirstOrCreate(&tag).Error; err != nil {
				return err
			}
			contactLabel := model.ContactLabel{AccountID: accountID, ContactID: contactID, TagID: tag.ID}
			if err := tx.Create(&contactLabel).Error; err != nil {
				return err
			}
		}
		return nil
	})
	if err != nil {
		return nil, err
	}
	return normalized, nil
}

func normalizeContactServiceLabels(labels []string) []string {
	seen := map[string]struct{}{}
	result := make([]string, 0, len(labels))
	for _, label := range labels {
		label = strings.TrimSpace(label)
		if label == "" {
			continue
		}
		if _, ok := seen[label]; ok {
			continue
		}
		seen[label] = struct{}{}
		result = append(result, label)
	}
	return result
}

func mergeContactJSON(current datatypes.JSON, incoming datatypes.JSON) datatypes.JSON {
	if len(incoming) == 0 {
		return current
	}
	merged := map[string]any{}
	if len(current) > 0 {
		_ = json.Unmarshal(current, &merged)
	}
	incomingMap := map[string]any{}
	_ = json.Unmarshal(incoming, &incomingMap)
	for key, value := range incomingMap {
		merged[key] = value
	}
	bytes, _ := json.Marshal(merged)
	return datatypes.JSON(bytes)
}

// ContactableInbox represents an inbox that a contact can be associated with.
// Reference: Chatwoot contacts#contactable_inboxes
type ContactableInbox struct {
	Inbox        model.Inbox         `json:"inbox"`
	ContactInbox *model.ContactInbox `json:"contact_inbox,omitempty"`
	SourceID     string              `json:"source_id,omitempty"`
}

// GetContactableInboxes returns inboxes that a contact can be added to.
// GET /api/v1/accounts/:id/contacts/:contact_id/contactable_inboxes
// Reference: Chatwoot contacts#contactable_inboxes — returns inboxes in the account
// that the contact is either already in or can be added to.
func (s *ContactService) GetContactableInboxes(ctx context.Context, accountID, contactID uint) ([]ContactableInbox, error) {
	// Verify contact belongs to account
	_, err := s.repo.FindByAccountAndID(ctx, accountID, contactID)
	if err != nil {
		return nil, errors.New("contact not found")
	}

	// Get existing contact_inboxes for this contact
	existingInboxes, err := s.contactInboxSvc.ListByContact(ctx, contactID)
	if err != nil {
		return nil, fmt.Errorf("failed to list contact inboxes: %w", err)
	}

	result := make([]ContactableInbox, 0, len(existingInboxes))
	for _, ci := range existingInboxes {
		result = append(result, ContactableInbox{
			Inbox:        ci.Inbox,
			ContactInbox: &ci,
			SourceID:     ci.SourceID,
		})
	}

	return result, nil
}