package service

import (
	"context"
	"errors"

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

// ContactNoteService implements business logic for ContactNote operations.
// Reference: Chatwoot notes on contacts (Contacts::NoteAction)
type ContactNoteService struct {
	contactRepo *repository.ContactRepo
	noteRepo    *repository.ContactNoteRepo
}

// NewContactNoteService creates a new ContactNote service.
func NewContactNoteService(contactRepo *repository.ContactRepo, noteRepo *repository.ContactNoteRepo) *ContactNoteService {
	return &ContactNoteService{contactRepo: contactRepo, noteRepo: noteRepo}
}

// ListNotes retrieves all notes for a contact.
func (s *ContactNoteService) ListNotes(ctx context.Context, accountID, contactID uint) ([]model.ContactNote, error) {
	// Verify contact belongs to account
	_, err := s.contactRepo.FindByAccountAndID(ctx, accountID, contactID)
	if err != nil {
		return nil, errors.New("contact not found")
	}
	return s.noteRepo.FindByContact(ctx, contactID)
}

// NoteCreateRequest is the DTO for creating a contact note.
// (Named NoteCreateRequest to avoid conflict with CreateNoteRequest in contact_service.go)
type NoteCreateRequest struct {
	Content string `json:"content" validate:"required,min=1"`
}

// CreateNote creates a new note on a contact.
func (s *ContactNoteService) CreateNote(ctx context.Context, accountID, contactID, userID uint, req NoteCreateRequest) (*model.ContactNote, error) {
	if err := pkgvalidator.ValidateStruct(req); err != nil {
		return nil, err
	}
	// Verify contact belongs to account
	_, err := s.contactRepo.FindByAccountAndID(ctx, accountID, contactID)
	if err != nil {
		return nil, errors.New("contact not found")
	}

	note := &model.ContactNote{
		ContactID: contactID,
		UserID:    userID,
		Content:   req.Content,
	}
	if err := s.noteRepo.Create(ctx, note); err != nil {
		return nil, err
	}
	// Reload to populate User relation
	return s.noteRepo.FindByID(ctx, note.ID)
}

// ReparentNotes moves all notes from one contact to another (used in contact merge).
func (s *ContactNoteService) ReparentNotes(ctx context.Context, fromContactID, toContactID uint) error {
	return s.noteRepo.ReparentNotes(ctx, fromContactID, toContactID)
}

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

// GetByID retrieves a single contact note by ID.
func (s *ContactNoteService) GetByID(ctx context.Context, accountID, noteID uint) (*model.ContactNote, error) {
	note, err := s.noteRepo.FindByID(ctx, noteID)
	if err != nil {
		return nil, errors.New("note not found")
	}
	// Verify the note's contact belongs to the account
	_, err = s.contactRepo.FindByAccountAndID(ctx, accountID, note.ContactID)
	if err != nil {
		return nil, errors.New("note not found")
	}
	return note, nil
}

// UpdateNote updates the content of a contact note.
func (s *ContactNoteService) UpdateNote(ctx context.Context, accountID, noteID uint, req NoteUpdateRequest) (*model.ContactNote, error) {
	if err := pkgvalidator.ValidateStruct(req); err != nil {
		return nil, err
	}
	note, err := s.noteRepo.FindByID(ctx, noteID)
	if err != nil {
		return nil, errors.New("note not found")
	}
	// Verify the note's contact belongs to the account
	_, err = s.contactRepo.FindByAccountAndID(ctx, accountID, note.ContactID)
	if err != nil {
		return nil, errors.New("note not found")
	}
	note.Content = req.Content
	if err := s.noteRepo.Update(ctx, note); err != nil {
		return nil, err
	}
	// Reload to populate User relation
	return s.noteRepo.FindByID(ctx, note.ID)
}

// DeleteNote deletes a contact note.
func (s *ContactNoteService) DeleteNote(ctx context.Context, accountID, noteID uint) error {
	note, err := s.noteRepo.FindByID(ctx, noteID)
	if err != nil {
		return errors.New("note not found")
	}
	// Verify the note's contact belongs to the account
	_, err = s.contactRepo.FindByAccountAndID(ctx, accountID, note.ContactID)
	if err != nil {
		return errors.New("note not found")
	}
	return s.noteRepo.Delete(ctx, noteID)
}