package translation

import (
	"context"
	"errors"
	"tercul/internal/domain"
)

// TranslationCommands contains the command handlers for the translation aggregate.
type TranslationCommands struct {
	repo domain.TranslationRepository
}

// NewTranslationCommands creates a new TranslationCommands handler.
func NewTranslationCommands(repo domain.TranslationRepository) *TranslationCommands {
	return &TranslationCommands{
		repo: repo,
	}
}

// CreateTranslationInput represents the input for creating a new translation.
type CreateTranslationInput struct {
	Title            string
	Language         string
	Content          string
	WorkID           uint
	IsOriginalLanguage bool
}

// CreateTranslation creates a new translation.
func (c *TranslationCommands) CreateTranslation(ctx context.Context, input CreateTranslationInput) (*domain.Translation, error) {
	if input.Title == "" {
		return nil, errors.New("translation title cannot be empty")
	}
	if input.Language == "" {
		return nil, errors.New("translation language cannot be empty")
	}
	if input.WorkID == 0 {
		return nil, errors.New("work ID cannot be zero")
	}

	translation := &domain.Translation{
		Title:              input.Title,
		Language:           input.Language,
		Content:            input.Content,
		TranslatableID:     input.WorkID,
		TranslatableType:   "Work",
		IsOriginalLanguage: input.IsOriginalLanguage,
	}

	err := c.repo.Create(ctx, translation)
	if err != nil {
		return nil, err
	}

	return translation, nil
}

// UpdateTranslationInput represents the input for updating an existing translation.
type UpdateTranslationInput struct {
	ID       uint
	Title    string
	Language string
	Content  string
}

// UpdateTranslation updates an existing translation.
func (c *TranslationCommands) UpdateTranslation(ctx context.Context, input UpdateTranslationInput) (*domain.Translation, error) {
	if input.ID == 0 {
		return nil, errors.New("translation ID cannot be zero")
	}
	if input.Title == "" {
		return nil, errors.New("translation title cannot be empty")
	}
	if input.Language == "" {
		return nil, errors.New("translation language cannot be empty")
	}

	// Fetch the existing translation
	translation, err := c.repo.GetByID(ctx, input.ID)
	if err != nil {
		return nil, err
	}
	if translation == nil {
		return nil, errors.New("translation not found")
	}

	// Update fields
	translation.Title = input.Title
	translation.Language = input.Language
	translation.Content = input.Content

	err = c.repo.Update(ctx, translation)
	if err != nil {
		return nil, err
	}

	return translation, nil
}

// DeleteTranslation deletes a translation by ID.
func (c *TranslationCommands) DeleteTranslation(ctx context.Context, id uint) error {
	if id == 0 {
		return errors.New("invalid translation ID")
	}
	return c.repo.Delete(ctx, id)
}