package repository

import (
	"errors"

	"accounting-app/internal/models"

	"gorm.io/gorm"
)

// User preference repository errors
var (
	ErrUserPreferenceNotFound = errors.New("user preference not found")
)

// UserPreferenceRepository handles database operations for user preferences
type UserPreferenceRepository struct {
	db *gorm.DB
}

// NewUserPreferenceRepository creates a new UserPreferenceRepository instance
func NewUserPreferenceRepository(db *gorm.DB) *UserPreferenceRepository {
	return &UserPreferenceRepository{db: db}
}

// Create creates a new user preference record
func (r *UserPreferenceRepository) Create(pref *models.UserPreference) error {
	return r.db.Create(pref).Error
}

// GetByUserID retrieves user preference by user ID
func (r *UserPreferenceRepository) GetByUserID(userID uint) (*models.UserPreference, error) {
	var pref models.UserPreference
	err := r.db.Where("user_id = ?", userID).First(&pref).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrUserPreferenceNotFound
		}
		return nil, err
	}
	return &pref, nil
}

// GetOrCreate retrieves user preference or creates a new one if not exists
func (r *UserPreferenceRepository) GetOrCreate(userID uint) (*models.UserPreference, error) {
	pref, err := r.GetByUserID(userID)
	if err == nil {
		return pref, nil
	}
	if !errors.Is(err, ErrUserPreferenceNotFound) {
		return nil, err
	}

	// Create new preference
	newPref := &models.UserPreference{
		UserID: &userID,
	}
	if err := r.Create(newPref); err != nil {
		return nil, err
	}
	return newPref, nil
}

// Update updates an existing user preference
func (r *UserPreferenceRepository) Update(pref *models.UserPreference) error {
	return r.db.Save(pref).Error
}

// UpdateLastAccount updates the last used account ID
func (r *UserPreferenceRepository) UpdateLastAccount(userID uint, accountID uint) error {
	pref, err := r.GetOrCreate(userID)
	if err != nil {
		return err
	}
	pref.LastAccountID = &accountID
	return r.Update(pref)
}

// UpdateLastCategory updates the last used category ID
func (r *UserPreferenceRepository) UpdateLastCategory(userID uint, categoryID uint) error {
	pref, err := r.GetOrCreate(userID)
	if err != nil {
		return err
	}
	pref.LastCategoryID = &categoryID
	return r.Update(pref)
}

// UpdateFrequentAccounts updates the frequent accounts list
func (r *UserPreferenceRepository) UpdateFrequentAccounts(userID uint, accountsJSON string) error {
	pref, err := r.GetOrCreate(userID)
	if err != nil {
		return err
	}
	pref.FrequentAccounts = accountsJSON
	return r.Update(pref)
}

// UpdateFrequentCategories updates the frequent categories list
func (r *UserPreferenceRepository) UpdateFrequentCategories(userID uint, categoriesJSON string) error {
	pref, err := r.GetOrCreate(userID)
	if err != nil {
		return err
	}
	pref.FrequentCategories = categoriesJSON
	return r.Update(pref)
}

// Delete deletes a user preference record
func (r *UserPreferenceRepository) Delete(userID uint) error {
	result := r.db.Where("user_id = ?", userID).Delete(&models.UserPreference{})
	if result.Error != nil {
		return result.Error
	}
	if result.RowsAffected == 0 {
		return ErrUserPreferenceNotFound
	}
	return nil
}