// Package uisettings provides generic UI key-value settings storage (e.g. demo dashboard state,
// feature flags, saved filters). Callers partition data via namespace (e.g. "demo-dashboard:{userId}").
// It handles CRUD and soft-delete semantics; value is stored as JSON.
package uisettings

import (
	"context"
	"errors"
	"fmt"

	"queryorchestration/internal/database/repository"
	"queryorchestration/internal/serviceconfig"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
)

// Service provides UI settings operations.
type Service struct {
	cfg serviceconfig.ConfigProvider
}

// New creates a new UI settings service.
func New(cfg serviceconfig.ConfigProvider) *Service {
	return &Service{cfg: cfg}
}

// Create creates a new UI setting.
func (s *Service) Create(ctx context.Context, namespace, key string, value []byte) (*repository.UiSetting, error) {
	row, err := s.cfg.GetDBQueries().CreateUISetting(ctx, &repository.CreateUISettingParams{
		Namespace: namespace,
		Key:       key,
		Value:     value,
	})
	if err != nil {
		return nil, fmt.Errorf("create UI setting: %w", err)
	}
	return row, nil
}

// List returns all non-deleted UI settings.
func (s *Service) List(ctx context.Context) ([]*repository.UiSetting, error) {
	rows, err := s.cfg.GetDBQueries().ListUISettings(ctx)
	if err != nil {
		return nil, fmt.Errorf("list UI settings: %w", err)
	}
	return rows, nil
}

// ListByNamespace returns non-deleted UI settings for the given namespace.
func (s *Service) ListByNamespace(ctx context.Context, namespace string) ([]*repository.UiSetting, error) {
	rows, err := s.cfg.GetDBQueries().ListUISettingsByNamespace(ctx, namespace)
	if err != nil {
		return nil, fmt.Errorf("list UI settings by namespace: %w", err)
	}
	return rows, nil
}

// Get returns a single setting by id, or ErrNotFound if not found or soft-deleted.
func (s *Service) Get(ctx context.Context, id uuid.UUID) (*repository.UiSetting, error) {
	row, err := s.cfg.GetDBQueries().GetUISetting(ctx, id)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, ErrNotFound
		}
		return nil, fmt.Errorf("get UI setting: %w", err)
	}
	if row == nil {
		return nil, ErrNotFound
	}
	return row, nil
}

// Update updates a setting's value. Returns ErrNotFound if the setting does not exist or is soft-deleted.
func (s *Service) Update(ctx context.Context, id uuid.UUID, value []byte) error {
	err := s.cfg.GetDBQueries().UpdateUISetting(ctx, &repository.UpdateUISettingParams{
		ID:    id,
		Value: value,
	})
	if err != nil {
		return fmt.Errorf("update UI setting: %w", err)
	}
	return nil
}

// SoftDelete soft-deletes a setting by id.
func (s *Service) SoftDelete(ctx context.Context, id uuid.UUID) error {
	err := s.cfg.GetDBQueries().SoftDeleteUISetting(ctx, id)
	if err != nil {
		return fmt.Errorf("soft delete UI setting: %w", err)
	}
	return nil
}

// ErrNotFound is returned when a setting is not found or is soft-deleted.
var ErrNotFound = errors.New("UI setting not found")