package validation

import (
	"context"
	"fmt"
	"reflect"
	"regexp"
	"strings"
	"sync"
	"time"

	v10 "github.com/go-playground/validator/v10"
	"gorm.io/gorm"
)

type ValidatorOptionSource interface {
	GetValidOptions(key string) ([]string, error)
	GetValidKeys() []string
	Refresh() error
	StartAutoRefresh(ctx context.Context, interval time.Duration)
	HasKey(key string) bool
}

// --------------------
// DBOptionSource with Safe Handling
// --------------------

type DBOptionSource struct {
	db         *gorm.DB
	options    map[string][]string
	mu         sync.RWMutex
	lastUpdate time.Time
	expiry     time.Duration
	stopChan   chan struct{}
}

func NewDBOptionSource(db *gorm.DB, expiry time.Duration) (*DBOptionSource, error) {
	source := &DBOptionSource{
		db:       db,
		expiry:   expiry,
		stopChan: make(chan struct{}),
	}
	if err := source.Refresh(); err != nil {
		return nil, fmt.Errorf("failed to initialize DB option source: %w", err)
	}
	return source, nil
}

func (s *DBOptionSource) Refresh() error {
	s.mu.Lock()
	defer s.mu.Unlock()

	// Buat session baru tanpa transaction
	tx := s.db.Session(&gorm.Session{SkipDefaultTransaction: true})

	var results []struct {
		Slug  string `gorm:"column:slug"`
		Value string `gorm:"column:value"`
	}

	err := tx.Raw(`
        SELECT
            c.option_slug AS slug,
            v.option_value AS value
        FROM option_categories c
        JOIN option_values v ON c.id = v.option_category_id
        ORDER BY c.id, v.id
    `).Scan(&results).Error

	if err != nil {
		return fmt.Errorf("failed to refresh options: %w", err)
	}

	newOptions := make(map[string][]string)
	for _, r := range results {
		newOptions[r.Slug] = append(newOptions[r.Slug], r.Value)
	}

	s.options = newOptions
	s.lastUpdate = time.Now()

	fmt.Println("options refreshed")

	return nil
}

func (s *DBOptionSource) StartAutoRefresh(ctx context.Context, interval time.Duration) {
	ticker := time.NewTicker(interval)
	go func() {
		for {
			select {
			case <-ticker.C:
				s.mu.Lock()
				needsRefresh := time.Since(s.lastUpdate) > s.expiry
				s.mu.Unlock()

				if needsRefresh {
					if err := s.Refresh(); err != nil {
						fmt.Printf("failed to auto-refresh options: %v\n", err)
					}
				}
			case <-ctx.Done():
				ticker.Stop()
				return
			case <-s.stopChan:
				ticker.Stop()
				return
			}
		}
	}()
}

func (s *DBOptionSource) StopAutoRefresh() {
	close(s.stopChan)
}

func (s *DBOptionSource) HasKey(key string) bool {
	s.mu.RLock()
	defer s.mu.RUnlock()
	_, exists := s.options[key]
	return exists
}

func (s *DBOptionSource) GetValidOptions(key string) ([]string, error) {
	s.mu.RLock()
	needsRefresh := time.Since(s.lastUpdate) > s.expiry
	s.mu.RUnlock()

	if needsRefresh {
		if err := s.Refresh(); err != nil {
			return nil, fmt.Errorf("failed to refresh options: %w", err)
		}
	}

	s.mu.RLock()
	defer s.mu.RUnlock()

	options, exists := s.options[key]
	if !exists {
		return nil, nil // Return nil instead of error for missing keys
	}

	copied := make([]string, len(options))
	copy(copied, options)
	return copied, nil
}

func (s *DBOptionSource) GetValidKeys() []string {
	s.mu.RLock()
	defer s.mu.RUnlock()

	keys := make([]string, 0, len(s.options))
	for k := range s.options {
		keys = append(keys, k)
	}
	return keys
}

// --------------------
// Validator with Safe Rule Handling
// --------------------

type Validator struct {
	source   ValidatorOptionSource
	validate *v10.Validate
}

func NewValidator(source ValidatorOptionSource) *Validator {
	validate := v10.New()
	return &Validator{
		source:   source,
		validate: validate,
	}
}

func (v *Validator) RegisterAllCustomRules() error {
	// First register static validation rules
	staticRules := map[string]func(v10.FieldLevel) bool{
		"password":     v.validatePassword,
		"phone-number": v.validatePhoneNumber,
	}

	for name, fn := range staticRules {
		if err := v.validate.RegisterValidation(name, fn); err != nil {
			return fmt.Errorf("failed to register %s validation: %w", name, err)
		}
	}

	// Then register dynamic option rules
	for _, key := range v.source.GetValidKeys() {
		if !v.source.HasKey(key) {
			continue // Skip if key doesn't exist
		}

		if err := v.validate.RegisterValidation(key, v.createOptionRule(key)); err != nil {
			return fmt.Errorf("failed to register validation for %s: %w", key, err)
		}
	}

	return nil
}
func (v *Validator) Validate(input interface{}) error {
	if input == nil {
		return nil
	}

	val := reflect.ValueOf(input)
	if val.Kind() == reflect.Ptr {
		if val.IsNil() {
			return nil
		}
		val = val.Elem() // Dereference the pointer
	}

	err := v.validate.Struct(input)
	if err == nil {
		return nil
	}

	// Filter out errors for nil/empty fields
	if ve, ok := err.(v10.ValidationErrors); ok {
		var filteredErrors v10.ValidationErrors
		for _, fe := range ve {
			fieldValue := val.FieldByName(fe.StructField())
			if !fieldValue.IsValid() {
				continue
			}

			if !isEmpty(fieldValue) {
				filteredErrors = append(filteredErrors, fe)
			} else {
				fmt.Printf("Ignoring validation error for empty field: %s\n", fe.Field())
			}
		}

		if len(filteredErrors) > 0 {
			return filteredErrors
		}
		return nil
	}

	return err
}

// isEmpty checks if a value is nil or empty
func isEmpty(v reflect.Value) bool {
	switch v.Kind() {
	case reflect.String:
		return v.Len() == 0
	case reflect.Ptr, reflect.Interface:
		return v.IsNil()
	case reflect.Slice, reflect.Map, reflect.Array:
		return v.Len() == 0
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return v.Int() == 0
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		return v.Uint() == 0
	case reflect.Float32, reflect.Float64:
		return v.Float() == 0
	case reflect.Bool:
		return !v.Bool()
	case reflect.Struct:
		if t, ok := v.Interface().(time.Time); ok {
			return t.IsZero()
		}
		// Consider non-time structs as non-empty
		return false
	default:
		return false
	}
}

// createOptionRule remains the same as previous version
func (v *Validator) createOptionRule(key string) func(v10.FieldLevel) bool {
	return func(fl v10.FieldLevel) bool {
		field := fl.Field()
		if isEmpty(field) {
			return true
		}

		value := field.String()
		validOptions, err := v.source.GetValidOptions(key)
		if err != nil || validOptions == nil {
			return true
		}

		for _, opt := range validOptions {
			if opt == value {
				return true
			}
		}

		return false
	}
}

func (v *Validator) validatePassword(fl v10.FieldLevel) bool {
	password := fl.Field().String()
	return len(password) >= 8 &&
		strings.ContainsAny(password, "abcdefghijklmnopqrstuvwxyz") &&
		strings.ContainsAny(password, "ABCDEFGHIJKLMNOPQRSTUVWXYZ") &&
		strings.ContainsAny(password, "0123456789")
}

func (v *Validator) validatePhoneNumber(fl v10.FieldLevel) bool {
	phone := NormalizePhoneNumber(fl.Field().String())
	return strings.HasPrefix(phone, "+62")
}

func NormalizePhoneNumber(input string) string {
	re := regexp.MustCompile(`[^0-9\+]`)
	input = re.ReplaceAllString(input, "")

	switch {
	case strings.HasPrefix(input, "0"):
		return "+62" + input[1:]
	case strings.HasPrefix(input, "62") && !strings.HasPrefix(input, "+62"):
		return "+" + input
	case strings.HasPrefix(input, "8"):
		return "+62" + input
	default:
		return input
	}
}