package database

import (
	"fmt"
	"strings"
)

// Trackable interface for models that can track field changes
type Trackable interface {
	GetTableName() string
	GetID() int
	GetDirtyFields() map[string]any
	SetDirty(field string, value any)
	ClearDirty()
	IsDirty() bool
}

// FieldTracker provides dirty field tracking functionality
type FieldTracker struct {
	dirty map[string]any
}

// SetDirty marks a field as dirty with its new value
func (ft *FieldTracker) SetDirty(field string, value any) {
	if ft.dirty == nil {
		ft.dirty = make(map[string]any)
	}
	ft.dirty[field] = value
}

// GetDirtyFields returns map of dirty fields and their values
func (ft *FieldTracker) GetDirtyFields() map[string]any {
	if ft.dirty == nil {
		return make(map[string]any)
	}
	return ft.dirty
}

// ClearDirty clears all dirty field tracking
func (ft *FieldTracker) ClearDirty() {
	ft.dirty = nil
}

// IsDirty returns true if any fields have been modified
func (ft *FieldTracker) IsDirty() bool {
	return len(ft.dirty) > 0
}

// UpdateDirty updates only dirty fields in the database
func UpdateDirty(model Trackable) error {
	if !model.IsDirty() {
		return nil // No changes to save
	}

	dirty := model.GetDirtyFields()
	if len(dirty) == 0 {
		return nil
	}

	// Build dynamic UPDATE query
	var setParts []string
	var args []any

	for field, value := range dirty {
		setParts = append(setParts, field+" = ?")
		args = append(args, value)
	}

	args = append(args, model.GetID()) // Add ID for WHERE clause

	query := fmt.Sprintf("UPDATE %s SET %s WHERE id = ?",
		model.GetTableName(),
		strings.Join(setParts, ", "))

	err := Exec(query, args...)
	if err != nil {
		return fmt.Errorf("failed to update %s: %w", model.GetTableName(), err)
	}

	model.ClearDirty()
	return nil
}