package fieldextraction

import (
	"fmt"

	"queryorchestration/internal/database/repository"

	"github.com/google/uuid"
)

// CreateFieldExtractionInput represents the complete input for creating a field extraction
type CreateFieldExtractionInput struct {
	DocumentID   uuid.UUID
	SingleFields *repository.AddFieldExtractionParams
	ArrayFields  []*repository.AddFieldExtractionArrayFieldParams // All arrays must be same length N
}

// MaxArrayFieldCount is the maximum number of array field rows allowed per field extraction.
// This prevents excessively large payloads that could impact performance.
const MaxArrayFieldCount = 10000

// ValidateArrayConsistency validates the array fields for a field extraction.
// It checks:
// - No nil entries in the array
// - Array length does not exceed MaxArrayFieldCount
// - Empty arrays are allowed (returns 0, nil)
//
// Note: The service layer assigns arrayIndex values sequentially (0, 1, 2, ...)
// when inserting, so we don't validate incoming arrayIndex values here.
// The database enforces uniqueness and non-negative constraints.
//
// Returns the array length if valid, error if validation fails.
func ValidateArrayConsistency(arrayFields []*repository.AddFieldExtractionArrayFieldParams) (int, error) {
	// Empty array is valid
	if len(arrayFields) == 0 {
		return 0, nil
	}

	// Check for maximum array size to prevent performance issues
	if len(arrayFields) > MaxArrayFieldCount {
		return 0, fmt.Errorf("array field count %d exceeds maximum allowed %d", len(arrayFields), MaxArrayFieldCount)
	}

	// Check for nil entries which would cause issues during insertion
	for i, field := range arrayFields {
		if field == nil {
			return 0, fmt.Errorf("array field at index %d is nil", i)
		}
	}

	return len(arrayFields), nil
}