// Package ulid provides thread-safe ULID (Universally Unique Lexicographically Sortable Identifier) generation.
//
// ULIDs are 128-bit identifiers that are lexicographically sortable and contain
// a timestamp component. This package uses cryptographically secure random
// generation optimized for simplicity and performance in concurrent environments.
package ulid

import (
	cryptorand "crypto/rand"
	"time"

	oklid "github.com/oklog/ulid/v2"
)

// MakeULID generates a new ULID with the specified timestamp using cryptographically secure randomness.
// The function is thread-safe and optimized for high-concurrency environments.
//
// This implementation prioritizes simplicity and performance over strict monotonicity within
// the same millisecond. Each ULID is guaranteed to be unique and lexicographically sortable
// across different timestamps.
//
// Returns a pointer to the generated ULID or an error if generation fails.
// Generation should only fail under extreme circumstances (entropy exhaustion).
func MakeULID(t time.Time) (*oklid.ULID, error) {
	id, err := oklid.New(oklid.Timestamp(t), cryptorand.Reader)
	if err != nil {
		return nil, err
	}

	return &id, nil
}

// Make generates a new ULID with the current timestamp using cryptographically secure randomness.
// This is a convenience function equivalent to MakeULID(time.Now()).
//
// The function is thread-safe and optimized for high-concurrency environments.
//
// Returns a pointer to the generated ULID or an error if generation fails.
// Generation should only fail under extreme circumstances (entropy exhaustion).
func Make() (*oklid.ULID, error) {
	id, err := oklid.New(oklid.Now(), cryptorand.Reader)
	if err != nil {
		return nil, err
	}

	return &id, nil
}