Add UnifiedAccountId

package net.thunderbird.feature.account

import kotlin.uuid.ExperimentalUuidApi

import kotlin.uuid.Uuid

import net.thunderbird.core.architecture.model.Id

/**

 * Constant for the unified account ID.

 *

 * This ID is used to identify the unified account, which is a special account for aggregation purposes.

 *

 * The unified account ID is represented by a nil UUID (all zeros).

 *

 * See [RFC 4122 Section 4.1.7](https://datatracker.ietf.org/doc/html/rfc4122#section-4.1.7) for more details on nil UUIDs.

 */

@OptIn(ExperimentalUuidApi::class)

val UnifiedAccountId: AccountId = Id(Uuid.NIL)

/**

 * Extension property to check if an [AccountId] is the unified account ID.

 */

val AccountId.isUnified: Boolean

    get() = this == UnifiedAccountId

/**

 * Ensures that the [AccountId] is not the unified account ID.

 */

fun AccountId.requireReal(): AccountId {

    check(!isUnified) { "Operation not allowed on unified account" }

    return this

}

package net.thunderbird.feature.account

import assertk.assertFailure

import assertk.assertThat

import assertk.assertions.hasMessage

import assertk.assertions.isEqualTo

import assertk.assertions.isFalse

import assertk.assertions.isTrue

import kotlin.test.Test

class UnifiedAccountIdTest {

    @Test

    fun `unified account id is nil uuid`() {

        assertThat(UnifiedAccountId.asRaw()).isEqualTo("00000000-0000-0000-0000-000000000000")

    }

    @Test

    fun `isUnified returns true for unified account id`() {

        assertThat(UnifiedAccountId.isUnified).isTrue()

    }

    @Test

    fun `isUnified returns false for non-unified account id`() {

        val nonUnifiedAccountId = AccountIdFactory.of("123e4567-e89b-12d3-a456-426614174000")

        assertThat(nonUnifiedAccountId.isUnified).isFalse()

    }

    @Test

    fun `requireReal returns the same id if not unified`() {

        val nonUnifiedAccountId = AccountIdFactory.of("123e4567-e89b-12d3-a456-426614174000")

        assertThat(nonUnifiedAccountId.requireReal()).isEqualTo(nonUnifiedAccountId)

    }

    @Test

    fun `requireReal throws exception if unified`() {

        assertFailure {

            UnifiedAccountId.requireReal()

        }.hasMessage("Operation not allowed on unified account")

    }

}