Predetermined Balances

Overview

Predetermined balances provide fine-grained control over the exact amounts and order of transfers in an approval. Unlike traditional tally-based systems where you approve a total amount (e.g., 100 badges) without controlling the specific combinations, predetermined balances let you explicitly define:

  • Exact amounts that must be transferred

  • Specific order of transfers

  • Precise badge IDs and ownership times for each transfer

Key Principle: The transfer will fail if the balances are not EXACTLY as defined in the predetermined balances.

Interface Definition

export interface PredeterminedBalances<T extends NumberType> {
    manualBalances: ManualBalances<T>[];
    incrementedBalances: IncrementedBalances<T>;
    orderCalculationMethod: PredeterminedOrderCalculationMethod;
}

Balance Definition Methods

There are two mutually exclusive ways to define balances:

1. Manual Balances

Define an array of specific balance sets manually. Each element corresponds to a different transfer.

{
    "manualBalances": [
        {
            "amount": "1",
            "badgeIds": [
                {
                    "start": "1",
                    "end": "1"
                }
            ],
            "ownershipTimes": [
                {
                    "start": "1691978400000",
                    "end": "1723514400000"
                }
            ]
        },
        {
            "amount": "5",
            "badgeIds": [
                {
                    "start": "2",
                    "end": "6"
                }
            ],
            "ownershipTimes": [
                {
                    "start": "1691978400000",
                    "end": "1723514400000"
                }
            ]
        }
    ]
}

Use Case: When you need complete control over each specific transfer amount and timing.

2. Incremented Balances

Define starting balances and rules for subsequent transfers. Perfect for sequential minting or time-based releases or other common patterns. Note that most options are incompatible with each other.

{
    "incrementedBalances": {
        "startBalances": [
            {
                "amount": "1",
                "badgeIds": [
                    {
                        "start": "1",
                        "end": "1"
                    }
                ],
                "ownershipTimes": [
                    {
                        "start": "1691978400000",
                        "end": "1723514400000"
                    }
                ]
            }
        ],
        "incrementBadgeIdsBy": "1",
        "incrementOwnershipTimesBy": "0",
        "durationFromTimestamp": "0",
        "allowOverrideTimestamp": false,
        "allowOverrideWithAnyValidBadge": false,
        "recurringOwnershipTimes": {
            "startTime": "0",
            "intervalLength": "0",
            "chargePeriodLength": "0"
        }
    }
}

Increment Options

Field
Description
Example

incrementBadgeIdsBy

Amount to increment badge IDs by after each transfer

"1" = next transfer gets badge ID 2, then 3, etc.

incrementOwnershipTimesBy

Amount to increment ownership times by

"86400000" = add 1 day to ownership times

durationFromTimestamp

Calculate ownership times from timestamp + duration

"2592000000" = 30 days from transfer time

allowOverrideTimestamp

Allow custom timestamp override in transfer

true = users can specify custom start time

allowOverrideWithAnyValidBadge

Allow any valid badge ID (one) override

true = users can specify any single valid badge ID

recurringOwnershipTimes

Define recurring time intervals

Monthly subscriptions, weekly rewards

Duration From Timestamp

Dynamically calculate ownership times from a timestamp plus a set duration. This overwrites all ownership times in the starting balances.

{
    "durationFromTimestamp": "2592000000", // 30 days in milliseconds
    "allowOverrideTimestamp": true
}

Behavior:

  • Default: Uses transfer time as the base timestamp

  • Override: If allowOverrideTimestamp is true, users can specify a custom timestamp in MsgTransferBadges precalculationOptions

  • Calculation: ownershipTime = baseTimestamp + durationFromTimestamp

  • Overwrite: All ownership times in starting balances are replaced with [{ "start": baseTimestamp, "end": baseTimestamp + durationFromTimestamp }]

Recurring Ownership Times

Define repeating time intervals for subscriptions or periodic rewards:

{
    "recurringOwnershipTimes": {
        "startTime": "1691978400000", // When intervals begin
        "intervalLength": "2592000000", // 30 days in milliseconds
        "chargePeriodLength": "604800000" // 7 days advance charging
    }
}

Example: Monthly subscription starting August 13, 2023, with 7-day advance charging period.

Precalculating Balances

The Race Condition Problem

Predetermined balances can change rapidly between transaction broadcast and confirmation. For example:

  • Other users' mints get processed

  • Badge IDs shift due to concurrent activity

  • Manual balance specification becomes unreliable

The Solution: Precalculation

Use precalculateBalancesFromApproval in MsgTransferBadges to dynamically calculate balances at execution time.

{
  precalculateBalancesFromApproval: {
    approvalId: string;           // The approval to precalculate from
    approvalLevel: string;        // "collection" | "incoming" | "outgoing"
    approverAddress: string;      // "" if collection-level
    version: string;              // Must specify exact version
  },
  precalculationOptions: {
    // Additional override options dependent on the selections
  }
}

Order Calculation Methods

The system needs to determine which balance set to use for each transfer. This is controlled by the orderCalculationMethod.

How Order Numbers Work

The order number determines which balances to transfer, but it works differently depending on the balance type:

Manual Balances

  • Order number = 0: Transfer manualBalances[0] (first element)

  • Order number = 1: Transfer manualBalances[1] (second element)

  • Order number = 5: Transfer manualBalances[5] (sixth element)

Example: If you have 3 manual balance sets, order numbers 0, 1, and 2 will use each set once. Order number 3 would be out of bounds.

Incremented Balances

  • Order number = 0: Use starting balances as-is (no increments)

  • Order number = 1: Apply increments once to starting balances

  • Order number = 5: Apply increments five times to starting balances

Example: Starting with badge ID 1, increment by 1:

  • Order 0: Badge ID 1

  • Order 1: Badge ID 2

  • Order 2: Badge ID 3

  • Order 5: Badge ID 6

Transfer-Based Order Numbers

Track the number of transfers to determine order:

Method
Description
Use Case

useOverallNumTransfers

Global transfer count

Simple sequential transfers

usePerToAddressNumTransfers

Per-recipient count

User-specific limits

usePerFromAddressNumTransfers

Per-sender count

Sender-specific limits

usePerInitiatedByAddressNumTransfers

Per-initiator count

Initiator-specific limits

Important: Uses the same tracker as Max Number of Transfers. Trackers are:

  • Increment-only and immutable

  • Shared between predetermined balances and max transfer limits

  • Must be carefully managed to avoid conflicts

Merkle-Based Order Numbers

Use Merkle challenge leaf indices (leftmost = 0, rightmost = numLeaves - 1) for reserved transfers:

{
  "useMerkleChallengeLeafIndex": true,
  "challengeTrackerId": "uniqueId"
}

Use Case: Reserve specific badge IDs for specific users or claim codes.

Order Calculation Interface

export interface PredeterminedOrderCalculationMethod {
    useOverallNumTransfers: boolean;
    usePerToAddressNumTransfers: boolean;
    usePerFromAddressNumTransfers: boolean;
    usePerInitiatedByAddressNumTransfers: boolean;
    useMerkleChallengeLeafIndex: boolean;
    challengeTrackerId: string;
}

Boundary Handling

Understanding Bounds

Every approval defines bounds through its core fields (badgeIds, ownershipTimes, etc.). For example:

  • Badge IDs: 1-100

  • Ownership Times: Mon-Fri only

  • Transfer Times: Specific date range

Predetermined balances must work within these bounds, but note that order numbers can eventually exceed them.

Boundary Scenarios

Complete Out-of-Bounds

Scenario: Order number corresponds to balances completely outside approval bounds.

Example:

  • Approval allows badge IDs 1-100

  • Increment by 1 for each transfer

  • Order number 101 would require badge ID 101 (out of bounds)

Result: Transfer is ignored because badge ID 101 never matches the approval's badge ID range.

Partial Overlap

Scenario: Order number corresponds to balances that partially overlap with approval bounds.

Example:

  • Approval allows badge IDs 1-100

  • Transfer requires badge IDs 95-105

  • Badge IDs 95-100 are in bounds, 101-105 are out of bounds

Result:

  • Only in-bounds balances (95-100) are approved by current approval

  • Out-of-bounds balances (101-105) must be approved by a separate approval

  • The complete transfer (95-105) must still be exactly as defined

Important: The transfer will fail unless all out-of-bounds balances are approved by other approvals.

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