Class: Wallets::Wallet

Inherits:
ApplicationRecord show all
Defined in:
lib/wallets/models/wallet.rb

Overview

Wallet is the owner-facing API for one asset balance.

Balances are not maintained by incrementing a counter in place. Instead, the wallet derives its current balance from transactions and allocations so it can support FIFO consumption, expirations, transfers, and a durable audit trail at the same time.

This class supports embedding: subclasses can override config, callbacks, table names, and related model classes without affecting the base Wallets::* behavior in the same application.

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.allocation_class ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 51

def self.allocation_class
  allocation_class_name.constantize
end

.create_for_owner!(owner:, asset_code:, initial_balance: 0, metadata: {}) ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 89

def create_for_owner!(owner:, asset_code:, initial_balance: 0, metadata: {})
  initial_balance = normalize_initial_balance(initial_balance)
  asset_code = normalize_asset_code(asset_code)
  metadata = metadata.respond_to?(:to_h) ? metadata.to_h : {}

  existing_wallet = find_by(owner: owner, asset_code: asset_code)
  return existing_wallet if existing_wallet.present?

  transaction do
    wallet = create!(
      owner: owner,
      asset_code: asset_code,
      balance: 0,
      metadata: metadata
    )

    if initial_balance.positive?
      wallet.credit(initial_balance, **initial_balance_credit_attributes)
    end

    wallet
  rescue ActiveRecord::RecordNotUnique, ActiveRecord::RecordInvalid => error
    wallet = find_by(owner: owner, asset_code: asset_code)
    raise error if wallet.nil?

    if record_conflict_due_to_existing_wallet?(error)
      wallet
    else
      raise error
    end
  end
end

.resolved_config ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 42

def self.resolved_config
  value = config_provider
  value.respond_to?(:call) ? value.call : value
end

.table_name ⇒ Object

Table Name Resolution



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# File 'lib/wallets/models/wallet.rb', line 38

def self.table_name
  embedded_table_name || "#{resolved_config.table_prefix}wallets"
end

.transaction_class ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 47

def self.transaction_class
  transaction_class_name.constantize
end

.transfer_class ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 55

def self.transfer_class
  transfer_class_name.constantize
end

Instance Method Details

#balance ⇒ Object

Balance & History



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# File 'lib/wallets/models/wallet.rb', line 175

def balance
  current_balance
end

#credit(amount, metadata: {}, category: :credit, expires_at: nil, transfer: nil, **extra_transaction_attributes) ⇒ Object

Credit & Debit Operations



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# File 'lib/wallets/models/wallet.rb', line 198

def credit(amount, metadata: {}, category: :credit, expires_at: nil, transfer: nil, **extra_transaction_attributes)
  metadata = normalize_metadata(metadata)

  with_lock do
    apply_credit(
      amount,
      metadata: metadata,
      category: category,
      expires_at: expires_at,
      transfer: transfer,
      extra_attributes: extra_transaction_attributes
    )
  end
end

#current_balance ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 179

def current_balance
  positive_remaining_balance - unbacked_negative_balance
end

#debit(amount, metadata: {}, category: :debit, transfer: nil, **extra_transaction_attributes) ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 213

def debit(amount, metadata: {}, category: :debit, transfer: nil, **extra_transaction_attributes)
  metadata = normalize_metadata(metadata)

  with_lock do
    apply_debit(
      amount,
      metadata: metadata,
      category: category,
      transfer: transfer,
      extra_attributes: extra_transaction_attributes
    )
  end
end

#has_enough_balance?(amount) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/wallets/models/wallet.rb', line 187

def has_enough_balance?(amount)
  normalized_amount = normalize_positive_amount!(amount)
  balance >= normalized_amount
rescue ArgumentError
  false
end

#history ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 183

def history
  transactions.order(created_at: :asc)
end

#metadata ⇒ Object

Metadata Handling



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# File 'lib/wallets/models/wallet.rb', line 157

def metadata
  @indifferent_metadata ||= ActiveSupport::HashWithIndifferentAccess.new(super || {})
end

#metadata=(hash) ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 161

def metadata=(hash)
  @indifferent_metadata = nil
  super(hash.respond_to?(:to_h) ? hash.to_h : {})
end

#reload ⇒ Object 



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# File 'lib/wallets/models/wallet.rb', line 166

def reload(*)
  @indifferent_metadata = nil
  super
end

#transfer_to(other_wallet, amount, category: :transfer, metadata: {}, expiration_policy: nil, expires_at: nil) ⇒ Object

Transfers

Raises:



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# File 'lib/wallets/models/wallet.rb', line 231

def transfer_to(other_wallet, amount, category: :transfer, metadata: {}, expiration_policy: nil, expires_at: nil)
  raise InvalidTransfer, "Target wallet is required" if other_wallet.nil?
  raise InvalidTransfer, "Target wallet must be persisted" unless other_wallet.persisted?
  raise InvalidTransfer, "Cannot transfer to the same wallet" if other_wallet.id == id
  raise InvalidTransfer, "Wallet assets must match" unless asset_code == other_wallet.asset_code
  raise InvalidTransfer, "Wallet classes must match" unless other_wallet.class == self.class

  amount = normalize_positive_amount!(amount)
  metadata = normalize_metadata(metadata)
  resolved_policy, inbound_expires_at = resolve_transfer_expiration!(expiration_policy, expires_at)

  ActiveRecord::Base.transaction do
    lock_wallet_pair!(other_wallet)

    previous_balance = balance

    # Insufficient-balance gate.
    #
    # `allow_negative_balance` is the single source of truth for whether
    # the gem permits a wallet to drop below zero. Direct `wallet.debit`
    # has always honored it via `apply_debit`; transfers must too, or
    # the flag is half-applied and surprising (debits go through, the
    # canonical transfer primitive doesn't).
    #
    # When the flag is OFF, this is the only chance to refuse cleanly:
    # we want to dispatch `:insufficient_balance` for the observability
    # callback, then raise BEFORE creating the Transfer row. (The later
    # `apply_debit` call would also catch this, but only after a
    # pointless Transfer row was created.)
    #
    # When the flag is ON, we let the transfer through. `apply_debit`
    # below will allocate as many positive buckets as exist; the
    # remaining shortfall lands as an unbacked negative transaction the
    # wallet's `balance` accounting accommodates via
    # `unbacked_negative_balance`.
    if amount > previous_balance && !allow_negative_balance?
      dispatch_insufficient_balance!(amount, previous_balance, metadata)
      raise InsufficientBalance, "Insufficient balance (#{previous_balance} < #{amount})"
    end

    # When a transfer dips below zero we can't faithfully apply the
    # `:preserve` expiration policy: there are no positive source
    # buckets to inherit expirations from for the deficit portion.
    # `build_preserved_transfer_inbound_credit_specs` would refuse with
    # `InvalidTransfer` on the count mismatch, defeating the very
    # callers who opted into negative balances. The only honest
    # fallback is to collapse the inbound side to a single evergreen
    # credit (`:none`) — value created without a source bucket has no
    # source expiration to preserve.
    #
    # Callers who care about a specific expiration on the inbound side
    # should pass `expiration_policy: :fixed, expires_at: …`. Those are
    # honored unchanged because they don't depend on source-bucket
    # walking. Same for an explicit `:none`.
    if resolved_policy == "preserve" && amount > previous_balance
      resolved_policy = "none"
      inbound_expires_at = nil
    end

    transfer = transfer_class.create!(
      from_wallet: self,
      to_wallet: other_wallet,
      asset_code: asset_code,
      amount: amount,
      category: category,
      expiration_policy: resolved_policy,
      metadata: metadata
    )

    shared_metadata = metadata.to_h.deep_stringify_keys.merge(
      "transfer_id" => transfer.id,
      "asset_code" => asset_code,
      "transfer_category" => category.to_s,
      "transfer_expiration_policy" => resolved_policy
    )

    outbound_transaction = apply_debit(
      amount,
      category: :transfer_out,
      metadata: shared_metadata.merge(
        "counterparty_wallet_id" => other_wallet.id,
        "counterparty_owner_id" => other_wallet.owner_id,
        "counterparty_owner_type" => other_wallet.owner_type
      ),
      transfer: transfer
    )

    build_transfer_inbound_credit_specs(
      transfer: transfer,
      outbound_transaction: outbound_transaction,
      amount: amount,
      expiration_policy: resolved_policy,
      expires_at: inbound_expires_at
    ).each do |spec|
      other_wallet.send(
        :apply_credit,
        spec[:amount],
        category: :transfer_in,
        metadata: shared_metadata.merge(
          "counterparty_wallet_id" => id,
          "counterparty_owner_id" => owner_id,
          "counterparty_owner_type" => owner_type
        ),
        expires_at: spec[:expires_at],
        transfer: transfer
      )
    end

    dispatch_callback(:transfer_completed,
      wallet: self,
      transfer: transfer,
      amount: amount,
      category: category,
      metadata: metadata
    )

    transfer
  end
end