Progressive Banking Service Operations

Process banking operations in strictly increasing timestamp order. Money values are integer cents. An account is created with zero available balance on first reference.

• DEPOSIT t account amount credits the amount.
• WITHDRAW t account amount debits available funds or fails without mutation.
• TRANSFER t from to amount performs an instant internal transfer or fails without mutation.
• EXTERNAL_OUT t account amount debits amount + 1 cents, including the one-cent fee, or fails.
• EXTERNAL_IN t account amount credits amount - 1 cents after the one-cent fee; the amount is at least one.
• SLOW_INIT t transferId from to amount reserves funds by removing them from the source available balance. It fails for a duplicate ID or insufficient funds.
• SLOW_COMPLETE t transferId credits the reserved funds to the destination and removes the pending transfer, or returns NOT_FOUND.
• BALANCE t account returns the available balance.
• STATEMENT t account returns all mutation records for that account, joined with commas. Each record is timestamp:type:amount:status:resultingBalance.

Mutations return OK|balance or FAILED|balance. Instant transfers return OK|fromBalance|toBalance or FAILED|fromBalance|toBalance. Slow completion returns OK|destinationBalance or NOT_FOUND. Return one result per operation.