declare namespace Ledger {

  interface Ledger<EntityName extends string> extends Entity.Entity<any, EntityName> {
    readonly REST: import("@ledger/mod.ts").LedgerRest<EntityName>

    /**
     * Add a new entry to the ledger.
     * Updates the user balance and updates the ledger meta.
     * 
     * *Runs on a processor*
     */
    AddEntry(params: Ledger.Entry.Unentered & Ledger.Expiration.Override): Promise<Ledger.Entry.Response>

    /**
     * Consume from positive past entries linked to a specific user.
     * Updates the user balance and updates the ledger meta.
     * 
     * *Runs on a processor*
     */
    ConsumeEntries(params: Ledger.Entry.Unentered): Promise<Ledger.Consumption.ConsumptionResponse>

    /**
     * Get recent entries to the ledger history
     */
    History(count: number, page: number): Promise<Ledger.Entry[]>

    /**
     * Fetch ledger data for a particular user
     * 
     * @param key The unique value referring to a user. Usually their `msisdn`
     */
    UserData(key: string, count: number, page: number): Promise<Ledger.User.Response>

    /**
     * Get the ledger history for a user
     * 
     * @param key The unique value referring to a user. Usually their `msisdn`
     * @param limit How many entries should be retrieved?
     * 
     * Default: 10
     */
    HistoryFor(key: string, count: number, page: number): Promise<Ledger.Entry[]>

    /**
     * Get information regarding an entry, including consumption entries
     * 
     * @param key The unique value referring to a user. Usually their `msisdn`
     * @param limit How many entries should be retrieved?
     * 
     * Default: 10
     */
    EntryData(id: number): void

    /**
     * Get the total balance for a user
     * 
     * @param key The unique value referring to a user. Usually their `msisdn`
     */
    BalanceFor(key: string): Promise<number | undefined>

    /**
     * Get the total balance for multiple user
     * 
     * @param keys The unique values used to refer to a user. Usually their `msisdn`
     */
    Balances(...keys: string[]): Promise<Pick<User, 'key' | 'balance'>[]>

    /**
     * Get the amount of ledger entries for a user
     * 
     * @param key The unique value referring to a user. Usually their `msisdn`
     */
    CountFor(key: string): Promise<number | undefined>

    /**
     * Get the total number of users that have been tracked in this ledger.
     * 
     * A user is only tracked once an entry has been added for them.
     */
    UserCount(): Promise<number>

    /**
     * The name of the database table where this ledger stores entries
     */
    entries_table: string

    /**
     * The name of the database table where this ledger stores user data
     */
    user_table: string

    /**
     * The name of the database table where this ledger records consumptions
     */
    consumption_table: string
  }
}