name-system.js

// A simple name system:
// Supports just one level of names.
// Supports transferring a name.
// Supports associating a string with a name.
// Supports giving up a name.

// Note: this is untested example atm.

// TODO: require a minimum reward or burn of Ar to register a name.

export function handle (state, action) {
  if (action.input.function === 'register') {
    if (typeof action.input.name !== 'string' || action.input.name.length < 3) {
      throw new ContractError(`Invalid name provided: ${action.input.name}`)
    }
    if (typeof action.input.data !== 'string') {
      throw new ContractError('Must provide data to be associated with the name')
    }
    if (state.names[action.input.name]) {
      throw new ContractError('Name already registered')
    }
    state.names[action.input.name] = {
      ownedBy: action.caller,
      data: action.input.data
    }

    return { state }
  }

  if (action.input.function === 'update') {
    if (typeof action.input.name !== 'string' || action.input.name.length < 3) {
      throw new ContractError(`Invalid name provided: ${action.input.name}`)
    }
    if (typeof action.input.data !== 'string') {
      throw new ContractError('Must provide data to be associated with the name')
    }
    if (!state.names[action.input.name]) {
      throw new ContractError('Name not registered')
    }
    if (state.names[action.input.name].ownedBy !== action.caller) {
      throw new ContractError('Name not owned by caller')
    }

    state.names[action.input.name].data = action.input.data

    return { state }
  }

  if (action.input.function === 'transfer') {
    if (typeof action.input.name !== 'string' || action.input.name.length < 3) {
      throw new ContractError(`Invalid name provided: ${action.input.name}`)
    }
    if (typeof action.input.target !== 'string') {
      throw new ContractError('Must provide a target to transfer the name to')
    }
    if (!state.names[action.input.name]) {
      throw new ContractError('Name not registered')
    }
    if (state.names[action.input.name].ownedBy !== action.caller) {
      throw new ContractError('Name not owned by caller')
    }

    state.names[action.input.name].ownedBy = action.input.target

    return { state }
  }

  if (action.input.function === 'giveup') {
    if (typeof action.input.name !== 'string' || action.input.name.length < 3) {
      throw new ContractError(`Invalid name provided: ${action.input.name}`)
    }
    if (!state.names[action.input.name]) {
      throw new ContractError('Name not registered')
    }
    if (state.names[action.input.name].ownedBy !== action.caller) {
      throw new ContractError('Name not owned by caller')
    }

    delete state.names[action.input.name]

    return { state }
  }

  throw new ContractError('Invalid input')
}