// Available variables:
  // - Machine
  // - interpret
  // - assign
  // - send
  // - sendParent
  // - spawn
  // - raise
  // - actions
  // - XState (all XState exports)

  const invoiceMachine = Machine({
    id: 'invoice',
    initial: 'draft',
    context: {
      openBalance: 10,
      paymentMade: 10,
    },
    states: {
      draft: {
        on: {
          SEND_EMAIL: {
            target: 'emailed', actions: ['sendInvoiceEmail']
          },
          VOID: 'voided',
        }
      },
      emailed: {
        on: {
          APPROVE: {
            target: 'approved', actions: ['saveInvoiceState']
          },
          AUTO_APPROVE: {
            target: 'approved', actions: ['saveInvoiceState']
          },
          REJECT: {
            target: 'approved', actions: ['saveInvoiceState']
          },
        }
      },
      rejected: {
        on: {
          APPROVE: {
            target: 'approved', actions: ['saveInvoiceState']
          },
        }
      },
      approved: {
        on: {
          '': { target: 'unpaid', cond: context => context && context.paymentMade === 0, actions: ['saveInvoiceState'] },
          PAY: [
            { target: 'paid', cond: context => context && context.openBalance === 0, actions: ['payInvoice'] },
            { target: 'partial', cond: context => context && context.openBalance > 0, actions: ['payInvoice'] },
          ],
          GEN_NUMBER: {
            target: 'approved', actions: ['generateInvoiceNumber']
          },
          MOVE_TO_WALLET: {
            target: 'paid', actions: ['moveToWallet']
          },
        }
      },
      paid: {
        on: {
          BOUNCE: {
            target: 'bounced',
            actions: ['bounceInvoice']
          },
          REGEN: 'checking',
        },
      },
      bounced: {
        on: {
          PAY: [
            { target: 'paid', cond: context => context && context.openBalance === 0, actions: ['payInvoice'] },
            { target: 'partial', cond: context => context && context.openBalance > 0, actions: ['payInvoice'] },
          ],
          MOVE_TO_WALLET: {
            target: 'paid', actions: ['moveToWallet']
          },
        }
      },
      checking: {
        on: {
          '': [
            { target: 'paid', cond: context => context && context.openBalance === 0, actions: ['payInvoice'] },
            { target: 'partial', cond: context => context && context.openBalance > 0 , actions: ['payInvoice'] },
            { target: 'unpaid', cond: context => context && context.paymentMade === 0, actions: ['payInvoice'] },
          ]
        }
      },

      partial: {
        on: {
          PAY: [
            { target: 'paid', cond: context => context && context.openBalance === 0, actions: ['payInvoice'] },
            { target: 'partial', cond: context => context && context.openBalance > 0, actions: ['payInvoice'] },
          ],
          BOUNCE: {
            target: 'bounced',
            actions: ['bounceInvoice']
          },
          GEN_NUMBER: {
            target: 'partial', actions: ['generateInvoiceNumber']
          },
          MOVE_TO_WALLET: {
            target: 'paid', actions: ['moveToWallet']
          },
        }
      },
      unpaid: {
        on: {
          PAY: [
            { target: 'paid', cond: context => context && context.openBalance === 0, actions: ['payInvoice'] },
            { target: 'partial', cond: context => context && context.openBalance > 0, actions: ['payInvoice'] },
          ],
          GEN_NUMBER: {
            target: 'unpaid', actions: ['generateInvoiceNumber']
          },
          MOVE_TO_WALLET: {
            target: 'paid', actions: ['moveToWallet']
          },
        }
      },
      voided: {
        type: 'final',
      }
    }
  }, {
    actions: {
      bounceInvoice: () => {
        console.log('bounce Invoice')
      },
      sendInvoiceEmail: () => {
        console.log('Invoice Email')
      },
      saveInvoiceState: (_1, _2, { state }) => {
        console.log('Save Invoice', state)
      },
      payInvoice: () => {
        console.log('Pay Invoice');
      },
      generateInvoiceNumber: () => {
        console.log('Gen Invoice Number');
      },
      moveToWallet: () => {
        console.log('Move to wallet');
      },
    }
  });