Write some Software

I would like an Add-On for Saasu Accounting Software, in which it will securely pull an event from my Google Calendar, and add it as an Invoice for Saasu. For example, I put an event into a chosen Google Calendar. Event runs from: 8pm-10pm Friday 1st January 2016 Event location is: 123 Smith Street, Sydney NSW 2000 Event Description is: Consult for Project ABC The Add-On sees that the event location is 123 Smith Street, Sydney, and matches that to \"John Smith Company\" which is already entered in Saasu. It then creates a Google Spreadsheet which displays the above data (including client address, and auto fills in client name), and all other variables for an invoice. I can tell the Add-On any default preferences (eg rate, tax code) for any client so it creates a complete invoice. Any changes to the Google Calendar Event, should be updated in the spreadsheet within a reasonable time. It then creates a invoice in Sassu with the following details: Company name: John Smith Company Line description \"2 Hours @ 100/hr, Consult for Project ABC, 8pm-10pm, Friday 1st January 2016,\" with totals of $200. It should allow me to set a default invoice amount for each client. Saasu API can be found here: [login to view URL]