The system should not make assumptions about specific reimbursement policies

or invoicing requirements.  Instead, it should be possible for a bookkeeper

or administrator to define follow-up questions and what responses are and are

not eligible for reimbursement or payment.  Early versions may require

sysadmin-level technical expertise to do this, but ultimately it should be

doable by a bookkeeper with appropriate privileges.

## Requirements for first release

### Defining the request form

Accepted, and Rejected.

Administrators can define questions to ask the requestor about the entire

request, and about each expense in the request.  The system can display

forms, validate answers, and record answers for questions with the following

types of answers:

* Text

* Boolean (yes/no)

* Selection (from a list of values)

* Number

* Currency (this is probably a string that's validated to have a numeric part plus an optional currency code)

Using these same conditions, the administrator can define questions that are

conditional on other questions' answers.  These questions are only presented

to the requestors when they submit an answer that meets the specified conditions.

For illustration purposes, the canonical deployment will have

relatively few unconditional questions about each expense (type of expense,

receipt, amount), and then a series of conditional questions based on those

answers (e.g., follow-up questions specific to airfare expenses,

accommodations expenses, etc.).

### Requestor workflow

Requestors can log in and see the status of all their requests.  They can also

state.

When they view a report, it shows the questions and answers about the entire

report, and a list of associated expenses.  Viewing a specific expense

similarly shows all the questions and answers about it.

When a report is In Progress state, the requestor can edit any answer in the

report or an associated expense.  They can also add an expense, which begins

by asking them unconditional questions associated with expenses, and then

follow-up questions as necessary based on those answers.

When an In Progress report has at least one expense associated with it, and

all questions have been answered, the requestor may submit the request for

approval.  If any of the answers do not meet the administrator's conditions

for payment, the requestor may still submit the request, and provide an

explanation for why the request should be paid (e.g., because it was

approved in advance).  Once the request is submitted, it moves to the

Submitted state.

These are features that we would ultimately like the system to have, but we

know aren't possible for the first version given time allotted for its

development.  It's good to keep them in mind when architecting, but also to

know that they've been considered and aren't immediately possible.

* Allow optional questions: With this, question conditions probably need to

be extended to address the case of "other question isn't answered"

* Additional exporters:

  * Export to SQLedger

  * [Certainly many more, feel free to add them here]

* Various currency improvements:

   * Automatic currency conversion for validation (e.g., validate that an amount

     in an aribtrary currency is within a limit in USD)

   * Validate currency amounts from outside data sources: The main case for

     this is per diem, where many organizations use rates that are determined

     by another party (e.g., US GSA) and updated periodically.

   * Handle totaling the request based on currency (e.g., expenses can are in

     USD, EUR, CHR but the traveler may want payment in INR.)  Unclear what

     interface for this would look like, but real-time data about past