# req-037

Schist must implement the procedure, described below as
`update_budget_drips_for_bucket`.

Sources: req-030, req-097

Satisfied by: task-001, task-006, task-054, req-117

## update_budget_drips_for_bucket

Inputs:

- A bucket, `bucket`

1. Let `prev_drip` be a drip `d` with a most recent value for the property
   `date` such that `d.bucket_id = bucket.id`
2. For each calendar date `d` in the range `(prev_drip.date, today]`, let `pipe`
   be the result of `get_current_pipe_for_bucket_on_date(bucket, d)` as
   described in req-117, and insert a new drip with these properties:
   - `bucket_id`: `pipe.bucket_id`
   - `pipe_id`: `pipe.id`
   - `date`: `d`
   - `amount`: the result of the sub-procedure, `pipe_amount_for_day(pipe, d)`
     as described below
   - `timestamp`: now as a Unix timestamp

## pipe_amount_for_date

Inputs:

- A pipe, `pipe`
- A calendar date, `date`

1. If `pipe.period` is `day`, return `pipe.amount`.
2. If `pipe.period` is `week`, return `pipe.amount ÷ 7`.
3. Let `days_in_month` be the number of days in the month to which `date`
   belongs.
4. If `pipe.period` is `month`, return `pipe.amount ÷ days_in_month`.
5. Let `days_in_year` be the number of days in the year to which `date` belongs.
6. If `period` is not `year`, panic.
7. Return `pipe.amount ÷ days_in_year`.