add req-037

1 files changed, 48 insertions, 0 deletions

diff --git a/requirements/catalogue/req-037.md b/requirements/catalogue/req-037.md
new file mode 100644
index 0000000..0d27984
--- /dev/null
+++ b/requirements/catalogue/req-037.md
@@ -0,0 +1,48 @@
+# req-037
+
+Schist must implement the procedure, described below as
+`update_budget_drips_for_bucket`.
+
+## update_budget_drips_for_bucket
+
+Inputs:
+
+- A bucket, `bucket`
+
+1. For each pipe `p` such that `p.bucket_id = bucket.id`, carry out the
+   sub-procedure, `update_budget_drips_for_pipe(pipe)`, as described below.
+
+## update_budget_drips_for_pipe
+
+Inputs:
+
+- A pipe, `pipe`
+
+1. Let `prev_drip` be a drip `d` with a most recent value for the property
+   `date` such that `d.pipe_id = pipe.id`
+2. For each calendar date `d` in the range `(prev_drip.date, today]`, insert
+   a new drip for `pipe`:
+   - `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`.
+
+Source: req-030
\ No newline at end of file