implement takes

gratipay/models/team/__init__.py

@@ -7,6 +7,7 @@
 from aspen import json, log
 from gratipay.exceptions import InvalidTeamName
 from gratipay.models import add_event
+from gratipay.models.team import mixins
 from postgres.orm import Model
 
 from gratipay.billing.exchanges import MINIMUM_CHARGE
@@ -30,7 +31,7 @@ def slugize(name):
     return slug
 
 
-class Team(Model):
+class Team(Model, mixins.Takes):
     """Represent a Gratipay team.
     """
 

sql/branch.sql

@@ -54,3 +54,39 @@ BEGIN;
     DROP VIEW current_payroll;
     DROP TABLE payroll;
 END;
+
+
+-- https://github.com/gratipay/gratipay.com/pull/4023
+
+BEGIN;
+
+    -- takes - how participants express membership in teams
+    CREATE TABLE takes
+    ( id                bigserial                   PRIMARY KEY
+    , ctime             timestamp with time zone    NOT NULL
+    , mtime             timestamp with time zone    NOT NULL DEFAULT now()
+    , participant_id    bigint                      NOT NULL REFERENCES participants(id)
+    , team_id           bigint                      NOT NULL REFERENCES teams(id)
+    , ntakes            int                         NOT NULL
+    , recorder_id       bigint                      NOT NULL REFERENCES participants(id)
+    , CONSTRAINT not_negative CHECK (ntakes >= 0)
+     );
+
+    CREATE VIEW memberships AS
+        SELECT * FROM (
+             SELECT DISTINCT ON (participant_id, team_id) t.*
+               FROM takes t
+               JOIN participants p ON p.id = t.participant_id
+              WHERE p.is_suspicious IS NOT TRUE
+           ORDER BY participant_id
+                  , team_id
+                  , mtime DESC
+        ) AS anon WHERE ntakes > 0;
+
+    ALTER TABLE teams ADD COLUMN ntakes int default 0;
+    ALTER TABLE teams ADD COLUMN ntakes_unclaimed int default 0;
+    ALTER TABLE teams ADD COLUMN ntakes_claimed int default 0;
+    ALTER TABLE teams ADD CONSTRAINT ntakes_sign CHECK (ntakes >= 0);
+    ALTER TABLE teams ADD CONSTRAINT ntakes_sum CHECK (ntakes = ntakes_claimed + ntakes_unclaimed);
+
+END;