Initial support for funding-goals-over-time; gratipay#141

TODO:
 * Tests
 * Migration of current `goal` field to goals table entry for each user
 * Removing the `goal` column from participant

gittip/models/__init__.py

@@ -6,5 +6,6 @@
 from gittip.models.tip import Tip
 from gittip.models.transfer import Transfer
 from gittip.models.user import User
+from gittip.models.goal import Goal
 
-all = [Elsewhere, Exchange, Participant, Payday, Tip, Transfer, User]
+all = [Elsewhere, Exchange, Participant, Payday, Tip, Transfer, User]

gittip/models/goal.py

@@ -0,0 +1,15 @@
+from sqlalchemy.schema import Column, ForeignKey
+from sqlalchemy.types import Integer, Numeric, Text, TIMESTAMP
+
+from gittip.orm import db
+
+class Goal(db.Model):
+    __tablename__ = 'goals'
+
+    id = Column(Integer, nullable=False, primary_key=True)
+    ctime = Column(TIMESTAMP(timezone=True), nullable=False)
+    mtime = Column(TIMESTAMP(timezone=True), nullable=False, default="now()")
+    participant = Column(Text, ForeignKey("participants.id", onupdate="CASCADE",
+                                     ondelete="RESTRICT"), nullable=False)
+    amount = Column(Numeric(precision=35, scale=2), nullable=False)
+

gittip/models/participant.py

@@ -11,6 +11,7 @@
 from sqlalchemy.orm import relationship
 from sqlalchemy.schema import Column, CheckConstraint, UniqueConstraint
 from sqlalchemy.types import Text, TIMESTAMP, Boolean, Numeric
+from sqlalchemy.sql.expression import desc
 
 import gittip
 from gittip.models.tip import Tip
@@ -45,7 +46,6 @@ class Participant(db.Model):
                      default=0.0, nullable=False)
     pending = Column(Numeric(precision=35, scale=2), default=None)
     anonymous = Column(Boolean, default=False, nullable=False)
-    goal = Column(Numeric(precision=35, scale=2), default=None)
     balanced_account_uri = Column(Text)
     last_ach_result = Column(Text)
     is_suspicious = Column(Boolean)
@@ -80,6 +80,12 @@ class Participant(db.Model):
                              , foreign_keys="Transfer.tippee"
                               )
 
+    _goal = relationship( "Goal"
+                        , backref="goal"
+                        , foreign_keys="Goal.participant"
+                        , lazy="dynamic"
+                         )
+
     def __eq__(self, other):
         return self.id == other.id
 
@@ -112,6 +118,12 @@ def valid_tips_receiving(self):
                    .filter( 'participants.is_suspicious IS NOT true'
                           , Participant.last_bill_result == ''
                            )
+    @property
+    def goal(self):
+        query = self._goal.distinct("goals.participant")\
+                                .order_by("goals.participant, goals.mtime DESC")
+        res = query.first()
+        return res.amount if res is not None else None
 
     def resolve_unclaimed(self):
         if self.accounts_elsewhere:

schema.sql

@@ -310,3 +310,15 @@ ALTER TABLE exchanges ADD COLUMN recorder text DEFAULT NULL
         ON UPDATE CASCADE ON DELETE RESTRICT;
 
 ALTER TABLE exchanges ADD COLUMN note text DEFAULT NULL;
+
+-------------------------------------------------------------------------------
+-- https://github.com/gittip/www.gittip.com/issues/141
+
+-- goals -- all goals a participant has stated over time
+CREATE TABLE goals
+( id                    serial                      PRIMARY KEY
+, ctime                 timestamp with time zone    NOT NULL
+, mtime                 timestamp with time zone    NOT NULL DEFAULT CURRENT_TIMESTAMP
+, participant           text                        NOT NULL REFERENCES participants ON DELETE RESTRICT
+, amount                numeric(35,2)               NOT NULL
+ );

www/%participant_id/goal.json

@@ -23,11 +23,25 @@ if goal is not None:
     except decimal.InvalidOperation:
         raise Response(400, "Bad input.")
 
-rec = db.fetchone( "UPDATE participants SET goal=%s "
-                   "WHERE id=%s RETURNING goal"
-                 , (goal, user.id)
+GOAL = """\
+
+    INSERT INTO goals
+                (ctime, participant, amount)
+         VALUES ( COALESCE (( SELECT ctime
+                                FROM goals
+                               WHERE (participant=%s)
+                               LIMIT 1
+                              ), CURRENT_TIMESTAMP)
+                , %s, %s
+                 )
+         RETURNING amount
+
+"""
+rec = db.fetchone( GOAL
+                 , (user.id, user.id, goal)
                   )
-goal = rec['goal']
+
+goal = rec['amount']
 if goal is not None:
-    goal = locale.format("%.2f", rec['goal'], grouping=True)
+    goal = locale.format("%.2f", rec['amount'], grouping=True)
 response.body = {"goal": goal}