Merge pull request #102 from political-memory/fix-101

Fix underflow #101

representatives_recommendations/migrations/0007_fix_underflow.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('representatives_recommendations', '0006_score_formula'),
+    ]
+
+    operations = [
+        migrations.RunSQL(
+            """
+            CREATE FUNCTION decay_score(
+                score NUMERIC,
+                vote_date timestamp with time zone,
+                decay_num NUMERIC,
+                decay_denom NUMERIC,
+                exponent NUMERIC,
+                decimals integer)
+            RETURNS NUMERIC AS $$
+                SELECT ROUND(
+                    CAST(
+                        $1 * EXP(
+                            GREATEST(
+                                -700,
+                                LEAST(
+                                    700,
+                                    -(($3 * EXTRACT(days FROM CURRENT_DATE - $2) / $4) ^ (2 * $5))
+                                )
+                            )
+                        )
+                        AS NUMERIC
+                    ),
+                    $6
+                )
+            $$ LANGUAGE SQL;
+            """
+        ),
+
+        migrations.RunSQL(
+            """
+            CREATE OR REPLACE VIEW "representatives_recommendations_votescores"
+            AS SELECT
+                representatives_votes_vote.id,
+                representatives_votes_vote."position",
+                representatives_votes_vote.proposal_id,
+                representatives_votes_vote.representative_id,
+                decay_score(
+                    CAST(CASE
+                        WHEN representatives_votes_vote."position"::text = representatives_recommendations_recommendation.recommendation::text THEN representatives_recommendations_recommendation.weight
+                        ELSE 0 - representatives_recommendations_recommendation.weight
+                    END AS NUMERIC),
+                    representatives_votes_proposal.datetime,
+                    decay_num.value,
+                    decay_denom.value,
+                    exponent.value,
+                    decimals.value
+                ) AS score
+            FROM representatives_votes_vote
+                JOIN (SELECT CAST(TO_NUMBER(value, '99999') AS NUMERIC) AS value FROM memopol_settings_setting WHERE key = 'SCORE_DECAY_NUM') decay_num ON 1=1
+                JOIN (SELECT CAST(TO_NUMBER(value, '99999') AS NUMERIC) AS value FROM memopol_settings_setting WHERE key = 'SCORE_DECAY_DENOM') decay_denom ON 1=1
+                JOIN (SELECT CAST(TO_NUMBER(value, '99999') AS NUMERIC) AS value FROM memopol_settings_setting WHERE key = 'SCORE_EXPONENT') exponent ON 1=1
+                JOIN (SELECT CAST(TO_NUMBER(value, '99999') AS INTEGER) AS value FROM memopol_settings_setting WHERE key = 'SCORE_DECIMALS') decimals ON 1=1
+                JOIN representatives_votes_proposal ON representatives_votes_vote.proposal_id = representatives_votes_proposal.id
+                LEFT JOIN representatives_recommendations_recommendation ON representatives_votes_proposal.id = representatives_recommendations_recommendation.proposal_id
+            WHERE representatives_recommendations_recommendation.id IS NOT NULL;
+            """
+        ),
+    ]