"""hockey_function

Revision ID: 6dbc7ce2fd71
Revises: bffb600877ea
Create Date: 2019-05-02 13:19:50.328349

"""

# revision identifiers, used by Alembic.
revision = '6dbc7ce2fd71'
down_revision = 'bffb600877ea'
branch_labels = None
depends_on = None

from alembic import op
import sqlalchemy as sa


def upgrade():
    op.execute('''
create or replace function hockey(vals double precision[], t1 integer, t2 integer, t3 integer DEFAULT '-1'::integer, t0 integer DEFAULT 1) returns double precision[]
	immutable
	strict
	language sql
as $$
-- arr [ p ] - arr [ p - s ] f2,
-- arr [ p - s ] - arr [ 1 ] f1,
select array[
   ((t1 - t0)::float*(vals[t2] - vals[t0]) - (t2 - t0)::float*(vals[t1] - vals[t0])) / nullif(vals[t0], 0),
   ((t1 - t0)::float*(vals[coalesce(nullif(t3, -1), array_length(vals, 1))] - vals[t0]) - (coalesce(nullif(t3, -1), array_length(vals, 1)) - t0)::float*(vals[t1] - vals[t0])) / nullif(vals[t0], 0),
   vals [ t0 ],
   vals [ t1 ],
   vals [ t2 ],
   vals [ coalesce(nullif(t3, -1), array_length(vals, 1)) ],
   t0::float,
   t1::float,
   t2::float,
   coalesce(nullif(t3, -1), array_length(vals, 1))::float
]

$$;

    ''')

def downgrade():
    op.execute('''drop function hockey(double precision[], integer, integer, integer, integer)''')