"""Reading attached to a study plan block, and who has finished it.

Revision ID: f4a5b6c7d8e9
Revises: e3f4a5b6c7d8
"""
import sqlalchemy as sa
from alembic import op

revision = "f4a5b6c7d8e9"
down_revision = "e3f4a5b6c7d8"
branch_labels = None
depends_on = None


def upgrade():
    op.create_table(
        "study_plan_block_articles",
        sa.Column("id", sa.Integer, primary_key=True),
        sa.Column("block_id", sa.Integer,
                  sa.ForeignKey("study_plan_blocks.id", ondelete="CASCADE"), nullable=False, index=True),
        sa.Column("article_id", sa.Integer,
                  sa.ForeignKey("articles.id", ondelete="CASCADE"), nullable=False, index=True),
        sa.Column("position", sa.Integer, server_default="0"),
        sa.UniqueConstraint("block_id", "article_id", name="uq_block_article"),
    )
    # Opening an article is not the same claim as having finished with it, so
    # this is its own table rather than a flag on article_views.
    op.create_table(
        "study_plan_article_reads",
        sa.Column("id", sa.Integer, primary_key=True),
        sa.Column("block_article_id", sa.Integer,
                  sa.ForeignKey("study_plan_block_articles.id", ondelete="CASCADE"), nullable=False, index=True),
        sa.Column("user_id", sa.Integer,
                  sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True),
        sa.Column("read_at", sa.DateTime, server_default=sa.func.now()),
        sa.UniqueConstraint("block_article_id", "user_id", name="uq_block_article_read"),
    )


def downgrade():
    op.drop_table("study_plan_article_reads")
    op.drop_table("study_plan_block_articles")