"""social graph: friendships, follows, blocks

Revision ID: 0002_social_graph
Revises: 0001_initial
Create Date: 2026-08-18 00:00:00.000000
"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa

# revision identifiers, used by Alembic.
revision: str = "0002_social_graph"
down_revision: Union[str, None] = "0001_initial"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    """Create friendships, follows, and blocks tables."""
    op.create_table(
        "friendships",
        sa.Column("id", sa.Integer(), nullable=False),
        sa.Column("requester_id", sa.Integer(), nullable=False),
        sa.Column("addressee_id", sa.Integer(), nullable=False),
        sa.Column("status", sa.String(length=20), nullable=False),
        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=True),
        sa.CheckConstraint(
            "status IN ('pending', 'accepted')",
            name="ck_friendships_status",
        ),
        sa.CheckConstraint(
            "requester_id <> addressee_id",
            name="ck_friendships_no_self",
        ),
        sa.ForeignKeyConstraint(
            ["addressee_id"],
            ["users.id"],
            ondelete="CASCADE",
        ),
        sa.ForeignKeyConstraint(
            ["requester_id"],
            ["users.id"],
            ondelete="CASCADE",
        ),
        sa.PrimaryKeyConstraint("id"),
        sa.UniqueConstraint(
            "requester_id",
            "addressee_id",
            name="uq_friendships_pair",
        ),
    )
    op.create_index(op.f("ix_friendships_id"), "friendships", ["id"], unique=False)
    op.create_index(op.f("ix_friendships_addressee_id"), "friendships", ["addressee_id"], unique=False)
    op.create_index(op.f("ix_friendships_requester_id"), "friendships", ["requester_id"], unique=False)

    op.create_table(
        "follows",
        sa.Column("follower_id", sa.Integer(), nullable=False),
        sa.Column("followed_id", sa.Integer(), nullable=False),
        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
        sa.CheckConstraint(
            "follower_id <> followed_id",
            name="ck_follows_no_self",
        ),
        sa.ForeignKeyConstraint(
            ["followed_id"],
            ["users.id"],
            ondelete="CASCADE",
        ),
        sa.ForeignKeyConstraint(
            ["follower_id"],
            ["users.id"],
            ondelete="CASCADE",
        ),
        sa.PrimaryKeyConstraint("follower_id", "followed_id"),
        sa.UniqueConstraint(
            "follower_id",
            "followed_id",
            name="uq_follows_pair",
        ),
    )
    op.create_index(op.f("ix_follows_followed_id"), "follows", ["followed_id"], unique=False)

    op.create_table(
        "blocks",
        sa.Column("blocker_id", sa.Integer(), nullable=False),
        sa.Column("blocked_id", sa.Integer(), nullable=False),
        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
        sa.CheckConstraint(
            "blocker_id <> blocked_id",
            name="ck_blocks_no_self",
        ),
        sa.ForeignKeyConstraint(
            ["blocked_id"],
            ["users.id"],
            ondelete="CASCADE",
        ),
        sa.ForeignKeyConstraint(
            ["blocker_id"],
            ["users.id"],
            ondelete="CASCADE",
        ),
        sa.PrimaryKeyConstraint("blocker_id", "blocked_id"),
        sa.UniqueConstraint(
            "blocker_id",
            "blocked_id",
            name="uq_blocks_pair",
        ),
    )
    op.create_index(op.f("ix_blocks_blocked_id"), "blocks", ["blocked_id"], unique=False)


def downgrade() -> None:
    """Drop friendships, follows, and blocks tables."""
    op.drop_index(op.f("ix_blocks_blocked_id"), table_name="blocks")
    op.drop_table("blocks")

    op.drop_index(op.f("ix_follows_followed_id"), table_name="follows")
    op.drop_table("follows")

    op.drop_index(op.f("ix_friendships_requester_id"), table_name="friendships")
    op.drop_index(op.f("ix_friendships_addressee_id"), table_name="friendships")
    op.drop_index(op.f("ix_friendships_id"), table_name="friendships")
    op.drop_table("friendships")