"""add ai_session_embeddings table for similar-session matching

Revision ID: a7c9e3b1f402
Revises: dbf67047d4c8
Create Date: 2026-03-20
"""
from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa
from sqlalchemy.dialects import postgresql


# revision identifiers, used by Alembic.
revision: str = "a7c9e3b1f402"
down_revision: Union[str, None] = "dbf67047d4c8"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    # pgvector extension should already exist from migration 042
    op.execute("CREATE EXTENSION IF NOT EXISTS vector")

    op.create_table(
        "ai_session_embeddings",
        sa.Column(
            "id",
            postgresql.UUID(as_uuid=True),
            primary_key=True,
            server_default=sa.text("gen_random_uuid()"),
        ),
        sa.Column(
            "session_id",
            postgresql.UUID(as_uuid=True),
            sa.ForeignKey("ai_sessions.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column(
            "account_id",
            postgresql.UUID(as_uuid=True),
            sa.ForeignKey("accounts.id", ondelete="CASCADE"),
            nullable=False,
        ),
        sa.Column("chunk_text", sa.Text(), nullable=False),
        sa.Column(
            "embedding_model",
            sa.String(50),
            nullable=False,
            server_default="voyage-3.5",
        ),
        sa.Column(
            "created_at",
            sa.DateTime(timezone=True),
            server_default=sa.text("now()"),
        ),
        sa.Column(
            "updated_at",
            sa.DateTime(timezone=True),
            server_default=sa.text("now()"),
        ),
    )

    # Add vector column via raw SQL (pgvector type not in SA dialect)
    op.execute(
        "ALTER TABLE ai_session_embeddings ADD COLUMN embedding vector(1024)"
    )

    op.create_index(
        "ix_ai_session_embeddings_session_id",
        "ai_session_embeddings",
        ["session_id"],
        unique=True,
    )
    op.create_index(
        "ix_ai_session_embeddings_account_id",
        "ai_session_embeddings",
        ["account_id"],
    )


def downgrade() -> None:
    op.drop_table("ai_session_embeddings")