"""Register the original knowledge table without replacing existing data."""

import sqlalchemy as sa
from alembic import op

revision = "0001_baseline"
down_revision = None
branch_labels = None
depends_on = None


def upgrade():
    bind = op.get_bind()
    op.execute("CREATE EXTENSION IF NOT EXISTS vector")
    inspector = sa.inspect(bind)
    if inspector.has_table("knowledge_items"):
        columns = {column["name"] for column in inspector.get_columns("knowledge_items")}
        expected = {
            "id",
            "title",
            "category",
            "content",
            "source_url",
            "verification_status",
            "created_at",
        }
        if columns != expected:
            raise RuntimeError("已有 knowledge_items 结构与基础版本不同，请先核对结构并备份")
        return
    op.create_table(
        "knowledge_items",
        sa.Column("id", sa.Integer(), primary_key=True),
        sa.Column("title", sa.String(250), nullable=False),
        sa.Column("category", sa.String(80), nullable=False),
        sa.Column("content", sa.Text(), nullable=False),
        sa.Column("source_url", sa.String(1000)),
        sa.Column("verification_status", sa.String(30), nullable=False),
        sa.Column(
            "created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False
        ),
    )
    op.create_index("ix_knowledge_items_id", "knowledge_items", ["id"])
    op.create_index("ix_knowledge_items_title", "knowledge_items", ["title"])


def downgrade():
    op.drop_table("knowledge_items")
    # 扩展可能由其他项目共享，不在回滚时删除。