"""打通采购申请与采购入库的按单入库链路

Revision ID: a1b2c3d4e5f6
Revises: None (或填当前最新 revision)
Create Date: 2026-07-14

变更内容:
  1. purchase_request 表新增 base_id (FK → material_base.id)
  2. stock_buy 表新增 request_id (FK → purchase_request.id)
"""
from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision = 'a1b2c3d4e5f6'
down_revision = None   # ← 替换为当前最新 revision ID
branch_labels = None
depends_on = None


def upgrade():
    # ============================================================
    # 1. purchase_request 新增 base_id
    # ============================================================
    with op.batch_alter_table('purchase_request', schema=None) as batch_op:
        batch_op.add_column(
            sa.Column('base_id', sa.Integer(), nullable=True,
                      comment='关联基础物料ID')
        )
        batch_op.create_foreign_key(
            'fk_purchase_request_base_id',
            'material_base',
            ['base_id'],
            ['id'],
            ondelete='SET NULL'
        )
        batch_op.create_index(
            'ix_purchase_request_base_id',
            ['base_id']
        )

    # ============================================================
    # 2. stock_buy 新增 request_id
    # ============================================================
    with op.batch_alter_table('stock_buy', schema=None) as batch_op:
        batch_op.add_column(
            sa.Column('request_id', sa.Integer(), nullable=True,
                      comment='关联采购申请单ID')
        )
        batch_op.create_foreign_key(
            'fk_stock_buy_request_id',
            'purchase_request',
            ['request_id'],
            ['id'],
            ondelete='SET NULL'
        )
        batch_op.create_index(
            'ix_stock_buy_request_id',
            ['request_id']
        )


def downgrade():
    # ============================================================
    # 回滚：stock_buy 删除 request_id
    # ============================================================
    with op.batch_alter_table('stock_buy', schema=None) as batch_op:
        batch_op.drop_constraint('fk_stock_buy_request_id', type_='foreignkey')
        batch_op.drop_index('ix_stock_buy_request_id')
        batch_op.drop_column('request_id')

    # ============================================================
    # 回滚：purchase_request 删除 base_id
    # ============================================================
    with op.batch_alter_table('purchase_request', schema=None) as batch_op:
        batch_op.drop_constraint('fk_purchase_request_base_id', type_='foreignkey')
        batch_op.drop_index('ix_purchase_request_base_id')
        batch_op.drop_column('base_id')