"""#632 - 一键生成输出分辨率可配置

Revision ID: 051
Revises: 050
Create Date: 2026-07-23

Changes:
1. generation_tasks 表新增 resolution 字段，存储用户指定的输出分辨率（如 "1280x720"）
2. 为空时使用默认值（1280x720）
"""

import sqlalchemy as sa

from alembic import context, op

revision = "051_generation_task_resolution"
down_revision = "050_video_shares"
branch_labels = None
depends_on = None


def upgrade() -> None:
    conn = op.get_bind()
    if context.get_context().dialect.name == "postgresql":
        # 检查列是否已存在（幂等）
        result = conn.execute(
            sa.text(
                "SELECT column_name FROM information_schema.columns "
                "WHERE table_name = 'generation_tasks' AND column_name = 'resolution'"
            )
        )
        if result.scalar() is not None:
            return

    op.add_column(
        "generation_tasks",
        sa.Column("resolution", sa.String(20), nullable=False, server_default=""),
    )


def downgrade() -> None:
    conn = op.get_bind()
    if context.get_context().dialect.name == "postgresql":
        result = conn.execute(
            sa.text(
                "SELECT column_name FROM information_schema.columns "
                "WHERE table_name = 'generation_tasks' AND column_name = 'resolution'"
            )
        )
        if result.scalar() is None:
            return

    op.drop_column("generation_tasks", "resolution")