from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker, AsyncSession
from sqlalchemy import inspect, text
from sqlalchemy.orm import DeclarativeBase
from config import settings

engine = create_async_engine(settings.DATABASE_URL, echo=settings.DEBUG, pool_size=10, max_overflow=20)
async_session = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)


class Base(DeclarativeBase):
    pass


async def get_db():
    async with async_session() as session:
        try:
            yield session
        finally:
            await session.close()


async def init_db():
    from models.template import Template
    from models.paragraph import Paragraph
    from models.template_block import TemplateBlock
    from models.ai_model import AiModel
    from models.document import Document
    from models.generation_log import GenerationLog
    from models.reference_file import ReferenceFile
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
        dialect_name = conn.dialect.name
        columns = await conn.run_sync(lambda sync_conn: [column["name"] for column in inspect(sync_conn).get_columns("ai_models")])
        if "supports_streaming" not in columns:
            if dialect_name == "sqlite":
                await conn.execute(text("ALTER TABLE ai_models ADD COLUMN supports_streaming BOOLEAN DEFAULT 0"))
            else:
                await conn.execute(text("ALTER TABLE ai_models ADD COLUMN supports_streaming TINYINT(1) DEFAULT 0"))
        if "enable_reasoning" not in columns:
            if dialect_name == "sqlite":
                await conn.execute(text("ALTER TABLE ai_models ADD COLUMN enable_reasoning BOOLEAN DEFAULT 0"))
            else:
                await conn.execute(text("ALTER TABLE ai_models ADD COLUMN enable_reasoning TINYINT(1) DEFAULT 0"))
        document_columns = await conn.run_sync(
            lambda sync_conn: [column["name"] for column in inspect(sync_conn).get_columns("documents")]
        )
        if "request_payload_json" not in document_columns:
            await conn.execute(text("ALTER TABLE documents ADD COLUMN request_payload_json TEXT"))
        paragraph_columns = await conn.run_sync(
            lambda sync_conn: [column["name"] for column in inspect(sync_conn).get_columns("paragraphs")]
        )
        if "anchor_title" not in paragraph_columns:
            await conn.execute(text("ALTER TABLE paragraphs ADD COLUMN anchor_title VARCHAR(500) DEFAULT ''"))
            await conn.execute(text("UPDATE paragraphs SET anchor_title = title WHERE anchor_title = '' OR anchor_title IS NULL"))
        if "write_mode" not in paragraph_columns:
            await conn.execute(text("ALTER TABLE paragraphs ADD COLUMN write_mode VARCHAR(30) DEFAULT 'replace_section'"))
        block_tables = await conn.run_sync(lambda sync_conn: inspect(sync_conn).get_table_names())
        if "template_blocks" not in block_tables:
            await conn.run_sync(lambda sync_conn: TemplateBlock.__table__.create(sync_conn))