from contextlib import asynccontextmanager
import sys
from typing import Annotated
from collections.abc import AsyncGenerator
from asyncio import sleep
import logging

from fastapi import Depends
from sqlalchemy.ext.asyncio import create_async_engine
from sqlmodel.ext.asyncio.session import AsyncSession
from sqlmodel import SQLModel, select, func, col

from treetrail.config import conf

logger = logging.getLogger(__name__)

CREATE_DB_TIMEOUT = 30

engine = create_async_engine(
    conf.db.get_sqla_url(),
    echo=conf.db.echo,
    pool_size=conf.db.pool_size,
    max_overflow=conf.db.max_overflow,
)


async def create_db(drop=False):
    attempts = CREATE_DB_TIMEOUT

    async def try_once():
        async with engine.begin() as conn:
            if drop:
                await conn.run_sync(SQLModel.metadata.drop_all)
            await conn.run_sync(SQLModel.metadata.create_all)

    logger.debug(f'Connect to database with config: {conf.db}')
    while attempts > 0:
        try:
            await try_once()
        except ConnectionRefusedError:
            logger.debug(
                f"Cannot connect to database during init (create_db), "
                f"waiting {attempts} more seconds"
            )
            attempts -= 1
            await sleep(1)
        else:
            if await is_fresh_install():
                await populate_init_db()
            return
    else:
        logger.warning(
            f"Cannot connect to database after {CREATE_DB_TIMEOUT}, giving up."
        )
        sys.exit(1)


async def is_fresh_install() -> bool:
    """Detect is the database is newly created, without data"""
    from treetrail.models import User

    async with db_session() as session:
        nb_users = (await session.exec(select(func.count(col(User.username))))).one()
        return nb_users == 0


async def populate_init_db():
    """Populate the database for a fresh install"""
    from sqlalchemy import text
    from treetrail.security import create_user, add_role, add_user_role
    logger.info("Populating initial database")

    user = await create_user(username="admin", password="admin")
    role = await add_role(role_id="admin")
    await add_user_role(user.username, role.name)
    async with db_session() as session:
        for initial in initials:
            await session.execute(text(initial))
            logger.debug(f'Added map style {initial}')
        await session.commit()


## Default styles, to be inserted in the DB
initials: list[str] = [
    """INSERT INTO map_style (layer, paint, layout) values ('trail', '{"line-color": "#cd861a", "line-width": 6, "line-blur": 2, "line-opacity": 0.9 }', '{"line-join": "bevel"}');""",
    """INSERT INTO map_style (layer, layout) values ('tree', '{"icon-image":"tree", "icon-size": 0.4}');""",
    """INSERT INTO map_style (layer, layout) values ('tree-hl', '{"icon-image":"tree", "icon-size": 0.4}');""",
    """INSERT INTO map_style (layer, layout) values ('poi', '{"icon-image":"poi", "icon-size": 0.4}');""",
    """INSERT INTO map_style (layer, paint) VALUES ('zone', '{"fill-color": ["match", ["string", ["get", "type"]], "Forest", "#00FF00", "Master Plan", "#EE4455", "#000000"], "fill-opacity": 0.5}');""",
]  # noqa: E501


async def get_db_session() -> AsyncGenerator[AsyncSession]:
    async with AsyncSession(engine) as session:
        yield session


@asynccontextmanager
async def db_session() -> AsyncGenerator[AsyncSession]:
    async with AsyncSession(engine) as session:
        yield session


fastapi_db_session = Annotated[AsyncSession, Depends(get_db_session)]