from typing import AsyncGenerator

from sqlalchemy import text
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine, async_sessionmaker
from sqlalchemy.orm import declarative_base

from app.core.config import settings
from app.core.logging import get_logger

logger = get_logger(__name__)

DB_POOL_CONFIG = {
    "pool_pre_ping": True,
    "pool_recycle": 1800,
    "pool_size": 10,
    "max_overflow": 20,
    "pool_timeout": 30,
}

engine = create_async_engine(
    settings.DATABASE_URL,
    echo=settings.DEBUG if hasattr(settings, "DEBUG") else False,
    **DB_POOL_CONFIG,
)

async_session_factory = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)

Base = declarative_base()


async def get_db() -> AsyncGenerator[AsyncSession, None]:
    async with async_session_factory() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise


async def seed_default_datasources(session: AsyncSession):
    from app.core.datasource_defaults import DEFAULT_DATASOURCES
    from app.models.datasource import DataSource

    for source, info in DEFAULT_DATASOURCES.items():
        existing = await session.get(DataSource, info["id"])
        if existing:
            existing.name = info["name"]
            existing.source = source
            existing.module = info["module"]
            existing.priority = info["priority"]
            existing.frequency_minutes = info["frequency_minutes"]
            existing.collector_class = source
            if existing.config is None:
                existing.config = "{}"
            continue

        session.add(
            DataSource(
                id=info["id"],
                name=info["name"],
                source=source,
                module=info["module"],
                priority=info["priority"],
                frequency_minutes=info["frequency_minutes"],
                collector_class=source,
                config="{}",
                is_active=True,
            )
        )

    await session.commit()


DEFAULT_LOGIN_USERS = (
    {
        "username": "admin",
        "email": "admin@planet.local",
        "password": "admin123",
        "role": "super_admin",
    },
    {
        "username": "linkong",
        "email": "linkong@planet.local",
        "password": "12345678",
        "role": "super_admin",
    },
)


async def ensure_default_admin_user(session: AsyncSession):
    from app.core.security import get_password_hash
    from app.models.user import User

    for default_user in DEFAULT_LOGIN_USERS:
        result = await session.execute(
            text("SELECT id FROM users WHERE username = :username"),
            {"username": default_user["username"]},
        )
        if result.fetchone():
            continue

        session.add(
            User(
                username=default_user["username"],
                email=default_user["email"],
                password_hash=get_password_hash(default_user["password"]),
                role=default_user["role"],
                is_active=True,
                email_verified=True,
            )
        )
    await session.commit()


async def init_db():
    import app.models.user  # noqa: F401
    import app.models.gpu_cluster  # noqa: F401
    import app.models.task  # noqa: F401
    import app.models.data_snapshot  # noqa: F401
    import app.models.datasource  # noqa: F401
    import app.models.datasource_config  # noqa: F401
    import app.models.alert  # noqa: F401
    import app.models.bgp_anomaly  # noqa: F401
    import app.models.bgp_collector_location  # noqa: F401
    import app.models.bgp_incident  # noqa: F401
    import app.models.bgp_observation  # noqa: F401
    import app.models.collected_data  # noqa: F401
    import app.models.compute_center_location  # noqa: F401
    import app.models.system_setting  # noqa: F401
    import app.models.playground_session  # noqa: F401
    import app.models.playground_message  # noqa: F401
    import app.models.system_log  # noqa: F401
    import app.models.vessel  # noqa: F401
    import app.models.vessel_enrichment  # noqa: F401
    import app.models.datasource_mapping  # noqa: F401
    import app.models.earth_news  # noqa: F401

    logger.warning_event(
        "Database pool settings active",
        event="database.pool.initialized",
        context={
            "pool_pre_ping": DB_POOL_CONFIG["pool_pre_ping"],
            "pool_recycle": DB_POOL_CONFIG["pool_recycle"],
            "pool_size": DB_POOL_CONFIG["pool_size"],
            "max_overflow": DB_POOL_CONFIG["max_overflow"],
            "pool_timeout": DB_POOL_CONFIG["pool_timeout"],
        },
    )

    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
        users_email_verified_existed = (
            await conn.execute(
                text(
                    """
                    SELECT 1
                    FROM information_schema.columns
                    WHERE table_name = 'users' AND column_name = 'email_verified'
                    """
                )
            )
        ).fetchone() is not None
        await conn.execute(
            text(
                """
                ALTER TABLE users
                ADD COLUMN IF NOT EXISTS gatekeeper_groups JSONB DEFAULT '[]'::jsonb,
                ADD COLUMN IF NOT EXISTS email_verified BOOLEAN NOT NULL DEFAULT FALSE,
                ADD COLUMN IF NOT EXISTS pending_email VARCHAR(255)
                """
            )
        )
        if not users_email_verified_existed:
            await conn.execute(
                text("UPDATE users SET email_verified = TRUE WHERE email_verified = FALSE")
            )
        await conn.execute(
            text(
                """
                ALTER TABLE collected_data
                ADD COLUMN IF NOT EXISTS snapshot_id INTEGER,
                ADD COLUMN IF NOT EXISTS task_id INTEGER,
                ADD COLUMN IF NOT EXISTS entity_key VARCHAR(255),
                ADD COLUMN IF NOT EXISTS is_current BOOLEAN DEFAULT TRUE,
                ADD COLUMN IF NOT EXISTS previous_record_id INTEGER,
                ADD COLUMN IF NOT EXISTS change_type VARCHAR(20),
                ADD COLUMN IF NOT EXISTS change_summary JSONB DEFAULT '{}'::jsonb,
                ADD COLUMN IF NOT EXISTS deleted_at TIMESTAMPTZ
                """
            )
        )
        await conn.execute(
            text(
                """
                ALTER TABLE collection_tasks
                ADD COLUMN IF NOT EXISTS phase VARCHAR(30) DEFAULT 'queued',
                ADD COLUMN IF NOT EXISTS phase_progress DOUBLE PRECISION,
                ADD COLUMN IF NOT EXISTS phase_message VARCHAR(255),
                ADD COLUMN IF NOT EXISTS phase_current BIGINT,
                ADD COLUMN IF NOT EXISTS phase_total BIGINT,
                ADD COLUMN IF NOT EXISTS phase_unit VARCHAR(30)
                """
            )
        )
        await conn.execute(
            text(
                """
                CREATE INDEX IF NOT EXISTS idx_collected_data_source_source_id
                ON collected_data (source, source_id)
                """
            )
        )
        await conn.execute(
            text(
                """
                CREATE INDEX IF NOT EXISTS idx_collected_data_source_current_id
                ON collected_data (source, is_current, id)
                """
            )
        )
        await conn.execute(
            text(
                """
                CREATE INDEX IF NOT EXISTS idx_collected_data_source_task_id
                ON collected_data (source, task_id, id)
                """
            )
        )
        await conn.execute(
            text(
                """
                CREATE INDEX IF NOT EXISTS idx_ais_raw_schema_observed_entity
                ON ais_raw_observations (target_schema, observed_at, entity_key)
                """
            )
        )
        await conn.execute(
            text(
                """
                CREATE INDEX IF NOT EXISTS idx_ais_raw_schema_observed_desc
                ON ais_raw_observations (target_schema, observed_at DESC)
                """
            )
        )
        await conn.execute(
            text(
                """
                CREATE INDEX IF NOT EXISTS idx_ais_raw_payload_lon_lat
                ON ais_raw_observations (
                    ((normalized_payload->>'lon')::double precision),
                    ((normalized_payload->>'lat')::double precision)
                )
                WHERE target_schema = 'vessel_ais'
                """
            )
        )
        await conn.execute(
            text(
                """
                UPDATE collected_data
                SET entity_key = source || ':' || COALESCE(source_id, id::text)
                WHERE entity_key IS NULL
                """
            )
        )
        await conn.execute(
            text(
                """
                UPDATE collected_data
                SET is_current = TRUE
                WHERE is_current IS NULL
                """
            )
        )

    async with async_session_factory() as session:
        from app.services.bgp_collector_locations import (
            seed_default_bgp_collector_locations,
        )
        from app.services.compute_center_locations import (
            seed_compute_center_locations_from_source_coords,
        )

        await seed_default_bgp_collector_locations(session)
        await seed_compute_center_locations_from_source_coords(session)
        await seed_default_datasources(session)
        await ensure_default_admin_user(session)