"""FastAPI application factory."""

import logging
from contextlib import asynccontextmanager

from fastapi import FastAPI

from gps_denied import __version__
from gps_denied.api.routers import flights
from gps_denied.config import get_settings

logger = logging.getLogger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Initialise core pipeline components on startup."""
    from gps_denied.core.chunk_manager import RouteChunkManager
    from gps_denied.core.coordinates import CoordinateTransformer
    from gps_denied.core.gpr import GlobalPlaceRecognition
    from gps_denied.core.graph import FactorGraphOptimizer
    from gps_denied.core.mavlink import MAVLinkBridge
    from gps_denied.core.metric import MetricRefinement
    from gps_denied.core.models import ModelManager
    from gps_denied.core.recovery import FailureRecoveryCoordinator
    from gps_denied.core.rotation import ImageRotationManager
    from gps_denied.core.satellite import SatelliteDataManager
    from gps_denied.core.vo import create_vo_backend
    from gps_denied.schemas.eskf import ESKFConfig
    from gps_denied.schemas.graph import FactorGraphConfig

    settings = get_settings()

    mm = ModelManager(engine_dir=str(settings.models.weights_dir))
    vo = create_vo_backend(model_manager=mm)
    gpr = GlobalPlaceRecognition(mm)
    metric = MetricRefinement(mm)
    graph = FactorGraphOptimizer(FactorGraphConfig())
    chunk_mgr = RouteChunkManager(graph)
    recovery = FailureRecoveryCoordinator(chunk_mgr, gpr, metric)
    rotation = ImageRotationManager(mm)
    coord = CoordinateTransformer()
    satellite = SatelliteDataManager(tile_dir=settings.satellite.tile_dir)
    mavlink = MAVLinkBridge(
        connection_string=settings.mavlink.connection,
        output_hz=settings.mavlink.output_hz,
        telemetry_hz=settings.mavlink.telemetry_hz,
    )

    # ESKF config from env vars (per-airframe tuning)
    eskf_config = ESKFConfig(**settings.eskf.model_dump())

    # Store on app.state so deps can access them
    app.state.pipeline_components = {
        "vo": vo, "gpr": gpr, "metric": metric,
        "graph": graph, "recovery": recovery,
        "chunk_mgr": chunk_mgr, "rotation": rotation,
        "coord": coord, "satellite": satellite,
        "mavlink": mavlink,
    }
    app.state.eskf_config = eskf_config

    logger.info(
        "Pipeline ready — MAVLink: %s, tiles: %s",
        settings.mavlink.connection, settings.satellite.tile_dir,
    )
    yield

    # Cleanup
    try:
        await mavlink.stop()
    except Exception:
        pass
    app.state.pipeline_components = None


def create_app() -> FastAPI:
    """Factory function to create and configure the FastAPI application."""
    app = FastAPI(
        title="GPS-Denied Onboard API",
        description="REST API for UAV Flight Processing in GPS-denied environments.",
        version=__version__,
        lifespan=lifespan,
    )

    app.include_router(flights.router)

    @app.get("/health", tags=["Health"])
    async def health() -> dict[str, str]:
        """Simple health check endpoint."""
        return {"status": "ok"}

    return app


app = create_app()