from __future__ import annotations

from pydantic import BaseModel

from app.core.errors import AppError
from app.providers.base import ProviderCapability
from app.providers.fixture import FixtureProvider
from app.providers.grb import GRBProvider
from app.providers.manual import ManualProvider
from app.providers.osm import OSMProvider


class ProviderDatasetMapping(BaseModel):
    provider_name: str
    dataset_role: str
    source_name: str
    reference_required: bool
    write_path: str = "DatasetService"


class ProviderImportResult(BaseModel):
    provider_name: str
    status: str
    message: str
    requested_layers: list[str]
    dataset_id: str | None = None
    dataset_role: str | None = None
    source_name: str | None = None


class ExternalProviderRegistry:
    def __init__(self) -> None:
        self.providers = {
            "grb": GRBProvider(),
            "osm": OSMProvider(),
            "manual": ManualProvider(),
            "fixture": FixtureProvider(),
        }

    def list_capabilities(self) -> list[ProviderCapability]:
        return [provider.capability for provider in self.providers.values()]

    def get(self, provider_name: str):
        normalized = provider_name.strip().lower()
        if normalized not in self.providers:
            raise AppError(code="PROVIDER_NOT_FOUND", message="Provider not found", status_code=404)
        return self.providers[normalized]

    def fetch(self, provider_name: str, project_id: str, area_id: str | None, layers: list[str]) -> dict:
        provider = self.get(provider_name)
        return provider.fetch(project_id=project_id, area_id=area_id, layers=layers)

    def dataset_mapping(self, provider_name: str, requested_dataset_role: str | None = None) -> ProviderDatasetMapping:
        provider = self.get(provider_name)
        if provider.provider_name == "osm":
            dataset_role = "reference" if requested_dataset_role == "reference" else "source"
            return ProviderDatasetMapping(
                provider_name="osm",
                dataset_role=dataset_role,
                source_name="osm",
                reference_required=requested_dataset_role == "reference",
            )
        return ProviderDatasetMapping(
            provider_name=provider.provider_name,
            dataset_role="reference",
            source_name=provider.provider_name,
            reference_required=True,
        )

    def import_contract(
        self,
        provider_name: str,
        project_id: str,
        area_id: str | None,
        layers: list[str],
        requested_dataset_role: str | None = None,
    ) -> ProviderImportResult:
        del project_id, area_id
        provider = self.get(provider_name)
        mapping = self.dataset_mapping(provider.provider_name, requested_dataset_role=requested_dataset_role)
        if provider.provider_name == "grb":
            return ProviderImportResult(
                provider_name="grb",
                status="bounded_request_required",
                message=(
                    "Use the governed project GRB acquisition endpoint with an EPSG:4326 bounding box "
                    "and one supported layer."
                ),
                requested_layers=layers,
                dataset_role=mapping.dataset_role,
                source_name=mapping.source_name,
            )
        if provider.provider_name == "osm":
            return ProviderImportResult(
                provider_name=provider.provider_name,
                status="not_configured",
                message=f"No live {provider.display_name} import is configured.",
                requested_layers=layers,
                dataset_role=mapping.dataset_role,
                source_name=mapping.source_name,
            )
        if provider.provider_name == "manual":
            return ProviderImportResult(
                provider_name="manual",
                status="upload_flow_required",
                message="Manual provider data must use the existing dataset upload/reference flow.",
                requested_layers=layers,
                dataset_role=mapping.dataset_role,
                source_name=mapping.source_name,
            )
        return ProviderImportResult(
            provider_name="fixture",
            status="fixture_flow_required",
            message="Fixture provider data must use checked-in demo/test fixture flows.",
            requested_layers=layers,
            dataset_role=mapping.dataset_role,
            source_name=mapping.source_name,
        )


_registry = ExternalProviderRegistry()


def list_provider_capabilities() -> list[ProviderCapability]:
    return _registry.list_capabilities()


def get_provider(provider_name: str):
    return _registry.get(provider_name)


def fetch_provider_data(provider_name: str, project_id: str, area_id: str | None, layers: list[str]) -> dict:
    return _registry.fetch(provider_name, project_id, area_id, layers)


def get_provider_dataset_mapping(provider_name: str, requested_dataset_role: str | None = None) -> ProviderDatasetMapping:
    return _registry.dataset_mapping(provider_name, requested_dataset_role=requested_dataset_role)


def import_provider_dataset(
    provider_name: str,
    project_id: str,
    area_id: str | None,
    layers: list[str],
    requested_dataset_role: str | None = None,
) -> ProviderImportResult:
    return _registry.import_contract(
        provider_name=provider_name,
        project_id=project_id,
        area_id=area_id,
        layers=layers,
        requested_dataset_role=requested_dataset_role,
    )