import { Eta, Resolvers } from "../generated/graphql";
import { ServerContext } from "../ServerContext";

export const ShuttleResolvers: Resolvers<ServerContext> = {
  Shuttle: {
    eta: async (parent, args, contextValue, _) => {
      if (!args.forStopId) return null;

      const system = contextValue.findSystemById(parent.systemId);
      if (!system) return null;

      const etaForStopId = await system.etaRepository.getEtaForShuttleAndStopId(parent.id, args.forStopId);
      if (etaForStopId === null) return null;

      return {
        stopId: args.forStopId,
        secondsRemaining: etaForStopId.secondsRemaining,
        shuttleId: parent.id,
        shuttle: parent,
        systemId: system.id,
        updatedTimeMs: etaForStopId.updatedTime,
      };
    },
    etas: async (parent, args, contextValue, _) => {
      const system = contextValue.findSystemById(parent.systemId);
      if (!system) return null;

      const etasForShuttle = await system.etaRepository.getEtasForShuttleId(parent.id);
      if (!etasForShuttle) return null;

      const computedEtas = await Promise.all(
        etasForShuttle.map(async ({
          secondsRemaining,
          stopId,
          updatedTime
        }): Promise<Eta | null> => {
          return {
            secondsRemaining,
            stopId,
            shuttle: parent,
            shuttleId: parent.id,
            systemId: system.id,
            updatedTime: updatedTime,
          }
      }));

      if (computedEtas.every((eta) => eta !== null)) {
        return computedEtas
          .slice()
          .sort((a, b) => (a!.secondsRemaining - b!.secondsRemaining));
      }

      return [];
    },
    route: async (parent, args, contextValue, _) => {
      const system = contextValue.findSystemById(parent.systemId);
      if (!system) return null;

      const route = await system.shuttleRepository.getRouteById(parent.routeId);
      if (route === null) return null;

      return {
        color: route.color,
        id: route.id,
        name: route.name,
        polylineCoordinates: route.polylineCoordinates,
        systemId: system.id,
        updatedTimeMs: route.updatedTime
      }
    }
  },
}