import { useCallback, useMemo, useState } from 'react';
import {
  getProceduralDemoMachine,
  proceduralDemoMachines,
} from './proceduralDemoManifest';
import type {
  ProceduralMachineId,
  ProceduralMachineModule,
} from './types';

export interface UseProceduralDemoMachineResult {
  machine: ProceduralMachineModule;
  machines: ProceduralMachineModule[];
  selectedMachineId: ProceduralMachineId;
  selectMachine: (machineId: ProceduralMachineId) => void;
  selectNextMachine: () => void;
  selectPreviousMachine: () => void;
}

export function useProceduralDemoMachine(
  initialMachineId?: string | null,
): UseProceduralDemoMachineResult {
  const initial = getProceduralDemoMachine(initialMachineId);
  const [selectedMachineId, setSelectedMachineId] = useState<ProceduralMachineId>(initial.definition.id);

  const machine = useMemo(
    () => getProceduralDemoMachine(selectedMachineId),
    [selectedMachineId],
  );

  const selectMachine = useCallback((machineId: ProceduralMachineId) => {
    setSelectedMachineId(machineId);
  }, []);

  const selectNextMachine = useCallback(() => {
    setSelectedMachineId((currentId) => {
      const index = proceduralDemoMachines.findIndex((candidate) => candidate.definition.id === currentId);
      return proceduralDemoMachines[(index + 1) % proceduralDemoMachines.length].definition.id;
    });
  }, []);

  const selectPreviousMachine = useCallback(() => {
    setSelectedMachineId((currentId) => {
      const index = proceduralDemoMachines.findIndex((candidate) => candidate.definition.id === currentId);
      return proceduralDemoMachines[
        (index - 1 + proceduralDemoMachines.length) % proceduralDemoMachines.length
      ].definition.id;
    });
  }, []);

  return {
    machine,
    machines: proceduralDemoMachines,
    selectedMachineId,
    selectMachine,
    selectNextMachine,
    selectPreviousMachine,
  };
}