school_compare/nextjs-app/context/ComparisonContext.tsx

/**
 * ComparisonContext
 * Global state for school comparison basket
 */

'use client';

import { createContext, useContext } from 'react';
import type { CompareGroup } from '@/lib/compareLogic';
import type { School } from '@/lib/types';

interface ComparisonContextType {
  selectedSchools: School[];
  comparisonData: any;
  isLoading: boolean;
  error: any;
  addSchool: (school: School) => void;
  removeSchool: (urn: number) => void;
  replaceSchools: (schools: School[]) => void;
  /** Fill in phases missing from stored entries; never overwrites one. */
  backfillPhases: (phases: Record<number, string | null | undefined>) => void;
  clearAll: () => void;
  isSelected: (urn: number) => boolean;
  /** The comparison group with no room for this school, or null. */
  fullGroupFor: (school: Pick<School, 'phase'>) => CompareGroup | null;
  isInitialized: boolean;
  mutate: () => void;
}

export const ComparisonContext = createContext<ComparisonContextType | undefined>(undefined);

export function useComparisonContext() {
  const context = useContext(ComparisonContext);
  if (!context) {
    throw new Error('useComparisonContext must be used within ComparisonProvider');
  }
  return context;
}