import { createContext, useContext, useState, useEffect, useCallback, type ReactNode } from 'react';
import { campaignApi, type Campaign } from '../api';

interface CampaignContextType {
  currentCampaign: Campaign | null;
  setCampaign: (c: Campaign | null) => void;
  campaigns: Campaign[];
  refreshCampaigns: () => void;
}

const CampaignContext = createContext<CampaignContextType | null>(null);

export function CampaignProvider({ children }: { children: ReactNode }) {
  const [campaigns, setCampaigns] = useState<Campaign[]>([]);
  const [currentCampaign, setCurrentCampaign] = useState<Campaign | null>(null);

  const refreshCampaigns = useCallback(async () => {
    try {
      const list = await campaignApi.list();
      setCampaigns(list);
    } catch {}
  }, []);

  useEffect(() => {
    refreshCampaigns();
  }, [refreshCampaigns]);

  useEffect(() => {
    if (campaigns.length === 0) return;
    if (!currentCampaign) {
      const stored = localStorage.getItem('campaignId');
      const match = stored ? campaigns.find(c => c.id === stored) : null;
      setCurrentCampaign(match || campaigns[0]);
    } else {
      const stillExists = campaigns.find(c => c.id === currentCampaign.id);
      if (!stillExists) {
        setCurrentCampaign(campaigns[0] || null);
      }
    }
  }, [campaigns]);

  const setCampaign = (c: Campaign | null) => {
    if (c) localStorage.setItem('campaignId', c.id);
    else localStorage.removeItem('campaignId');
    setCurrentCampaign(c);
  };

  return (
    <CampaignContext.Provider value={{ currentCampaign, setCampaign, campaigns, refreshCampaigns }}>
      {children}
    </CampaignContext.Provider>
  );
}

export function useCampaign() {
  const ctx = useContext(CampaignContext);
  if (!ctx) throw new Error('useCampaign must be used within CampaignProvider');
  return ctx;
}