import React, { useState, useEffect, useCallback } from 'react';
import { initializeApp } from 'firebase/app';
import { getAuth, signInAnonymously, onAuthStateChanged, signInWithCustomToken } from 'firebase/auth';
import { getFirestore, doc, setDoc, addDoc, getDoc, getDocs, collection, onSnapshot, updateDoc, deleteDoc, query, where, writeBatch } from 'firebase/firestore';
import { ArrowLeft, PlusCircle, Users, Swords, Shield, Trash2, Eye, Edit3, Save, XCircle, ChevronsUpDown, ChevronDown, ChevronUp, UserCheck, UserX, HeartCrack, HeartPulse, Zap, Share2, Copy as CopyIcon } from 'lucide-react';

// --- Firebase Configuration ---
// Read from environment variables
const firebaseConfig = {
  apiKey: process.env.REACT_APP_FIREBASE_API_KEY,
  authDomain: process.env.REACT_APP_FIREBASE_AUTH_DOMAIN,
  projectId: process.env.REACT_APP_FIREBASE_PROJECT_ID,
  storageBucket: process.env.REACT_APP_FIREBASE_STORAGE_BUCKET,
  messagingSenderId: process.env.REACT_APP_FIREBASE_MESSAGING_SENDER_ID,
  appId: process.env.REACT_APP_FIREBASE_APP_ID
};

// --- Initialize Firebase ---
// Check if all necessary Firebase config values are present
const requiredFirebaseConfigKeys = [
  'apiKey', 'authDomain', 'projectId', 'appId'
  // storageBucket and messagingSenderId might be optional depending on usage
];
const missingKeys = requiredFirebaseConfigKeys.filter(key => !firebaseConfig[key]);

let app;
if (missingKeys.length > 0) {
  console.error(`Missing Firebase config keys from environment variables: ${missingKeys.join(', ')}`);
  console.warn("Firebase is not initialized. Please set up your .env.local file with the necessary REACT_APP_FIREBASE_... variables.");
  // You might want to render an error message or a fallback UI here
} else {
  app = initializeApp(firebaseConfig);
}

const db = app ? getFirestore(app) : null; // Conditionally get Firestore
const auth = app ? getAuth(app) : null;   // Conditionally get Auth

// --- Firestore Paths ---
const APP_ID = process.env.REACT_APP_TRACKER_APP_ID || 'ttrpg-initiative-tracker-default';
// ... rest of your code

// --- Helper Functions ---
const generateId = () => crypto.randomUUID();

function getShareableLinkBase() {
  return window.location.origin + window.location.pathname;
}

// --- Main App Component ---
function App() {
  const [userId, setUserId] = useState(null);
  const [isAuthReady, setIsAuthReady] = useState(false);
  const [viewMode, setViewMode] = useState('admin'); 
  const [isLoading, setIsLoading] = useState(true);
  const [error, setError] = useState(null);
  const [directDisplayParams, setDirectDisplayParams] = useState(null); 

  useEffect(() => {
    const handleHashChange = () => {
      const hash = window.location.hash; 
      if (hash.startsWith('#/display/')) {
        const parts = hash.substring('#/display/'.length).split('/');
        if (parts.length === 2 && parts[0] && parts[1]) {
          setDirectDisplayParams({ campaignId: parts[0], encounterId: parts[1] });
          setViewMode('display'); 
        } else {
          setDirectDisplayParams(null); 
        }
      } else {
        setDirectDisplayParams(null); 
      }
    };
    window.addEventListener('hashchange', handleHashChange);
    handleHashChange(); 
    return () => window.removeEventListener('hashchange', handleHashChange);
  }, []);

  useEffect(() => {
    const initAuth = async () => {
      try {
        if (typeof __initial_auth_token !== 'undefined' && __initial_auth_token) {
          await signInWithCustomToken(auth, __initial_auth_token);
        } else {
          await signInAnonymously(auth);
        }
      } catch (err) {
        console.error("Authentication error:", err);
        setError("Failed to authenticate. Please try again later.");
      }
    };
    const unsubscribe = onAuthStateChanged(auth, (user) => {
      setUserId(user ? user.uid : null);
      setIsAuthReady(true);
      setIsLoading(false);
    });
    initAuth();
    return () => unsubscribe();
  }, []);

  if (isLoading || !isAuthReady) {
    return (
      <div className="min-h-screen bg-slate-900 text-white flex flex-col items-center justify-center p-4">
        <div className="animate-spin rounded-full h-16 w-16 border-t-4 border-blue-500 border-solid"></div>
        <p className="mt-4 text-xl">Loading Initiative Tracker...</p>
        {error && <p className="mt-2 text-red-400">{error}</p>}
      </div>
    );
  }

  return (
    <div className="min-h-screen bg-slate-800 text-slate-100 font-sans">
      {!directDisplayParams && ( 
        <header className="bg-slate-900 p-4 shadow-lg">
          <div className="container mx-auto flex justify-between items-center">
            <h1 className="text-3xl font-bold text-sky-400">TTRPG Initiative Tracker</h1>
            <div className="flex items-center space-x-4">
              {userId && <span className="text-xs text-slate-400">UID: {userId}</span>}
              {viewMode !== 'display' && ( // Only show Admin View button if not in display mode (when header is visible)
                 <button
                    onClick={() => { setViewMode('admin'); setDirectDisplayParams(null); window.location.hash = '';}}
                    className={`px-4 py-2 rounded-md text-sm font-medium transition-colors ${viewMode === 'admin' && !directDisplayParams ? 'bg-sky-500 text-white' : 'bg-slate-700 hover:bg-slate-600'}`}
                 >
                    Admin View
                 </button>
              )}
              {viewMode !== 'admin' && ( // Only show Player Display button if not in admin mode
                <button
                    onClick={() => { setViewMode('display'); setDirectDisplayParams(null); window.location.hash = '';}}
                    className={`px-4 py-2 rounded-md text-sm font-medium transition-colors ${viewMode === 'display' && !directDisplayParams ? 'bg-teal-500 text-white' : 'bg-slate-700 hover:bg-slate-600'}`}
                >
                    Player Display
                </button>
              )}
               {/* If in admin mode, show player display button. If in player mode, show admin button (unless hidden above) */}
               {/* This logic seems a bit complex, let's simplify: always show both if header is visible, style active one */}
                {viewMode === 'admin' && ( // Show Player Display button if in Admin mode
                    <button
                        onClick={() => { setViewMode('display'); setDirectDisplayParams(null); window.location.hash = '';}}
                        className={`px-4 py-2 rounded-md text-sm font-medium transition-colors bg-slate-700 hover:bg-slate-600`}
                    >
                        Player Display
                    </button>
                )}
            </div>
          </div>
        </header>
      )}

      <main className={`container mx-auto p-4 md:p-8 ${directDisplayParams ? 'pt-8' : ''}`}>
        {directDisplayParams && isAuthReady && (
          <DisplayView campaignIdFromUrl={directDisplayParams.campaignId} encounterIdFromUrl={directDisplayParams.encounterId} />
        )}
        {!directDisplayParams && viewMode === 'admin' && isAuthReady && userId && <AdminView userId={userId} />}
        {!directDisplayParams && viewMode === 'display' && isAuthReady && <DisplayView />}
        {!isAuthReady && <p>Authenticating...</p>}
      </main>
       {!directDisplayParams && (
         <footer className="bg-slate-900 p-4 text-center text-sm text-slate-400 mt-8">
          TTRPG Initiative Tracker v0.1.12
        </footer>
       )}
    </div>
  );
}

// --- Admin View Component ---
function AdminView({ userId }) {
  const [campaigns, setCampaigns] = useState([]);
  const [selectedCampaignId, setSelectedCampaignId] = useState(null);
  const [showCreateCampaignModal, setShowCreateCampaignModal] = useState(false);
  const [initialActiveInfo, setInitialActiveInfo] = useState(null);

  useEffect(() => {
    const campaignsCollectionRef = collection(db, CAMPAIGNS_COLLECTION);
    const q = query(campaignsCollectionRef); 
    const unsubscribeCampaigns = onSnapshot(q, (snapshot) => {
      setCampaigns(snapshot.docs.map(doc => ({ id: doc.id, ...doc.data(), characters: doc.data().players || [] })));
    }, (err) => console.error("Error fetching campaigns:", err));
    
    const activeDisplayRef = doc(db, ACTIVE_DISPLAY_DOC);
    const unsubscribeActiveDisplay = onSnapshot(activeDisplayRef, (docSnap) => {
        if (docSnap.exists()) {
            setInitialActiveInfo(docSnap.data());
        } else {
            setInitialActiveInfo(null);
        }
    }, (err) => {
        console.error("Error fetching initial active display info for AdminView:", err);
    });

    return () => {
        unsubscribeCampaigns();
        unsubscribeActiveDisplay();
    };
  }, []);

  useEffect(() => {
    if (initialActiveInfo && initialActiveInfo.activeCampaignId && campaigns.length > 0 && !selectedCampaignId) {
        const campaignExists = campaigns.some(c => c.id === initialActiveInfo.activeCampaignId);
        if (campaignExists) {
            setSelectedCampaignId(initialActiveInfo.activeCampaignId);
        }
    }
  }, [initialActiveInfo, campaigns, selectedCampaignId]);


  const handleCreateCampaign = async (name) => {
    if (!name.trim()) return;
    const newCampaignId = generateId();
    try {
      await setDoc(doc(db, CAMPAIGNS_COLLECTION, newCampaignId), {
        name: name.trim(), ownerId: userId, createdAt: new Date().toISOString(), players: [], 
      });
      setShowCreateCampaignModal(false);
      setSelectedCampaignId(newCampaignId); 
    } catch (err) { console.error("Error creating campaign:", err); }
  };

  const handleDeleteCampaign = async (campaignId) => {
    // TODO: Implement custom confirmation modal for deleting campaigns
    console.warn("Attempting to delete campaign without confirmation:", campaignId);
    try {
      const encountersPath = `${CAMPAIGNS_COLLECTION}/${campaignId}/encounters`;
      const encountersSnapshot = await getDocs(collection(db, encountersPath));
      const batch = writeBatch(db);
      encountersSnapshot.docs.forEach(encounterDoc => batch.delete(encounterDoc.ref));
      await batch.commit();
      await deleteDoc(doc(db, CAMPAIGNS_COLLECTION, campaignId));
      if (selectedCampaignId === campaignId) setSelectedCampaignId(null);
      const activeDisplayRef = doc(db, ACTIVE_DISPLAY_DOC);
      const activeDisplaySnap = await getDoc(activeDisplayRef);
      if (activeDisplaySnap.exists() && activeDisplaySnap.data().activeCampaignId === campaignId) {
        await updateDoc(activeDisplayRef, { activeCampaignId: null, activeEncounterId: null });
      }
    } catch (err) { console.error("Error deleting campaign:", err); }
  };

  const selectedCampaign = campaigns.find(c => c.id === selectedCampaignId);

  return (
    <div className="space-y-6">
      <div>
        <div className="flex justify-between items-center mb-4">
          <h2 className="text-2xl font-semibold text-sky-300">Campaigns</h2>
          <button onClick={() => setShowCreateCampaignModal(true)} className="bg-green-500 hover:bg-green-600 text-white font-bold py-2 px-4 rounded-lg flex items-center transition-colors">
            <PlusCircle size={20} className="mr-2" /> Create Campaign
          </button>
        </div>
        {campaigns.length === 0 && <p className="text-slate-400">No campaigns yet.</p>}
        <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-4">
          {campaigns.map(campaign => (
            <div 
              key={campaign.id} 
              onClick={() => setSelectedCampaignId(campaign.id)}
              className={`p-4 rounded-lg shadow-md cursor-pointer transition-all ${selectedCampaignId === campaign.id ? 'bg-sky-700 ring-2 ring-sky-400' : 'bg-slate-700 hover:bg-slate-600'}`}
            >
              <h3 className="text-xl font-semibold text-white">{campaign.name}</h3>
              <p className="text-xs text-slate-400">ID: {campaign.id}</p>
              <button 
                onClick={(e) => { 
                  e.stopPropagation(); 
                  handleDeleteCampaign(campaign.id); 
                }} 
                className="mt-2 text-red-400 hover:text-red-300 text-xs flex items-center"
              >
                <Trash2 size={14} className="mr-1" /> Delete
              </button>
            </div>
          ))}
        </div>
      </div>
      {showCreateCampaignModal && <Modal onClose={() => setShowCreateCampaignModal(false)} title="Create New Campaign"><CreateCampaignForm onCreate={handleCreateCampaign} onCancel={() => setShowCreateCampaignModal(false)} /></Modal>}
      {selectedCampaign && (
        <div className="mt-6 p-6 bg-slate-750 rounded-lg shadow-xl">
          <h2 className="text-2xl font-semibold text-amber-300 mb-4">Managing: {selectedCampaign.name}</h2>
          <CharacterManager campaignId={selectedCampaignId} campaignCharacters={selectedCampaign.players || []} />
          <hr className="my-6 border-slate-600" />
          <EncounterManager 
            campaignId={selectedCampaignId} 
            initialActiveEncounterId={initialActiveInfo && initialActiveInfo.activeCampaignId === selectedCampaignId ? initialActiveInfo.activeEncounterId : null}
            campaignCharacters={selectedCampaign.players || []} 
          />
        </div>
      )}
    </div>
  );
}

function CreateCampaignForm({ onCreate, onCancel }) {
  const [name, setName] = useState('');
  return (
    <form onSubmit={(e) => { e.preventDefault(); onCreate(name); }} className="space-y-4">
      <div>
        <label htmlFor="campaignName" className="block text-sm font-medium text-slate-300">Campaign Name</label>
        <input type="text" id="campaignName" value={name} onChange={(e) => setName(e.target.value)} className="mt-1 block w-full px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" required />
      </div>
      <div className="flex justify-end space-x-3">
        <button type="button" onClick={onCancel} className="px-4 py-2 text-sm font-medium text-slate-300 bg-slate-600 hover:bg-slate-500 rounded-md transition-colors">Cancel</button>
        <button type="submit" className="px-4 py-2 text-sm font-medium text-white bg-green-500 hover:bg-green-600 rounded-md transition-colors">Create</button>
      </div>
    </form>
  );
}

function CharacterManager({ campaignId, campaignCharacters }) {
  const [characterName, setCharacterName] = useState('');
  const [editingCharacter, setEditingCharacter] = useState(null); 

  const handleAddCharacter = async () => {
    if (!characterName.trim() || !campaignId) return;
    const newCharacter = { id: generateId(), name: characterName.trim() };
    try {
      await updateDoc(doc(db, CAMPAIGNS_COLLECTION, campaignId), { players: [...campaignCharacters, newCharacter] });
      setCharacterName('');
    } catch (err) { console.error("Error adding character:", err); }
  };

  const handleUpdateCharacter = async (characterId, newName) => {
    if (!newName.trim() || !campaignId) return;
    const updatedCharacters = campaignCharacters.map(c => c.id === characterId ? { ...c, name: newName.trim() } : c);
    try {
      await updateDoc(doc(db, CAMPAIGNS_COLLECTION, campaignId), { players: updatedCharacters });
      setEditingCharacter(null); 
    } catch (err) { console.error("Error updating character:", err); }
  };

  const handleDeleteCharacter = async (characterId) => {
    // TODO: Implement custom confirmation modal for deleting characters
    console.warn("Attempting to delete character without confirmation:", characterId);
    const updatedCharacters = campaignCharacters.filter(c => c.id !== characterId);
    try {
      await updateDoc(doc(db, CAMPAIGNS_COLLECTION, campaignId), { players: updatedCharacters });
    } catch (err) { console.error("Error deleting character:", err); }
  };

  return (
    <div className="p-4 bg-slate-800 rounded-lg shadow">
      <h3 className="text-xl font-semibold text-sky-300 mb-3 flex items-center"><Users size={24} className="mr-2" /> Campaign Characters</h3>
      <form onSubmit={(e) => { e.preventDefault(); handleAddCharacter(); }} className="flex gap-2 mb-4">
        <input type="text" value={characterName} onChange={(e) => setCharacterName(e.target.value)} placeholder="New character name" className="flex-grow px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" />
        <button type="submit" className="px-4 py-2 text-sm font-medium text-white bg-sky-500 hover:bg-sky-600 rounded-md transition-colors flex items-center"><PlusCircle size={18} className="mr-1" /> Add Character</button>
      </form>
      {campaignCharacters.length === 0 && <p className="text-sm text-slate-400">No characters added.</p>}
      <ul className="space-y-2">
        {campaignCharacters.map(character => (
          <li key={character.id} className="flex justify-between items-center p-3 bg-slate-700 rounded-md">
            {editingCharacter && editingCharacter.id === character.id ? (
              <input type="text" defaultValue={character.name} onBlur={(e) => handleUpdateCharacter(character.id, e.target.value)} onKeyDown={(e) => { if (e.key === 'Enter') handleUpdateCharacter(character.id, e.target.value); if (e.key === 'Escape') setEditingCharacter(null); }} autoFocus className="flex-grow px-3 py-2 bg-slate-600 border border-slate-500 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white"/>
            ) : ( <span className="text-slate-100">{character.name}</span> )}
            <div className="flex space-x-2">
              <button onClick={() => setEditingCharacter(character)} className="p-1 rounded transition-colors text-yellow-400 hover:text-yellow-300 bg-slate-600 hover:bg-slate-500" aria-label="Edit character"><Edit3 size={18} /></button>
              <button onClick={() => handleDeleteCharacter(character.id)} className="p-1 rounded transition-colors text-red-400 hover:text-red-300 bg-slate-600 hover:bg-slate-500" aria-label="Delete character"><Trash2 size={18} /></button>
            </div>
          </li>
        ))}
      </ul>
    </div>
  );
}

function EncounterManager({ campaignId, initialActiveEncounterId, campaignCharacters }) { 
  const [encounters, setEncounters] = useState([]);
  const [selectedEncounterId, setSelectedEncounterId] = useState(null);
  const [showCreateEncounterModal, setShowCreateEncounterModal] = useState(false);
  const [activeDisplayInfo, setActiveDisplayInfo] = useState(null); 
  const [copiedLinkEncounterId, setCopiedLinkEncounterId] = useState(null); 
  const encountersPath = `${CAMPAIGNS_COLLECTION}/${campaignId}/encounters`;
  const selectedEncounterIdRef = React.useRef(selectedEncounterId); // Ref to track current selection for initial set

  useEffect(() => {
    selectedEncounterIdRef.current = selectedEncounterId;
  }, [selectedEncounterId]);

  useEffect(() => {
    if (!campaignId) {
      setEncounters([]);
      setSelectedEncounterId(null);
      return;
    }
    const unsubEncounters = onSnapshot(query(collection(db, encountersPath)), (snapshot) => {
      const fetchedEncounters = snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));
      setEncounters(fetchedEncounters);

      if (selectedEncounterIdRef.current === null || !fetchedEncounters.some(e => e.id === selectedEncounterIdRef.current)) {
        if (initialActiveEncounterId && fetchedEncounters.some(e => e.id === initialActiveEncounterId)) {
          setSelectedEncounterId(initialActiveEncounterId);
        } else if (activeDisplayInfo && activeDisplayInfo.activeCampaignId === campaignId && 
                   fetchedEncounters.some(e => e.id === activeDisplayInfo.activeEncounterId)) {
          setSelectedEncounterId(activeDisplayInfo.activeEncounterId);
        }
      }
    }, (err) => console.error(`Error fetching encounters for campaign ${campaignId}:`, err));
    
    return () => unsubEncounters();
  }, [campaignId, initialActiveEncounterId, activeDisplayInfo]);


  useEffect(() => {
    const unsub = onSnapshot(doc(db, ACTIVE_DISPLAY_DOC), (docSnap) => {
      setActiveDisplayInfo(docSnap.exists() ? docSnap.data() : null);
    }, (err) => { console.error("Error fetching active display info:", err); setActiveDisplayInfo(null); });
    return () => unsub();
  }, []);


  const handleCreateEncounter = async (name) => {
    if (!name.trim() || !campaignId) return;
    const newEncounterId = generateId();
    try {
      await setDoc(doc(db, encountersPath, newEncounterId), {
        name: name.trim(), createdAt: new Date().toISOString(), participants: [], round: 0, currentTurnParticipantId: null, isStarted: false,
      });
      setShowCreateEncounterModal(false);
      setSelectedEncounterId(newEncounterId);
    } catch (err) { console.error("Error creating encounter:", err); }
  };

  const handleDeleteEncounter = async (encounterId) => {
    // TODO: Implement custom confirmation modal for deleting encounters
    console.warn("Attempting to delete encounter without confirmation:", encounterId);
    try {
      await deleteDoc(doc(db, encountersPath, encounterId));
      if (selectedEncounterId === encounterId) setSelectedEncounterId(null);
      if (activeDisplayInfo && activeDisplayInfo.activeEncounterId === encounterId) {
        await updateDoc(doc(db, ACTIVE_DISPLAY_DOC), { activeEncounterId: null });
      }
    } catch (err) { console.error("Error deleting encounter:", err); }
  };
  
  const handleSetEncounterAsActiveDisplay = async (encounterId) => {
    try {
      await setDoc(doc(db, ACTIVE_DISPLAY_DOC), { activeCampaignId: campaignId, activeEncounterId: encounterId }, { merge: true });
      console.log("Encounter set as active for DM's main display!"); 
    } catch (err) { console.error("Error setting active display:", err); }
  };

  const handleCopyToClipboard = (encounterId) => {
    const link = `${getShareableLinkBase()}#/display/${campaignId}/${encounterId}`;
    navigator.clipboard.writeText(link).then(() => {
      setCopiedLinkEncounterId(encounterId);
      setTimeout(() => setCopiedLinkEncounterId(null), 2000); 
    }).catch(err => console.error('Failed to copy link: ', err));
  };

  const selectedEncounter = encounters.find(e => e.id === selectedEncounterId);

  return (
    <div className="mt-6 p-4 bg-slate-800 rounded-lg shadow">
      <div className="flex justify-between items-center mb-3">
        <h3 className="text-xl font-semibold text-sky-300 flex items-center"><Swords size={24} className="mr-2" /> Encounters</h3>
        <button onClick={() => setShowCreateEncounterModal(true)} className="px-4 py-2 text-sm font-medium text-white bg-orange-500 hover:bg-orange-600 rounded-md transition-colors flex items-center"><PlusCircle size={18} className="mr-1" /> Create Encounter</button>
      </div>
      {encounters.length === 0 && <p className="text-sm text-slate-400">No encounters yet.</p>}
      <div className="space-y-3">
        {encounters.map(encounter => {
          const isDmActiveDisplay = activeDisplayInfo && activeDisplayInfo.activeCampaignId === campaignId && activeDisplayInfo.activeEncounterId === encounter.id;
          return (
            <div key={encounter.id} className={`p-3 rounded-md shadow transition-all ${selectedEncounterId === encounter.id ? 'bg-sky-600 ring-2 ring-sky-400' : 'bg-slate-700 hover:bg-slate-650'} ${isDmActiveDisplay ? 'ring-2 ring-green-500 shadow-md shadow-green-500/30' : ''}`}>
              <div className="flex justify-between items-center">
                <div onClick={() => setSelectedEncounterId(encounter.id)} className="cursor-pointer flex-grow">
                  <h4 className="font-medium text-white">{encounter.name}</h4>
                  <p className="text-xs text-slate-300">Participants: {encounter.participants?.length || 0}</p>
                  {isDmActiveDisplay && <span className="text-xs text-green-400 font-semibold block mt-1">LIVE ON DM DISPLAY</span>}
                </div>
                <div className="flex items-center space-x-2">
                  <button onClick={() => handleSetEncounterAsActiveDisplay(encounter.id)} className={`p-1 rounded transition-colors ${isDmActiveDisplay ? 'bg-green-500 hover:bg-green-600 text-white' : 'text-teal-400 hover:text-teal-300 bg-slate-600 hover:bg-slate-500'}`} title="Set as DM's Active Display"><Eye size={18} /></button>
                  <button onClick={() => handleCopyToClipboard(encounter.id)} className="p-1 rounded transition-colors text-sky-400 hover:text-sky-300 bg-slate-600 hover:bg-slate-500" title="Copy Share Link for Players"><Share2 size={18} /></button>
                  {copiedLinkEncounterId === encounter.id && <span className="text-xs text-green-400">Copied!</span>}
                  <button onClick={(e) => { e.stopPropagation(); handleDeleteEncounter(encounter.id); }} className="p-1 rounded transition-colors text-red-400 hover:text-red-300 bg-slate-600 hover:bg-slate-500" title="Delete Encounter"><Trash2 size={18} /></button>
                </div>
              </div>
              {selectedEncounterId === encounter.id && (
                <div className="mt-2 pt-2 border-t border-slate-600">
                  <p className="text-xs text-slate-400">Shareable Link for Players:</p>
                  <div className="flex items-center gap-2">
                    <input type="text" readOnly value={`${getShareableLinkBase()}#/display/${campaignId}/${encounter.id}`} className="text-xs w-full bg-slate-600 px-3 py-2 border border-slate-500 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" />
                    <button onClick={() => handleCopyToClipboard(encounter.id)} className="px-4 py-2 text-xs font-medium text-slate-300 bg-slate-500 hover:bg-slate-400 rounded-md transition-colors p-1">
                      {copiedLinkEncounterId === encounter.id ? 'Copied!' : <CopyIcon size={14}/>}
                    </button>
                  </div>
                </div>
              )}
            </div>
          );
        })}
      </div>
      {showCreateEncounterModal && <Modal onClose={() => setShowCreateEncounterModal(false)} title="Create New Encounter"><CreateEncounterForm onCreate={handleCreateEncounter} onCancel={() => setShowCreateEncounterModal(false)} /></Modal>}
      {selectedEncounter && (
        <div className="mt-6 p-4 bg-slate-750 rounded-lg shadow-inner">
          <h3 className="text-xl font-semibold text-amber-300 mb-3">Managing Encounter: {selectedEncounter.name}</h3>
          <ParticipantManager encounter={selectedEncounter} encounterPath={`${encountersPath}/${selectedEncounterId}`} campaignCharacters={campaignCharacters} /> 
          <InitiativeControls campaignId={campaignId} encounter={selectedEncounter} encounterPath={`${encountersPath}/${selectedEncounterId}`} />
        </div>
      )}
    </div>
  );
}

function CreateEncounterForm({ onCreate, onCancel }) { 
  const [name, setName] = useState('');
  return (
    <form onSubmit={(e) => { e.preventDefault(); onCreate(name); }} className="space-y-4">
      <div>
        <label htmlFor="encounterName" className="block text-sm font-medium text-slate-300">Encounter Name</label>
        <input type="text" id="encounterName" value={name} onChange={(e) => setName(e.target.value)} className="mt-1 block w-full px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" required />
      </div>
      <div className="flex justify-end space-x-3">
        <button type="button" onClick={onCancel} className="px-4 py-2 text-sm font-medium text-slate-300 bg-slate-600 hover:bg-slate-500 rounded-md transition-colors">Cancel</button>
        <button type="submit" className="px-4 py-2 text-sm font-medium text-white bg-orange-500 hover:bg-orange-600 rounded-md transition-colors">Create</button>
      </div>
    </form>
  );
}

function ParticipantManager({ encounter, encounterPath, campaignCharacters }) { 
  const [participantName, setParticipantName] = useState('');
  const [participantType, setParticipantType] = useState('monster'); 
  const [selectedCharacterId, setSelectedCharacterId] = useState(''); 
  const [initiative, setInitiative] = useState(10);
  const [maxHp, setMaxHp] = useState(10);
  const [editingParticipant, setEditingParticipant] = useState(null); 
  const [hpChangeValues, setHpChangeValues] = useState({}); 
  const [draggedItemId, setDraggedItemId] = useState(null);

  const participants = encounter.participants || [];

  const handleAddParticipant = async () => {
    if ((participantType === 'monster' && !participantName.trim()) || (participantType === 'character' && !selectedCharacterId)) return;
    let nameToAdd = participantName.trim();
    if (participantType === 'character') {
      const character = campaignCharacters.find(c => c.id === selectedCharacterId);
      if (!character) { console.error("Selected character not found"); return; }
      if (participants.some(p => p.type === 'character' && p.originalCharacterId === selectedCharacterId)) {
        alert(`${character.name} is already in this encounter.`); return;
      }
      nameToAdd = character.name;
    }
    const newParticipant = {
      id: generateId(), name: nameToAdd, type: participantType, 
      originalCharacterId: participantType === 'character' ? selectedCharacterId : null, 
      initiative: parseInt(initiative, 10) || 0, maxHp: parseInt(maxHp, 10) || 1, currentHp: parseInt(maxHp, 10) || 1, 
      conditions: [], isActive: true, 
    };
    try {
      await updateDoc(doc(db, encounterPath), { participants: [...participants, newParticipant] });
      setParticipantName(''); setInitiative(10); setMaxHp(10); setSelectedCharacterId(''); 
    } catch (err) { console.error("Error adding participant:", err); }
  };

  const handleUpdateParticipant = async (updatedData) => {
    if (!editingParticipant) return;
    const { flavorText, ...restOfData } = updatedData; 
    const updatedParticipants = participants.map(p => p.id === editingParticipant.id ? { ...p, ...restOfData } : p );
    try {
      await updateDoc(doc(db, encounterPath), { participants: updatedParticipants });
      setEditingParticipant(null);
    } catch (err) { console.error("Error updating participant:", err); }
  };

  const handleDeleteParticipant = async (participantId) => {
    // TODO: Implement custom confirmation modal for deleting participants
    console.warn("Attempting to delete participant without confirmation:", participantId);
    const updatedParticipants = participants.filter(p => p.id !== participantId);
    try {
      await updateDoc(doc(db, encounterPath), { participants: updatedParticipants });
    } catch (err) { console.error("Error deleting participant:", err); }
  };
  
  const toggleParticipantActive = async (participantId) => {
    const pToToggle = participants.find(p => p.id === participantId);
    if (!pToToggle) return;
    const updatedPs = participants.map(p => p.id === participantId ? { ...p, isActive: !p.isActive } : p);
    try { await updateDoc(doc(db, encounterPath), { participants: updatedPs }); } 
    catch (err) { console.error("Error toggling active state:", err); }
  };

  const handleHpInputChange = (participantId, value) => setHpChangeValues(prev => ({ ...prev, [participantId]: value }));

  const applyHpChange = async (participantId, changeType) => {
    const amountStr = hpChangeValues[participantId];
    if (amountStr === undefined || amountStr.trim() === '') return;
    const amount = parseInt(amountStr, 10);
    if (isNaN(amount) || amount === 0) { setHpChangeValues(prev => ({ ...prev, [participantId]: '' })); return; }
    const pToChange = participants.find(p => p.id === participantId);
    if (!pToChange) return;
    let newHp = pToChange.currentHp;
    if (changeType === 'damage') newHp = Math.max(0, pToChange.currentHp - amount);
    else if (changeType === 'heal') newHp = Math.min(pToChange.maxHp, pToChange.currentHp + amount);
    const updatedPs = participants.map(p => p.id === participantId ? { ...p, currentHp: newHp } : p);
    try {
      await updateDoc(doc(db, encounterPath), { participants: updatedPs });
      setHpChangeValues(prev => ({ ...prev, [participantId]: '' })); 
    } catch (err) { console.error("Error applying HP change:", err); }
  };

  const handleDragStart = (e, id) => {
    setDraggedItemId(id);
    e.dataTransfer.effectAllowed = 'move';
  };

  const handleDragOver = (e) => {
    e.preventDefault(); 
    e.dataTransfer.dropEffect = 'move';
  };

  const handleDrop = async (e, targetId) => {
    e.preventDefault();
    if (draggedItemId === null || draggedItemId === targetId) {
      setDraggedItemId(null);
      return;
    }
    const currentParticipants = [...participants];
    const draggedItemIndex = currentParticipants.findIndex(p => p.id === draggedItemId);
    const targetItemIndex = currentParticipants.findIndex(p => p.id === targetId);

    if (draggedItemIndex === -1 || targetItemIndex === -1) {
      setDraggedItemId(null); return;
    }
    const draggedItem = currentParticipants[draggedItemIndex];
    const targetItem = currentParticipants[targetItemIndex];

    if (draggedItem.initiative !== targetItem.initiative) {
      console.log("Cannot drag between different initiative groups for tie-breaking.");
      setDraggedItemId(null); return;
    }
    const reorderedParticipants = [...currentParticipants];
    const [removedItem] = reorderedParticipants.splice(draggedItemIndex, 1);
    reorderedParticipants.splice(targetItemIndex, 0, removedItem);
    try {
      await updateDoc(doc(db, encounterPath), { participants: reorderedParticipants });
    } catch (err) { console.error("Error updating participants after drag-drop:", err); }
    setDraggedItemId(null);
  };
  
  const handleDragEnd = () => {
    setDraggedItemId(null);
  };

  const sortedAdminParticipants = [...participants].sort((a, b) => {
    if (a.initiative === b.initiative) {
      const indexA = participants.findIndex(p => p.id === a.id);
      const indexB = participants.findIndex(p => p.id === b.id);
      return indexA - indexB; 
    }
    return b.initiative - a.initiative; 
  });
  
  const initiativeGroups = participants.reduce((acc, p) => {
    acc[p.initiative] = (acc[p.initiative] || 0) + 1;
    return acc;
  }, {});
  const tiedInitiatives = Object.keys(initiativeGroups).filter(init => initiativeGroups[init] > 1).map(Number);


  return (
    <div className="p-3 bg-slate-800 rounded-md mt-4">
      <h4 className="text-lg font-medium text-sky-200 mb-3">Participants</h4>
      <form onSubmit={(e) => { e.preventDefault(); handleAddParticipant(); }} className="grid grid-cols-1 md:grid-cols-2 gap-4 mb-4 p-3 bg-slate-700 rounded">
        <div>
          <label className="block text-sm font-medium text-slate-300">Type</label>
          <select value={participantType} onChange={(e) => setParticipantType(e.target.value)} className="mt-1 w-full px-3 py-2 bg-slate-600 border-slate-500 rounded text-white">
            <option value="monster">Monster</option>
            <option value="character">Character</option>
          </select>
        </div>

        {participantType === 'monster' && (
          <div className="md:col-span-2"> 
            <label className="block text-sm font-medium text-slate-300">Monster Name</label>
            <input type="text" value={participantName} onChange={(e) => setParticipantName(e.target.value)} placeholder="e.g., Dire Wolf" className="mt-1 w-full px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" />
          </div>
        )}
        {participantType === 'character' && (<div><label className="block text-sm font-medium text-slate-300">Select Character</label><select value={selectedCharacterId} onChange={(e) => setSelectedCharacterId(e.target.value)} className="mt-1 w-full px-3 py-2 bg-slate-600 border-slate-500 rounded text-white"><option value="">-- Select from Campaign --</option>{campaignCharacters.map(c => <option key={c.id} value={c.id}>{c.name}</option>)}</select></div>)}
        
        <div><label className="block text-sm font-medium text-slate-300">Initiative</label><input type="number" value={initiative} onChange={(e) => setInitiative(e.target.value)} className="mt-1 w-full px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" /></div>
        <div><label className="block text-sm font-medium text-slate-300">Max HP</label><input type="number" value={maxHp} onChange={(e) => setMaxHp(e.target.value)} className="mt-1 w-full px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" /></div>
        
        <div className="md:col-span-2 flex justify-end">
            <button type="submit" className="px-4 py-2 text-sm font-medium text-white bg-green-500 hover:bg-green-600 rounded-md transition-colors flex items-center">
                <PlusCircle size={18} className="mr-1" /> Add to Encounter
            </button>
        </div>
      </form>
      {participants.length === 0 && <p className="text-sm text-slate-400">No participants.</p>}
      <ul className="space-y-2">
        {sortedAdminParticipants.map((p, index) => {
          const isCurrentTurn = encounter.isStarted && p.id === encounter.currentTurnParticipantId;
          const isDraggable = !encounter.isStarted && tiedInitiatives.includes(p.initiative);
          return (
            <li 
              key={p.id} 
              draggable={isDraggable}
              onDragStart={isDraggable ? (e) => handleDragStart(e, p.id) : undefined}
              onDragOver={isDraggable ? handleDragOver : undefined}
              onDrop={isDraggable ? (e) => handleDrop(e, p.id) : undefined}
              onDragEnd={isDraggable ? handleDragEnd : undefined}
              className={`p-3 rounded-md flex flex-col sm:flex-row justify-between items-start sm:items-center gap-2 transition-all 
                         ${isCurrentTurn ? 'bg-green-600 ring-2 ring-green-300 shadow-lg' : (p.type === 'character' ? 'bg-sky-800' : 'bg-red-800')} 
                         ${!p.isActive ? 'opacity-50' : ''}
                         ${isDraggable ? 'cursor-grab' : ''}
                         ${draggedItemId === p.id ? 'opacity-50 ring-2 ring-yellow-400' : ''}
                        `}
            >
              <div className="flex-1 flex items-center">
                {isDraggable && <ChevronsUpDown size={18} className="mr-2 text-slate-400 flex-shrink-0" />}
                <div>
                  <p className={`font-semibold text-lg ${isCurrentTurn ? 'text-white' : 'text-white'}`}>{p.name} <span className="text-xs">({p.type})</span>{isCurrentTurn && <span className="ml-2 px-2 py-0.5 bg-yellow-400 text-black text-xs font-bold rounded-full inline-flex items-center"><Zap size={12} className="mr-1"/> CURRENT</span>}</p>
                  <p className={`text-sm ${isCurrentTurn ? 'text-green-100' : 'text-slate-200'}`}>Init: {p.initiative} | HP: {p.currentHp}/{p.maxHp}</p>
                </div>
              </div>
              <div className="flex flex-wrap items-center space-x-2 mt-2 sm:mt-0">
                {encounter.isStarted && p.isActive && (<div className="flex items-center space-x-1 bg-slate-700 p-1 rounded-md"><input type="number" placeholder="HP" value={hpChangeValues[p.id] || ''} onChange={(e) => handleHpInputChange(p.id, e.target.value)} className="w-16 p-1 text-sm bg-slate-600 border border-slate-500 rounded-md text-white focus:ring-sky-500 focus:border-sky-500" aria-label={`HP change for ${p.name}`}/><button onClick={() => applyHpChange(p.id, 'damage')} className="p-1 bg-red-500 hover:bg-red-600 text-white rounded-md text-xs" title="Damage"><HeartCrack size={16}/></button><button onClick={() => applyHpChange(p.id, 'heal')} className="p-1 bg-green-500 hover:bg-green-600 text-white rounded-md text-xs" title="Heal"><HeartPulse size={16}/></button></div>)}
                <button onClick={() => toggleParticipantActive(p.id)} className={`p-1 rounded transition-colors ${p.isActive ? 'text-yellow-400 hover:text-yellow-300 bg-slate-600 hover:bg-slate-500' : 'text-slate-400 hover:text-slate-300 bg-slate-600 hover:bg-slate-500'}`} title={p.isActive ? "Mark Inactive" : "Mark Active"}>{p.isActive ? <UserCheck size={18} /> : <UserX size={18} />}</button>
                <button onClick={() => setEditingParticipant(p)} className="p-1 rounded transition-colors text-yellow-400 hover:text-yellow-300 bg-slate-600 hover:bg-slate-500" title="Edit"><Edit3 size={18} /></button>
                <button onClick={() => handleDeleteParticipant(p.id)} className="p-1 rounded transition-colors text-red-400 hover:text-red-300 bg-slate-600 hover:bg-slate-500" title="Remove"><Trash2 size={18} /></button>
              </div>
            </li>
          );
        })}
      </ul>
      {editingParticipant && <EditParticipantModal participant={editingParticipant} onClose={() => setEditingParticipant(null)} onSave={handleUpdateParticipant} />}
    </div>
  );
}

function EditParticipantModal({ participant, onClose, onSave }) {
  const [name, setName] = useState(participant.name);
  const [initiative, setInitiative] = useState(participant.initiative);
  const [currentHp, setCurrentHp] = useState(participant.currentHp);
  const [maxHp, setMaxHp] = useState(participant.maxHp);

  const handleSubmit = (e) => {
    e.preventDefault();
    onSave({
      name: name.trim(), initiative: parseInt(initiative, 10),
      currentHp: parseInt(currentHp, 10), maxHp: parseInt(maxHp, 10),
    });
  };
  return (
    <Modal onClose={onClose} title={`Edit ${participant.name}`}>
      <form onSubmit={handleSubmit} className="space-y-4">
        <div><label className="block text-sm font-medium text-slate-300">Name</label><input type="text" value={name} onChange={(e) => setName(e.target.value)} className="mt-1 block w-full px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" /></div>
        <div><label className="block text-sm font-medium text-slate-300">Initiative</label><input type="number" value={initiative} onChange={(e) => setInitiative(e.target.value)} className="mt-1 block w-full px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" /></div>
        <div className="flex gap-4">
          <div className="flex-1"><label className="block text-sm font-medium text-slate-300">Current HP</label><input type="number" value={currentHp} onChange={(e) => setCurrentHp(e.target.value)} className="mt-1 block w-full px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" /></div>
          <div className="flex-1"><label className="block text-sm font-medium text-slate-300">Max HP</label><input type="number" value={maxHp} onChange={(e) => setMaxHp(e.target.value)} className="mt-1 block w-full px-3 py-2 bg-slate-700 border border-slate-600 rounded-md shadow-sm focus:outline-none focus:ring-sky-500 focus:border-sky-500 sm:text-sm text-white" /></div>
        </div>
        <div className="flex justify-end space-x-3 pt-2">
          <button type="button" onClick={onClose} className="px-4 py-2 text-sm font-medium text-slate-300 bg-slate-600 hover:bg-slate-500 rounded-md transition-colors">Cancel</button>
          <button type="submit" className="px-4 py-2 text-sm font-medium text-white bg-sky-500 hover:bg-sky-600 rounded-md transition-colors"><Save size={18} className="mr-1 inline-block" /> Save</button>
        </div>
      </form>
    </Modal>
  );
}

function InitiativeControls({ campaignId, encounter, encounterPath }) { 
  const handleStartEncounter = async () => {
    if (!encounter.participants || encounter.participants.length === 0) { alert("Add participants first."); return; }
    const activePs = encounter.participants.filter(p => p.isActive);
    if (activePs.length === 0) { alert("No active participants."); return; }
    
    const sortedPs = [...activePs].sort((a, b) => {
        if (a.initiative === b.initiative) {
            const indexA = encounter.participants.findIndex(p => p.id === a.id);
            const indexB = encounter.participants.findIndex(p => p.id === b.id);
            return indexA - indexB;
        }
        return b.initiative - a.initiative; 
    });

    try {
      await updateDoc(doc(db, encounterPath), {
        isStarted: true, round: 1, currentTurnParticipantId: sortedPs[0].id, turnOrderIds: sortedPs.map(p => p.id) 
        // Participants array in DB already reflects D&D order, so no need to update it here again unless sorting changes it.
        // The `participants` field in the database should be the source of truth for the D&D order.
        // The `turnOrderIds` is derived from this for active combat.
      });
      await setDoc(doc(db, ACTIVE_DISPLAY_DOC), { 
        activeCampaignId: campaignId, 
        activeEncounterId: encounter.id 
      }, { merge: true });
      console.log("Encounter started and set as active display.");

    } catch (err) { console.error("Error starting encounter:", err); }
  };

  const handleNextTurn = async () => {
    if (!encounter.isStarted || !encounter.currentTurnParticipantId || !encounter.turnOrderIds || encounter.turnOrderIds.length === 0) return;
    const activePsInOrder = encounter.turnOrderIds.map(id => encounter.participants.find(p => p.id === id && p.isActive)).filter(Boolean); 
    if (activePsInOrder.length === 0) {
      alert("No active participants left.");
      await updateDoc(doc(db, encounterPath), { isStarted: false, currentTurnParticipantId: null, round: encounter.round }); return;
    }
    const currentIndex = activePsInOrder.findIndex(p => p.id === encounter.currentTurnParticipantId);
    let nextIndex = (currentIndex + 1) % activePsInOrder.length;
    let nextRound = encounter.round;
    if (nextIndex === 0 && currentIndex !== -1) nextRound += 1;
    try {
      await updateDoc(doc(db, encounterPath), { currentTurnParticipantId: activePsInOrder[nextIndex].id, round: nextRound });
    } catch (err) { console.error("Error advancing turn:", err); }
  };
  
  const handleEndEncounter = async () => {
    // TODO: Implement custom confirmation modal for ending encounter
    console.warn("Attempting to end encounter without confirmation");
    try {
      await updateDoc(doc(db, encounterPath), { isStarted: false, currentTurnParticipantId: null, round: 0, turnOrderIds: [] });
    } catch (err) { console.error("Error ending encounter:", err); }
  };

  if (!encounter || !encounter.participants) return null;
  return (
    <div className="mt-6 p-3 bg-slate-800 rounded-md">
      <h4 className="text-lg font-medium text-sky-200 mb-3">Combat Controls</h4>
      <div className="flex flex-wrap gap-3">
        {!encounter.isStarted ? (
          <button onClick={handleStartEncounter} className="px-4 py-2 text-sm font-medium text-white bg-green-600 hover:bg-green-700 rounded-md transition-colors flex items-center" disabled={!encounter.participants || encounter.participants.filter(p=>p.isActive).length === 0}><PlayIcon size={18} className="mr-2" /> Start</button>
        ) : (
          <>
            <button onClick={handleNextTurn} className="px-4 py-2 text-sm font-medium text-white bg-blue-600 hover:bg-blue-700 rounded-md transition-colors flex items-center" disabled={!encounter.currentTurnParticipantId}><SkipForwardIcon size={18} className="mr-2" /> Next Turn</button>
            <button onClick={handleEndEncounter} className="px-4 py-2 text-sm font-medium text-white bg-red-600 hover:bg-red-700 rounded-md transition-colors flex items-center"><StopCircleIcon size={18} className="mr-2" /> End</button>
            <p className="text-slate-300 self-center">Round: {encounter.round}</p>
          </>
        )}
      </div>
    </div>
  );
}

function DisplayView({ campaignIdFromUrl, encounterIdFromUrl }) { 
  const [activeEncounterData, setActiveEncounterData] = useState(null);
  const [isLoading, setIsLoading] = useState(true);
  const [error, setError] = useState(null);

  useEffect(() => {
    setIsLoading(true); setError(null); setActiveEncounterData(null);
    let unsubscribeEncounter;

    if (campaignIdFromUrl && encounterIdFromUrl) {
      const encounterPath = `${CAMPAIGNS_COLLECTION}/${campaignIdFromUrl}/encounters/${encounterIdFromUrl}`;
      unsubscribeEncounter = onSnapshot(doc(db, encounterPath), (encDocSnap) => {
        if (encDocSnap.exists()) setActiveEncounterData({ id: encDocSnap.id, ...encDocSnap.data() });
        else setError("The requested encounter was not found or is not accessible.");
        setIsLoading(false);
      }, (err) => { console.error("Error fetching specific encounter for display:", err); setError("Error loading encounter data from link."); setIsLoading(false); });
    } else {
      const activeDisplayRef = doc(db, ACTIVE_DISPLAY_DOC);
      const unsubDisplayConfig = onSnapshot(activeDisplayRef, async (docSnap) => {
        if (docSnap.exists()) {
          const { activeCampaignId, activeEncounterId } = docSnap.data();
          if (activeCampaignId && activeEncounterId) {
            const encounterPath = `${CAMPAIGNS_COLLECTION}/${activeCampaignId}/encounters/${activeEncounterId}`;
            if(unsubscribeEncounter) unsubscribeEncounter(); 
            unsubscribeEncounter = onSnapshot(doc(db, encounterPath), (encDocSnap) => {
              if (encDocSnap.exists()) setActiveEncounterData({ id: encDocSnap.id, ...encDocSnap.data() });
              else { setActiveEncounterData(null); setError("Active encounter not found. The DM might have deleted it.");}
              setIsLoading(false);
            }, (err) => { console.error("Error fetching active encounter details:", err); setError("Error loading active encounter data."); setIsLoading(false);});
          } else { setActiveEncounterData(null); setIsLoading(false); }
        } else { setActiveEncounterData(null); setIsLoading(false); }
      }, (err) => { console.error("Error fetching active display config:", err); setError("Could not load display configuration."); setIsLoading(false); });
      return () => { unsubDisplayConfig(); if (unsubscribeEncounter) unsubscribeEncounter(); };
    }
    return () => { if (unsubscribeEncounter) unsubscribeEncounter(); };
  }, [campaignIdFromUrl, encounterIdFromUrl]);

  if (isLoading) return <div className="text-center py-10 text-2xl text-slate-300">Loading Player Display...</div>;
  if (error) return <div className="text-center py-10 text-2xl text-red-400">{error}</div>;
  if (!activeEncounterData) return <div className="text-center py-10 text-3xl text-slate-400">No active encounter to display.</div>;

  const { name, participants, round, currentTurnParticipantId, isStarted } = activeEncounterData;
  
  let displayParticipants = [];
  if (isStarted && activeEncounterData.turnOrderIds?.length > 0 && participants) { 
    displayParticipants = activeEncounterData.turnOrderIds
        .map(id => participants.find(p => p.id === id)).filter(p => p && p.isActive); 
  } else if (participants) {
     displayParticipants = [...participants].filter(p => p.isActive)
        .sort((a, b) => {
            if (a.initiative === b.initiative) {
                const indexA = participants.findIndex(p => p.id === a.id);
                const indexB = participants.findIndex(p => p.id === b.id);
                return indexA - indexB;
            }
            return b.initiative - a.initiative; 
        });
  }

  return (
    <div className="p-4 md:p-8 bg-slate-900 rounded-xl shadow-2xl">
      <h2 className="text-4xl md:text-5xl font-bold text-center text-amber-400 mb-2">{name}</h2>
      {isStarted && <p className="text-2xl text-center text-sky-300 mb-6">Round: {round}</p>}
      {!isStarted && participants?.length > 0 && <p className="text-2xl text-center text-slate-400 mb-6">Awaiting Start</p>}
      {!isStarted && (!participants || participants.length === 0) && <p className="text-2xl text-slate-500 mb-6">No participants.</p>}
      {displayParticipants.length === 0 && isStarted && <p className="text-xl text-slate-400">No active participants.</p>}
      <div className="space-y-4 max-w-3xl mx-auto">
        {displayParticipants.map(p => (
          <div key={p.id} className={`p-4 md:p-6 rounded-lg shadow-lg transition-all ${p.id === currentTurnParticipantId && isStarted ? 'bg-green-700 ring-4 ring-green-400 scale-105' : (p.type === 'character' ? 'bg-sky-700' : 'bg-red-700')} ${!p.isActive ? 'opacity-40 grayscale' : ''}`}>
            <div className="flex justify-between items-center mb-2">
              <h3 className={`text-2xl md:text-3xl font-bold ${p.id === currentTurnParticipantId && isStarted ? 'text-white' : (p.type === 'character' ? 'text-sky-100' : 'text-red-100')}`}>{p.name}{p.id === currentTurnParticipantId && isStarted && <span className="text-yellow-300 animate-pulse ml-2">(Current)</span>}</h3>
              <span className={`text-xl md:text-2xl font-semibold ${p.id === currentTurnParticipantId && isStarted ? 'text-green-200' : 'text-slate-200'}`}>Init: {p.initiative}</span>
            </div>
            <div className="flex justify-between items-center">
              <div className="w-full bg-slate-600 rounded-full h-6 md:h-8 relative overflow-hidden border-2 border-slate-500">
                <div className={`h-full rounded-full transition-all ${p.currentHp <= p.maxHp / 4 ? 'bg-red-500' : (p.currentHp <= p.maxHp / 2 ? 'bg-yellow-500' : 'bg-green-500')}`} style={{ width: `${Math.max(0, (p.currentHp / p.maxHp) * 100)}%` }}></div>
                {p.type !== 'monster' && ( // Only show HP text if not a monster
                    <span className="absolute inset-0 flex items-center justify-center text-xs md:text-sm font-medium text-white mix-blend-difference px-2">
                    HP: {p.currentHp} / {p.maxHp}
                    </span>
                )}
              </div>
            </div>
            {p.conditions?.length > 0 && <p className="text-sm text-yellow-300 mt-2">Conditions: {p.conditions.join(', ')}</p>}
            {!p.isActive && <p className="text-center text-lg font-semibold text-slate-300 mt-2">(Inactive)</p>}
          </div>
        ))}
      </div>
    </div>
  );
}

function Modal({ onClose, title, children }) {
  useEffect(() => {
    const handleEsc = (event) => { if (event.key === 'Escape') onClose(); };
    window.addEventListener('keydown', handleEsc);
    return () => window.removeEventListener('keydown', handleEsc);
  }, [onClose]);
  return (
    <div className="fixed inset-0 bg-black bg-opacity-75 flex items-center justify-center p-4 z-50">
      <div className="bg-slate-800 p-6 rounded-lg shadow-xl w-full max-w-md">
        <div className="flex justify-between items-center mb-4">
          <h2 className="text-xl font-semibold text-sky-300">{title}</h2>
          <button onClick={onClose} className="text-slate-400 hover:text-slate-200"><XCircle size={24} /></button>
        </div>
        {children}
      </div>
    </div>
  );
}

const PlayIcon = ({ size = 24, className = '' }) => <svg xmlns="http://www.w3.org/2000/svg" width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" className={className}><polygon points="5 3 19 12 5 21 5 3"></polygon></svg>;
const SkipForwardIcon = ({ size = 24, className = '' }) => <svg xmlns="http://www.w3.org/2000/svg" width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" className={className}><polygon points="5 4 15 12 5 20 5 4"></polygon><line x1="19" y1="5" x2="19" y2="19"></line></svg>;
const StopCircleIcon = ({size=24, className=''}) => <svg xmlns="http://www.w3.org/2000/svg" width={size} height={size} viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" className={className}><circle cx="12" cy="12" r="10"></circle><rect x="9" y="9" width="6" height="6"></rect></svg>;

export default App;