// Both the studio and the example dapp use the same wallet selection rules.
const ids = new WeakMap();
let nextId = 0;
const chain = 'solana:devnet';

export function walletChoices(registry, capability, host = globalThis.window) {
  if (!host) return [];
  const choices = [];
  const feature = 'solana:' + capability;
  for (const wallet of registry.get()) {
    if (!wallet.chains.includes(chain) || !wallet.features['standard:connect'] || !wallet.features[feature]) continue;
    if (capability === 'signTransaction' && !wallet.features[feature].supportedTransactionVersions?.includes('legacy')) continue;
    if (!ids.has(wallet)) ids.set(wallet, 'standard-' + ++nextId);
    choices.push({id:ids.get(wallet),name:wallet.name,available:true,standard:wallet});
  }
  for (const [id,name,provider] of [
    ['phantom','Phantom',host.phantom?.solana ?? (host.solana?.isPhantom ? host.solana : null)],
    ['solflare','Solflare',host.solflare?.isSolflare ? host.solflare : null],
  ]) {
    if (!choices.some(choice=>choice.name.toLowerCase()===id)) choices.push({id,name,provider,available:typeof provider?.[capability]==='function'});
  }
  return choices;
}

export async function openWallet(choice, capability) {
  if (!choice?.available) throw Error('Enable your wallet extension or open this page in its wallet browser.');
  if (!choice.standard) {
    const p=choice.provider;
    await p.connect();
    return {
      get address(){return p.publicKey?.toBase58();},
      disconnect:()=>p.disconnect?.(),
      signMessage:async bytes=>{const signed=await p.signMessage(bytes,'utf8');return signed.signature ?? signed;},
      signTransaction:tx=>p.signTransaction(tx),
      watch:fn=>{
        p.on?.('accountChanged',fn);p.on?.('disconnect',fn);
        return ()=>{p.removeListener?.('accountChanged',fn);p.removeListener?.('disconnect',fn);};
      },
    };
  }
  const w=choice.standard, feature='solana:'+capability;
  const {accounts}=await w.features['standard:connect'].connect();
  const selected=accounts.find(a=>a.chains.includes(chain) && a.features.includes(feature));
  if (!selected) throw Error('Choose an account that supports this action on Solana devnet.');
  const account=()=>{
    const current=w.accounts.find(a=>a.address===selected.address && a.chains.includes(chain) && a.features.includes(feature));
    if (!current) throw Error('Wallet account changed. Reconnect to continue.');
    return current;
  };
  return {
    get address(){return w.accounts.find(a=>a.address===selected.address)?.address;},
    disconnect:()=>w.features['standard:disconnect']?.disconnect(),
    watch:fn=>w.features['standard:events']?.on('change',event=>{if(event.accounts && !event.accounts.some(a=>a.address===selected.address)) fn();}) ?? (()=>{}),
    signMessage:async bytes=>{
      const [result]=await w.features['solana:signMessage'].signMessage({account:account(),message:bytes});
      if (result.signedMessage.length!==bytes.length || !bytes.every((v,i)=>result.signedMessage[i]===v)) throw Error('The signed message changed.');
      return result.signature;
    },
    signTransaction:async tx=>{
      const [result]=await w.features['solana:signTransaction'].signTransaction({account:account(),chain,
        transaction:tx.serialize({requireAllSignatures:false,verifySignatures:false})});
      return tx.constructor.from(result.signedTransaction);
    },
  };
}