import * as Y from 'yjs';
// server/api/polls/[id].ts
export default defineEventHandler(async (event) => {
    const method = event.node.req.method;
    const pollId = getRouterParam(event, 'id');

    // We use Nitro's built-in storage. 
    // 'polls' is the storage namespace.
    const storage = useStorage('polls'); 

    if (!pollId) {
        throw createError({ statusCode: 400, statusMessage: 'Poll ID required' });
    }

    // GET: Fetch the saved Yjs document state
    if (method === 'GET') {
        const data = await storage.getItem(`poll:${pollId}`);
        // Return the array of numbers (or null if it doesn't exist yet)
        return { update: data || null };
    }

    // POST: Save a new Yjs document state
    if (method === 'POST') {
        const body = await readBody(event);

        if (body.update && Array.isArray(body.update)) {
            // create a temp Y.Doc to encode the Data
            const tempDoc = new Y.Doc();
            Y.applyUpdate(tempDoc, new Uint8Array(body.update));
            const yMap = tempDoc.getMap('shared-poll');
            const pollData = yMap.toJSON();

            // verify pollData
            for(var option in pollData){
                const votes = pollData[option] || [];
                var pubKeys: CryptoKey[] = [];

                const verifyAllVotesForOption = async (votes: SignedData<VoteData>[]) => {
                    console.log("verifying votes for option " + option,votes);
                    // check last votes first. if there is something wrong, its likely in the last vote.
                    for (let i = votes.length-1; i >= 0 ; i--) {
                        const userStorage = useStorage('users'); 
                        const votePubKeyString = await userStorage.getItem(`user:${votes[i]?.data.userid}`);
                        //console.log("Using public key: "+votePubKeyString)
                        const votePubKey = await stringToCryptoKey(String(votePubKeyString),'public')
                        const isValid = await verifyChainedVote(votes, i,votePubKey);
                        if(!isValid){
                            console.error("Error! Invalid Vote at: " + i,votes)
                            return false;
                        }
                    }
                    return true;
                };
                const verified = await verifyAllVotesForOption(votes);
                if(!verified){
                    console.error("Failed to verify option: "+option)
                    throw createError({ statusCode: 400, statusMessage: 'PollData contains unverifyable content!' });
                }
            }

            // Save the binary update (sent as an array of numbers) to storage
            await storage.setItem(`poll:${pollId}`, body.update);
            return { success: true };
        }

        throw createError({ statusCode: 400, statusMessage: 'Invalid update payload' });
    }
});