import { Block, Transaction } from 'bitcoinjs-lib';
import * as bitcoinjs from 'bitcoinjs-lib';
import { plainToInstance } from 'class-transformer';
import { validate, ValidatorOptions } from 'class-validator';
import * as crypto from 'crypto';
import { Socket } from 'net';
import { combineLatest, interval, startWith } from 'rxjs';

import { BitcoinRpcService } from '../bitcoin-rpc.service';
import { BlockTemplateService } from '../BlockTemplateService';
import { StratumV1JobsService } from '../stratum-v1-jobs.service';
import { EasyUnsubscribe } from '../utils/AutoUnsubscribe';
import { eRequestMethod } from './enums/eRequestMethod';
import { MiningJob } from './MiningJob';
import { AuthorizationMessage } from './stratum-messages/AuthorizationMessage';
import { ConfigurationMessage } from './stratum-messages/ConfigurationMessage';
import { MiningSubmitMessage } from './stratum-messages/MiningSubmitMessage';
import { SubscriptionMessage } from './stratum-messages/SubscriptionMessage';
import { SuggestDifficulty } from './stratum-messages/SuggestDifficultyMessage';
import { StratumV1ClientStatistics } from './StratumV1ClientStatistics';


export class StratumV1Client extends EasyUnsubscribe {

    public clientSubscription: SubscriptionMessage;
    public clientConfiguration: ConfigurationMessage;
    public clientAuthorization: AuthorizationMessage;
    public clientSuggestedDifficulty: SuggestDifficulty;

    public statistics: StratumV1ClientStatistics = new StratumV1ClientStatistics();

    public id: string;
    public stratumInitialized = false;

    public refreshInterval: NodeJS.Timer;

    public clientDifficulty: number = 512;

    public jobRefreshInterval: NodeJS.Timer;




    constructor(
        public readonly socket: Socket,
        private readonly stratumV1JobsService: StratumV1JobsService,
        private readonly blockTemplateService: BlockTemplateService,
        private readonly bitcoinRpcService: BitcoinRpcService
    ) {
        super();
        this.id = this.getRandomHexString();

        console.log(`New client ID: : ${this.id}`);

        this.socket.on('data', this.handleData.bind(this, this.socket));

    }

    private getRandomHexString() {
        const randomBytes = crypto.randomBytes(4); // 4 bytes = 32 bits
        const randomNumber = randomBytes.readUInt32BE(0); // Convert bytes to a 32-bit unsigned integer
        const hexString = randomNumber.toString(16).padStart(8, '0'); // Convert to hex and pad with zeros
        return hexString;
    }

    private async handleData(socket: Socket, data: Buffer) {
        const message = data.toString();

        message.split('\n')
            .filter(m => m.length > 0)
            .forEach(this.handleMessage.bind(this, socket));

    }


    private async handleMessage(socket: Socket, message: string) {
        console.log('Received:', message);

        // Parse the message and check if it's the initial subscription message
        let parsedMessage = null;
        try {
            parsedMessage = JSON.parse(message);
        } catch (e) {
            console.log(e);
        }

        switch (parsedMessage.method) {
            case eRequestMethod.SUBSCRIBE: {
                const subscriptionMessage = plainToInstance(
                    SubscriptionMessage,
                    parsedMessage,
                );

                const validatorOptions: ValidatorOptions = {
                    whitelist: true,
                    forbidNonWhitelisted: true,
                };

                const errors = await validate(subscriptionMessage, validatorOptions);

                if (errors.length === 0) {
                    this.clientSubscription = subscriptionMessage;

                    socket.write(JSON.stringify(this.clientSubscription.response(this.id)) + '\n');
                } else {
                    console.error(errors);
                }

                break;
            }
            case eRequestMethod.CONFIGURE: {

                const configurationMessage = plainToInstance(
                    ConfigurationMessage,
                    parsedMessage,
                );

                const validatorOptions: ValidatorOptions = {
                    whitelist: true,
                    forbidNonWhitelisted: true,
                };

                const errors = await validate(configurationMessage, validatorOptions);

                if (errors.length === 0) {
                    this.clientConfiguration = configurationMessage;
                    //const response = this.buildSubscriptionResponse(configurationMessage.id);
                    socket.write(JSON.stringify(this.clientConfiguration.response()) + '\n');
                } else {
                    console.error(errors);
                }

                break;
            }
            case eRequestMethod.AUTHORIZE: {
                const authorizationMessage = plainToInstance(
                    AuthorizationMessage,
                    parsedMessage,
                );

                const validatorOptions: ValidatorOptions = {
                    whitelist: true,
                    forbidNonWhitelisted: true,
                };

                const errors = await validate(authorizationMessage, validatorOptions);

                if (errors.length === 0) {
                    this.clientAuthorization = authorizationMessage;

                    //const response = this.buildSubscriptionResponse(authorizationMessage.id);
                    socket.write(JSON.stringify(this.clientAuthorization.response()) + '\n');
                } else {
                    console.error(errors);
                }

                break;
            }
            case eRequestMethod.SUGGEST_DIFFICULTY: {

                const suggestDifficultyMessage = plainToInstance(
                    SuggestDifficulty,
                    parsedMessage
                );

                const validatorOptions: ValidatorOptions = {
                    whitelist: true,
                    forbidNonWhitelisted: true,
                };

                const errors = await validate(suggestDifficultyMessage, validatorOptions);

                if (errors.length === 0) {

                    this.clientSuggestedDifficulty = suggestDifficultyMessage;
                    this.clientDifficulty = suggestDifficultyMessage.suggestedDifficulty;
                    socket.write(JSON.stringify(this.clientSuggestedDifficulty.response(this.clientDifficulty)) + '\n');
                } else {
                    console.error(errors);
                }
                break;
            }
            case eRequestMethod.SUBMIT: {
                const miningSubmitMessage = plainToInstance(
                    MiningSubmitMessage,
                    parsedMessage,
                );

                const validatorOptions: ValidatorOptions = {
                    whitelist: true,
                    forbidNonWhitelisted: true,
                };

                const errors = await validate(miningSubmitMessage, validatorOptions);

                if (errors.length === 0) {
                    this.handleMiningSubmission(miningSubmitMessage);
                    socket.write(JSON.stringify(miningSubmitMessage.response()) + '\n');
                } else {
                    console.error(errors);
                }
                break;
            }
        }


        if (this.clientSubscription != null
            && this.clientConfiguration != null
            && this.clientAuthorization != null
            && this.clientSuggestedDifficulty != null
            && this.stratumInitialized == false) {

            this.stratumInitialized = true;


            let lastIntervalCount = undefined;
            combineLatest([this.blockTemplateService.currentBlockTemplate$, interval(60000).pipe(startWith(-1))]).subscribe(([{ miningInfo, blockTemplate }, interValCount]) => {
                let clearJobs = false;
                if (lastIntervalCount === interValCount) {
                    clearJobs = true;
                }
                lastIntervalCount = interValCount;

                const job = new MiningJob(this.stratumV1JobsService.getNextId(), [{ address: this.clientAuthorization.address, percent: 100 }], blockTemplate, miningInfo.difficulty, clearJobs);

                this.stratumV1JobsService.addJob(job, clearJobs);

                this.socket.write(job.response + '\n');
            })




        }
    }


    private handleMiningSubmission(submission: MiningSubmitMessage) {

        const job = this.stratumV1JobsService.getJobById(submission.jobId);
        // a miner may submit a job that doesn't exist anymore if it was removed by a new block notification 
        if (job == null) {
            return;
        }
        const diff = submission.calculateDifficulty(this.id, job, submission);
        console.log(`DIFF: ${diff}`);

        if (diff >= this.clientDifficulty) {
            const networkDifficulty = this.calculateNetworkDifficulty(parseInt(job.blockTemplate.bits, 16));
            this.statistics.addSubmission(this.clientDifficulty, diff, networkDifficulty);
            if (diff >= networkDifficulty) {
                console.log('!!! BOCK FOUND !!!');
                this.constructBlockAndBroadcast(job, submission);
            }
        } else {
            console.log(`Difficulty too low`);
        }

    }

    private calculateNetworkDifficulty(nBits: number) {
        const mantissa: number = nBits & 0x007fffff;       // Extract the mantissa from nBits
        const exponent: number = (nBits >> 24) & 0xff;       // Extract the exponent from nBits

        const target: number = mantissa * Math.pow(256, (exponent - 3));   // Calculate the target value

        const difficulty: number = (Math.pow(2, 208) * 65535) / target;    // Calculate the difficulty

        return difficulty;
    }

    private constructBlockAndBroadcast(job: MiningJob, submission: MiningSubmitMessage) {
        const block = new Block();

        const blockHeightScript = `03${job.blockTemplate.height.toString(16).padStart(8, '0')}${job.id}${submission.extraNonce2}`;

        const inputScript = bitcoinjs.script.compile([bitcoinjs.opcodes.OP_RETURN, Buffer.from(blockHeightScript, 'hex')]);
        job.coinbaseTransaction.ins[0].script = inputScript;


        const versionMask = parseInt(submission.versionMask, 16);
        let version = job.version;
        if (versionMask !== undefined && versionMask != 0) {
            version = (version ^ versionMask);
        }

        block.version = version;
        block.prevHash = Buffer.from(job.prevhash, 'hex');

        block.timestamp = job.ntime;
        block.bits = job.nbits;
        block.nonce = parseInt(submission.nonce, 16);

        block.transactions = job.blockTemplate.transactions.map(tx => {
            return Transaction.fromHex(tx.data);
        });
        block.transactions.unshift(job.coinbaseTransaction);

        block.merkleRoot = bitcoinjs.Block.calculateMerkleRoot(block.transactions, false);
        block.witnessCommit = bitcoinjs.Block.calculateMerkleRoot(block.transactions, true);

        // const test1 = block.getWitnessCommit();
        // const test2 = block.checkTxRoots();


        const blockHex = block.toHex(false);
        this.bitcoinRpcService.SUBMIT_BLOCK(blockHex);

    }

}