import { __ } from 'embark-i18n';
import { dappPath, sha3 } from 'embark-utils';
import * as fs from 'fs-extra';

class DeployTracker {

  constructor(embark, options) {
    this.logger = embark.logger;
    this.events = embark.events;
    this.embark = embark;
    this.trackContracts = (options.trackContracts !== false);

    // TODO: unclear where it comes from
    this.env = options.env;
    this.chainConfig = {};
    this.chainFile = embark.config.contractsConfig.tracking;
    this.loadChainTrackerFile();
    this.registerEvents();
  }

  loadChainTrackerFile() {
    if (this.chainFile === false) return;
    if (this.chainFile === undefined) this.chainFile = ".embark/chains.json";
    this.chainFile = dappPath(this.chainFile);
    if (!fs.existsSync(this.chainFile)) {
      this.logger.info(this.chainFile + ' ' + __('file not found, creating it...'));
      fs.outputJSONSync(this.chainFile, {});
    }

    this.chainConfig = fs.readJSONSync(this.chainFile);
  }

  registerEvents() {
    if (this.chainFile === false) return;
    const self = this;

    this.embark.registerActionForEvent("deploy:beforeAll", this.setCurrentChain.bind(this));

    this.events.on("deploy:contract:deployed", (contract) => {
      self.trackContract(contract.className, contract.realRuntimeBytecode, contract.realArgs, contract.deployedAddress);
      self.save();
    });

    self.embark.registerActionForEvent("deploy:contract:shouldDeploy", (params, cb) => {
      if (!self.trackContracts) {
        return cb(null, params);
      }

      let contract = params.contract;
      let trackedContract = self.getContract(contract.className, contract.realRuntimeBytecode, contract.realArgs);
      if (trackedContract) {
        params.contract.address = trackedContract.address;
      }
      if (params.shouldDeploy && trackedContract) {
         params.shouldDeploy = true;
      }
      cb(null, params);
    });
  }

  setCurrentChain(callback) {
    const self = this;
    if (this.chainConfig === false) {
      this.currentChain = {contracts: []};
      return callback();
    }

    function getBlock(blockNum, cb) {
      self.events.request("blockchain:block:byNumber", blockNum, (err, block) => {
        if (err) {
          return cb(err);
        }
        let chainId = block.hash;

        if (self.chainConfig[chainId] === undefined) {
          self.chainConfig[chainId] = {contracts: {}};
        }

        self.currentChain = self.chainConfig[chainId];

        self.currentChain.name = self.env;
        cb();
      });
    }

    getBlock(0, (err) => {
      if (err) {
        // Retry with block 1 (Block 0 fails with Ganache-cli using the --fork option)
        return getBlock(1, (err) => {
          if (err) {
            self.logger.error(__('Error getting block data. The deploy-tracker will not work'), err);
          }
          callback();
        });
      }
      callback();
    });
  }

  loadConfig(config) {
    this.chainConfig = config;
    return this;
  }

  trackContract(contractName, code, args, address) {
    if (!this.currentChain) return false;
    this.currentChain.contracts[sha3(code + contractName + args.join(','))] = {
      name: contractName,
      address: address
    };
  }

  getContract(contractName, code, args) {
    if (!this.currentChain) return false;
    let contract = this.currentChain.contracts[sha3(code + contractName + args.join(','))];
    if (contract && contract.address === undefined) {
      return false;
    }
    return contract;
  }

  // TODO: abstract this
  // chainConfig can be an abstract PersistentObject
  save() {
    if (this.chainConfig === false) {
      return;
    }
    fs.writeJSONSync(this.chainFile, this.chainConfig, {spaces: 2});
  }

}

module.exports = DeployTracker;