const debug = require('debug')('ipfs-pinner');

class IpfsPinner {
  constructor (kredits, ipfsApi) {
    this.kredits = kredits;
    this.ipfsApi = ipfsApi || this.kredits.ipfs;
  }

  async pinAll () {
    const contributorHashes  = await this._pinAllFromContract(this.kredits.Contributor);
    const contributionHashes = await this._pinAllFromContract(this.kredits.Contribution);
    const proposalHashes     = await this._pinAllFromContract(this.kredits.Proposal);

    return contributorHashes.concat(contributionHashes)
                            .concat(proposalHashes);
  }

  monitor (callback) {
    this.kredits.Contribution.on('ContributionAdded', (id) => {
      this.kredits.Contribution.getData(id)
        .then(data => { return this.ipfsApi.pin(data); })
        .then(callback);
    });
    this.kredits.Contributor.on('ContributorAdded', (id) => {
      this.kredits.Contribution.getData(id)
        .then(data => { return this.ipfsApi.pin(data); })
        .then(callback);
    });
    this.kredits.Contributor.on('ContributorProfileUpdated', (id) => {
      this.kredits.Contributor.getData(id)
        .then(data => { return this.ipfsApi.pin(data); })
        .then(callback);
    });
  }

  _pinAllFromContract (contract) {
    debug(`Pinning data from ${contract.constructor.name}...`);
    return contract.count.then(count => {
      let promises = [...Array(count).keys()].map(i => {
        let id = i + 1; // 0 => 1 - ids start with 1 and not with 0
        debug(`Loading ${contract.constructor.name} #${id}`);
        return contract.getData(id).then(data => {
          debug(`Pinning ${contract.constructor.name} #${id}`);
          return this.ipfsApi.pin(data);
        });
      });
      return Promise.all(promises);
    });
  }
}
module.exports = IpfsPinner;