const debug = require('debug')('ipfs-pinner');
const cliProgress = require('cli-progress');

class IpfsPinner {
  constructor (kredits, options={}) {
    this.kredits = kredits;
    this.ipfsApi = this.kredits.ipfs;
    this.progressBars = !!options.progress && !process.env.DEBUG;

    if (this.progressBars) {
      this.multibar = new cliProgress.MultiBar({
        stopOnComplete: true,
        clearOnComplete: false,
        hideCursor: false,
        etaBuffer: 30,
        format: '{entity} [{bar}] {percentage}% | ETA: {eta_formatted} | {value}/{total}'
      }, cliProgress.Presets.shades_grey);
    }
  }

  async pinAll () {
    console.log('Pinning IPFS documents for all known items...\n')
    const cids = [];
    const promises = [];
    const contracts = [
      this.kredits.Contributor,
      this.kredits.Contribution,
      // TODO uncomment once we have data here
      // this.kredits.Reimbursement
    ]

    for (const contract of contracts) {
      debug(`Pinning data from ${contract.constructor.name}...`);
      const itemCount = await contract.count;
      debug('Item count:', itemCount);
      let bar;

      if (this.progressBars) {
        bar = this.multibar.create(itemCount, 0);
        bar.update(0, {entity: `${contract.constructor.name}s`.padEnd(14)});
      }

      promises.push(this._pinAllFromContract(contract, itemCount, bar)
                        .then(res => { cids.push(...res); }));
    }

    await Promise.all(promises);

    return cids;
  }

  watch (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);
    });
  }

  async _pinAllFromContract (contract, itemCount, progressBar) {
    const ids = [...Array(itemCount).keys()].map(i => i+1);
    const cids = [];
    const batchSize = 20;
    let position = 0;

    while (position < itemCount) {
      const batchIds = ids.slice(position, position + batchSize);
      await Promise.all(batchIds.map(async id => {
        const data = await contract.getData(id);
        debug(`Loaded ${contract.constructor.name} #${id}`);
        const cid = await this.ipfsApi.pin(data);
        debug(`Pinned ${contract.constructor.name} #${id} at ${cid}`);
        cids.push(cid);
        if (this.progressBars) { progressBar.increment(); }
      }));
      position += batchSize;
    }

    return cids;
  }
}

module.exports = IpfsPinner;