import { Source, SourceCallback, SourceOptions } from '@neoskop/paperboy';

import { connect, Message } from 'amqplib';

import { fetchDamAssets } from './dam.util';
import { MagnoliaSourceOptions } from './magnolia-source-options.interface';
import {
    fetchPages, fetchSitemap, fetchWorkspace, sanitizeJson, writePagesFile, writeWorkspaceFile
} from './pages.util';
import AsyncLock = require("async-lock");

export class MagnoliaSource implements Source {
  private readonly options: MagnoliaSourceOptions;
  private readonly callback: SourceCallback;
  private readonly generationLock: AsyncLock = new AsyncLock({maxPending: 1});

  constructor(options: SourceOptions, callback: SourceCallback) {
    this.options = <MagnoliaSourceOptions>options;
    this.callback = callback;
  }

  public generate(): Promise<void> {
    return new Promise(async resolve => {
      const sitemap = await fetchSitemap(this.options);
      const website = await fetchPages(this.options);
      const pages = sitemap
        .map(path => website.find((page: any) => page['@path'] === path))
        .filter(page => typeof page !== 'undefined');

      const workspaces: { [workspace: string]: any } = {};

      for (const workspace of this.options.magnolia.workspaces) {
        workspaces[workspace] = await fetchWorkspace(workspace, this.options);
      }

      // get dam jcr ids
      const nodes = pages.concat(
        Object.keys(workspaces).reduce((prev, current) => prev.concat(workspaces[current]), [])
      );
      const match = JSON.stringify(nodes).match(
        /jcr:([0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12})/g
      );

      let damUuids = match ? match.map(id => id.substring(4)) : [];
      damUuids = damUuids.filter((id, pos) => {
        return damUuids.indexOf(id) === pos;
      });

      const damAssets = await fetchDamAssets(damUuids, this.options);
      const pagesObj: any = pages.map((page: any) =>
        sanitizeJson(page, damAssets, pages, this.options)
      );

      await writePagesFile(pagesObj, this.options);

      if (this.options.magnolia.workspaces) {
        for (const workspace of Object.keys(workspaces)) {
          const workspaceData = workspaces[workspace];

          if (workspaceData) {
            const sanitized: any[] = [];

            for (const item of workspaceData) {
              sanitized.push(sanitizeJson(item, damAssets, workspaceData, this.options));
            }

            await writeWorkspaceFile(workspace, sanitized, this.options);
          }
        }
      }

      resolve();
    });
  }

  public async start(): Promise<void> {
    connect(this.options.queue.uri)
      .then(conn => {
        conn.on('error', this.retryConnection.bind(this, this.options.queue));
        return conn.createChannel();
      })
      .then(channel => {
        channel
          .assertExchange(this.options.queue.exchangeName || 'paperboy', 'fanout', {
            durable: false
          })
          .then(() => {
            return channel.assertQueue(null, {
              autoDelete: true
            });
          })
          .then(qok => {
            channel.bindQueue(qok.queue, this.options.queue.exchangeName || 'paperboy', '');
            channel.consume(qok.queue, this.consumeMessage.bind(this), {
              noAck: true
            });
          });
      })
      .catch(() => {
        this.retryConnection();
      });
  }

  private retryConnection() {
    console.info('Connection to queue failed, will retry in 10s...');
    setTimeout(() => {
      this.start();
    }, 10000);
  }

  private consumeMessage(message: Message | null) {
    console.info(
      "[x] from Magnolia: %s -> '%s'",
      message.fields.routingKey,
      message.content.toString()
    );

    this.generationLock.acquire('generationLock', (done) => {
        this.generate().then(() => {
          this.callback().then(() => done());
        }).catch((err) => {
          console.error('Generation failed.', err);
          done()
        });
    }, (err, ret) => {
        if (err) {
          console.info('Already another pending message. Message discarded!');
        }
    });
  }
}