// Copyright 2015, 2016 Ethcore (UK) Ltd.
// This file is part of Parity.

// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Parity.  If not, see <http://www.gnu.org/licenses/>.

import { action, computed, observable, transaction } from 'mobx';

import Contracts from '../../contracts';
import { hashToImageUrl } from '../../redux/util';

import builtinApps from './builtin.json';

const LS_KEY_HIDDEN = 'hiddenApps';
const LS_KEY_EXTERNAL = 'externalApps';

export default class DappsStore {
  @observable apps = [];
  @observable externalApps = [];
  @observable hiddenApps = [];
  @observable modalOpen = false;

  constructor (api) {
    this._api = api;

    this._readHiddenApps();
    this._readExternalApps();

    this._fetchBuiltinApps();
    this._fetchLocalApps();
    this._fetchRegistryApps();
  }

  @computed get visible () {
    return this.apps
      .filter((app) => {
        return this.externalApps.includes(app.id) || !this.hiddenApps.includes(app.id);
      })
      .sort((a, b) => a.name.localeCompare(b.name));
  }

  @action openModal = () => {
    this.modalOpen = true;
  }

  @action closeModal = () => {
    this.modalOpen = false;
  }

  @action hideApp = (id) => {
    this.hiddenApps = this.hiddenApps.concat(id);
    this._writeHiddenApps();
  }

  @action showApp = (id) => {
    this.hiddenApps = this.hiddenApps.filter((_id) => _id !== id);
    this._writeHiddenApps();
  }

  _getHost (api) {
    return process.env.NODE_ENV === 'production'
      ? this._api.dappsUrl
      : '';
  }

  _fetchBuiltinApps () {
    const { dappReg } = Contracts.get();

    return Promise
      .all(builtinApps.map((app) => dappReg.getImage(app.id)))
      .then((imageIds) => {
        transaction(() => {
          builtinApps.forEach((app, index) => {
            app.type = 'builtin';
            app.image = hashToImageUrl(imageIds[index]);
            this.apps.push(app);
          });
        });
      });
  }

  _fetchLocalApps () {
    return fetch(`${this._getHost()}/api/apps`)
      .then((response) => {
        return response.ok
          ? response.json()
          : [];
      })
      .then((apps) => {
        return apps
          .map((app) => {
            app.type = 'local';
            return app;
          })
          .filter((app) => app.id && !['ui'].includes(app.id));
      })
      .then((apps) => {
        transaction(() => {
          (apps || []).forEach((app) => this.apps.push(app));
        });
      })
      .catch((error) => {
        console.warn('DappsStore:fetchLocal', error);
      });
  }

  _fetchRegistryApps () {
    const { dappReg } = Contracts.get();

    return dappReg
      .count()
      .then((_count) => {
        const count = _count.toNumber();
        const promises = [];

        for (let index = 0; index < count; index++) {
          promises.push(dappReg.at(index));
        }

        return Promise.all(promises);
      })
      .then((appsInfo) => {
        const appIds = appsInfo
          .map(([appId, owner]) => this._api.util.bytesToHex(appId))
          .filter((appId) => !builtinApps.find((app) => app.id === appId));

        return Promise
          .all([
            Promise.all(appIds.map((appId) => dappReg.getImage(appId))),
            Promise.all(appIds.map((appId) => dappReg.getContent(appId))),
            Promise.all(appIds.map((appId) => dappReg.getManifest(appId)))
          ])
          .then(([imageIds, contentIds, manifestIds]) => {
            return appIds.map((appId, index) => {
              const app = {
                id: appId,
                image: hashToImageUrl(imageIds[index]),
                contentHash: this._api.util.bytesToHex(contentIds[index]).substr(2),
                manifestHash: this._api.util.bytesToHex(manifestIds[index]).substr(2),
                type: 'network'
              };

              return app;
            });
          });
      })
      .then((apps) => {
        return Promise
          .all(apps.map((app) => this._fetchManifest(app.manifestHash)))
          .then((manifests) => {
            return apps.map((app, index) => {
              const manifest = manifests[index];

              if (manifest) {
                app.manifestHash = null;
                Object.keys(manifest)
                  .filter((key) => ['author', 'description', 'name', 'version'].includes(key))
                  .forEach((key) => {
                    app[key] = manifest[key];
                  });
              }

              return app;
            });
          })
          .then((apps) => {
            return apps.filter((app) => {
              return !app.manifestHash && app.id;
            });
          });
      })
      .then((apps) => {
        transaction(() => {
          (apps || []).forEach((app) => this.apps.push(app));
        });
      })
      .catch((error) => {
        console.warn('DappsStore:fetchRegistry', error);
      });
  }

  _fetchManifest (manifestHash) {
    return fetch(`${this._getHost()}/api/content/${manifestHash}/`, { redirect: 'follow', mode: 'cors' })
      .then((response) => {
        return response.ok
          ? response.json()
          : null;
      })
      .catch((error) => {
        console.warn('DappsStore:fetchManifest', error);
        return null;
      });
  }

  _readHiddenApps () {
    const stored = localStorage.getItem(LS_KEY_HIDDEN);

    if (stored) {
      try {
        this.hiddenApps = JSON.parse(stored);
      } catch (error) {
        console.warn('DappsStore:readHiddenApps', error);
      }
    }
  }

  _readExternalApps () {
    const stored = localStorage.getItem(LS_KEY_EXTERNAL);

    if (stored) {
      try {
        this.externalApps = JSON.parse(stored);
      } catch (error) {
        console.warn('DappsStore:readExternalApps', error);
      }
    }
  }

  _writeExternalApps () {
    try {
      localStorage.setItem(LS_KEY_EXTERNAL, JSON.stringify(this.externalApps));
    } catch (error) {
      console.error('DappsStore:writeExternalApps', error);
    }
  }

  _writeHiddenApps () {
    try {
      localStorage.setItem(LS_KEY_HIDDEN, JSON.stringify(this.hiddenApps));
    } catch (error) {
      console.error('DappsStore:writeHiddenApps', error);
    }
  }
}