const { URL } = require('url');
const bytes = require('bytes');
const slugify = require('slugify');
const config = require('../next.config.js');

module.exports.ckanToDataPackage = function (descriptor) {
  // Make a copy
  const datapackage = JSON.parse(JSON.stringify(descriptor));

  // Lowercase name
  datapackage.name = datapackage.name.toLowerCase();

  // Rename notes => description
  if (datapackage.notes) {
    datapackage.description = datapackage.notes;
    delete datapackage.notes;
  }

  // Rename ckan_url => homepage
  if (datapackage.ckan_url) {
    datapackage.homepage = datapackage.ckan_url;
    delete datapackage.ckan_url;
  }

  // Parse license
  const license = {};
  if (datapackage.license_id) {
    license.type = datapackage.license_id;
    delete datapackage.license_id;
  }
  if (datapackage.license_title) {
    license.title = datapackage.license_title;
    delete datapackage.license_title;
  }
  if (datapackage.license_url) {
    license.url = datapackage.license_url;
    delete datapackage.license_url;
  }
  if (Object.keys(license).length > 0) {
    datapackage.license = license;
  }

  // Parse author and sources
  const source = {};
  if (datapackage.author) {
    source.name = datapackage.author;
    delete datapackage.author;
  }
  if (datapackage.author_email) {
    source.email = datapackage.author_email;
    delete datapackage.author_email;
  }
  if (datapackage.url) {
    source.web = datapackage.url;
    delete datapackage.url;
  }
  if (Object.keys(source).length > 0) {
    datapackage.sources = [source];
  }

  // Parse maintainer
  const author = {};
  if (datapackage.maintainer) {
    author.name = datapackage.maintainer;
    delete datapackage.maintainer;
  }
  if (datapackage.maintainer_email) {
    author.email = datapackage.maintainer_email;
    delete datapackage.maintainer_email;
  }
  if (Object.keys(author).length > 0) {
    datapackage.author = author;
  }

  // Parse tags
  if (datapackage.tags) {
    datapackage.keywords = [];
    datapackage.tags.forEach((tag) => {
      datapackage.keywords.push(tag.name);
    });
    delete datapackage.tags;
  }

  // Parse extras
  // TODO

  // Resources
  datapackage.resources = datapackage.resources.map((resource) => {
    if (resource.name) {
      resource.title = resource.title || resource.name;
      resource.name = resource.name.toLowerCase().replace(/ /g, '_');
    } else {
      resource.name = resource.id;
    }

    if (resource.url) {
      resource.path = resource.url;
      delete resource.url;
    }

    if (!resource.schema) {
      // If 'fields' property exists use it as schema fields
      if (resource.fields) {
        if (typeof resource.fields === 'string') {
          try {
            resource.fields = JSON.parse(resource.fields);
          } catch (e) {
            console.log('Could not parse resource.fields');
          }
        }
        resource.schema = { fields: resource.fields };
        delete resource.fields;
      }
    }

    return resource;
  });

  return datapackage;
};

/*
  At the moment, we're considering only following examples of CKAN view:
  1. recline_view => Data Explorer with Table view, Chart Builder, Map Builder
    and Query Builder.
  2. geojson_view => Leaflet map
  3. pdf_view => our PDF viewer
  4. recline_grid_view => our Table viewer
  5. recline_graph_view => our Simple graph
  6. recline_map_view => our Leaflet map
  7. image_view => not supported at the moment
  8. text_view => not supported at the moment
  9. webpage_view => not supported at the moment
*/
module.exports.ckanViewToDataPackageView = (ckanView) => {
  const viewTypeToSpecType = {
    recline_view: 'dataExplorer', // from datastore data
    recline_grid_view: 'table',
    recline_graph_view: 'simple',
    recline_map_view: 'tabularmap',
    geojson_view: 'map',
    pdf_view: 'document',
    image_view: 'web',
    webpage_view: 'web',
  };
  const dataPackageView = JSON.parse(JSON.stringify(ckanView));
  dataPackageView.specType =
    viewTypeToSpecType[ckanView.view_type] ||
    dataPackageView.specType ||
    'unsupported';

  if (dataPackageView.specType === 'dataExplorer') {
    dataPackageView.spec = {
      widgets: [
        { specType: 'table' },
        { specType: 'simple' },
        { specType: 'tabularmap' },
      ],
    };
  } else if (dataPackageView.specType === 'simple') {
    const graphTypeConvert = {
      lines: 'line',
      'lines-and-points': 'lines-and-points',
      points: 'points',
      bars: 'horizontal-bar',
      columns: 'bar',
    };
    dataPackageView.spec = {
      group: ckanView.group,
      series: Array.isArray(ckanView.series)
        ? ckanView.series
        : [ckanView.series],
      type: graphTypeConvert[ckanView.graph_type] || 'line',
    };
  } else if (dataPackageView.specType === 'tabularmap') {
    if (ckanView.map_field_type === 'geojson') {
      dataPackageView.spec = {
        geomField: ckanView.geojson_field,
      };
    } else {
      dataPackageView.spec = {
        lonField: ckanView.longitude_field,
        latField: ckanView.latitude_field,
      };
    }
  }

  return dataPackageView;
};

/*
Takes single field descriptor from datastore data dictionary and coverts into
tableschema field descriptor.
*/
module.exports.dataStoreDataDictionaryToTableSchema = (dataDictionary) => {
  const internalDataStoreFields = ['_id', '_full_text', '_count'];
  if (internalDataStoreFields.includes(dataDictionary.id)) {
    return null;
  }
  const dataDictionaryType2TableSchemaType = {
    text: 'string',
    int: 'integer',
    float: 'number',
    date: 'date',
    time: 'time',
    timestamp: 'datetime',
    bool: 'boolean',
    json: 'object',
  };
  const field = {
    name: dataDictionary.id,
    type: dataDictionaryType2TableSchemaType[dataDictionary.type] || 'any',
  };
  if (dataDictionary.info) {
    const constraintsAttributes = [
      'required',
      'unique',
      'minLength',
      'maxLength',
      'minimum',
      'maximum',
      'pattern',
      'enum',
    ];
    field.constraints = {};
    Object.keys(dataDictionary.info).forEach((key) => {
      if (constraintsAttributes.includes(key)) {
        field.constraints[key] = dataDictionary.info[key];
      } else {
        field[key] = dataDictionary.info[key];
      }
    });
  }
  return field;
};

module.exports.convertToStandardCollection = (descriptor) => {
  const standard = {
    name: '',
    title: '',
    summary: '',
    image: '',
    count: null,
  };

  standard.name = descriptor.name;
  standard.title = descriptor.title || descriptor.display_name;
  standard.summary = descriptor.description || '';
  standard.image = descriptor.image_display_url || descriptor.image_url;
  standard.count = descriptor.package_count || 0;
  standard.extras = descriptor.extras || [];
  standard.groups = descriptor.groups || [];

  return standard;
};

module.exports.convertToCkanSearchQuery = (query) => {
  const ckanQuery = {
    q: '',
    fq: '',
    rows: '',
    start: '',
    sort: '',
    'facet.field': [
      'organization',
      'groups',
      'tags',
      'res_format',
      'license_id',
    ],
    'facet.limit': 5,
    'facet.mincount': 0,
  };
  // Split by space but ignore spaces within double quotes:
  if (query.q) {
    query.q.match(/(?:[^\s"]+|"[^"]*")+/g).forEach((part) => {
      if (part.includes(':')) {
        ckanQuery.fq += part + ' ';
      } else {
        ckanQuery.q += part + ' ';
      }
    });
    ckanQuery.fq = ckanQuery.fq.trim();
    ckanQuery.q = ckanQuery.q.trim();
  }

  if (query.fq) {
    ckanQuery.fq = ckanQuery.fq ? ckanQuery.fq + ' ' + query.fq : query.fq;
  }

  // standard 'size' => ckan 'rows'
  ckanQuery.rows = query.size || '';

  // standard 'from' => ckan 'start'
  ckanQuery.start = query.from || '';

  // standard 'sort' => ckan 'sort'
  const sortQueries = [];
  if (query.sort && query.sort.constructor == Object) {
    for (let [key, value] of Object.entries(query.sort)) {
      sortQueries.push(`${key} ${value}`);
    }
    ckanQuery.sort = sortQueries.join(',');
  } else if (query.sort && query.sort.constructor == String) {
    ckanQuery.sort = query.sort.replace(':', ' ');
  } else if (query.sort && query.sort.constructor == Array) {
    query.sort.forEach((sort) => {
      sortQueries.push(sort.replace(':', ' '));
    });
    ckanQuery.sort = sortQueries.join(',');
  }

  // Facets
  ckanQuery['facet.field'] = query['facet.field'] || ckanQuery['facet.field'];
  ckanQuery['facet.limit'] = query['facet.limit'] || ckanQuery['facet.limit'];
  ckanQuery['facet.mincount'] =
    query['facet.mincount'] || ckanQuery['facet.mincount'];
  ckanQuery['facet.field'] = query['facet.field'] || ckanQuery['facet.field'];

  // Remove attributes with empty string, null or undefined values
  Object.keys(ckanQuery).forEach(
    (key) => !ckanQuery[key] && delete ckanQuery[key]
  );

  return ckanQuery;
};

module.exports.pagination = (c, m) => {
  let current = c,
    last = m,
    delta = 2,
    left = current - delta,
    right = current + delta + 1,
    range = [],
    rangeWithDots = [],
    l;

  range.push(1);
  for (let i = c - delta; i <= c + delta; i++) {
    if (i >= left && i < right && i < m && i > 1) {
      range.push(i);
    }
  }
  range.push(m);

  for (let i of range) {
    if (l) {
      if (i - l === 2) {
        rangeWithDots.push(l + 1);
      } else if (i - l !== 1) {
        rangeWithDots.push('...');
      }
    }
    rangeWithDots.push(i);
    l = i;
  }
  return rangeWithDots;
};

module.exports.processMarkdown = require('markdown-it')({
  html: true,
  linkify: true,
  typographer: true,
});

/**
 * Process data package attributes prior to display to users.
 * Process markdown
 * Convert bytes to human readable format
 * etc.
 **/
module.exports.processDataPackage = function (datapackage) {
  const newDatapackage = JSON.parse(JSON.stringify(datapackage));
  if (newDatapackage.description) {
    newDatapackage.descriptionHtml = module.exports.processMarkdown.render(
      newDatapackage.description
    );
  }

  if (newDatapackage.readme) {
    newDatapackage.readmeHtml = module.exports.processMarkdown.render(
      newDatapackage.readme
    );
  }

  newDatapackage.formats = newDatapackage.formats || [];
  // Per each resource:
  newDatapackage.resources.forEach((resource) => {
    if (resource.description) {
      resource.descriptionHtml = module.exports.processMarkdown.render(
        resource.description
      );
    }
    // Normalize format (lowercase)
    if (resource.format) {
      resource.format = resource.format.toLowerCase();
      newDatapackage.formats.push(resource.format);
    }

    // Convert bytes into human-readable format:
    if (resource.size) {
      resource.sizeFormatted = bytes(resource.size, { decimalPlaces: 0 });
    }
  });

  return newDatapackage;
};

/**
 * Create 'displayResources' property which has:
 * resource: Object containing resource descriptor
 * api: API URL for the resource if available, e.g., Datastore
 * proxy: path via proxy for the resource if available
 * cc_proxy: path via CKAN Classic proxy if available
 * slug: slugified name of a resource
 **/
module.exports.prepareResourcesForDisplay = function (datapackage) {
  const newDatapackage = JSON.parse(JSON.stringify(datapackage));
  newDatapackage.displayResources = [];
  newDatapackage.resources.forEach((resource, index) => {
    const api = resource.datastore_active
      ? config.get('API_URL') +
        'datastore_search?resource_id=' +
        resource.id +
        '&sort=_id asc'
      : null;
    // Use proxy path if datastore/filestore proxies are given:
    let proxy, cc_proxy;
    try {
      const resourceUrl = new URL(resource.path);
      if (
        resourceUrl.host === config.get('PROXY_DATASTORE') &&
        resource.format !== 'pdf'
      ) {
        proxy = '/proxy/datastore' + resourceUrl.pathname + resourceUrl.search;
      }
      if (
        resourceUrl.host === config.get('PROXY_FILESTORE') &&
        resource.format !== 'pdf'
      ) {
        proxy = '/proxy/filestore' + resourceUrl.pathname + resourceUrl.search;
      }
      // Store a CKAN Classic proxy path
      // https://github.com/ckan/ckan/blob/master/ckanext/resourceproxy/plugin.py#L59
      const apiUrlObject = new URL(config.get('API_URL'));
      cc_proxy =
        apiUrlObject.origin +
        `/dataset/${datapackage.id}/resource/${resource.id}/proxy`;
    } catch (e) {
      console.warn(e);
    }
    const displayResource = {
      resource,
      api, // URI for getting the resource via API, e.g., Datastore. Useful when you want to fetch only 100 rows or similar.
      proxy, // alternative for path in case there is CORS issue
      cc_proxy,
      slug: slugify(resource.name) + '-' + index, // Used for anchor links
    };
    newDatapackage.displayResources.push(displayResource);
  });
  return newDatapackage;
};

/**
 * Prepare 'views' property which is used by 'datapackage-views-js' library to
 * render visualizations such as tables, graphs and maps.
 **/
module.exports.prepareViews = function (datapackage) {
  const newDatapackage = JSON.parse(JSON.stringify(datapackage));
  newDatapackage.views = newDatapackage.views || [];
  newDatapackage.resources.forEach((resource) => {
    const resourceViews =
      resource.views &&
      resource.views.map((view) => {
        view.resources = [resource.name];
        return view;
      });

    newDatapackage.views = newDatapackage.views.concat(resourceViews);
  });

  return newDatapackage;
};

/**
 * Create 'dataExplorers' property which is used by 'data-explorer' library to
 * render data explorer widgets.
 **/
module.exports.prepareDataExplorers = function (datapackage) {
  const newDatapackage = JSON.parse(JSON.stringify(datapackage));
  newDatapackage.displayResources.forEach((displayResource, idx) => {
    newDatapackage.displayResources[idx].dataExplorers = [];
    displayResource.resource.views &&
      displayResource.resource.views.forEach((view) => {
        const widgets = [];
        if (view.specType === 'dataExplorer') {
          view.spec.widgets.forEach((widget, index) => {
            const widgetNames = {
              table: 'Table',
              simple: 'Chart',
              tabularmap: 'Map',
            };
            widget = {
              name: widgetNames[widget.specType] || 'Widget-' + index,
              active: index === 0 ? true : false,
              datapackage: {
                views: [
                  {
                    id: view.id,
                    specType: widget.specType,
                  },
                ],
              },
            };
            widgets.push(widget);
          });
        } else {
          const widget = {
            name: view.title || '',
            active: true,
            datapackage: {
              views: [view],
            },
          };
          widgets.push(widget);
        }

        displayResource.resource.api =
          displayResource.resource.api || displayResource.api;
        const dataExplorer = JSON.stringify({
          widgets,
          datapackage: {
            resources: [displayResource.resource],
          },
        }).replace(/'/g, '&#x27;');
        newDatapackage.displayResources[idx].dataExplorers.push(dataExplorer);
      });
  });

  return newDatapackage;
};