'use strict';

const https = require('https');

const OPENLIBRARY_API_BASE = 'openlibrary.org';
const OPENLIBRARY_API_BOOK = '/api/books';

module.exports = {
  lookup: function(isbn, callback) {

    var standardize = function standardize(book) {
        var standardBook = {
            'title': book.details.title,
            'publishedDate': book.details.publish_date,
            'authors': [],
            'description': book.details.subtitle,
            'industryIdentifiers': [],
            'pageCount': book.details.number_of_pages,
            'printType': 'BOOK',
            'categories': [],
            'imageLinks': {
                'smallThumbnail': book.thumbnail_url,
                'thumbnail': book.thumbnail_url
            },
            'previewLink': book.preview_url,
            'infoLink': book.info_url
        };

        if (undefined !== book.details.isbn_13) {
            standardBook.industryIdentifiers.push({type: 'ISBN-13', identifier: book.details.isbn_13});
        }
        if (undefined !== book.details.isbn_10) {
            standardBook.industryIdentifiers.push({type: 'ISBN-10', identifier: book.details.isbn_10});
        }

        if (undefined !== book.details.goodreads) {
            standardBook.industryIdentifiers.push({type: 'Goodreads', identifier: book.details.goodreads});
        }
        if (undefined !== book.details.librarything) {
            standardBook.industryIdentifiers.push({type: 'LibraryThing', identifier: book.details.librarything});
        }

        if (book.details.publishers) {
            standardBook.publisher = book.details.publishers[0];
        } else {
            standardBook.publisher = '';
        }

        if (book.details.authors) {
            book.details.authors.forEach(function (author) {
                standardBook.authors.push(author.name);
            });
        }

        if (book.details.languages) {
            book.details.languages.forEach(function (language) {
                standardBook.language = language.key.replace("/languages/", "");
            });
        } else {
            standardBook.language = 'unknown';
        }

        return standardBook;
    };

    var requestOptions = {
        host: OPENLIBRARY_API_BASE,
        path: OPENLIBRARY_API_BOOK + '?bibkeys=ISBN:' + isbn + '&format=json&jscmd=details'
    };

    var request = https.request(requestOptions, function (response) {
        if (response.statusCode !== 200) {
            return callback(new Error('wrong response code: ' + response.statusCode));
        }

        var body = '';
        response.on('data', function (chunk) {
            body += chunk;
        })

        response.on('end', function () {
            var books = JSON.parse(body);
            var book = books['ISBN:' + isbn];

            if (!book) {
                return callback(new Error('no books found with isbn: ' + isbn));
            }

            return callback(null, standardize(book));
        })
    });

    request.on('error', function (err) {
        return callback(err);
    })

    request.end();
}
}