// # DB API
// API for DB operations
var dataExport       = require('../data/export'),
    dataImport       = require('../data/import'),
    dataProvider     = require('../models'),
    fs               = require('fs-extra'),
    Promise          = require('bluebird'),
    _                = require('lodash'),
    path             = require('path'),
    os               = require('os'),
    glob             = require('glob'),
    uuid             = require('node-uuid'),
    extract          = require('extract-zip'),
    errors           = require('../../server/errors'),
    canThis          = require('../permissions').canThis,
    utils            = require('./utils'),
    api              = {},
    db,
    types = ['application/octet-stream', 'application/json', 'application/zip', 'application/x-zip-compressed'],
    extensions = ['.json', '.zip'];

api.settings         = require('./settings');

// TODO refactor this out of here
function isJSON(ext) {
    return ext === '.json';
}

function isZip(ext) {
    return ext === '.zip';
}

function getJSONFileContents(filepath, ext) {
    if (isJSON(ext)) {
    // if it's just a JSON file, read it
        return Promise.promisify(fs.readFile)(filepath);
    } else if (isZip(ext)) {
        var tmpdir = path.join(os.tmpdir(), uuid.v4());

        return Promise.promisify(extract)(filepath, {dir: tmpdir}).then(function () {
            return Promise.promisify(glob)('**/*.json', {cwd: tmpdir}).then(function (files) {
                if (files[0]) {
                    // @TODO: handle multiple JSON files
                    return Promise.promisify(fs.readFile)(path.join(tmpdir, files[0]));
                } else {
                    return Promise.reject(new errors.UnsupportedMediaTypeError(
                        'Zip did not include any content to import.'
                    ));
                }
            });
        });
    }
}

/**
 * ## DB API Methods
 *
 * **See:** [API Methods](index.js.html#api%20methods)
 */
db = {
    /**
     * ### Export Content
     * Generate the JSON to export
     *
     * @public
     * @param {{context}} options
     * @returns {Promise} Ghost Export JSON format
     */
    exportContent: function (options) {
        options = options || {};

        // Export data, otherwise send error 500
        return canThis(options.context).exportContent.db().then(function () {
            return dataExport().then(function (exportedData) {
                return {db: [exportedData]};
            }).catch(function (error) {
                return Promise.reject(new errors.InternalServerError(error.message || error));
            });
        }, function () {
            return Promise.reject(new errors.NoPermissionError('You do not have permission to export data (no rights).'));
        });
    },
    /**
     * ### Import Content
     * Import posts, tags etc from a JSON blob
     *
     * @public
     * @param {{context}} options
     * @returns {Promise} Success
     */
    importContent: function (options) {
        options = options || {};
        var databaseVersion,
            ext,
            filepath;

        // Check if a file was provided
        if (!utils.checkFileExists(options, 'importfile')) {
            return Promise.reject(new errors.NoPermissionError('Please select a file to import.'));
        }

        // Check if the file is valid
        if (!utils.checkFileIsValid(options.importfile, types, extensions)) {
            return Promise.reject(new errors.UnsupportedMediaTypeError(
                'Please select either a .json or .zip file to import.'
            ));
        }

        // TODO refactor this out of here
        filepath = options.importfile.path;
        ext = path.extname(options.importfile.name).toLowerCase();

        // Permissions check
        return canThis(options.context).importContent.db().then(function () {
            return api.settings.read(
                {key: 'databaseVersion', context: {internal: true}}
            ).then(function (response) {
                var setting = response.settings[0];

                return setting.value;
            }).then(function (version) {
                databaseVersion = version;
                // Read the file contents
                return getJSONFileContents(filepath, ext);
            }).then(function (fileContents) {
                var importData;

                // Parse the json data
                try {
                    importData = JSON.parse(fileContents);

                    // if importData follows JSON-API format `{ db: [exportedData] }`
                    if (_.keys(importData).length === 1 && Array.isArray(importData.db)) {
                        importData = importData.db[0];
                    }
                } catch (e) {
                    errors.logError(e, 'API DB import content', 'check that the import file is valid JSON.');
                    return Promise.reject(new errors.BadRequestError('Failed to parse the import JSON file.'));
                }

                if (!importData.meta || !importData.meta.version) {
                    return Promise.reject(
                        new errors.ValidationError('Import data does not specify version', 'meta.version')
                    );
                }

                // Import for the current version
                return dataImport(databaseVersion, importData);
            }).then(api.settings.updateSettingsCache)
            .return({db: []})
            .finally(function () {
                // Unlink the file after import
                return Promise.promisify(fs.unlink)(filepath);
            });
        }, function () {
            return Promise.reject(new errors.NoPermissionError('You do not have permission to import data (no rights).'));
        });
    },
    /**
     * ### Delete All Content
     * Remove all posts and tags
     *
     * @public
     * @param {{context}} options
     * @returns {Promise} Success
     */
    deleteAllContent: function (options) {
        options = options || {};

        return canThis(options.context).deleteAllContent.db().then(function () {
            return Promise.resolve(dataProvider.deleteAllContent())
                .return({db: []})
                .catch(function (error) {
                    return Promise.reject(new errors.InternalServerError(error.message || error));
                });
        }, function () {
            return Promise.reject(new errors.NoPermissionError('You do not have permission to export data (no rights).'));
        });
    }
};

module.exports = db;