dhis2/d2

import { isString } from '../lib/check'
import Api from '../api/Api'

/**
 * @description
 * Handles communication with the systemSettings endpoint. Can be used to get or save systemSettings.
 *
 * @memberof module:system
 * @requires lib/check
 * @requires api/Api
 */
// TODO: Return the values from the local cache if we have not updated it? We could
class SystemSettings {
    constructor(api = Api.getApi()) {
        this.api = api
    }

    /**
     * Loads all the system settings in the system and returns them as an object from the promise.
     *
     * @returns {Promise} Promise that resolves with the systemsettings object from the api.
     *
     * @example
     * d2.system.settings.all()
     *  .then(systemSettings => {
     *    console.log('Analytics was last updated on: ' + systemSettings.keyLastSuccessfulResourceTablesUpdate);
     *  });
     */
    all() {
        return this.settings
            ? Promise.resolve(this.settings)
            : this.api.get('systemSettings').then((settings) => {
                  this.settings = settings
                  return Promise.resolve(this.settings)
              })
    }

    /**
     * Get a single systemSetting for the given key.
     *
     * This will use the cached value of the key if it has been previously loaded.
     *
     * @param {String} systemSettingsKey The identifier of the system setting that should be retrieved.
     * @returns {Promise} A promise that resolves with the value or will fail if the value is not available.
     *
     * @example
     * d2.system.settings.get('keyLastSuccessfulResourceTablesUpdate')
     *  .then(systemSettingsValue => {
     *    console.log('Analytics was last updated on: ' + systemSettingsValue);
     *  });
     */
    get(systemSettingsKey) {
        if (this.settings && this.settings[systemSettingsKey]) {
            return Promise.resolve(this.settings[systemSettingsKey])
        }

        function processValue(value) {
            // Attempt to parse the response as JSON. If this fails we return the value as is.
            try {
                return JSON.parse(value)
            } catch (e) {
                return value
            }
        }

        return new Promise((resolve, reject) => {
            if (!isString(systemSettingsKey)) {
                throw new TypeError(
                    'A "key" parameter should be specified when calling get() on systemSettings'
                )
            }

            const options = { headers: { accept: 'text/plain' } }
            this.api
                .get(
                    ['systemSettings', systemSettingsKey].join('/'),
                    undefined,
                    options
                )
                .then((response) => {
                    if (response) {
                        resolve(processValue(response))
                    }
                    reject(
                        new Error(
                            'The requested systemSetting has no value or does not exist.'
                        )
                    )
                })
        })
    }

    set(systemSettingsKey, value) {
        const settingUrl = ['systemSettings', systemSettingsKey].join('/')
        if (value === null || `${value}`.length === 0) {
            return this.api.delete(settingUrl).then((response) => {
                // Update cache if present
                if (this.settings && this.settings[systemSettingsKey]) {
                    delete this.settings[systemSettingsKey]
                }
                return response
            })
        }
        return this.api
            .post(settingUrl, value, {
                headers: { 'Content-Type': 'text/plain' },
            })
            .then((response) => {
                // update cache if present
                if (this.settings) {
                    this.settings[systemSettingsKey] = value
                }
                return response
            })
    }
}

export default SystemSettings