/**
 * Functions to interact with 3rd party merchanct aquirers
 */
'use strict';

var Q = require('q');
var errors = require(global.pathPrefix + '../utils/acquirers/acquirer_errors.js');
var credorax = require(global.pathPrefix + '../utils/acquirers/credorax.js');
var utils = require(global.pathPrefix + 'utils.js');
var config = require(global.configFile);
var testAcquirer = require(global.pathPrefix + '../utils/acquirers/test_acquirer.js');
var worldpayAcquirer = require(global.pathPrefix + '../utils/acquirers/worldpay_acquirer.js');
var demoAcquirer = require(global.pathPrefix + '../utils/acquirers/demo_acquirer.js');
var forceAcquirer = null; // Set to 'Test' to force use of Test acquirer

module.exports = {
    invalidateMerchantAccount: invalidateMerchantAccount,
    payTokenised: payTokenised,
    payTransaction: payTransaction,
    tokeniseCard: tokeniseCard,

    validateMerchantAccount: validateMerchantAccount,

    ERRORS: errors
};

/**
 * Define the list of acquirers we have available
 */
const ACQUIRERS = {
    Test: testAcquirer,
    Worldpay: worldpayAcquirer,
    Demo: demoAcquirer
};

/**
 * Generic function to call the appropriate implementation based on the given
 * acquirer name and function name.
 *
 * @param {string} acquirer     - the acquirer that should be used
 * @param {string} functionName - the name of the function to call
 * @param {any[]} params        - array of parameters for the function to be called
 * @returns {Promise}           - the result of the function or rejects with UNKNOWN_ACQUIRER
 */
function callImplIfExists(acquirer, functionName, params) {
    const acquirerName = forceAcquirer || acquirer;
    const acquirerImpl = ACQUIRERS[acquirerName];
    if (!acquirerImpl || !acquirerImpl[functionName]) {
        return Q.reject({name: errors.UNKNOWN_ACQUIRER});
    }

    return acquirerImpl[functionName].apply(null, params);
}

/**
 * Attempts to invalidate the token with the merchant enquirer
 *
 * @param {string} acquirer         - The merchant acquirer's name
 * @param {string} token            - The token to be invalidated
 * @param {string} merchantID       - The merchant ID for the merchant account
 * @param {string} cipher           - The merchant cipher for the merchant account
 * @param {string} accountID        - The accountID for creating a tracking id
 *
 * @returns {promise}   - A promise that resolves on success, or rejects on fail
 */
function invalidateMerchantAccount(acquirer, token, merchantID, cipher, accountID) {
    const acquirerName = forceAcquirer || acquirer;
    const acquirerImpl = ACQUIRERS[acquirerName];
    if (!acquirerImpl || !acquirerImpl.invalidateMerchantAccount) {
        return Q.reject({name: errors.UNKNOWN_ACQUIRER});
    }

    return acquirerImpl.invalidateMerchantAccount(token, merchantID, cipher, accountID);
}

/**
 * Makes a payment from customer to merchant using the specified acquirer. This
 * requires the card to be pre-tokenised by the selected acquirer.
 *
 * @param {Object} transaction      - The transaction being completed
 * @param {Object} customerAccount  - The customer's payment account
 * @param {string} customerIP       - The IP address the customer is connected from
 * @param {Object} merchantAccount  - The merchant's payment account
 *
 * @returns {Promise}   - A promise that resolves on success, or rejects on fail
 */
function payTokenised(
    transaction,
    customerAccount,
    customerIP,
    merchantAccount
) {
    //
    // Check the token exists
    //
    if (!customerAccount.Token) {
        return Q.reject({name: errors.NO_TOKEN});
    }

    //
    // Check the merchant display name is long enough
    //
    if (utils.MinDisplayNameLength > transaction.MerchantDisplayName.length) {
        return Q.reject({name: errors.INVALID_MERCHANT_NAME});
    }

    switch (forceAcquirer || merchantAccount.AcquirerName) {
        case 'Credorax':
            return credorax.payTokenised(
                transaction,
                customerAccount,
                customerIP,
                merchantAccount
            );

        case 'Test':
            // Run the test version.  Note that `testAcquirer` will be undefined
            // unless this is in dev mode.
            return testAcquirer.payTokenised(
                transaction,
                customerAccount,
                customerIP,
                merchantAccount
            );
            // Else fall through to default.

        default:
            return Q.reject({name: errors.UNKNOWN_ACQUIRER});
    }
}

/**
 * Makes a payment from customer to merchant using the appropriate acquirer
 *
 * @param {Object} client       - the client making the payment
 * @param {Object} device       - the device making the payment
 * @param {Object} data         - various neccessary data
 * @param {String} data.ClientKey   - the client key required to decrypt the payment details
 * @param {String} data.ipAddress   - ipAddress of the client
 * @param {Object} [data.cardDetails]   - optional decrypted card details
 * @param {Object} transaction      - The transaction object with the payment info
 * @param {Object} merchantInfo     - Merchant account and address info
 * @param {Object} customerInfo     - Customer account and address info
 *
 * @returns {Promise}               - Resolves to payment info, or rejects ERRORS value
 */
function payTransaction(
    client,
    device,
    data,
    transaction,
    merchantInfo,
    customerInfo
) {
    //
    // Check the merchant display name is long enough
    //
    if (utils.MinDisplayNameLength > transaction.MerchantDisplayName.length) {
        return Q.reject({name: errors.INVALID_MERCHANT_NAME});
    }

    const acquirerName = forceAcquirer || merchantInfo.account.AcquirerName;
    const acquirer = ACQUIRERS[acquirerName];
    if (!acquirer || !acquirer.payTransaction) {
        return Q.reject({name: errors.UNKNOWN_ACQUIRER});
    }

    //
    // Call the specific aquirer to process the transaction
    //
    return acquirer.payTransaction(client, device, data, transaction, merchantInfo, customerInfo);
}

/**
 * Validates that a merchant account is valid with the given acquirer
 *
 * @param {Object} account      - the account to validate
 * @returns {Promise}           - resolves on succes or rejects with ERRORS value
 */
function validateMerchantAccount(account) {
    const acquirerName = forceAcquirer || account.AcquirerName;
    const acquirer = ACQUIRERS[acquirerName];
    if (!acquirer || !acquirer.validateMerchantAccount) {
        return Q.reject({name: errors.UNKNOWN_ACQUIRER});
    }

    //
    // Call the specific aquirer to process the transaction
    //
    return acquirer.validateMerchantAccount(account);
}

/**
 * Tokenises the card and returns some interesting information about it, along
 * with the encrypted token (assuming the appropriate keys are provided).
 *
 * @param {string} acquirer     - the acquirer to use to tokenise
 * @param {Object} cardDetails  - the card details to tokenise
 * @param {string?} clientKey   - the client Key (to encrypt the token)
 * @param {string?} clientID    - the client ID (to encrypt the token)
 * @returns {Promise}           - a promise for the successful tokenisation
 */
function tokeniseCard(acquirer, cardDetails, clientKey, clientID) {
    return callImplIfExists(acquirer, 'tokeniseCard', [cardDetails, clientKey, clientID]);
}