/* jslint node: true */
'use strict';

//  ENiGMA½
const moduleUtil            = require('./module_util.js');
const Log                   = require('./logger.js').log;
const Config                = require('./config.js').get;
const asset                 = require('./asset.js');
const { MCIViewFactory }    = require('./mci_view_factory.js');
const { Errors }            = require('./enig_error.js');

//  deps
const paths                 = require('path');
const async                 = require('async');
const _                     = require('lodash');

exports.loadMenu                        = loadMenu;
exports.getFormConfigByIDAndMap         = getFormConfigByIDAndMap;
exports.handleAction                    = handleAction;
exports.handleNext                      = handleNext;

function getMenuConfig(client, name, cb) {
    async.waterfall(
        [
            function locateMenuConfig(callback) {
                if(_.has(client.currentTheme, [ 'menus', name ])) {
                    const menuConfig = client.currentTheme.menus[name];
                    return callback(null, menuConfig);
                }
                return callback(Errors.DoesNotExist(`No menu entry for "${name}"`));
            },
            function locatePromptConfig(menuConfig, callback) {
                if(_.isString(menuConfig.prompt)) {
                    if(_.has(client.currentTheme, [ 'prompts', menuConfig.prompt ])) {
                        menuConfig.promptConfig = client.currentTheme.prompts[menuConfig.prompt];
                        return callback(null, menuConfig);
                    }
                    return callback(Error.DoesNotExist(`No prompt entry for "${menuConfig.prompt}"`));
                }
                return callback(null, menuConfig);
            }
        ],
        (err, menuConfig) => {
            return cb(err, menuConfig);
        }
    );
}

//  :TODO: name/client should not be part of options - they are required always
function loadMenu(options, cb) {
    if(!_.isString(options.name) || !_.isObject(options.client)) {
        return cb(Errors.MissingParam('Missing required options'));
    }

    async.waterfall(
        [
            function getMenuConfiguration(callback) {
                getMenuConfig(options.client, options.name, (err, menuConfig) => {
                    return callback(err, menuConfig);
                });
            },
            function loadMenuModule(menuConfig, callback) {

                menuConfig.options = menuConfig.options || {};
                menuConfig.options.menuFlags = menuConfig.options.menuFlags || [];
                if(!Array.isArray(menuConfig.options.menuFlags)) {
                    menuConfig.options.menuFlags = [ menuConfig.options.menuFlags ];
                }

                const modAsset      = asset.getModuleAsset(menuConfig.module);
                const modSupplied   = null !== modAsset;

                const modLoadOpts = {
                    name        : modSupplied ? modAsset.asset : 'standard_menu',
                    path        : (!modSupplied || 'systemModule' === modAsset.type) ? __dirname : Config().paths.mods,
                    category    : (!modSupplied || 'systemModule' === modAsset.type) ? null : 'mods',
                };

                moduleUtil.loadModuleEx(modLoadOpts, (err, mod) => {
                    const modData = {
                        name    : modLoadOpts.name,
                        config  : menuConfig,
                        mod     : mod,
                    };

                    return callback(err, modData);
                });
            },
            function createModuleInstance(modData, callback) {
                Log.trace(
                    { moduleName : modData.name, extraArgs : options.extraArgs, config : modData.config, info : modData.mod.modInfo },
                    'Creating menu module instance');

                let moduleInstance;
                try {
                    moduleInstance = new modData.mod.getModule({
                        menuName        : options.name,
                        menuConfig      : modData.config,
                        extraArgs       : options.extraArgs,
                        client          : options.client,
                        lastMenuResult  : options.lastMenuResult,
                    });
                } catch(e) {
                    return callback(e);
                }

                return callback(null, moduleInstance);
            }
        ],
        (err, modInst) => {
            return cb(err, modInst);
        }
    );
}

function getFormConfigByIDAndMap(menuConfig, formId, mciMap, cb) {
    if(!_.isObject(menuConfig.form)) {
        return cb(Errors.MissingParam('Invalid or missing "form" member for menu'));
    }

    if(!_.isObject(menuConfig.form[formId])) {
        return cb(Errors.DoesNotExist(`No form found for formId ${formId}`));
    }

    const formForId = menuConfig.form[formId];
    const mciReqKey = _.filter(_.map(_.sortBy(mciMap, 'code'), 'code'), (mci) => {
        return MCIViewFactory.UserViewCodes.indexOf(mci) > -1;
    }).join('');

    Log.trace( { mciKey : mciReqKey }, 'Looking for MCI configuration key');

    //
    //  Exact, explicit match?
    //
    if(_.isObject(formForId[mciReqKey])) {
        Log.trace( { mciKey : mciReqKey }, 'Using exact configuration key match');
        return cb(null, formForId[mciReqKey]);
    }

    //
    //  Generic match
    //
    if(_.has(formForId, 'mci') || _.has(formForId, 'submit')) {
        Log.trace('Using generic configuration');
        return cb(null, formForId);
    }

    return cb(Errors.DoesNotExist(`No matching form configuration found for key "${mciReqKey}"`));
}

//  :TODO: Most of this should be moved elsewhere .... DRY...
function callModuleMenuMethod(client, asset, path, formData, extraArgs, cb) {
    if('' === paths.extname(path)) {
        path += '.js';
    }

    try {
        client.log.trace(
            { path : path, methodName : asset.asset, formData : formData, extraArgs : extraArgs },
            'Calling menu method');

        const methodMod = require(path);
        return methodMod[asset.asset](client.currentMenuModule, formData || { }, extraArgs, cb);
    } catch(e) {
        client.log.error( { error : e.toString(), methodName : asset.asset }, 'Failed to execute asset method');
        return cb(e);
    }
}

function handleAction(client, formData, conf, cb) {
    if(!_.isObject(conf)) {
        return cb(Errors.MissingParam('Missing config'));
    }

    const actionAsset = asset.parseAsset(conf.action);
    if(!_.isObject(actionAsset)) {
        return cb(Errors.Invalid('Unable to parse "conf.action"'));
    }

    switch(actionAsset.type) {
        case 'method' :
        case 'systemMethod' :
            if(_.isString(actionAsset.location)) {
                return callModuleMenuMethod(
                    client,
                    actionAsset,
                    paths.join(Config().paths.mods, actionAsset.location),
                    formData,
                    conf.extraArgs,
                    cb);
            } else if('systemMethod' === actionAsset.type) {
                //  :TODO: Need to pass optional args here -- conf.extraArgs and args between e.g. ()
                //  :TODO: Probably better as system_method.js
                return callModuleMenuMethod(
                    client,
                    actionAsset,
                    paths.join(__dirname, 'system_menu_method.js'),
                    formData,
                    conf.extraArgs,
                    cb);
            } else {
                //  local to current module
                const currentModule = client.currentMenuModule;
                if(_.isFunction(currentModule.menuMethods[actionAsset.asset])) {
                    return currentModule.menuMethods[actionAsset.asset](formData, conf.extraArgs, cb);
                }

                const err = Errors.DoesNotExist('Method does not exist');
                client.log.warn( { method : actionAsset.asset }, err.message);
                return cb(err);
            }

        case 'menu' :
            return client.currentMenuModule.gotoMenu(actionAsset.asset, { formData : formData, extraArgs : conf.extraArgs }, cb );
    }
}

function handleNext(client, nextSpec, conf, cb) {
    nextSpec = client.acs.getConditionalValue(nextSpec, 'next');    //  handle any conditionals

    const nextAsset = asset.getAssetWithShorthand(nextSpec, 'menu');
    //  :TODO: getAssetWithShorthand() can return undefined - handle it!

    conf = conf || {};
    const extraArgs = conf.extraArgs || {};

    //  :TODO: DRY this with handleAction()
    switch(nextAsset.type) {
        case 'method' :
        case 'systemMethod' :
            if(_.isString(nextAsset.location)) {
                return callModuleMenuMethod(client, nextAsset, paths.join(Config().paths.mods, nextAsset.location), {}, extraArgs, cb);
            } else if('systemMethod' === nextAsset.type) {
                //  :TODO: see other notes about system_menu_method.js here
                return callModuleMenuMethod(client, nextAsset, paths.join(__dirname, 'system_menu_method.js'), {}, extraArgs, cb);
            } else {
                //  local to current module
                const currentModule = client.currentMenuModule;
                if(_.isFunction(currentModule.menuMethods[nextAsset.asset])) {
                    const formData = {};    //   we don't have any
                    return currentModule.menuMethods[nextAsset.asset]( formData, extraArgs, cb );
                }

                const err = Errors.DoesNotExist('Method does not exist');
                client.log.warn( { method : nextAsset.asset }, err.message);
                return cb(err);
            }

        case 'menu' :
            return client.currentMenuModule.gotoMenu(nextAsset.asset, { extraArgs : extraArgs }, cb );
    }

    const err = Errors.Invalid('Invalid asset type for "next"');
    client.log.error( { nextSpec : nextSpec }, err.message);
    return cb(err);
}