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

const PluginModule              = require('./plugin_module.js').PluginModule;
const theme                     = require('./theme.js');
const ansi                      = require('./ansi_term.js');
const ViewController            = require('./view_controller.js').ViewController;
const menuUtil                  = require('./menu_util.js');
const Config                    = require('./config.js').get;
const stringFormat              = require('../core/string_format.js');
const MultiLineEditTextView     = require('../core/multi_line_edit_text_view.js').MultiLineEditTextView;
const Errors                    = require('../core/enig_error.js').Errors;
const { getPredefinedMCIValue } = require('../core/predefined_mci.js');

//  deps
const async                 = require('async');
const assert                = require('assert');
const _                     = require('lodash');
const iconvDecode           = require('iconv-lite').decode;

exports.MenuModule = class MenuModule extends PluginModule {

    constructor(options) {
        super(options);

        this.menuName           = options.menuName;
        this.menuConfig         = options.menuConfig;
        this.client             = options.client;
        this.menuMethods        = {};   //  methods called from @method's
        this.menuConfig.config  = this.menuConfig.config || {};
        this.cls                = _.get(this.menuConfig.config, 'cls', Config().menus.cls);
        this.viewControllers    = {};
        this.interrupt          = (_.get(this.menuConfig.config, 'interrupt', MenuModule.InterruptTypes.Queued)).toLowerCase();

        if(MenuModule.InterruptTypes.Realtime === this.interrupt) {
            this.realTimeInterrupt  = 'blocked';
        }
    }

    static get InterruptTypes() {
        return {
            Never       : 'never',
            Queued      : 'queued',
            Realtime    : 'realtime',
        };
    }

    enter() {
        this.initSequence();
    }

    leave() {
        this.detachViewControllers();
    }

    initSequence() {
        const self      = this;
        const mciData   = {};
        let pausePosition = {row: 0, column: 0};

        const hasArt = () => {
            return _.isString(self.menuConfig.art) ||
                (Array.isArray(self.menuConfig.art) && _.has(self.menuConfig.art[0], 'acs'));
        };

        async.waterfall(
            [
                function beforeArtInterrupt(callback) {
                    return self.displayQueuedInterruptions(callback);
                },
                function beforeDisplayArt(callback) {
                    return self.beforeArt(callback);
                },
                function displayMenuArt(callback) {
                    if(!hasArt()) {
                        return callback(null, null);
                    }

                    self.displayAsset(
                        self.menuConfig.art,
                        self.menuConfig.config,
                        (err, artData) => {
                            if(err) {
                                self.client.log.trace('Could not display art', { art : self.menuConfig.art, reason : err.message } );
                            } else {
                                mciData.menu = artData.mciMap;
                            }

                            if(artData) {
                                pausePosition.row = artData.height + 1;
                            }

                            return callback(null, artData);  //  any errors are non-fatal
                        }
                    );
                },
                function displayPromptArt(artData, callback) {
                    if(!_.isString(self.menuConfig.prompt)) {
                        return callback(null);
                    }

                    if(!_.isObject(self.menuConfig.promptConfig)) {
                        return callback(Errors.MissingConfig('Prompt specified but no "promptConfig" block found'));
                    }

                    const options = Object.assign({}, self.menuConfig.config);

                    if(_.isNumber(artData?.height)) {
                        options.startRow = artData.height + 1;
                    }

                    self.displayAsset(
                        self.menuConfig.promptConfig.art,
                        options,
                        (err, artData) => {
                            if(artData) {
                                mciData.prompt = artData.mciMap;
                                pausePosition.row = artData.height + 1;
                            }

                            return callback(err);   //  pass err here; prompts *must* have art
                        }
                    );
                },
                function afterArtDisplayed(callback) {
                    return self.mciReady(mciData, callback);
                },
                function displayPauseIfRequested(callback) {
                    if(!self.shouldPause()) {
                        return callback(null, null);
                    }

                    if(self.client.term.termHeight > 0 && pausePosition.row > self.client.termHeight) {
                        // If this scrolled, the prompt will go to the bottom of the screen
                        pausePosition.row = self.client.termHeight;
                    }

                    return self.pausePrompt(pausePosition, callback);
                },
                function finishAndNext(artInfo, callback) {
                    self.finishedLoading();
                    self.realTimeInterrupt = 'allowed';
                    return self.autoNextMenu(callback);
                }
            ],
            err => {
                if(err) {
                    self.client.log.warn('Error during init sequence', { error : err.message } );

                    return self.prevMenu( () => { /* dummy */ } );
                }
            }
        );
    }

    beforeArt(cb) {
        if(_.isNumber(this.menuConfig.config.baudRate)) {
            //  :TODO: some terminals not supporting cterm style emulated baud rate end up displaying a broken ESC sequence or a single "r" here
            this.client.term.rawWrite(ansi.setEmulatedBaudRate(this.menuConfig.config.baudRate));
        }

        if(this.cls) {
            this.client.term.rawWrite(ansi.resetScreen());
        }

        return cb(null);
    }

    mciReady(mciData, cb) {
        //  available for sub-classes
        return cb(null);
    }

    finishedLoading() {
        //  nothing in base
    }

    displayQueuedInterruptions(cb) {
        if(MenuModule.InterruptTypes.Never === this.interrupt) {
            return cb(null);
        }

        let opts = { cls : true };  //  clear screen for first message

        async.whilst(
            (callback) => callback(null, this.client.interruptQueue.hasItems()),
            next => {
                this.client.interruptQueue.displayNext(opts, err => {
                    opts = {};
                    return next(err);
                });
            },
            err => {
                return cb(err);
            }
        );
    }

    attemptInterruptNow(interruptItem, cb) {
        if(this.realTimeInterrupt !== 'allowed' || MenuModule.InterruptTypes.Realtime !== this.interrupt) {
            return cb(null, false); //  don't eat up the item; queue for later
        }

        this.realTimeInterrupt = 'blocked';

        //
        //  Default impl: clear screen -> standard display -> reload menu
        //
        const done = (err, removeFromQueue) => {
            this.realTimeInterrupt = 'allowed';
            return cb(err, removeFromQueue);
        };

        this.client.interruptQueue.displayWithItem(
            Object.assign({}, interruptItem, { cls : true }),
            err => {
                if(err) {
                    return done(err, false);
                }
                this.reload(err => {
                    return done(err, err ? false : true);
                });
            });
    }

    getSaveState() {
        //  nothing in base
    }

    restoreSavedState(/*savedState*/) {
        //  nothing in base
    }

    getMenuResult() {
        //  default to the formData that was provided @ a submit, if any
        return this.submitFormData;
    }

    nextMenu(cb) {
        if(!this.haveNext()) {
            return this.prevMenu(cb);   //  no next, go to prev
        }

        this.displayQueuedInterruptions( () => {
            return this.client.menuStack.next(cb);
        });
    }

    prevMenu(cb) {
        this.displayQueuedInterruptions( () => {
            return this.client.menuStack.prev(cb);
        });
    }

    gotoMenu(name, options, cb) {
        return this.client.menuStack.goto(name, options, cb);
    }

    gotoMenuOrPrev(name, options, cb) {
        this.client.menuStack.goto(name, options, err => {
            if(!err) {
                if(cb) {
                    return cb(null);
                }
            }

            return this.prevMenu(cb);
        });
    }

    gotoMenuOrShowMessage(name, message, options, cb) {
        if(!cb && _.isFunction(options)) {
            cb = options;
            options = {};
        }

        options = options || { clearScreen: true };

        this.gotoMenu(name, options, err => {
            if(err) {
                if(options.clearScreen) {
                    this.client.term.rawWrite(ansi.resetScreen());
                }

                this.client.term.write(`${message}\n`);
                return this.pausePrompt( () => {
                    return this.prevMenu(cb);
                });
            }

            if(cb) {
                return cb(null);
            }
        });
    }

    reload(cb) {
        const prevMenu = this.client.menuStack.pop();
        prevMenu.instance.leave();
        return this.client.menuStack.goto(prevMenu.name, cb);
    }

    prevMenuOnTimeout(timeout, cb) {
        setTimeout( () => {
            return this.prevMenu(cb);
        }, timeout);
    }

    addViewController(name, vc) {
        assert(!this.viewControllers[name], `ViewController by the name of "${name}" already exists!`);

        this.viewControllers[name] = vc;
        return vc;
    }

    removeViewController(name) {
        if(this.viewControllers[name]) {
            this.viewControllers[name].detachClientEvents();
            delete this.viewControllers[name];
        }
    }

    detachViewControllers() {
        Object.keys(this.viewControllers).forEach( name => {
            this.viewControllers[name].detachClientEvents();
        });
    }

    shouldPause() {
        return ('end' === this.menuConfig.config.pause || true === this.menuConfig.config.pause);
    }

    hasNextTimeout() {
        return _.isNumber(this.menuConfig.config.nextTimeout);
    }

    haveNext() {
        return (_.isString(this.menuConfig.next) || _.isArray(this.menuConfig.next));
    }

    autoNextMenu(cb) {
        const gotoNextMenu = () => {
            if(this.haveNext()) {
                this.displayQueuedInterruptions( () => {
                    return menuUtil.handleNext(this.client, this.menuConfig.next, {}, cb);
                });
            } else {
                return this.prevMenu(cb);
            }
        };

        if(_.has(this.menuConfig, 'runtime.autoNext') && true === this.menuConfig.runtime.autoNext) {
            if(this.hasNextTimeout()) {
                setTimeout( () => {
                    return gotoNextMenu();
                }, this.menuConfig.config.nextTimeout);
            } else {
                return gotoNextMenu();
            }
        }
    }

    standardMCIReadyHandler(mciData, cb) {
        //
        //  A quick rundown:
        //  *   We may have mciData.menu, mciData.prompt, or both.
        //  *   Prompt form is favored over menu form if both are present.
        //  *   Standard/predefined MCI entries must load both (e.g. %BN is expected to resolve)
        //
        const self = this;

        async.series(
            [
                function addViewControllers(callback) {
                    _.forEach(mciData, (mciMap, name) => {
                        assert('menu' === name || 'prompt' === name);
                        self.addViewController(name, new ViewController( { client : self.client } ) );
                    });

                    return callback(null);
                },
                function createMenu(callback) {
                    if(!self.viewControllers.menu) {
                        return callback(null);
                    }

                    const menuLoadOpts = {
                        mciMap      : mciData.menu,
                        callingMenu : self,
                        withoutForm : _.isObject(mciData.prompt),
                    };

                    self.viewControllers.menu.loadFromMenuConfig(menuLoadOpts, err => {
                        return callback(err);
                    });
                },
                function createPrompt(callback) {
                    if(!self.viewControllers.prompt) {
                        return callback(null);
                    }

                    const promptLoadOpts = {
                        callingMenu     : self,
                        mciMap          : mciData.prompt,
                    };

                    self.viewControllers.prompt.loadFromPromptConfig(promptLoadOpts, err => {
                        return callback(err);
                    });
                }
            ],
            err => {
                return cb(err);
            }
        );
    }

    displayAsset(nameOrData, options, cb) {
        if(_.isFunction(options)) {
            cb = options;
            options = {};
        }

        if(options.clearScreen) {
            this.client.term.rawWrite(ansi.resetScreen());
        }

        options = Object.assign( { client : this.client, font : this.menuConfig.config.font }, options );

        if(Buffer.isBuffer(nameOrData)) {
            const data = iconvDecode(nameOrData, options.encoding || 'cp437');
            return theme.displayPreparedArt(
                options,
                { data },
                (err, artData) => {
                    if(cb) {
                        return cb(err, artData);
                    }
                }
            );
        }

        return theme.displayThemedAsset(
            nameOrData,
            this.client,
            options,
            (err, artData) => {
                if(cb) {
                    return cb(err, artData);
                }
            }
        );
    }

    prepViewController(name, formId, mciMap, cb) {
        const needsCreated = _.isUndefined(this.viewControllers[name]);
        if(needsCreated) {
            const vcOpts = {
                client      : this.client,
                formId      : formId,
            };

            const vc = this.addViewController(name, new ViewController(vcOpts));

            const loadOpts = {
                callingMenu     : this,
                mciMap          : mciMap,
                formId          : formId,
            };

            return vc.loadFromMenuConfig(loadOpts, err => {
                return cb(err, vc, true);
            });
        }

        this.viewControllers[name].setFocus(true);

        return cb(null, this.viewControllers[name], false);
    }

    prepViewControllerWithArt(name, formId, options, cb) {
        this.displayAsset(
            this.menuConfig.config.art[name],
            options,
            (err, artData) => {
                if(err) {
                    return cb(err);
                }

                return this.prepViewController(name, formId, artData.mciMap, cb);
            }
        );
    }

    optionalMoveToPosition(position) {
        if(position) {
            position.x = position.row || position.x || 1;
            position.y = position.col || position.y || 1;

            this.client.term.rawWrite(ansi.goto(position.x, position.y));
        }
    }

    pausePrompt(position, cb) {
        if(!cb && _.isFunction(position)) {
            cb = position;
            position = null;
        }

        this.optionalMoveToPosition(position);

        return theme.displayThemedPause(this.client, {position}, cb);
    }

    promptForInput( { formName, formId, promptName, prevFormName, position } = {}, options, cb) {
        if(!cb && _.isFunction(options)) {
            cb = options;
            options = {};
        }

        options.viewController = this.addViewController(
            formName,
            new ViewController( { client : this.client, formId } )
        );

        options.trailingLF = _.get(options, 'trailingLF', false);

        let prevVc;
        if(prevFormName) {
            prevVc = this.viewControllers[prevFormName];
            if(prevVc) {
                prevVc.setFocus(false);
            }
        }

        //let artHeight;
        options.submitNotify = () => {
            if(prevVc) {
                prevVc.setFocus(true);
            }
            this.removeViewController(formName);
            if(options.clearAtSubmit) {
                this.optionalMoveToPosition(position);
                if(options.clearWidth) {
                    this.client.term.rawWrite(`${ansi.reset()}${' '.repeat(options.clearWidth)}`);
                } else {
                    //  :TODO: handle multi-rows via artHeight
                    this.client.term.rawWrite(ansi.eraseLine());
                }
            }
        };

        options.viewController.setFocus(true);

        this.optionalMoveToPosition(position);
        theme.displayThemedPrompt(promptName, this.client, options, (err, artInfo) => {
            /*
            if(artInfo) {
                artHeight = artInfo.height;
            }
            */
            return cb(err, artInfo);
        });
    }

    setViewText(formName, mciId, text, appendMultiLine) {
        const view = this.getView(formName, mciId);
        if(!view) {
            return;
        }

        if(appendMultiLine && (view instanceof MultiLineEditTextView)) {
            view.addText(text);
        } else {
            view.setText(text);
        }
    }

    getView(formName, id) {
        const form = this.viewControllers[formName];
        return form && form.getView(id);
    }

    updateCustomViewTextsWithFilter(formName, startId, fmtObj, options) {
        options = options || {};

        let textView;
        let customMciId = startId;
        const config    = this.menuConfig.config;
        const endId     = options.endId || 99;  //  we'll fail to get a view before 99

        while(customMciId <= endId && (textView = this.viewControllers[formName].getView(customMciId)) ) {
            const key       = `${formName}InfoFormat${customMciId}`;    //  e.g. "mainInfoFormat10"
            const format    = config[key];

            if(format && (!options.filter || options.filter.find(f => format.indexOf(f) > - 1))) {
                const text = stringFormat(format, fmtObj);

                if(options.appendMultiLine && (textView instanceof MultiLineEditTextView)) {
                    textView.addText(text);
                } else if (textView.getData() != text) {
                    textView.setText(text);
                }
            }

            ++customMciId;
        }
    }

    refreshPredefinedMciViewsByCode(formName, mciCodes) {
        const form = _.get(this, [ 'viewControllers', formName] );
        if(form) {
            form.getViewsByMciCode(mciCodes).forEach(v => {
                if(!v.setText) {
                    return;
                }

                v.setText(getPredefinedMCIValue(this.client, v.mciCode));
            });
        }
    }

    validateMCIByViewIds(formName, viewIds, cb) {
        if(!Array.isArray(viewIds)) {
            viewIds = [ viewIds ];
        }
        const form = _.get(this, [ 'viewControllers', formName ] );
        if(!form) {
            return cb(Errors.DoesNotExist(`Form does not exist: ${formName}`));
        }
        for(let i = 0; i < viewIds.length; ++i) {
            if(!form.hasView(viewIds[i])) {
                return cb(Errors.MissingMci(`Missing MCI ${viewIds[i]}`));
            }
        }
        return cb(null);
    }

    validateConfigFields(fields, cb) {
        //
        //  fields is expected to be { key : type || validator(key, config) }
        //  where |type| is 'string', 'array', object', 'number'
        //
        if(!_.isObject(fields)) {
            return cb(Errors.Invalid('Invalid validator!'));
        }

        const config = this.config || this.menuConfig.config;
        let firstBadKey;
        let badReason;
        const good = _.every(fields, (type, key) => {
            if(_.isFunction(type)) {
                if(!type(key, config)) {
                    firstBadKey = key;
                    badReason   = 'Validate failure';
                    return false;
                }
                return true;
            }

            const c = config[key];
            let typeOk;
            if(_.isUndefined(c)) {
                typeOk = false;
                badReason = `Missing "${key}", expected ${type}`;
            } else {
                switch(type) {
                    case 'string'   : typeOk = _.isString(c); break;
                    case 'object'   : typeOk = _.isObject(c); break;
                    case 'array'    : typeOk = Array.isArray(c); break;
                    case 'number'   : typeOk = !isNaN(parseInt(c)); break;
                    default :
                        typeOk = false;
                        badReason = `Don't know how to validate ${type}`;
                        break;
                }
            }
            if(!typeOk) {
                firstBadKey = key;
                if(!badReason) {
                    badReason = `Expected ${type}`;
                }
            }
            return typeOk;
        });

        return cb(good ? null : Errors.Invalid(`Invalid or missing config option "${firstBadKey}" (${badReason})`));
    }

    //  Various common helpers
    getDateFormat(defaultStyle='short') {
        return this.config.dateFormat ||
            this.client.currentTheme.helpers.getDateFormat(defaultStyle);
    }

    getTimeFormat(defaultStyle='short') {
        return this.config.timeFormat ||
            this.client.currentTheme.helpers.getTimeFormat(defaultStyle);
    }

    getDateTimeFormat(defaultStyle='short') {
        return this.config.dateTimeFormat ||
            this.client.currentTheme.helpers.getDateTimeFormat(defaultStyle);
    }
};