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

//  ENiGMA½
const MenuModule                    = require('./menu_module.js').MenuModule;
const ViewController                = require('./view_controller.js').ViewController;
const messageArea                   = require('./message_area.js');
const MessageAreaConfTempSwitcher   = require('./mod_mixins.js').MessageAreaConfTempSwitcher;
const Errors                        = require('./enig_error.js').Errors;
const Message                       = require('./message.js');

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

/*
    Available listFormat/focusListFormat members for |msgList|

    msgNum          : Message number
    to              : To username/handle
    from            : From username/handle
    subj            : Subject
    ts              : Message mod timestamp (format with config.dateTimeFormat)
    newIndicator    : New mark/indicator (config.newIndicator)
*/
exports.moduleInfo = {
    name    : 'Message List',
    desc    : 'Module for listing/browsing available messages',
    author  : 'NuSkooler',
};

const FormIds = {
    allViews    : 0,
    delPrompt   : 1,
};

const MciViewIds = {
    allViews : {
        msgList             : 1,    //  VM1 - see above
        delPromptXy         : 2,    //  %XY2, e.g: delete confirmation
        customRangeStart    : 10,   //  Everything |msgList| has plus { msgNumSelected, msgNumTotal }
    },

    delPrompt: {
        prompt  : 1,
    }
};

exports.getModule = class MessageListModule extends MessageAreaConfTempSwitcher(MenuModule) {
    constructor(options) {
        super(options);

        //  :TODO: consider this pattern in base MenuModule - clean up code all over
        this.config = Object.assign({}, _.get(options, 'menuConfig.config'), options.extraArgs);

        this.lastMessageReachedExit = _.get(options, 'lastMenuResult.lastMessageReached', false);

        this.menuMethods = {
            selectMessage : (formData, extraArgs, cb) => {
                if(MciViewIds.allViews.msgList === formData.submitId) {
                    this.initialFocusIndex = formData.value.message;

                    const modOpts = {
                        extraArgs   : {
                            messageAreaTag      : this.getSelectedAreaTag(formData.value.message),
                            messageList         : this.config.messageList,
                            messageIndex        : formData.value.message,
                            lastMessageNextExit : true,
                        }
                    };

                    if(_.isBoolean(this.config.noUpdateLastReadId)) {
                        modOpts.extraArgs.noUpdateLastReadId = this.config.noUpdateLastReadId;
                    }

                    //
                    //  Provide a serializer so we don't dump *huge* bits of information to the log
                    //  due to the size of |messageList|. See https://github.com/trentm/node-bunyan/issues/189
                    //
                    const self = this;
                    modOpts.extraArgs.toJSON = function() {
                        const logMsgList = (self.config.messageList.length <= 4) ?
                            self.config.messageList :
                            self.config.messageList.slice(0, 2).concat(self.config.messageList.slice(-2));

                        return {
                            //  note |this| is scope of toJSON()!
                            messageAreaTag      : this.messageAreaTag,
                            apprevMessageList   : logMsgList,
                            messageCount        : this.messageList.length,
                            messageIndex        : this.messageIndex,
                        };
                    };

                    return this.gotoMenu(this.config.menuViewPost || 'messageAreaViewPost', modOpts, cb);
                } else {
                    return cb(null);
                }
            },
            fullExit : (formData, extraArgs, cb) => {
                this.menuResult = { fullExit : true };
                return this.prevMenu(cb);
            },
            deleteSelected : (formData, extraArgs, cb) => {
                if(MciViewIds.allViews.msgList != formData.submitId) {
                    return cb(null);
                }
                const messageIndex = _.get(formData, 'value.message');
                return this.promptDeleteMessageConfirm(messageIndex, cb);
            },
            deleteMessageYes : (formData, extraArgs, cb) => {
                const msgListView = this.viewControllers.allViews.getView(MciViewIds.allViews.msgList);
                this.enableMessageListIndexUpdates(msgListView);
                if(this.selectedMessageForDelete) {
                    this.selectedMessageForDelete.deleteMessage(this.client.user, err => {
                        if(err) {
                            this.client.log.error(`Failed to delete message: ${this.selectedMessageForDelete.messageUuid}`);
                        } else {
                            this.client.log.info(`User deleted message: ${this.selectedMessageForDelete.messageUuid}`);
                            this.config.messageList.splice(msgListView.focusedItemIndex, 1);
                            this.updateMessageNumbersAfterDelete(msgListView.focusedItemIndex);
                            msgListView.setItems(this.config.messageList);
                        }
                        this.selectedMessageForDelete = null;
                        msgListView.redraw();
                        return cb(null);
                    });
                } else {
                    return cb(null);
                }
            },
            deleteMessageNo : (formData, extraArgs, cb) => {
                const msgListView = this.viewControllers.allViews.getView(MciViewIds.allViews.msgList);
                this.enableMessageListIndexUpdates(msgListView);
                return cb(null);
            },
            markAllRead : (formData, extraArgs, cb) => {
                if(this.config.noUpdateLastReadId) {
                    return cb(null);
                }

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

    getSelectedAreaTag(listIndex) {
        return this.config.messageList[listIndex].areaTag || this.config.messageAreaTag;
    }

    enter() {
        if(this.lastMessageReachedExit) {
            return this.prevMenu();
        }

        super.enter();

        //
        //  Config can specify |messageAreaTag| else it comes from
        //  the user's current area. If |messageList| is supplied,
        //  each item is expected to contain |areaTag|, so we use that
        //  instead in those cases.
        //
        if(!Array.isArray(this.config.messageList)) {
            if(this.config.messageAreaTag) {
                this.tempMessageConfAndAreaSwitch(this.config.messageAreaTag);
            } else {
                this.config.messageAreaTag = this.client.user.properties.message_area_tag;
            }
        }
    }

    leave() {
        this.tempMessageConfAndAreaRestore();
        super.leave();
    }

    populateCustomLabelsForSelected(selectedIndex) {
        const formatObj = Object.assign(
            {
                msgNumSelected  : (selectedIndex + 1),
                msgNumTotal     : this.config.messageList.length,
            },
            this.config.messageList[selectedIndex] //  plus, all the selected message props
        );
        return this.updateCustomViewTextsWithFilter('allViews', MciViewIds.allViews.customRangeStart, formatObj);
    }

    mciReady(mciData, cb) {
        super.mciReady(mciData, err => {
            if(err) {
                return cb(err);
            }

            const self  = this;
            const vc    = self.viewControllers.allViews = new ViewController( { client : self.client } );
            let configProvidedMessageList = false;

            async.series(
                [
                    function loadFromConfig(callback) {
                        const loadOpts = {
                            callingMenu     : self,
                            mciMap          : mciData.menu
                        };

                        return vc.loadFromMenuConfig(loadOpts, callback);
                    },
                    function fetchMessagesInArea(callback) {
                        //
                        //  Config can supply messages else we'll need to populate the list now
                        //
                        if(_.isArray(self.config.messageList)) {
                            configProvidedMessageList = true;
                            return callback(0 === self.config.messageList.length ? new Error('No messages in area') : null);
                        }

                        messageArea.getMessageListForArea(self.client, self.config.messageAreaTag, function msgs(err, msgList) {
                            if(!msgList || 0 === msgList.length) {
                                return callback(new Error('No messages in area'));
                            }

                            self.config.messageList = msgList;
                            return callback(err);
                        });
                    },
                    function getLastReadMesageId(callback) {
                        //  messageList entries can contain |isNew| if they want to be considered new
                        if(configProvidedMessageList) {
                            self.lastReadId = 0;
                            return callback(null);
                        }

                        messageArea.getMessageAreaLastReadId(self.client.user.userId, self.config.messageAreaTag, function lastRead(err, lastReadId) {
                            self.lastReadId = lastReadId || 0;
                            return callback(null);  //  ignore any errors, e.g. missing value
                        });
                    },
                    function updateMessageListObjects(callback) {
                        const dateTimeFormat    = self.menuConfig.config.dateTimeFormat || self.client.currentTheme.helpers.getDateTimeFormat();
                        const newIndicator      = self.menuConfig.config.newIndicator || '*';
                        const regIndicator      = ' '.repeat(newIndicator.length); //  fill with space to avoid draw issues

                        let msgNum = 1;
                        self.config.messageList.forEach( (listItem, index) => {
                            listItem.msgNum         = msgNum++;
                            listItem.ts             = moment(listItem.modTimestamp).format(dateTimeFormat);
                            const isNew             = _.isBoolean(listItem.isNew) ? listItem.isNew : listItem.messageId > self.lastReadId;
                            listItem.newIndicator   =  isNew ? newIndicator : regIndicator;

                            if(_.isUndefined(self.initialFocusIndex) && listItem.messageId > self.lastReadId) {
                                self.initialFocusIndex = index;
                            }

                            listItem.text           = `${listItem.msgNum} - ${listItem.subject} from ${listItem.fromUserName}`; //  default text
                        });
                        return callback(null);
                    },
                    function populateAndDrawViews(callback) {
                        const msgListView = vc.getView(MciViewIds.allViews.msgList);
                        msgListView.setItems(self.config.messageList);
                        self.enableMessageListIndexUpdates(msgListView);

                        if(self.initialFocusIndex > 0) {
                            //  note: causes redraw()
                            msgListView.setFocusItemIndex(self.initialFocusIndex);
                        } else {
                            msgListView.redraw();
                        }

                        self.populateCustomLabelsForSelected(self.initialFocusIndex || 0);
                        return callback(null);
                    },
                ],
                err => {
                    if(err) {
                        self.client.log.error( { error : err.message }, 'Error loading message list');
                    }
                    return cb(err);
                }
            );
        });
    }

    getSaveState() {
        return { initialFocusIndex : this.initialFocusIndex };
    }

    restoreSavedState(savedState) {
        if(savedState) {
            this.initialFocusIndex = savedState.initialFocusIndex;
        }
    }

    getMenuResult() {
        return this.menuResult;
    }

    enableMessageListIndexUpdates(msgListView) {
        msgListView.on('index update', idx => this.populateCustomLabelsForSelected(idx) );
    }

    markAllMessagesAsRead(cb) {
        if(!this.config.messageList || this.config.messageList.length === 0) {
            return cb(null);    //  nothing to do.
        }

        //
        //  Generally we'll have a message list for a specific area,
        //  but this is not always the case. For a given area, we need
        //  to find the highest message ID in the list to set a
        //  last read pointer.
        //
        const areaHighestIds = {};
        this.config.messageList.forEach(msg => {
            const highestId = areaHighestIds[msg.areaTag];
            if(highestId) {
                if(msg.messageId > highestId) {
                    areaHighestIds[msg.areaTag] = msg.messageId;
                }
            } else {
                areaHighestIds[msg.areaTag] = msg.messageId;
            }
        });

        const regIndicator = ' '.repeat( (this.menuConfig.config.newIndicator || '*').length );
        async.forEachOf(areaHighestIds, (highestId, areaTag, nextArea) => {
            messageArea.updateMessageAreaLastReadId(
                this.client.user.userId,
                areaTag,
                highestId,
                err => {
                    if(err) {
                        this.client.log.warn( { error : err.message }, 'Failed marking area as read');
                    } else {
                        //  update newIndicator on messages
                        this.config.messageList.forEach(msg => {
                            if(areaTag === msg.areaTag) {
                                msg.newIndicator = regIndicator;
                            }
                        });
                        const msgListView = this.viewControllers.allViews.getView(MciViewIds.allViews.msgList);
                        msgListView.setItems(this.config.messageList);
                        msgListView.redraw();
                        this.client.log.info( { highestId, areaTag }, 'User marked area as read');
                    }
                    return nextArea(null);  //  always continue
                }
            );
        }, () => {
            return cb(null);
        });
    }

    updateMessageNumbersAfterDelete(startIndex) {
        //  all index -= 1 from this point on.
        for(let i = startIndex; i < this.config.messageList.length; ++i) {
            const msgItem = this.config.messageList[i];
            msgItem.msgNum -= 1;
            msgItem.text = `${msgItem.msgNum} - ${msgItem.subject} from ${msgItem.fromUserName}`; //  default text
        }
    }

    promptDeleteMessageConfirm(messageIndex, cb) {
        const messageInfo = this.config.messageList[messageIndex];
        if(!_.isObject(messageInfo)) {
            return cb(Errors.Invalid(`Invalid message index: ${messageIndex}`));
        }

        //  :TODO: create static userHasDeleteRights() that takes id || uuid that doesn't require full msg load
        this.selectedMessageForDelete = new Message();
        this.selectedMessageForDelete.load( { uuid : messageInfo.messageUuid }, err => {
            if(err) {
                this.selectedMessageForDelete = null;
                return cb(err);
            }

            if(!this.selectedMessageForDelete.userHasDeleteRights(this.client.user)) {
                this.selectedMessageForDelete = null;
                return cb(Errors.AccessDenied('User does not have rights to delete this message'));
            }

            //  user has rights to delete -- prompt/confirm then proceed
            return this.promptConfirmDelete(cb);
        });
    }

    promptConfirmDelete(cb) {
        const promptXyView = this.viewControllers.allViews.getView(MciViewIds.allViews.delPromptXy);
        if(!promptXyView) {
            return cb(Errors.MissingMci(`Missing prompt XY${MciViewIds.allViews.delPromptXy} MCI`));
        }

        const promptOpts = {
            clearAtSubmit : true,
        };
        if(promptXyView.dimens.width) {
            promptOpts.clearWidth = promptXyView.dimens.width;
        }

        return this.promptForInput(
            {
                formName        : 'delPrompt',
                formId          : FormIds.delPrompt,
                promptName      : this.config.deleteMessageFromListPrompt || 'deleteMessageFromListPrompt',
                prevFormName    : 'allViews',
                position        : promptXyView.position,
            },
            promptOpts,
            err => {
                return cb(err);
            }
        );
    }
};