const errors = require('@tryghost/errors');
const nql = require('@tryghost/nql');

module.exports = class EventRepository {
    constructor({
        EmailRecipient,
        MemberSubscribeEvent,
        MemberPaymentEvent,
        MemberStatusEvent,
        MemberLoginEvent,
        MemberCreatedEvent,
        SubscriptionCreatedEvent,
        MemberPaidSubscriptionEvent,
        MemberLinkClickEvent,
        MemberFeedback,
        Comment,
        labsService,
        memberAttributionService
    }) {
        this._MemberSubscribeEvent = MemberSubscribeEvent;
        this._MemberPaidSubscriptionEvent = MemberPaidSubscriptionEvent;
        this._MemberPaymentEvent = MemberPaymentEvent;
        this._MemberStatusEvent = MemberStatusEvent;
        this._MemberLoginEvent = MemberLoginEvent;
        this._EmailRecipient = EmailRecipient;
        this._Comment = Comment;
        this._labsService = labsService;
        this._MemberCreatedEvent = MemberCreatedEvent;
        this._SubscriptionCreatedEvent = SubscriptionCreatedEvent;
        this._MemberLinkClickEvent = MemberLinkClickEvent;
        this._MemberFeedback = MemberFeedback;
        this._memberAttributionService = memberAttributionService;
    }

    async getEventTimeline(options = {}) {
        if (!options.limit) {
            options.limit = 10;
        }
        let filters = this.getNQLSubset(options.filter);

        // Changing this order might need a change in the query functions
        // because of the different underlying models.
        options.order = 'created_at desc';

        // Create a list of all events that can be queried
        const pageActions = [
            {type: 'comment_event', action: 'getCommentEvents'},
            {type: 'click_event', action: 'getClickEvents'},
            {type: 'signup_event', action: 'getSignupEvents'},
            {type: 'subscription_event', action: 'getSubscriptionEvents'}
        ];

        // Some events are not filterable by post_id
        if (!filters['data.post_id']) {
            pageActions.push(
                {type: 'newsletter_event', action: 'getNewsletterSubscriptionEvents'},
                {type: 'login_event', action: 'getLoginEvents'},
                {type: 'payment_event', action: 'getPaymentEvents'}
            );
        }

        if (this._EmailRecipient) {
            pageActions.push({type: 'email_sent_event', action: 'getEmailSentEvents'});
            pageActions.push({type: 'email_delivered_event', action: 'getEmailDeliveredEvents'});
            pageActions.push({type: 'email_opened_event', action: 'getEmailOpenedEvents'});
            pageActions.push({type: 'email_failed_event', action: 'getEmailFailedEvents'});
        }

        if (this._labsService.isSet('audienceFeedback')) {
            pageActions.push({type: 'feedback_event', action: 'getFeedbackEvents'});
        }

        //Filter events to query
        const filteredPages = filters.type ? pageActions.filter(page => nql(filters.type).queryJSON(page)) : pageActions;

        //Start the promises
        const pages = filteredPages.map(page => this[page.action](options, filters));

        const allEventPages = await Promise.all(pages);

        const allEvents = allEventPages.flatMap(page => page.data);
        const totalEvents = allEventPages.reduce((accumulator, page) => accumulator + page.meta.pagination.total, 0);

        return {
            events: allEvents.sort(
                (a, b) => {
                    return new Date(b.data.created_at).getTime() - new Date(a.data.created_at).getTime();
                }
            ).slice(0, options.limit),
            meta: {
                pagination: {
                    limit: options.limit,
                    total: totalEvents,
                    pages: options.limit > 0 ? Math.ceil(totalEvents / options.limit) : null,

                    // Other values are unavailable (not possible to calculate easily)
                    page: null,
                    next: null,
                    prev: null
                }
            }
        };
    }

    async registerPayment(data) {
        await this._MemberPaymentEvent.add({
            ...data,
            source: 'stripe'
        });
    }

    async getNewsletterSubscriptionEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member', 'newsletter'],
            filter: []
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
        }
        if (filters['data.source']) {
            options.filter.push(filters['data.source'].replace(/data.source:/g, 'source:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        options.filter = options.filter.join('+');

        const {data: models, meta} = await this._MemberSubscribeEvent.findPage(options);

        const data = models.map((model) => {
            return {
                type: 'newsletter_event',
                data: model.toJSON(options)
            };
        });

        return {
            data,
            meta
        };
    }

    async getSubscriptionEvents(options = {}, filters = {}) {
        if (!this._labsService.isSet('memberAttribution')){
            options = {
                ...options,
                withRelated: ['member'],
                filter: []
            };
            if (filters['data.created_at']) {
                options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
            }
            if (filters['data.member_id']) {
                options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
            }
            options.filter = options.filter.join('+');
    
            const {data: models, meta} = await this._MemberPaidSubscriptionEvent.findPage(options);
    
            const data = models.map((model) => {
                return {
                    type: 'subscription_event',
                    data: model.toJSON(options)
                };
            });
    
            return {
                data,
                meta
            };
        }

        options = {
            ...options,
            withRelated: ['member', 'subscriptionCreatedEvent.postAttribution', 'subscriptionCreatedEvent.userAttribution', 'subscriptionCreatedEvent.tagAttribution'],
            filter: []
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        if (filters['data.post_id']) {
            options.filter.push(filters['data.post_id'].replace(/data.post_id:/g, 'subscriptionCreatedEvent.attribution_id:'));
            options.filter.push('subscriptionCreatedEvent.attribution_type:post');
        }
        options.filter = options.filter.join('+');

        const {data: models, meta} = await this._MemberPaidSubscriptionEvent.findPage(options);

        const data = models.map((model) => {
            return {
                type: 'subscription_event',
                data: {
                    ...model.toJSON(options),
                    attribution: model.get('type') === 'created' && model.related('subscriptionCreatedEvent') && model.related('subscriptionCreatedEvent').id ? this._memberAttributionService.getEventAttribution(model.related('subscriptionCreatedEvent')) : null
                }
            };
        });

        return {
            data,
            meta
        };
    }

    async getPaymentEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member'],
            filter: []
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        options.filter = options.filter.join('+');

        const {data: models, meta} = await this._MemberPaymentEvent.findPage(options);

        const data = models.map((model) => {
            return {
                type: 'payment_event',
                data: model.toJSON(options)
            };
        });

        return {
            data,
            meta
        };
    }

    async getLoginEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member'],
            filter: []
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        options.filter = options.filter.join('+');

        const {data: models, meta} = await this._MemberLoginEvent.findPage(options);

        const data = models.map((model) => {
            return {
                type: 'login_event',
                data: model.toJSON(options)
            };
        });

        return {
            data,
            meta
        };
    }

    async getSignupEvents(options = {}, filters = {}) {
        if (!this._labsService.isSet('memberAttribution')){
            options = {
                ...options,
                withRelated: ['member'],
                filter: ['from_status:null']
            };
            if (filters['data.created_at']) {
                options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
            }
            if (filters['data.member_id']) {
                options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
            }
            options.filter = options.filter.join('+');
    
            const {data: models, meta} = await this._MemberStatusEvent.findPage(options);
    
            const data = models.map((model) => {
                return {
                    type: 'signup_event',
                    data: model.toJSON(options)
                };
            });
    
            return {
                data,
                meta
            };
        }

        return this.getCreatedEvents(options, filters);
    }

    async getCreatedEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member', 'postAttribution', 'userAttribution', 'tagAttribution'],
            filter: []
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        if (filters['data.source']) {
            options.filter.push(filters['data.source'].replace(/data.source:/g, 'source:'));
        }
        if (filters['data.post_id']) {
            options.filter.push(filters['data.post_id'].replace(/data.post_id:/g, 'attribution_id:'));
            options.filter.push('attribution_type:post');
        }
        options.filter = options.filter.join('+');

        const {data: models, meta} = await this._MemberCreatedEvent.findPage(options);

        const data = models.map((model) => {
            return {
                type: 'signup_event',
                data: {
                    ...model.toJSON(options),
                    attribution: this._memberAttributionService.getEventAttribution(model)
                }
            };
        });

        return {
            data,
            meta
        };
    }

    async getCommentEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member', 'post', 'parent'],
            filter: ['member_id:-null']
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        if (filters['data.post_id']) {
            options.filter.push(filters['data.post_id'].replace(/data.post_id:/g, 'post_id:'));
        }
        options.filter = options.filter.join('+');

        const {data: models, meta} = await this._Comment.findPage(options);

        const data = models.map((model) => {
            return {
                type: 'comment_event',
                data: model.toJSON(options)
            };
        });

        return {
            data,
            meta
        };
    }

    async getClickEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member', 'link', 'link.post'],
            filter: []
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        if (filters['data.post_id']) {
            options.filter.push(filters['data.post_id'].replace(/data.post_id:/g, 'post_id:'));
        }
        options.filter = options.filter.join('+');

        const {data: models, meta} = await this._MemberLinkClickEvent.findPage(options);

        const data = models.map((model) => {
            return {
                type: 'click_event',
                data: model.toJSON(options)
            };
        });

        return {
            data,
            meta
        };
    }

    async getFeedbackEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member', 'post'],
            filter: []
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'created_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        if (filters['data.post_id']) {
            options.filter.push(filters['data.post_id'].replace(/data.post_id:/g, 'post_id:'));
        }
        options.filter = options.filter.join('+');

        const {data: models, meta} = await this._MemberFeedback.findPage(options);

        const data = models.map((model) => {
            return {
                type: 'feedback_event',
                data: model.toJSON(options)
            };
        });

        return {
            data,
            meta
        };
    }

    async getEmailSentEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member', 'email'],
            filter: ['failed_at:null', 'processed_at:-null']
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'processed_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        if (filters['data.post_id']) {
            options.filter.push(filters['data.post_id'].replace(/data.post_id:/g, 'email.post_id:'));
        }
        options.filter = options.filter.join('+');
        options.order = options.order.replace(/created_at/g, 'processed_at');

        const {data: models, meta} = await this._EmailRecipient.findPage(
            options
        );

        const data = models.map((model) => {
            return {
                type: 'email_sent_event',
                data: {
                    member_id: model.get('member_id'),
                    created_at: model.get('processed_at'),
                    member: model.related('member').toJSON(),
                    email: model.related('email').toJSON()
                }
            };
        });

        return {
            data,
            meta
        };
    }

    async getEmailDeliveredEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member', 'email'],
            filter: ['delivered_at:-null']
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'delivered_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        if (filters['data.post_id']) {
            options.filter.push(filters['data.post_id'].replace(/data.post_id:/g, 'email.post_id:'));
        }
        options.filter = options.filter.join('+');
        options.order = options.order.replace(/created_at/g, 'delivered_at');

        const {data: models, meta} = await this._EmailRecipient.findPage(
            options
        );

        const data = models.map((model) => {
            return {
                type: 'email_delivered_event',
                data: {
                    member_id: model.get('member_id'),
                    created_at: model.get('delivered_at'),
                    member: model.related('member').toJSON(),
                    email: model.related('email').toJSON()
                }
            };
        });

        return {
            data,
            meta
        };
    }

    async getEmailOpenedEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member', 'email'],
            filter: ['opened_at:-null']
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'opened_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        if (filters['data.post_id']) {
            options.filter.push(filters['data.post_id'].replace(/data.post_id:/g, 'email.post_id:'));
        }
        options.filter = options.filter.join('+');
        options.order = options.order.replace(/created_at/g, 'opened_at');

        const {data: models, meta} = await this._EmailRecipient.findPage(
            options
        );

        const data = models.map((model) => {
            return {
                type: 'email_opened_event',
                data: {
                    member_id: model.get('member_id'),
                    created_at: model.get('opened_at'),
                    member: model.related('member').toJSON(),
                    email: model.related('email').toJSON()
                }
            };
        });

        return {
            data,
            meta
        };
    }

    async getEmailFailedEvents(options = {}, filters = {}) {
        options = {
            ...options,
            withRelated: ['member', 'email'],
            filter: ['failed_at:-null']
        };
        if (filters['data.created_at']) {
            options.filter.push(filters['data.created_at'].replace(/data.created_at:/g, 'failed_at:'));
        }
        if (filters['data.member_id']) {
            options.filter.push(filters['data.member_id'].replace(/data.member_id:/g, 'member_id:'));
        }
        if (filters['data.post_id']) {
            options.filter.push(filters['data.post_id'].replace(/data.post_id:/g, 'email.post_id:'));
        }
        options.filter = options.filter.join('+');
        options.order = options.order.replace(/created_at/g, 'failed_at');

        const {data: models, meta} = await this._EmailRecipient.findPage(
            options
        );

        const data = models.map((model) => {
            return {
                type: 'email_failed_event',
                data: {
                    member_id: model.get('member_id'),
                    created_at: model.get('failed_at'),
                    member: model.related('member').toJSON(),
                    email: model.related('email').toJSON()
                }
            };
        });

        return {
            data,
            meta
        };
    }

    /**
     * Extract a subset of NQL.
     * There are only a few properties allowed.
     * Parenthesis are forbidden.
     * Only ANDs are supported when combining properties.
     */
    getNQLSubset(filter) {
        if (!filter) {
            return {};
        }

        const lex = nql(filter).lex();

        const allowedFilters = ['type','data.created_at','data.member_id', 'data.post_id'];
        const properties = lex
            .filter(x => x.token === 'PROP')
            .map(x => x.matched.slice(0, -1));
        if (properties.some(prop => !allowedFilters.includes(prop))) {
            throw new errors.IncorrectUsageError({
                message: 'The only allowed filters are `type`, `data.created_at` and `data.member_id`'
            });
        }

        if (lex.find(x => x.token === 'LPAREN')) {
            throw new errors.IncorrectUsageError({
                message: 'The filter can\'t contain parenthesis.'
            });
        }

        const jsonFilter = nql(filter).toJSON();
        const keys = Object.keys(jsonFilter);

        if (keys.length === 1 && keys[0] === '$or') {
            throw new errors.IncorrectUsageError({
                message: 'The top level-filters can only combined with ANDs (+) and not ORs (,).'
            });
        }

        // The filter is validated, it only contains one level of filters concatenated with `+`
        const filters = filter.split('+');

        /** @type {Object.<string, string>} */
        let result = {};

        for (const f of filters) {
            // dirty way to parse a property, but it works according to https://github.com/NexesJS/NQL-Lang/blob/0e12d799a3a9c4d8651444e9284ce16c19cbc4f0/src/nql.l#L18
            const key = f.split(':')[0];
            if (!result[key]) {
                result[key] = f;
            } else {
                result[key] += '+' + f;
            }
        }

        return result;
    }

    async getSubscriptions() {
        const results = await this._MemberSubscribeEvent.findAll({
            aggregateSubscriptionDeltas: true
        });

        const resultsJSON = results.toJSON();

        const cumulativeResults = resultsJSON.reduce((accumulator, result, index) => {
            if (index === 0) {
                return [{
                    date: result.date,
                    subscribed: result.subscribed_delta
                }];
            }
            return accumulator.concat([{
                date: result.date,
                subscribed: result.subscribed_delta + accumulator[index - 1].subscribed
            }]);
        }, []);

        return cumulativeResults;
    }

    async getMRR() {
        const results = await this._MemberPaidSubscriptionEvent.findAll({
            aggregateMRRDeltas: true
        });

        const resultsJSON = results.toJSON();

        const cumulativeResults = resultsJSON.reduce((accumulator, result) => {
            if (!accumulator[result.currency]) {
                return {
                    ...accumulator,
                    [result.currency]: [{
                        date: result.date,
                        mrr: result.mrr_delta,
                        currency: result.currency
                    }]
                };
            }
            return {
                ...accumulator,
                [result.currency]: accumulator[result.currency].concat([{
                    date: result.date,
                    mrr: result.mrr_delta + accumulator[result.currency].slice(-1)[0].mrr,
                    currency: result.currency
                }])
            };
        }, {});

        return cumulativeResults;
    }

    async getVolume() {
        const results = await this._MemberPaymentEvent.findAll({
            aggregatePaymentVolume: true
        });

        const resultsJSON = results.toJSON();

        const cumulativeResults = resultsJSON.reduce((accumulator, result) => {
            if (!accumulator[result.currency]) {
                return {
                    ...accumulator,
                    [result.currency]: [{
                        date: result.date,
                        volume: result.volume_delta,
                        currency: result.currency
                    }]
                };
            }
            return {
                ...accumulator,
                [result.currency]: accumulator[result.currency].concat([{
                    date: result.date,
                    volume: result.volume_delta + accumulator[result.currency].slice(-1)[0].volume,
                    currency: result.currency
                }])
            };
        }, {});

        return cumulativeResults;
    }

    async getStatuses() {
        const results = await this._MemberStatusEvent.findAll({
            aggregateStatusCounts: true
        });

        const resultsJSON = results.toJSON();

        const cumulativeResults = resultsJSON.reduce((accumulator, result, index) => {
            if (index === 0) {
                return [{
                    date: result.date,
                    paid: result.paid_delta,
                    comped: result.comped_delta,
                    free: result.free_delta
                }];
            }
            return accumulator.concat([{
                date: result.date,
                paid: result.paid_delta + accumulator[index - 1].paid,
                comped: result.comped_delta + accumulator[index - 1].comped,
                free: result.free_delta + accumulator[index - 1].free
            }]);
        }, []);

        return cumulativeResults;
    }
};