const Schmervice = require('@hapipal/schmervice')
const cosineSimilarity = require('compute-cosine-similarity')
const haversine = require('haversine')
const profile = require('../plugins/profile')

const magic = 1000
const scoreResponses = (seeker, potentialMatch) => {
    if (seeker.responses.length != potentialMatch.responses.length)
        return {
            error: `complete responses for profile: ${seeker.profile_id} unqeual to profile: ${potentialMatch.profile_id} | ${seeker.responses.length}:${potentialMatch.responses.length}`,
        }

    const checkValCb = res => {
        const val = parseInt(res.val)
        return isNaN(val) ? 0 : val
    }

    return Math.floor(
        cosineSimilarity(
            seeker.responses.map(checkValCb),
            potentialMatch.responses.map(checkValCb),
        ) * magic,
    )
}

/**
 * Class to hold our retrieved profile information
 * in a convenient wrapper
 * !: This needs to match the responseSchema in profiles.js
 */
class CompleteProfile {
    constructor(profile, type) {
        this.user_id = profile.user_id // int user_id
        this.profile_id = profile.profile_id // int profile_id
        this.responses = profile.responses // [] of all responses
        this.user_type = type
    }
}

module.exports = class ProfileService extends Schmervice.Service {
    constructor(...args) {
        super(...args)
    }

    /**
     * Internal method to get list of profile_ids for this user
     * @param {number} userId
     * @returns {Array} List of all profile_ids for user
     */
    async _getProfileIdsForUserId(userId) {
        const { Profile } = this.server.models()

        /** Grab every Profile associated with this id */
        const allProfiles = await Profile.query().where('user_id', userId)

        /** Copy a list of the just the Profiles */
        const profileIdsToGrab = allProfiles.map(profile => profile.profile_id)

        /** Uncomment to dedupe the list just in case */
        return [...new Set(profileIdsToGrab)]
    }

    async getCompleteProfilesFor(userId, type) {
        const { Profile } = this.server.models()

        const dedupedProfileIds = await this._getProfileIdsForUserId(userId)

        const profilesEntries = await Profile.query()
            .whereIn('profile_id', dedupedProfileIds)
            .withGraphFetched('responses')

        //** Get responses asociated with each profile_id */
        return profilesEntries.map(profile => {
            return new CompleteProfile(profile, type)
        })
    }

    /**
     * Save responses in a profile
     * @param {number} userId
     * @param {Array} responses
     * @returns {object}
     */
    async saveResponsesCreateProfileFor(userId, responses, txn) {
        const { Profile, Response } = this.server.models()

        const profile = await Profile.query(txn).insert({
            user_id: userId,
        })
        for (const responseToSave of responses) {
            const responseInfo = {
                profile_id: profile.id,
                response_key_id: responseToSave.response_key_id,
                val: responseToSave.val,
            }
            await Response.query(txn).insert(responseInfo)
        }
        //** Work around for HAPI returning profile_id as id */
        return { user_id: profile.user_id, profile_id: profile.id }
    }

    /** Update responses in place
     * @param {number} profileId
     * @param {Array} responses
     * @returns {Array} updated responses
     */
    async updateResponsesInProfile(profileId, responses, txn) {
        const { Response } = this.server.models()
        for (const responseToSave of responses) {
            await Response.query(txn)
                .update({
                    response_id: responseToSave.response_id,
                    profile_id: responseToSave.profile_id,
                    response_key_id: responseToSave.response_key_id,
                    val: responseToSave.val,
                })
                .where({
                    profile_id: profileId,
                })
                .where({
                    response_id: responseToSave.response_id,
                })
        }
        return await Response.query(txn).where({
            profile_id: profileId,
        })
    }

    /** Add response
     * @param {Object} response to save
     * @returns {null} updated responses
     * @returns {Array} updated responses
     */
    async saveResponseForProfile(profileId, responseToSave) {
        const { Response } = this.server.models()
        let allResponses = await Response.query().where({
            profile_id: profileId,
        })
        const matchingResponses = allResponses.filter(response => response.response_key_id == responseToSave.response_key_id)
        
        // ?:Maybe bad idea
        if(matchingResponses.length > 0) { return null }

        await await Response.query().insert(responseToSave)
        return allResponses
    }

    /**
     * Delete a profile
     * @param {number} userId
     * @param {number} profileId
     * @returns
     */
    async deleteProfile(userId, profileId) {
        const { Profile } = this.server.models()

        const dedupedGroupings = await this._getProfileIdsForUserId(userId)

        /** Do NOTHING if NOT in Grouping */
        if (!dedupedGroupings.includes(profileId)) return

        return await Profile.query().delete().where('profile_id', profileId)
    }
    /** 
     * Grab the zip code string
    */
    _getZipCodeFromProfile(profile) {
        // There should only be one zip code entry per profile
        let zip = profile.responses.filter(response => response.response_key_id == 16)[0]
        const responseIndexForZip = profile.responses.indexOf(zip)
        if(responseIndexForZip >= 0) {
            profile.responses.splice(responseIndexForZip, 1)
        }
        return zip.val
    }
    /**
     * Score a profile
     * @param {number} profileId
     * @returns {Array} Ordered and scored Profiles
     */
    async scoreProfilesFor(profileId, maxDistanceMiles, distanceUnit) {
        const { Profile } = this.server.models()
        
        // Our User Profile to score for
        const userProfile = await Profile.query()
        .findOne('profile_id', profileId)
        .withGraphFetched('responses')
        .withGraphFetched('user')
        
        // Move unneeded responses
        const userZip = this._getZipCodeFromProfile(userProfile)

        // Find all Profiles that are NOT of our userProfile.type
        // ie. If userProfile.type == seeker, then find: poster
        let profileIdsOfOppositeType = await Profile.query()
        .withGraphFetched('responses')
        .withGraphFetched('user')
        
        // TODO: Let Objection optimize this
        const isPosterOpposite = userProfile.user.is_poster == 1 ? 0 : 1
        profileIdsOfOppositeType = profileIdsOfOppositeType.filter(profile => profile.user.is_poster == isPosterOpposite)
        
        const profilePlusDistance = await Promise.all(profileIdsOfOppositeType.map(async profile => {
            const targetZip = this._getZipCodeFromProfile(profile)
            const distance = await this._compareDistance(userZip, targetZip, distanceUnit)
            return {
                ...profile,
                distance: [distance.toFixed(2), distanceUnit]
            }
        }))

        // Filter by distance
        // TODO: probably do this with a query
        const distanceFiltered = profilePlusDistance.filter(profile => {
            const profileDistance = Math.floor(parseFloat(profile.distance) * 100)
            const adjustedMaxDistance = Math.floor(parseFloat(maxDistanceMiles) * 100)
            return profileDistance <= adjustedMaxDistance
        })

        const scored = distanceFiltered.map(profile => {
            return {
                // Uncomment to return the whole profile
                // ...profile,
                profile_id: profile.profile_id,
                score: scoreResponses(userProfile, profile),
                distance: profile.distance
            }
        })
        // Order by score
        return scored.sort((a, b) => a.score - b.score)
    }
    
    /**
     * Use the db for zipcode info
     * @param {string} zipCode
     * @param {object}
     */
    async _latLonForZip(zipCode) {
        const { ZipCode } = this.server.models()

        const zipInfo = await ZipCode.query().findOne('zip_code_id', parseInt(zipCode))
        const latitude = parseFloat(zipInfo.latitude)
        const longitude =  parseFloat(zipInfo.longitude)
        
        return { latitude, longitude }
    }
    /**
     * Get the distance between two zipcodes
     * using the haversine formula
     * @param {string} start_zip
     * @param {string} end_zip
     * @param {number} distance in miles
     */
    async _compareDistance(start_zip, end_zip, distanceUnit) {
        if(!start_zip || !end_zip) return
        
        const start = await this._latLonForZip(start_zip)
        const end = await this._latLonForZip(end_zip)
        
        return haversine(start, end, { unit: distanceUnit })
    }
}