const Schmervice = require('@hapipal/schmervice')
const cosineSimilarity = require('compute-cosine-similarity')
const haversine = require('haversine')
const zipcodeKey = 7
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,
    )
}
const filterByDistance = (profileList, max) => {
    return profileList.filter(profile => {
        const profileDistance = Math.floor(parseFloat(profile.distance) * 100)
        const adjustedMaxDistance = Math.floor(parseFloat(max) * 100)
        return profileDistance <= adjustedMaxDistance
    })
}
const scoreAll = (profileList, userProfile) => {
    return profileList.map(profile => {
        return {
            // Uncomment to return the whole profile
            // ...profile,
            profile_id: profile.profile_id,
            score: scoreResponses(userProfile, profile),
            distance: profile.distance,
        }
    })
}
/**
 * Grab the zip code string
 */
const getZipCodeFromProfile = profile => {
    // There should only be one zip code entry per profile
    let zipRes = profile.responses.filter(
        // Whatever the zipcode questions is
        response => response.response_key_id == zipcodeKey,
    )[0]

    const responseIndexForZip = profile.responses.indexOf(zipRes)
    if (responseIndexForZip >= 0) {
        profile.responses.splice(responseIndexForZip, 1)
    }
    return zipRes.val
}

/**
 * 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.user_name = profile.user.user_name // string user_name
        this.user_media = profile.user_media // string user_media
        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')
            // CHECKTHIS: Added this because we added user.user_name to CompleteProfile
            // so without this, we get undefined user_name
            .withGraphFetched('user')

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

    async getProfilesFor(profileIdArray, type) {
        const { Profile } = this.server.models()
        // profilesEntries is profiles in database row order 
        const profilesEntries = await Profile.query()
            .whereIn('profile_id', profileIdArray)
            .withGraphFetched('responses')
            .withGraphFetched('user')

        // taking the info from profilesEntries
        // to repack into completeProfiles
        // in same order as profileIdArray
        const completeProfiles = []
        profileIdArray.forEach(pid => {
            profilesEntries.forEach(entry => {
                if (entry.profile_id == pid) {
                    completeProfiles.push(new CompleteProfile(entry, type))
                }
            })
        })  
        return completeProfiles
    }

    /**
     * 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,
        )

        // Delete matches
        // ?:Maybe bad idea
        if (matchingResponses.length > 0) {
            const alreadyAnswered = matchingResponses.map(matchingRes => matchingRes.response_key_id)
            await Response.query()
                .where({ profile_id: profileId })
                .delete()
                .whereIn('response_key_id', alreadyAnswered)
        }

        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)
    }

    /**
     * Score a profile
     * @param {number} profileId
     * @returns {Array} Ordered and scored Profiles
     */
    async scoreProfilesFor(profileId, maxDistance, 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 = 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,
        )

        // Only include profiles that included zipcode response
        profileIdsOfOppositeType = profileIdsOfOppositeType.filter(profile => {
            const zipcodeResponses = profile.responses.filter(response => response.response_key_id == zipcodeKey)
            return zipcodeResponses.length > 0
        })

        const profilePlusDistance = await Promise.all(
            profileIdsOfOppositeType.map(async profile => {
                const targetZip = getZipCodeFromProfile(profile)

                if(!userZip || !targetZip) return { ...profile, distance: [9999, distanceUnit] }

                const distance = await this._compareDistance(
                    userZip,
                    targetZip,
                    distanceUnit,
                )
                return {
                    ...profile,
                    distance: [distance.toFixed(2), distanceUnit],
                }
            }),
        )

        const distanceFilteredProfiles = filterByDistance(
            profilePlusDistance,
            maxDistance,
        )

        const scoredProfilesWithDistance = scoreAll(
            distanceFilteredProfiles,
            userProfile,
        )

        // Order by score
        return scoredProfilesWithDistance.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),
        )
        if (!zipInfo) {
            console.error('zip:', zipCode)
        }

        return {
            latitude: parseFloat(zipInfo.latitude),
            longitude: parseFloat(zipInfo.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 || isNaN(start_zip) || isNaN(end_zip)) return

        const start = await this._latLonForZip(start_zip)
        const end = await this._latLonForZip(end_zip)

        return haversine(start, end, { unit: distanceUnit })
    }
}