'use strict'
require('dotenv').config()
const crypto = require('crypto')
const Util = require('util')
const JWT = require('jsonwebtoken')
const Schmervice = require('@hapipal/schmervice')
const SecurePassword = require('secure-password')

// Configuration for Brevo
const Brevo = require('@getbrevo/brevo')
const apiInstance = new Brevo.TransactionalEmailsApi()
const apiKey = apiInstance.apiClient.authentications['api-key']
apiKey.apiKey = process.env.BREVO_KEY
const sendSmtpEmail = new Brevo.SendSmtpEmail()

// TODO: Consider implementing, nice use of SecurePassword,
// but currently not used anywhere...
const hasher = async (pwd, steak) => {
    const hash = await pwd.hash(steak)
    const result = await pwd.verify(steak, hash)
    let squirtle = null

    switch (result) {
        case SecurePassword.INVALID_UNRECOGNIZED_HASH:
            return console.error(
                'This hash was not made with secure-password. Attempt legacy algorithm',
            )
        case SecurePassword.INVALID:
            return console.log('Invalid password')
        case SecurePassword.VALID:
            return result
        case SecurePassword.VALID_NEEDS_REHASH:
            console.log('Yay you made it, wait for us to improve your safety')
            try {
                squirtle = await pwd.hash(steak)
                // console.log('improvedHash', squirtle)
                // const saveHash = Auth.insert({user_email:
                // matchingEmails}).into('token')
                return squirtle
            } catch (err) {
                console.error(
                    'You are authenticated, but we could not improve your safety this time around',
                )
            }
            break
    }
}

/** Class for methods used in the User plugin */
module.exports = class UserService extends Schmervice.Service {
    /**
     * Unsure of what our constructor does
     * @param  {...any} args
     */
    constructor(...args) {
        super(...args)
        const pwd = new SecurePassword()
        // TODO: Invalidate this application state somehow after a
        // certain time period has passed
        this.activeSessions = {}

        this.pwd = {
            hash: Util.promisify(pwd.hash.bind(pwd)),
            verify: Util.promisify(pwd.verify.bind(pwd)),
        }
    }

    /**
     * Use knex to find users with id column
     * @param {number} id
     * @param {*} txn
     * @returns
     */
    async findById(id, txn) {
        const { User } = this.server.models()

        return await User.query(txn)
            .throwIfNotFound()
            .first()
            .where({ user_id: id })
    }

    /**
     * Use knew to find first user with username
     * @param {*} username
     * @param {*} txn
     * @returns
     */
    async findByUsername(username, txn) {
        const { User } = this.server.models()

        return await User.query(txn)
            .throwIfNotFound()
            .first()
            .where({ user_name: username })
    }

    /**
     * Use to find first user with useremail
     * @param {*} username
     * @param {*} txn
     * @returns
     */
    async findByUserEmail(userEmail, txn) {
        const { User } = this.server.models()
        const user = await User.query(txn)
            .throwIfNotFound()
            .first()
            .where({ user_email: userEmail })
        return user
    }

    hashToken(token) {
        const salt = process.env.APP_SESSION_SALT
        try {
            return crypto.createHmac('sha256', salt).update(token).digest('hex')
        } catch (err) {
            throw new Error(err.message)
        }
    }

    /**
     * Signup function
     * @param {*} param0
     * @param {*} txn
     * @returns
     */
    async signup({ password, userInfo, created_at }, txn) {
        const { User, Auth } = this.server.models()
        const matchingEmails = await User.query().where(
            'user_email',
            userInfo.user_email,
        )
        if (matchingEmails.length > 0) {
            throw `User ${userInfo.user_email} already exists: Cannot create a user without a unique email`
        }
        // Insert User Info to User table
        const insertUser = await User.query().insert(userInfo)
        // insert a row with blank password to be updated by changePassword()
        await Auth.query().insert({
            user_email: insertUser.user_email,
            created_at: created_at,
            token: null,
        })
        // update null token with hashed password
        await this.changePassword(insertUser.user_email, password, txn)
        return {
            user_id: insertUser.id,
            user_name: insertUser.user_name,
            user_email: insertUser.user_email,
            is_poster: insertUser.is_poster,
            is_admin: insertUser.is_admin,
            is_verified: insertUser.is_verified,
        }
    }

    /**
     * Updates user's info
     * @param {number} id
     * @param {*} param1
     * @param {*} txn
     * @returns
     */
    async update(id, { password, ...userInfo }, txn) {
        const { User } = this.server.models()

        if (Object.keys(userInfo).length > 0) {
            await User.query(txn)
                .throwIfNotFound()
                .where({ id })
                .patch(userInfo)
        }

        if (password) {
            await this.changePassword(id, password, txn)
        }

        return id
    }

    /**
     * Self explanatory
     * @param {*} param0
     * @param {*} txn
     * @returns
     */
    async login({ email, password }, txn) {
        const { User, Auth } = this.server.models()

        const user = await Auth.query(txn)
            .throwIfNotFound()
            .first()
            .where({ user_email: email })
        const bufferPepper = Buffer.from(process.env.PEPPER + password)

        /** Uncomment to run password check using SecurePassword */
        const passwordCheck = await this.pwd.verify(bufferPepper, user.token)

        if (passwordCheck === SecurePassword.VALID_NEEDS_REHASH) {
            await this.changePassword(user.user_email, password, txn)
        } else if (passwordCheck !== SecurePassword.VALID) {
            throw User.createNotFoundError()
        }

        return user
    }

    /**
     * Create a token to be sent in request headers
     * @param {data, expiration}
     * @returns {Token}
     */
    createToken(data, expiration = 600) {
        const key = process.env.APP_SECRET
        const obj = {}
        Object.assign(obj, { ...data })
        return JWT.sign(obj, key, { expiresIn: expiration })
    }

    async makeUserCredentials(email) {
        const user = await this.findByUserEmail(email)
        const userCredentials = {
            email: user.user_email,
            name: user.user_name,
            seeking: user.is_poster === 1 ? 'poster' : 'seeker',
        }
        const token = this.createToken({
            payload: userCredentials,
        })
        return {
            userCredentials,
            token,
        }
    }

    /**
     * Validates whether a token has expired or not
     * @param {User} user
     * @returns {Token}
     */
    validateToken(token) {
        const key = process.env.APP_SECRET
        try {
            return JWT.verify(token, key)
        } catch (err) {
            return { payload: null, message: err.message }
        }
    }
    /**
     * Uses this.validateToken() to verify hashedSessionToken's
     * existence, expiry, and also validates accessToken
     * @param {HashedSessionToken} hashedSessionToken
     * @returns {PayloadFromActiveSessions}
     */
    validateSession(hashedSessionToken) {}
    removeSession(hashedSessionToken) {
        const userSession = this.activeSessions[hashedSessionToken]
        if (!userSession) {
            throw new Error(
                'hashedSessionToken not in activeSessions registry!',
            )
        } else {
            delete this.activeSessions[hashedSessionToken]
        }
    }
    /**
     * Use knex to try to change password entry
     * @param {number} id
     * @param {string} password
     * @param {*} txn
     * @returns {number}
     */
    async changePassword(email, password, txn) {
        const { Auth } = this.server.models()

        const hashed = await this.pwd.hash(
            Buffer.from(process.env.PEPPER + password),
        )

        await Auth.query(txn)
            .throwIfNotFound()
            .where({ user_email: email })
            .patch({
                // user_email: email,
                token: hashed,
            })
        return email
    }

    async getPassword(email, txn) {
        const { Auth } = this.server.models()

        const passwordRow = await Auth.query(txn)
            .where('user_email', email)
            .first()
        return passwordRow ? passwordRow.token : null
    }

    /**
     * Sends a Transactional Email via Brevo
     * @ returns {Object}
     */
    async emailSent(userCredentials) {
        const hashedSessionToken = this.hashToken(userCredentials.sessionToken)
        if (Object.keys(this.activeSessions).includes(hashedSessionToken)) {
            return new Error('session already in cache!!')
        }
        // Set expiration time for ten minutes from now
        const duration = 600000

        this.activeSessions[hashedSessionToken] = {
            email: userCredentials.email,
            name: userCredentials.name,
            seeking: userCredentials.seeking,
            sessionToken: userCredentials.sessionToken,
            expiration: Date.now() + duration,
            emailWasRespondedTo: false,
            accessToken: null,
        }
        // NOTE: Although this looks messy, Brevo requries these
        // parameters be defined individually like this, attempts
        // to configure this in a singel object cause errors on their API
        sendSmtpEmail.sender = {
            name: 'My Test Company',
            email: 'mytestemail@email.com',
        }
        sendSmtpEmail.subject = 'My Test Company'
        sendSmtpEmail.to = [
            {
                email: userCredentials.email,
            },
        ]
        sendSmtpEmail.templateId = Number(process.env.BREVO_TEMPLATE_ID)
        sendSmtpEmail.params = {
            link: `${process.env.BREVO_LINK}/verify/${hashedSessionToken}`,
        }
        return await apiInstance.sendTransacEmail(sendSmtpEmail).then(
            data => {
                return { wasSuccessfull: true, data: data }
            },
            error => {
                return { wasSuccessfull: false, error: error }
            },
        )
    }
}