/**
 * AuthManager
 * 
 * This module aims to abstract login procedures. Results from Mojang's REST api
 * are retrieved through our Mojang module. These results are processed and stored,
 * if applicable, in the config using the ConfigManager. All login procedures should
 * be made through this module.
 * 
 * @module authmanager
 */
// Requirements
const ConfigManager          = require('./configmanager')
const { LoggerUtil }         = require('helios-core')
const { RestResponseStatus } = require('helios-core/common')
const { MojangRestAPI, mojangErrorDisplayable, MojangErrorCode } = require('helios-core/mojang')
const { MicrosoftAuth }      = require('helios-core/microsoft')
const { AZURE_CLIENT_ID }    = require('./ipcconstants')

const log = LoggerUtil.getLogger('AuthManager')

// Functions

/**
 * Add a Mojang account. This will authenticate the given credentials with Mojang's
 * authserver. The resultant data will be stored as an auth account in the
 * configuration database.
 * 
 * @param {string} username The account username (email if migrated).
 * @param {string} password The account password.
 * @returns {Promise.<Object>} Promise which resolves the resolved authenticated account object.
 */
exports.addMojangAccount = async function(username, password) {
    try {
        const response = await MojangRestAPI.authenticate(username, password, ConfigManager.getClientToken())
        console.log(response)
        if(response.responseStatus === RestResponseStatus.SUCCESS) {

            const session = response.data
            if(session.selectedProfile != null){
                const ret = ConfigManager.addMojangAuthAccount(session.selectedProfile.id, session.accessToken, username, session.selectedProfile.name)
                if(ConfigManager.getClientToken() == null){
                    ConfigManager.setClientToken(session.clientToken)
                }
                ConfigManager.save()
                return ret
            } else {
                return Promise.reject(mojangErrorDisplayable(MojangErrorCode.ERROR_NOT_PAID))
            }

        } else {
            return Promise.reject(mojangErrorDisplayable(response.mojangErrorCode))
        }
        
    } catch (err){
        log.error(err)
        return Promise.reject(mojangErrorDisplayable(MojangErrorCode.UNKNOWN))
    }
}

const AUTH_MODE = { FULL: 0, MS_REFRESH: 1, MC_REFRESH: 2 }

/**
 * Perform the full MS Auth flow in a given mode.
 * 
 * AUTH_MODE.FULL = Full authorization for a new account.
 * AUTH_MODE.MS_REFRESH = Full refresh authorization.
 * AUTH_MODE.MC_REFRESH = Refresh of the MC token, reusing the MS token.
 * 
 * @param {string} entryCode FULL-AuthCode. MS_REFRESH=refreshToken, MC_REFRESH=accessToken
 * @param {*} authMode The auth mode.
 * @returns An object with all auth data. AccessToken object will be null when mode is MC_REFRESH.
 */
async function fullMicrosoftAuthFlow(entryCode, authMode) {

    let accessTokenRaw
    let accessToken
    if(authMode !== AUTH_MODE.MC_REFRESH) {
        const accessTokenResponse = await MicrosoftAuth.getAccessToken(entryCode, authMode === AUTH_MODE.MS_REFRESH, AZURE_CLIENT_ID)
        if(accessTokenResponse.responseStatus === RestResponseStatus.ERROR) {
            // TODO Fail.
            return // TODO
        }
        accessToken = accessTokenResponse.data
        accessTokenRaw = accessToken.access_token
    } else {
        accessTokenRaw = entryCode
    }
    
    const xblResponse = await MicrosoftAuth.getXBLToken(accessTokenRaw)
    if(xblResponse.responseStatus === RestResponseStatus.ERROR) {
        // TODO Fail.
        return // TODO
    }
    const xstsResonse = await MicrosoftAuth.getXSTSToken(xblResponse.data)
    if(xstsResonse.responseStatus === RestResponseStatus.ERROR) {
        // TODO Fail.
        return // TODO
    }
    const mcTokenResponse = await MicrosoftAuth.getMCAccessToken(xstsResonse.data)
    if(mcTokenResponse.responseStatus === RestResponseStatus.ERROR) {
        // TODO Fail.
        return // TODO
    }
    const mcProfileResponse = await MicrosoftAuth.getMCProfile(mcTokenResponse.data.access_token)
    if(mcProfileResponse.responseStatus === RestResponseStatus.ERROR) {
        // TODO Fail.
        return // TODO
    }
    return {
        accessToken,
        accessTokenRaw,
        xbl: xblResponse.data,
        xsts: xstsResonse.data,
        mcToken: mcTokenResponse.data,
        mcProfile: mcProfileResponse.data
    }
}

/**
 * Calculate the expiry date. Advance the expiry time by 10 seconds
 * to reduce the liklihood of working with an expired token.
 * 
 * @param {number} nowMs Current time milliseconds.
 * @param {number} epiresInS Expires in (seconds)
 * @returns 
 */
async function calculateExpiryDate(nowMs, epiresInS) {
    return nowMs + ((epiresInS-10)*1000)
}

/**
 * Add a Microsoft account. This will pass the provided auth code to Mojang's OAuth2.0 flow.
 * The resultant data will be stored as an auth account in the configuration database.
 * 
 * @param {string} authCode The authCode obtained from microsoft.
 * @returns {Promise.<Object>} Promise which resolves the resolved authenticated account object.
 */
exports.addMicrosoftAccount = async function(authCode) {

    const fullAuth = await fullMicrosoftAuthFlow(authCode, AUTH_MODE.FULL)

    // Advance expiry by 10 seconds to avoid close calls.
    const now = new Date().getTime()

    const ret = ConfigManager.addMicrosoftAuthAccount(
        fullAuth.mcProfile.id,
        fullAuth.mcToken.access_token,
        fullAuth.mcProfile.name,
        calculateExpiryDate(now, fullAuth.mcToken.expires_in),
        fullAuth.accessToken.access_token,
        fullAuth.accessToken.refresh_token,
        calculateExpiryDate(now, fullAuth.accessToken.expires_in)
    )
    ConfigManager.save()

    return ret
}

/**
 * Remove a Mojang account. This will invalidate the access token associated
 * with the account and then remove it from the database.
 * 
 * @param {string} uuid The UUID of the account to be removed.
 * @returns {Promise.<void>} Promise which resolves to void when the action is complete.
 */
exports.removeMojangAccount = async function(uuid){
    try {
        const authAcc = ConfigManager.getAuthAccount(uuid)
        const response = await MojangRestAPI.invalidate(authAcc.accessToken, ConfigManager.getClientToken())
        if(response.responseStatus === RestResponseStatus.SUCCESS) {
            ConfigManager.removeAuthAccount(uuid)
            ConfigManager.save()
            return Promise.resolve()
        } else {
            log.error('Error while removing account', response.error)
            return Promise.reject(response.error)
        }
    } catch (err){
        log.error('Error while removing account', err)
        return Promise.reject(err)
    }
}

/**
 * Remove a Microsoft account. It is expected that the caller will invoke the OAuth logout
 * through the ipc renderer.
 * 
 * @param {string} uuid The UUID of the account to be removed.
 * @returns {Promise.<void>} Promise which resolves to void when the action is complete.
 */
exports.removeMicrosoftAccount = async function(uuid){
    try {
        ConfigManager.removeAuthAccount(uuid)
        ConfigManager.save()
        return Promise.resolve()
    } catch (err){
        log.error('Error while removing account', err)
        return Promise.reject(err)
    }
}

/**
 * Validate the selected account with Mojang's authserver. If the account is not valid,
 * we will attempt to refresh the access token and update that value. If that fails, a
 * new login will be required.
 * 
 * @returns {Promise.<boolean>} Promise which resolves to true if the access token is valid,
 * otherwise false.
 */
async function validateSelectedMojangAccount(){
    const current = ConfigManager.getSelectedAccount()
    const response = await MojangRestAPI.validate(current.accessToken, ConfigManager.getClientToken())

    if(response.responseStatus === RestResponseStatus.SUCCESS) {
        const isValid = response.data
        if(!isValid){
            const refreshResponse = await MojangRestAPI.refresh(current.accessToken, ConfigManager.getClientToken())
            if(refreshResponse.responseStatus === RestResponseStatus.SUCCESS) {
                const session = refreshResponse.data
                ConfigManager.updateMojangAuthAccount(current.uuid, session.accessToken)
                ConfigManager.save()
            } else {
                log.error('Error while validating selected profile:', refreshResponse.error)
                log.info('Account access token is invalid.')
                return false
            }
            log.info('Account access token validated.')
            return true
        } else {
            log.info('Account access token validated.')
            return true
        }
    }
    
}

/**
 * Validate the selected account with Microsoft's authserver. If the account is not valid,
 * we will attempt to refresh the access token and update that value. If that fails, a
 * new login will be required.
 * 
 * @returns {Promise.<boolean>} Promise which resolves to true if the access token is valid,
 * otherwise false.
 */
async function validateSelectedMicrosoftAccount(){
    const current = ConfigManager.getSelectedAccount()
    const now = new Date().getTime()
    const mcExpiresAt = Date.parse(current.expiresAt)
    const mcExpired = now >= mcExpiresAt

    if(!mcExpired) {
        return true
    }

    // MC token expired. Check MS token.

    const msExpiresAt = Date.parse(current.microsoft.expires_at)
    const msExpired = now >= msExpiresAt

    if(msExpired) {
        // MS expired, do full refresh.
        try {
            const res = await fullMicrosoftAuthFlow(current.microsoft.refresh_token, AUTH_MODE.MS_REFRESH)

            ConfigManager.updateMicrosoftAuthAccount(
                current.uuid,
                res.mcToken.access_token,
                res.accessToken.access_token,
                res.accessToken.refresh_token,
                calculateExpiryDate(now, res.accessToken.expires_in),
                calculateExpiryDate(now, res.mcToken.expires_in)
            )
            ConfigManager.save()
            return true
        } catch(err) {
            return false
        }
    } else {
        // Only MC expired, use existing MS token.
        try {
            const res = await fullMicrosoftAuthFlow(current.microsoft.access_token, AUTH_MODE.MC_REFRESH)

            ConfigManager.updateMicrosoftAuthAccount(
                current.uuid,
                res.mcToken.access_token,
                current.microsoft.access_token,
                current.microsoft.refresh_token,
                current.microsoft.expires_at,
                calculateExpiryDate(now, res.mcToken.expires_in)
            )
            ConfigManager.save()
            return true
        }
        catch(err) {
            return false
        }
    }
}

/**
 * Validate the selected auth account.
 * 
 * @returns {Promise.<boolean>} Promise which resolves to true if the access token is valid,
 * otherwise false.
 */
exports.validateSelected = async function(){
    const current = ConfigManager.getSelectedAccount()

    if(current.type === 'microsoft') {
        return await validateSelectedMicrosoftAccount()
    } else {
        return await validateSelectedMojangAccount()
    }
    
}