Roughly working account-merge-by-email callback endpoint

services/web/app/coffee/Features/AccountMerge/AccountMergeEmailController.coffee

@@ -1,5 +1,44 @@
+UserGetter = require '../User/UserGetter'
+UserUpdater = require '../User/UserUpdater'
+OneTimeTokenHandler = require '../Security/OneTimeTokenHandler'
+logger = require 'logger-sharelatex'
+Settings = require 'settings-sharelatex'
+
 
 module.exports = AccountMergeEmailController =
 
 	confirmMergeFromEmail: (req, res, next) ->
-		return res.render('account_merge/finish', {})
+		token = req.query.token
+		if !token
+			return res.status(400).send()
+		OneTimeTokenHandler.getValueFromTokenAndExpire 'account-merge-email-to-ol', token, (err, data) ->
+			return next(err) if err?
+			if !data
+				return res.status(404).send()
+			if data.origin != 'sl'
+				logger.log {}, "Only sharelatex origin supported"
+				# TODO: better error handling
+				return res.status(501).send()
+			{ sl_id, v1_id, final_email } = data
+			UserGetter.getUser sl_id, {_id: 1, overleaf: 1}, (err, user) ->
+				return next(err) if err?
+				if !user?
+					logger.err {userId: sl_id}, 'SL user not found for account-merge'
+					# TODO: better error handling
+					return res.status(400).send()
+				if user?.overleaf?.id?
+					logger.err {userId: sl_id}, 'SL user is already linked to overleaf'
+					return res.status(400).send()
+				logger.log {sl_id, v1_id, final_email, origin: data.origin},
+					"[AccountMergeEmailController] about to merge sharelatex and overleaf-v1 accounts"
+				UserUpdater.updateUser sl_id, {
+					'$set': {
+						'overleaf.id': v1_id,
+						email: final_email
+					}
+				}, (err) ->
+					return next(err) if err?
+					res.render 'account_merge/finish', {
+						finalEmail: final_email,
+						continueUrl: "#{Settings.accountMerge.sharelatexHost}/user/login_to_ol_v2"
+					}

services/web/app/views/account_merge/finish.pug

@@ -12,4 +12,6 @@ block content
 						div.container-fluid
 							.row
 								.col-md-12
-									p Test
+									p New email is #{finalEmail}
+									p
+										a.btn.btn-lg.btn-success(href=continueUrl) Continue

services/web/public/coffee/main/account-merge-checker.coffee

@@ -8,7 +8,6 @@ define [
 		$scope.olEmail = ""
 		$scope.errorCode = null
 		$scope.success = null
-		console.log ">>>> here"
 
 		$scope.submitEmail = () ->
 			return if !$scope.olEmail
@@ -16,15 +15,12 @@ define [
 				overleafEmail: $scope.olEmail
 				_csrf: window.csrfToken
 			}
-			console.log ">>>> sending email", data
 			$scope.errorCode = null
 			$http.post("/account-merge/email/overleaf", data)
 				.then (resp) ->
-					console.log ">>>> success", resp
 					$scope.errorCode = null
 					$scope.success = true
 				.catch (resp) ->
-					console.log ">>>> error", resp
 					$scope.errorCode = resp?.data?.errorCode || 'default_error'
 					$scope.success = false