From 9bfabcc1f1a04eeb5f704101d7b609c95f344fe6 Mon Sep 17 00:00:00 2001
From: Sam <sam@sam.wf>
Date: Tue, 14 Mar 2023 16:16:07 +0100
Subject: [PATCH] feat: cancel user deletion

---
 backend/db/user.go                            | 17 +++++
 backend/routes/auth/discord.go                | 23 ++++++
 backend/routes/auth/routes.go                 |  4 ++
 backend/routes/auth/undelete.go               | 70 +++++++++++++++++++
 backend/server/server.go                      |  6 +-
 frontend/src/lib/api/fetch.ts                 |  9 ++-
 .../routes/auth/login/discord/+page.server.ts |  3 +
 .../routes/auth/login/discord/+page.svelte    | 44 +++++++++++-
 frontend/src/routes/settings/invites/+page.ts |  2 +-
 9 files changed, 169 insertions(+), 9 deletions(-)
 create mode 100644 backend/routes/auth/undelete.go

diff --git a/backend/db/user.go b/backend/db/user.go
index eb3a7ae..36134b2 100644
--- a/backend/db/user.go
+++ b/backend/db/user.go
@@ -284,3 +284,20 @@ func (db *DB) DeleteUser(ctx context.Context, tx pgx.Tx, id xid.ID, selfDelete b
 	}
 	return nil
 }
+
+func (db *DB) UndoDeleteUser(ctx context.Context, id xid.ID) error {
+	sql, args, err := sq.Update("users").
+		Set("deleted_at", nil).
+		Set("self_delete", nil).
+		Set("delete_reason", nil).
+		Where("id = ?", id).ToSql()
+	if err != nil {
+		return errors.Wrap(err, "building sql")
+	}
+
+	_, err = db.Exec(ctx, sql, args...)
+	if err != nil {
+		return errors.Wrap(err, "executing query")
+	}
+	return nil
+}
diff --git a/backend/routes/auth/discord.go b/backend/routes/auth/discord.go
index 0c2b475..8e6f7ba 100644
--- a/backend/routes/auth/discord.go
+++ b/backend/routes/auth/discord.go
@@ -3,6 +3,7 @@ package auth
 import (
 	"net/http"
 	"os"
+	"time"
 
 	"codeberg.org/u1f320/pronouns.cc/backend/db"
 	"codeberg.org/u1f320/pronouns.cc/backend/log"
@@ -41,6 +42,9 @@ type discordCallbackResponse struct {
 	Discord       string `json:"discord,omitempty"` // username, for UI purposes
 	Ticket        string `json:"ticket,omitempty"`
 	RequireInvite bool   `json:"require_invite"` // require an invite for signing up
+
+	IsDeleted bool       `json:"is_deleted"`
+	DeletedAt *time.Time `json:"deleted_at,omitempty"`
 }
 
 func (s *Server) discordCallback(w http.ResponseWriter, r *http.Request) error {
@@ -77,6 +81,25 @@ func (s *Server) discordCallback(w http.ResponseWriter, r *http.Request) error {
 
 	u, err := s.DB.DiscordUser(ctx, du.ID)
 	if err == nil {
+		if u.DeletedAt != nil && *u.SelfDelete {
+			// store cancel delete token
+			token := undeleteToken()
+			err = s.saveUndeleteToken(ctx, u.ID, token)
+			if err != nil {
+				log.Errorf("saving undelete token: %v", err)
+				return err
+			}
+
+			render.JSON(w, r, discordCallbackResponse{
+				HasAccount: true,
+				Token:      token,
+				User:       dbUserToUserResponse(u, []db.Field{}),
+				IsDeleted:  true,
+				DeletedAt:  u.DeletedAt,
+			})
+			return nil
+		}
+
 		err = u.UpdateFromDiscord(ctx, s.DB, du)
 		if err != nil {
 			log.Errorf("updating user %v with Discord info: %v", u.ID, err)
diff --git a/backend/routes/auth/routes.go b/backend/routes/auth/routes.go
index 05e6628..e19fcf2 100644
--- a/backend/routes/auth/routes.go
+++ b/backend/routes/auth/routes.go
@@ -78,6 +78,10 @@ func Mount(srv *server.Server, r chi.Router) {
 		r.With(server.MustAuth).Get("/tokens", server.WrapHandler(s.getTokens))
 		r.With(server.MustAuth).Post("/tokens", server.WrapHandler(s.createToken))
 		r.With(server.MustAuth).Delete("/tokens/{id}", server.WrapHandler(s.deleteToken))
+
+		// cancel user delete
+		// uses a special token, so handled in the function itself
+		r.Get("/cancel-delete", server.WrapHandler(s.cancelDelete))
 	})
 }
 
diff --git a/backend/routes/auth/undelete.go b/backend/routes/auth/undelete.go
new file mode 100644
index 0000000..c9db8f1
--- /dev/null
+++ b/backend/routes/auth/undelete.go
@@ -0,0 +1,70 @@
+package auth
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"net/http"
+
+	"codeberg.org/u1f320/pronouns.cc/backend/log"
+	"codeberg.org/u1f320/pronouns.cc/backend/server"
+	"emperror.dev/errors"
+	"github.com/go-chi/render"
+	"github.com/mediocregopher/radix/v4"
+	"github.com/rs/xid"
+)
+
+func (s *Server) cancelDelete(w http.ResponseWriter, r *http.Request) error {
+	ctx := r.Context()
+	token := r.Header.Get("X-Delete-Token")
+	if token == "" {
+		return server.APIError{Code: server.ErrForbidden}
+	}
+
+	id, err := s.getUndeleteToken(ctx, token)
+	if err != nil {
+		log.Errorf("getting undelete token: %v", err)
+		return server.APIError{Code: server.ErrNotFound} // assume invalid token
+	}
+
+	err = s.DB.UndoDeleteUser(ctx, id)
+	if err != nil {
+		log.Errorf("executing undelete query: %v", err)
+	}
+
+	render.JSON(w, r, map[string]any{"success": true})
+	return nil
+}
+
+func undeleteToken() string {
+	b := make([]byte, 32)
+
+	_, err := rand.Read(b)
+	if err != nil {
+		panic(err)
+	}
+
+	return base64.RawURLEncoding.EncodeToString(b)
+}
+
+func (s *Server) saveUndeleteToken(ctx context.Context, userID xid.ID, token string) error {
+	err := s.DB.Redis.Do(ctx, radix.Cmd(nil, "SET", "undelete:"+token, userID.String(), "EX", "3600"))
+	if err != nil {
+		return errors.Wrap(err, "setting undelete key")
+	}
+	return nil
+}
+
+func (s *Server) getUndeleteToken(ctx context.Context, token string) (userID xid.ID, err error) {
+	var idString string
+	err = s.DB.Redis.Do(ctx, radix.Cmd(&idString, "GET", "undelete:"+token))
+	if err != nil {
+		return userID, errors.Wrap(err, "getting undelete key")
+	}
+
+	userID, err = xid.FromString(idString)
+	if err != nil {
+		return userID, errors.Wrap(err, "parsing ID")
+	}
+	return userID, nil
+}
diff --git a/backend/server/server.go b/backend/server/server.go
index 44365e3..1d419e3 100644
--- a/backend/server/server.go
+++ b/backend/server/server.go
@@ -77,15 +77,15 @@ func New() (*Server, error) {
 	// set scopes
 	// users
 	rateLimiter.Scope("GET", "/users/*", 60)
-	rateLimiter.Scope("PATCH", "/users/@me", 5)
+	rateLimiter.Scope("PATCH", "/users/@me", 10)
 
 	// members
 	rateLimiter.Scope("GET", "/users/*/members", 60)
 	rateLimiter.Scope("GET", "/users/*/members/*", 60)
 
-	rateLimiter.Scope("POST", "/members", 5)
+	rateLimiter.Scope("POST", "/members", 10)
 	rateLimiter.Scope("GET", "/members/*", 60)
-	rateLimiter.Scope("PATCH", "/members/*", 5)
+	rateLimiter.Scope("PATCH", "/members/*", 20)
 	rateLimiter.Scope("DELETE", "/members/*", 5)
 
 	// auth
diff --git a/frontend/src/lib/api/fetch.ts b/frontend/src/lib/api/fetch.ts
index b147ea5..3f080c2 100644
--- a/frontend/src/lib/api/fetch.ts
+++ b/frontend/src/lib/api/fetch.ts
@@ -3,13 +3,18 @@ import { PUBLIC_BASE_URL } from "$env/static/public";
 
 export async function apiFetch<T>(
   path: string,
-  { method, body, token }: { method?: string; body?: any; token?: string },
+  {
+    method,
+    body,
+    token,
+    headers,
+  }: { method?: string; body?: any; token?: string; headers?: Record<string, string> },
 ) {
-
   const resp = await fetch(`${PUBLIC_BASE_URL}/api/v1${path}`, {
     method: method || "GET",
     headers: {
       ...(token ? { Authorization: token } : {}),
+      ...(headers ? headers : {}),
       "Content-Type": "application/json",
     },
     body: body ? JSON.stringify(body) : null,
diff --git a/frontend/src/routes/auth/login/discord/+page.server.ts b/frontend/src/routes/auth/login/discord/+page.server.ts
index 472ca94..ec5828f 100644
--- a/frontend/src/routes/auth/login/discord/+page.server.ts
+++ b/frontend/src/routes/auth/login/discord/+page.server.ts
@@ -30,4 +30,7 @@ interface CallbackResponse {
   discord?: string;
   ticket?: string;
   require_invite: boolean;
+
+  is_deleted: boolean;
+  deleted_at?: Date;
 }
diff --git a/frontend/src/routes/auth/login/discord/+page.svelte b/frontend/src/routes/auth/login/discord/+page.svelte
index ca5e80d..703de43 100644
--- a/frontend/src/routes/auth/login/discord/+page.svelte
+++ b/frontend/src/routes/auth/login/discord/+page.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
   import { onMount } from "svelte";
-  import { Alert, Icon } from "sveltestrap";
+  import { Alert, Button, Icon } from "sveltestrap";
 
   import { goto } from "$app/navigation";
   import type { APIError, MeUser } from "$lib/api/entities";
@@ -16,7 +16,7 @@
   export let data: PageData;
 
   onMount(() => {
-    if (data.token && data.user) {
+    if (!data.is_deleted && data.token && data.user) {
       localStorage.setItem("pronouns-token", data.token);
       localStorage.setItem("pronouns-user", JSON.stringify(data.user));
       userStore.set(data.user);
@@ -46,6 +46,25 @@
       data.error = e as APIError;
     }
   };
+
+  let deleteCancelled = false;
+  let deleteError: APIError | null = null;
+  const cancelDelete = async () => {
+    try {
+      await apiFetch<any>("/auth/cancel-delete", {
+        method: "GET",
+        headers: {
+          "X-Delete-Token": data.token!,
+        },
+      });
+
+      deleteCancelled = true;
+      deleteError = null;
+    } catch (e) {
+      deleteCancelled = false;
+      deleteError = e as APIError;
+    }
+  };
 </script>
 
 <svelte:head>
@@ -91,8 +110,27 @@
       By signing up, you agree to the <a href="/page/tos">terms of service</a> and the
       <a href="/page/privacy">privacy policy</a>.
     </div>
-    <button type="submit" class="btn btn-primary">Sign up</button>
+    <Button type="submit" color="primary">Sign up</Button>
   </form>
+{:else if data.is_deleted && data.token}
+  <p>Your account is pending deletion since {data.deleted_at}.</p>
+  <p>If you wish to cancel deletion, press the button below.</p>
+  <p>
+    <Button color="primary" on:click={cancelDelete} disabled={deleteCancelled}
+      >Cancel account deletion</Button
+    >
+  </p>
+  {#if deleteCancelled}
+    <Alert color="secondary" fade={false}>
+      Account deletion cancelled! You can now <a href="/auth/login">log in</a> again.
+    </Alert>
+  {/if}
+  {#if deleteError}
+    <Alert color="danger" fade={false}>
+      <h4 class="alert-heading">An error occurred</h4>
+      <b>{deleteError.code}</b>: {deleteError.message}
+    </Alert>
+  {/if}
 {:else}
   Loading...
 {/if}
diff --git a/frontend/src/routes/settings/invites/+page.ts b/frontend/src/routes/settings/invites/+page.ts
index 15179ca..6e98a33 100644
--- a/frontend/src/routes/settings/invites/+page.ts
+++ b/frontend/src/routes/settings/invites/+page.ts
@@ -17,7 +17,7 @@ export const load = (async () => {
       data.invitesEnabled = false;
       data.invites = [];
     } else {
-      throw error(500, (e as APIError).message);
+      throw error((e as APIError).code, (e as APIError).message);
     }
   }