Fix unhelpful generic 401 error on AniList expiry (#3888)

A leftover of what I assume was the v1 API behaviour handling manually
multiplied the `expires` values by 1,000, supposedly to make it a
millisecond value. However, AL tokens have been saved as milliseconds
since at least the v2 API implementation in 2018, so this has made
every expiry comparison ludicrously impossible.

Example:
millisecond timestamp:
1788529931115 (2026-09-04T13:52:11.115Z)
*1,000
1788529931115000 (+58646-04-04T21:45:15Z)

So any expiry comparisons would say "yes this token is still totally
valid", causing Mihon to send expired credentials and AL to respond
with a 401.

With these changes (which include some loosely associated clean-up),
we now correctly identify expired credentials before we attempt any AL
requests & actually show a toast with the "Token expired." error
message for the first time in 8 years or so?

I was able to keep the new ALOAuth shape compatible with
already-serialized data, though whenever a user (re-)links AL from now
on, both the `token_type` and `expiresIn` fields won't exist any more.
Since they had no use in the current code anyway, I don't consider
this a problem.

I took the liberty of adding basic instructions to the error message
but these can't be i18n'd properly so I kept it short and sweet.

---

Side effect of expired credentials is Mihon erasing the token in
storage, meaning AL disappears from the tracker sheet until re-linked.
I would say this is acceptable, but we might see panicked users in
support saying "Mihon deleted my AL links" or something.

CHANGELOG.md

@@ -20,6 +20,7 @@ The format is a modified version of [Keep a Changelog](https://keepachangelog.co
 - Show updates and upcoming filter icon as active for categories ([@Secozzi](https://github.com/Secozzi)) ([#3772](https://github.com/mihonapp/mihon/pull/3772))
 - Show scores in MangaUpdates search results (and authors for `id:` prefix searches) ([@MajorTanya](https://github.com/MajorTanya)) ([#3795](https://github.com/mihonapp/mihon/pull/3795))
 - Remove whitespace from MAL and MB `id:` prefix search inputs before searching ([@MajorTanya](https://github.com/MajorTanya)) ([#3793](https://github.com/mihonapp/mihon/pull/3793))
+- Show a helpful error message for expired AniList credentials ([@MajorTanya](https://github.com/MajorTanya)) ([#3888](https://github.com/mihonapp/mihon/pull/3888))
 
 ### Fixed
 - Fixed app and extension update check running again on configuration change ([@AntsyLich](https://github.com/AntsyLich)) ([#3708](https://github.com/mihonapp/mihon/pull/3708))

app/src/main/java/eu/kanade/tachiyomi/data/track/anilist/Anilist.kt

@@ -218,7 +218,7 @@ class Anilist(id: Long) : BaseTracker(id, "AniList"), DeletableTracker {
 
     suspend fun login(token: String) {
         try {
-            val oauth = api.createOAuth(token)
+            val oauth = ALOAuth(token)
             interceptor.setAuth(oauth)
             val currentUser = api.getCurrentUser()
             scorePreference.set(currentUser.mediaListOptions.scoreFormat)

app/src/main/java/eu/kanade/tachiyomi/data/track/anilist/AnilistApi.kt

@@ -5,7 +5,6 @@ import androidx.core.net.toUri
 import eu.kanade.tachiyomi.data.database.models.Track
 import eu.kanade.tachiyomi.data.track.anilist.dto.ALAddMangaResult
 import eu.kanade.tachiyomi.data.track.anilist.dto.ALCurrentUserResult
-import eu.kanade.tachiyomi.data.track.anilist.dto.ALOAuth
 import eu.kanade.tachiyomi.data.track.anilist.dto.ALSearchResult
 import eu.kanade.tachiyomi.data.track.anilist.dto.ALUserListMangaQueryResult
 import eu.kanade.tachiyomi.data.track.anilist.dto.ALUserViewerData
@@ -283,10 +282,6 @@ class AnilistApi(val client: OkHttpClient, interceptor: AnilistInterceptor) {
         return findLibManga(track, userId) ?: throw Exception("Could not find manga")
     }
 
-    fun createOAuth(token: String): ALOAuth {
-        return ALOAuth(token, "Bearer", System.currentTimeMillis() + 31536000000, 31536000000)
-    }
-
     suspend fun getCurrentUser(): ALUserViewerData {
         return withIOContext {
             val query = """

app/src/main/java/eu/kanade/tachiyomi/data/track/anilist/AnilistInterceptor.kt

@@ -2,7 +2,6 @@ package eu.kanade.tachiyomi.data.track.anilist
 
 import eu.kanade.tachiyomi.BuildConfig
 import eu.kanade.tachiyomi.data.track.anilist.dto.ALOAuth
-import eu.kanade.tachiyomi.data.track.anilist.dto.isExpired
 import okhttp3.Interceptor
 import okhttp3.Response
 import java.io.IOException
@@ -11,14 +10,8 @@ class AnilistInterceptor(val anilist: Anilist, private var token: String?) : Int
 
     /**
      * OAuth object used for authenticated requests.
-     *
-     * Anilist returns the date without milliseconds. We fix that and make the token expire 1 minute
-     * before its original expiration date.
      */
     private var oauth: ALOAuth? = null
-        set(value) {
-            field = value?.copy(expires = value.expires * 1000 - 60 * 1000)
-        }
 
     override fun intercept(chain: Interceptor.Chain): Response {
         val originalRequest = chain.request()
@@ -27,17 +20,11 @@ class AnilistInterceptor(val anilist: Anilist, private var token: String?) : Int
             throw Exception("Not authenticated with Anilist")
         }
         if (oauth == null) {
-            oauth = anilist.loadOAuth()
+            oauth = anilist.loadOAuth() ?: throw IOException("No authentication token")
         }
-        // Refresh access token if null or expired.
         if (oauth!!.isExpired()) {
             anilist.logout()
-            throw IOException("Token expired")
-        }
-
-        // Throw on null auth.
-        if (oauth == null) {
-            throw IOException("No authentication token")
+            throw IOException("Token expired. Reconnect AniList in Settings.")
         }
 
         // Add the authorization header to the original request.

app/src/main/java/eu/kanade/tachiyomi/data/track/anilist/dto/ALOAuth.kt

@@ -1,17 +1,18 @@
 package eu.kanade.tachiyomi.data.track.anilist.dto
 
+import kotlinx.serialization.EncodeDefault
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+import kotlin.time.Clock
+import kotlin.time.Duration.Companion.days
+import kotlin.time.Duration.Companion.minutes
 
 @Serializable
 data class ALOAuth(
     @SerialName("access_token")
     val accessToken: String,
-    @SerialName("token_type")
-    val tokenType: String,
-    val expires: Long,
-    @SerialName("expires_in")
-    val expiresIn: Long,
-)
-
-fun ALOAuth.isExpired() = System.currentTimeMillis() > expires
+    @EncodeDefault
+    val expires: Long = Clock.System.now().plus(365.days).toEpochMilliseconds(),
+) {
+    fun isExpired() = Clock.System.now().plus(1.minutes).toEpochMilliseconds() > expires
+}