Add ursa client

src/main/kotlin/moe/nea/firmament/apis/UrsaManager.kt

@@ -0,0 +1,73 @@
+/*
+ * SPDX-FileCopyrightText: 2023 Linnea Gräf <nea@nea.moe>
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package moe.nea.firmament.apis
+
+import io.ktor.client.request.*
+import io.ktor.client.statement.*
+import io.ktor.http.*
+import java.time.Duration
+import java.time.Instant
+import java.util.*
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.withContext
+import net.minecraft.client.MinecraftClient
+import moe.nea.firmament.Firmament
+
+object UrsaManager {
+    private data class Token(
+        val validUntil: Instant,
+        val token: String,
+        val obtainedFrom: String,
+    ) {
+        fun isValid(host: String) = Instant.now().plusSeconds(60) < validUntil && obtainedFrom == host
+    }
+
+    private var currentToken: Token? = null
+    private val lock = Mutex()
+    private fun getToken(host: String) = currentToken?.takeIf { it.isValid(host) }
+
+    suspend fun request(path: List<String>): HttpResponse {
+        var didLock = false
+        try {
+            val host = "ursa.notenoughupdates.org"
+            var token = getToken(host)
+            if (token == null) {
+                lock.lock()
+                didLock = true
+                token = getToken(host)
+            }
+            val response = Firmament.httpClient.get {
+                url {
+                    this.host = host
+                    appendPathSegments(path, encodeSlash = true)
+                }
+                if (token == null) {
+                    withContext(Dispatchers.IO) {
+                        val mc = MinecraftClient.getInstance()
+                        val serverId = UUID.randomUUID().toString()
+                        mc.sessionService.joinServer(mc.session.profile, mc.session.accessToken, serverId)
+                        header("x-ursa-username", mc.session.profile.name)
+                        header("x-ursa-serverid", serverId)
+                    }
+                } else {
+                    header("x-ursa-token", token.token)
+                }
+            }
+            val savedToken = response.headers["x-ursa-token"]
+            if (savedToken != null) {
+                val validUntil = response.headers["x-ursa-expires"]?.toLongOrNull()?.let { Instant.ofEpochMilli(it) }
+                    ?: (Instant.now() + Duration.ofMinutes(55))
+                currentToken = Token(validUntil, savedToken, host)
+            }
+            return response
+        } finally {
+            if (didLock)
+                lock.unlock()
+        }
+    }
+}