1 files changed, 128 insertions, 0 deletions
diff --git a/src/main/kotlin/repo/RepoDownloadManager.kt b/src/main/kotlin/repo/RepoDownloadManager.kt
new file mode 100644
index 0000000..d674f23
--- /dev/null
+++ b/src/main/kotlin/repo/RepoDownloadManager.kt
@@ -0,0 +1,128 @@
+
+
+package moe.nea.firmament.repo
+
+import io.ktor.client.call.body
+import io.ktor.client.request.get
+import io.ktor.client.statement.bodyAsChannel
+import io.ktor.utils.io.jvm.nio.copyTo
+import java.io.IOException
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.StandardOpenOption
+import java.util.zip.ZipInputStream
+import kotlinx.coroutines.CoroutineName
+import kotlinx.coroutines.Dispatchers.IO
+import kotlinx.coroutines.withContext
+import kotlinx.serialization.Serializable
+import kotlin.io.path.createDirectories
+import kotlin.io.path.exists
+import kotlin.io.path.inputStream
+import kotlin.io.path.outputStream
+import kotlin.io.path.readText
+import kotlin.io.path.writeText
+import moe.nea.firmament.Firmament
+import moe.nea.firmament.Firmament.logger
+import moe.nea.firmament.util.iterate
+
+
+object RepoDownloadManager {
+
+    val repoSavedLocation = Firmament.DATA_DIR.resolve("repo-extracted")
+    val repoMetadataLocation = Firmament.DATA_DIR.resolve("loaded-repo-sha.txt")
+
+    private fun loadSavedVersionHash(): String? =
+        if (repoSavedLocation.exists()) {
+            if (repoMetadataLocation.exists()) {
+                try {
+                    repoMetadataLocation.readText().trim()
+                } catch (e: IOException) {
+                    null
+                }
+            } else {
+                null
+            }
+        } else null
+
+    private fun saveVersionHash(versionHash: String) {
+        latestSavedVersionHash = versionHash
+        repoMetadataLocation.writeText(versionHash)
+    }
+
+    var latestSavedVersionHash: String? = loadSavedVersionHash()
+        private set
+
+    @Serializable
+    private class GithubCommitsResponse(val sha: String)
+
+    private suspend fun requestLatestGithubSha(): String? {
+        if (RepoManager.Config.branch == "prerelease") {
+            RepoManager.Config.branch = "master"
+        }
+        val response =
+            Firmament.httpClient.get("https://api.github.com/repos/${RepoManager.Config.username}/${RepoManager.Config.reponame}/commits/${RepoManager.Config.branch}")
+        if (response.status.value != 200) {
+            return null
+        }
+        return response.body<GithubCommitsResponse>().sha
+    }
+
+    private suspend fun downloadGithubArchive(url: String): Path = withContext(IO) {
+        val response = Firmament.httpClient.get(url)
+        val targetFile = Files.createTempFile("firmament-repo", ".zip")
+        val outputChannel = Files.newByteChannel(targetFile, StandardOpenOption.CREATE, StandardOpenOption.WRITE)
+        response.bodyAsChannel().copyTo(outputChannel)
+        targetFile
+    }
+
+    /**
+     * Downloads the latest repository from github, setting [latestSavedVersionHash].
+     * @return true, if an update was performed, false, otherwise (no update needed, or wasn't able to complete update)
+     */
+    suspend fun downloadUpdate(force: Boolean): Boolean = withContext(CoroutineName("Repo Update Check")) {
+        val latestSha = requestLatestGithubSha()
+        if (latestSha == null) {
+            logger.warn("Could not request github API to retrieve latest REPO sha.")
+            return@withContext false
+        }
+        val currentSha = loadSavedVersionHash()
+        if (latestSha != currentSha || force) {
+            val requestUrl =
+                "https://github.com/${RepoManager.Config.username}/${RepoManager.Config.reponame}/archive/$latestSha.zip"
+            logger.info("Planning to upgrade repository from $currentSha to $latestSha from $requestUrl")
+            val zipFile = downloadGithubArchive(requestUrl)
+            logger.info("Download repository zip file to $zipFile. Deleting old repository")
+            withContext(IO) { repoSavedLocation.toFile().deleteRecursively() }
+            logger.info("Extracting new repository")
+            withContext(IO) { extractNewRepository(zipFile) }
+            logger.info("Repository loaded on disk.")
+            saveVersionHash(latestSha)
+            return@withContext true
+        } else {
+            logger.debug("Repository on latest sha $currentSha. Not performing update")
+            return@withContext false
+        }
+    }
+
+    private fun extractNewRepository(zipFile: Path) {
+        repoSavedLocation.createDirectories()
+        ZipInputStream(zipFile.inputStream()).use { cis ->
+            while (true) {
+                val entry = cis.nextEntry ?: break
+                if (entry.isDirectory) continue
+                val extractedLocation =
+                    repoSavedLocation.resolve(
+                        entry.name.substringAfter('/', missingDelimiterValue = "")
+                    )
+                if (repoSavedLocation !in extractedLocation.iterate { it.parent }) {
+                    logger.error("Firmament detected an invalid zip file. This is a potential security risk, please report this in the Firmament discord.")
+                    throw RuntimeException("Firmament detected an invalid zip file. This is a potential security risk, please report this in the Firmament discord.")
+                }
+                extractedLocation.parent.createDirectories()
+                extractedLocation.outputStream().use { cis.copyTo(it) }
+            }
+        }
+    }
+
+
+}