Stable per-branch report URLs and a reachable live view (v0.9.8)

A report directory holding a single page is now linked and served as a
directory, so Gradle's --profile report has a stable permanent URL although
its file name carries the build timestamp.

The permanent link moves to the build it resolves to — the branch's latest
green build — and appears on every build table instead of only the branches
view. The Current tab gave way to a link in the artifacts column, shown
while a build runs; /current itself stays routable.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/main/kotlin/de/hoennig/gittally/server/ArtifactFileController.kt

@@ -17,6 +17,7 @@ import java.net.URI
 import java.nio.file.Files
 import java.nio.file.LinkOption
 import java.nio.file.Path
+import kotlin.streams.asSequence
 
 /**
  * Streams stored build artifacts. Status pages, JSON, and logs are served with
@@ -31,12 +32,15 @@ class ArtifactFileController(
     fun serve(
         @PathVariable artifactKey: String,
         @PathVariable path: String,
+        request: HttpServletRequest,
     ): ResponseEntity<Resource> {
         val artifactDir =
             artifactStore.artifactDir(artifactKey)
                 ?: return ResponseEntity.notFound().build()
+        val relativePath = path.removePrefix("/").removeSuffix("/")
+        directoryResponse(artifactDir, relativePath, request, noStore = true)?.let { return it }
         val file =
-            resolveFile(artifactDir, path.removePrefix("/"))
+            resolveFile(artifactDir, relativePath)
                 ?: return ResponseEntity.notFound().build()
         return respond(file, noStore = file.extension() in NO_CACHE_EXTENSIONS)
     }
@@ -66,24 +70,53 @@ class ArtifactFileController(
             // the bare permanent URL is the artifact-index page rendered by the UI controller
             return redirect(request.requestURI.trimEnd('/'))
         }
-        val target = artifactDir.resolve(relativePath).normalize()
-        if (target.startsWith(artifactDir) &&
-            Files.isDirectory(target, LinkOption.NOFOLLOW_LINKS) &&
-            Files.isRegularFile(target.resolve(INDEX_FILE), LinkOption.NOFOLLOW_LINKS)
-        ) {
-            // relative links inside a report only resolve correctly under a trailing-slash URL
-            return if (request.requestURI.endsWith("/")) {
-                respond(target.resolve(INDEX_FILE), noStore = true)
-            } else {
-                redirect(request.requestURI + "/")
-            }
-        }
+        directoryResponse(artifactDir, relativePath, request, noStore = true)?.let { return it }
         val file =
             resolveFile(artifactDir, relativePath)
                 ?: return ResponseEntity.notFound().build()
         return respond(file, noStore = true)
     }
 
+    /**
+     * The response for a directory URL, or null when [relativePath] is no servable directory.
+     * A directory serves its `index.html`, or the single HTML page of a report directory without
+     * one — that keeps Gradle's `--profile` report, whose file name carries the build timestamp,
+     * reachable under a stable URL.
+     */
+    private fun directoryResponse(
+        artifactDir: Path,
+        relativePath: String,
+        request: HttpServletRequest,
+        noStore: Boolean,
+    ): ResponseEntity<Resource>? {
+        val target = artifactDir.resolve(relativePath).normalize()
+        if (relativePath.isBlank() || !target.startsWith(artifactDir) || !Files.isDirectory(target, LinkOption.NOFOLLOW_LINKS)) {
+            return null
+        }
+        val page = directoryPage(target) ?: return null
+        // relative links inside a report only resolve correctly under a trailing-slash URL
+        return if (request.requestURI.endsWith("/")) {
+            respond(page, noStore = noStore)
+        } else {
+            redirect(request.requestURI + "/")
+        }
+    }
+
+    private fun directoryPage(dir: Path): Path? {
+        val index = dir.resolve(INDEX_FILE)
+        if (Files.isRegularFile(index, LinkOption.NOFOLLOW_LINKS)) {
+            return index
+        }
+        return Files
+            .list(dir)
+            .use { entries ->
+                entries
+                    .asSequence()
+                    .filter { Files.isRegularFile(it, LinkOption.NOFOLLOW_LINKS) && it.extension() == "html" }
+                    .toList()
+            }.singleOrNull()
+    }
+
     /** Resolves [relativePath] inside [artifactDir]; null when it escapes the directory or is no regular file. */
     private fun resolveFile(
         artifactDir: Path,