3 files changed, 102 insertions, 0 deletions
diff --git a/test-runner/src/main/kotlin/org/terst/nav/data/model/GribFile.kt b/test-runner/src/main/kotlin/org/terst/nav/data/model/GribFile.kt
new file mode 100644
index 0000000..9d284b5
--- /dev/null
+++ b/test-runner/src/main/kotlin/org/terst/nav/data/model/GribFile.kt
@@ -0,0 +1,40 @@
+package org.terst.nav.data.model
+
+import java.time.Instant
+
+/**
+ * Metadata record for a locally-stored GRIB2 file.
+ *
+ * @param region          The geographic region this file covers.
+ * @param modelRunTime    When the NWP model run that produced this file started (UTC).
+ * @param forecastHours   Number of forecast hours included in this file.
+ * @param downloadedAt    Wall-clock time when the file was saved locally.
+ * @param filePath        Absolute path to the GRIB2 file on the device filesystem.
+ * @param sizeBytes       File size in bytes.
+ */
+data class GribFile(
+    val region: GribRegion,
+    val modelRunTime: Instant,
+    val forecastHours: Int,
+    val downloadedAt: Instant,
+    val filePath: String,
+    val sizeBytes: Long
+) {
+    /**
+     * The wall-clock time at which this GRIB file's forecast data expires.
+     * Per design doc §6.3: valid until model run + forecast hours.
+     */
+    fun validUntil(): Instant = modelRunTime.plusSeconds(forecastHours.toLong() * 3600)
+
+    /**
+     * Returns true if the data has expired relative to [now].
+     * Per design doc §6.3: stale after model run + forecast hour.
+     */
+    fun isStale(now: Instant = Instant.now()): Boolean = now.isAfter(validUntil())
+
+    /**
+     * Age of the download in seconds.
+     */
+    fun ageSeconds(now: Instant = Instant.now()): Long =
+        now.epochSecond - downloadedAt.epochSecond
+}
diff --git a/test-runner/src/main/kotlin/org/terst/nav/data/model/GribRegion.kt b/test-runner/src/main/kotlin/org/terst/nav/data/model/GribRegion.kt
new file mode 100644
index 0000000..5e32d6c
--- /dev/null
+++ b/test-runner/src/main/kotlin/org/terst/nav/data/model/GribRegion.kt
@@ -0,0 +1,20 @@
+package org.terst.nav.data.model
+
+/**
+ * Geographic bounding box used to identify a GRIB download region.
+ * @param name  Human-readable region name (e.g. "North Atlantic", "English Channel")
+ */
+data class GribRegion(
+    val name: String,
+    val latMin: Double,
+    val latMax: Double,
+    val lonMin: Double,
+    val lonMax: Double
+) {
+    /** True if [lat]/[lon] falls within this region's bounding box. */
+    fun contains(lat: Double, lon: Double): Boolean =
+        lat in latMin..latMax && lon in lonMin..lonMax
+
+    /** Area in square degrees (rough proxy for download size estimate). */
+    fun areaDegrees(): Double = (latMax - latMin) * (lonMax - lonMin)
+}
diff --git a/test-runner/src/main/kotlin/org/terst/nav/data/storage/GribFileManager.kt b/test-runner/src/main/kotlin/org/terst/nav/data/storage/GribFileManager.kt
new file mode 100644
index 0000000..e17e5ca
--- /dev/null
+++ b/test-runner/src/main/kotlin/org/terst/nav/data/storage/GribFileManager.kt
@@ -0,0 +1,42 @@
+package org.terst.nav.data.storage
+
+import org.terst.nav.data.model.GribFile
+import org.terst.nav.data.model.GribRegion
+import java.time.Instant
+
+interface GribFileManager {
+    /** Save metadata for a newly-downloaded GRIB file. */
+    fun saveMetadata(file: GribFile)
+    /** Return all stored GRIB files for [region], newest first. */
+    fun listFiles(region: GribRegion): List<GribFile>
+    /** Return the most-recently-downloaded GRIB file for [region], or null if none. */
+    fun latestFile(region: GribRegion): GribFile?
+    /** Delete a specific GRIB file's metadata and from disk. Returns true if deleted. */
+    fun delete(file: GribFile): Boolean
+    /** Delete all GRIB files older than [before]. Returns count of deleted files. */
+    fun purgeOlderThan(before: Instant): Int
+    /** Total size in bytes of all stored GRIB files. */
+    fun totalSizeBytes(): Long
+}
+
+class InMemoryGribFileManager : GribFileManager {
+    private val files = mutableListOf<GribFile>()
+
+    override fun saveMetadata(file: GribFile) { files.add(file) }
+
+    override fun listFiles(region: GribRegion): List<GribFile> =
+        files.filter { it.region.name == region.name }
+             .sortedByDescending { it.downloadedAt }
+
+    override fun latestFile(region: GribRegion): GribFile? = listFiles(region).firstOrNull()
+
+    override fun delete(file: GribFile): Boolean = files.remove(file)
+
+    override fun purgeOlderThan(before: Instant): Int {
+        val toRemove = files.filter { it.downloadedAt.isBefore(before) }
+        files.removeAll(toRemove)
+        return toRemove.size
+    }
+
+    override fun totalSizeBytes(): Long = files.sumOf { it.sizeBytes }
+}