From cd82fabfac3120179f947fba331025676dc1af7f Mon Sep 17 00:00:00 2001
From: Natsuu <natsukawa247@outlook.com>
Date: Wed, 14 Jan 2026 04:40:03 +0000
Subject: feat: add functionality to retrieve installed game versions

---
 src-tauri/src/main.rs              | 37 +++++++++++++++++++++++++++++++++++++
 ui/src/components/BottomBar.svelte |  7 +++++--
 ui/src/stores/game.svelte.ts       | 30 ++++++++++++++++++++++++++----
 3 files changed, 68 insertions(+), 6 deletions(-)

diff --git a/src-tauri/src/main.rs b/src-tauri/src/main.rs
index d7ae9a4..bf7504d 100644
--- a/src-tauri/src/main.rs
+++ b/src-tauri/src/main.rs
@@ -586,6 +586,42 @@ async fn get_versions() -> Result<Vec<core::manifest::Version>, String> {
     }
 }
 
+#[tauri::command]
+async fn get_installed_versions(app_handle: tauri::AppHandle) -> Result<Vec<String>, String> {
+    let game_dir = app_handle
+        .path()
+        .app_data_dir()
+        .map_err(|e| format!("Failed to get app data dir: {}", e))?;
+    
+    let versions_dir = game_dir.join("versions");
+    
+    if !versions_dir.exists() {
+        return Ok(Vec::new());
+    }
+    
+    let mut installed_versions = Vec::new();
+    
+    if let Ok(entries) = std::fs::read_dir(versions_dir) {
+        for entry in entries {
+            if let Ok(entry) = entry {
+                if let Ok(file_type) = entry.file_type() {
+                    if file_type.is_dir() {
+                        if let Ok(file_name) = entry.file_name().into_string() {
+                            // Optionally verify if {version_id}.json exists inside
+                            let json_path = entry.path().join(format!("{}.json", file_name));
+                            if json_path.exists() {
+                                installed_versions.push(file_name);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    
+    Ok(installed_versions)
+}
+
 #[tauri::command]
 async fn login_offline(
     window: Window,
@@ -784,6 +820,7 @@ fn main() {
         .invoke_handler(tauri::generate_handler![
             start_game,
             get_versions,
+            get_installed_versions,
             login_offline,
             get_active_account,
             logout,
diff --git a/ui/src/components/BottomBar.svelte b/ui/src/components/BottomBar.svelte
index dcad9e8..a96b086 100644
--- a/ui/src/components/BottomBar.svelte
+++ b/ui/src/components/BottomBar.svelte
@@ -65,10 +65,13 @@
       >
         {#if gameState.versions.length === 0}
           <option>Loading...</option>
+        {:else if gameState.installedVersionIds.length === 0}
+          <option disabled>No installed versions</option>
         {:else}
           {#each gameState.versions as version}
-            <option value={version.id}>{version.id} ({version.type})</option
-            >
+            {#if gameState.installedVersionIds.includes(version.id)}
+              <option value={version.id}>{version.id} ({version.type})</option>
+            {/if}
           {/each}
         {/if}
       </select>
diff --git a/ui/src/stores/game.svelte.ts b/ui/src/stores/game.svelte.ts
index 0af3daf..3128cc6 100644
--- a/ui/src/stores/game.svelte.ts
+++ b/ui/src/stores/game.svelte.ts
@@ -5,14 +5,36 @@ import { authState } from "./auth.svelte";
 
 export class GameState {
   versions = $state<Version[]>([]);
+  installedVersionIds = $state<string[]>([]);
   selectedVersion = $state("");
 
   async loadVersions() {
     try {
-      this.versions = await invoke<Version[]>("get_versions");
-      if (this.versions.length > 0) {
-        const latest = this.versions.find((v) => v.type === "release");
-        this.selectedVersion = latest ? latest.id : this.versions[0].id;
+      // Fetch both full version list and installed versions
+      const [allVersions, installedIds] = await Promise.all([
+        invoke<Version[]>("get_versions"),
+        invoke<string[]>("get_installed_versions")
+      ]);
+      
+      this.versions = allVersions;
+      this.installedVersionIds = installedIds;
+
+      if (this.installedVersionIds.length > 0) {
+        // Find the first installed version that appears in our manifest (preserving order)
+        // Usually we want the latest release that is installed
+        const installedVersions = this.versions.filter(v => this.installedVersionIds.includes(v.id));
+        
+        // Try to find latest release among installed
+        const latestInstalledRelease = installedVersions.find(v => v.type === "release");
+        
+        if (latestInstalledRelease) {
+          this.selectedVersion = latestInstalledRelease.id;
+        } else if (installedVersions.length > 0) {
+          this.selectedVersion = installedVersions[0].id;
+        } else {
+            // Fallback to just the first ID if not in manifest
+            this.selectedVersion = this.installedVersionIds[0];
+        }
       }
     } catch (e) {
       console.error("Failed to fetch versions:", e);
-- 
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