first commit

Services/HdbClientLocator.cs

@@ -0,0 +1,42 @@
+using HanaToolbox.Services.Interfaces;
+
+namespace HanaToolbox.Services;
+
+/// <summary>
+/// Locates hdbsql and hdbuserstore binaries using:
+/// 1. Value from config (if set)
+/// 2. `which` lookup on PATH
+/// 3. /usr/sap/hdbclient/
+/// 4. /usr/sap/&lt;SID&gt;/HDB&lt;instance&gt;/exe/
+/// </summary>
+public sealed class HdbClientLocator(IProcessRunner runner) : IHdbClientLocator
+{
+    public string LocateHdbsql(string? configuredPath, string sid, string instanceNumber) =>
+        Locate("hdbsql", configuredPath, sid, instanceNumber);
+
+    public string LocateHdbuserstore(string? configuredPath, string sid, string instanceNumber) =>
+        Locate("hdbuserstore", configuredPath, sid, instanceNumber);
+
+    private string Locate(string binary, string? configuredPath, string sid, string instanceNumber)
+    {
+        // 1. User-configured explicit path
+        if (!string.IsNullOrWhiteSpace(configuredPath) && File.Exists(configuredPath))
+            return configuredPath;
+
+        // 2. which <binary>
+        var whichResult = runner.RunAsync("/usr/bin/which", [binary]).GetAwaiter().GetResult();
+        if (whichResult.Success && !string.IsNullOrWhiteSpace(whichResult.StdOut))
+            return whichResult.StdOut.Split('\n')[0].Trim();
+
+        // 3. /usr/sap/hdbclient/
+        var path3 = $"/usr/sap/hdbclient/{binary}";
+        if (File.Exists(path3)) return path3;
+
+        // 4. /usr/sap/<SID>/HDB<instance>/exe/
+        var path4 = $"/usr/sap/{sid.ToUpperInvariant()}/HDB{instanceNumber}/exe/{binary}";
+        if (File.Exists(path4)) return path4;
+
+        throw new FileNotFoundException(
+            $"Could not locate '{binary}'. Set HdbsqlPath/HdbuserstorePath in hanatoolbox.json or ensure it is on PATH.");
+    }
+}