Added implementation for LibraryResolveDependency grpc call

Author: cmaglie

Diff for: commands/lib/resolve_deps.go

@@ -19,11 +19,29 @@ package lib
 
 import (
 	"context"
+	"fmt"
 
+	"github.com/arduino/arduino-cli/commands"
 	rpc "github.com/arduino/arduino-cli/rpc/commands"
 )
 
 // LibraryResolveDependencies FIXMEDOC
 func LibraryResolveDependencies(ctx context.Context, req *rpc.LibraryResolveDependenciesReq) (*rpc.LibraryResolveDependenciesResp, error) {
-	return &rpc.LibraryResolveDependenciesResp{}, nil
+	lm := commands.GetLibraryManager(req.GetInstance().GetId())
+
+	reqLibRelease, err := findLibraryIndexRelease(lm, req)
+	if err != nil {
+		return nil, fmt.Errorf("looking for library: %s", err)
+	}
+
+	deps := lm.Index.ResolveDependencies(reqLibRelease)
+
+	res := []*rpc.LibraryReference{}
+	for _, dep := range deps {
+		res = append(res, &rpc.LibraryReference{
+			Name:    dep.GetName(),
+			Version: dep.GetVersion().String(),
+		})
+	}
+	return &rpc.LibraryResolveDependenciesResp{Dependencies: res}, nil
 }