Add search condition behavior to the issues page.

src/main/scala/service/IssuesService.scala

@@ -64,4 +64,42 @@ trait IssuesService {
           currentDate) ).bind
     } firstOption
 
+}
+
+object IssuesService {
+  import java.net.URLEncoder
+  import javax.servlet.http.HttpServletRequest
+
+  case class IssueSearchCondition(labels: Set[String], milestoneId: Option[Int], state: Option[String], sort: Option[String], direction: Option[String]){
+    import IssueSearchCondition._
+
+    def toURL(repository: service.RepositoryService.RepositoryInfo)(implicit context: app.Context): String = {
+      val params = List(
+        if(labels.isEmpty) None else Some("labels=" + urlEncode(labels.mkString(" "))),
+        milestoneId.map("milestone=" + _),
+        state.map("state=" + urlEncode(_)),
+        sort.map("sort=" + urlEncode(_)),
+        direction.map("direction=" + urlEncode(_))
+      )
+      "%s/%s/%s/issues?%s".format(context.path, repository.owner, repository.name, params.flatten.mkString("&"))
+    }
+  }
+
+  object IssueSearchCondition {
+
+    private def urlEncode(value: String): String = URLEncoder.encode(value, "UTF-8")
+
+    private def param(request: HttpServletRequest, name: String): Option[String] = {
+      val value = request.getParameter(name)
+      if(value == null || value.isEmpty) None else Some(value)
+    }
+
+    def apply(request: HttpServletRequest): IssueSearchCondition =
+      IssueSearchCondition(
+        param(request, "labels").map(_.split(" ").toSet).getOrElse(Set.empty),
+        param(request, "milestone").map(_.toInt),
+        param(request, "state"),
+        param(request, "sort"),
+        param(request, "direction"))
+  }
 }