1 files changed, 74 insertions, 0 deletions
diff --git a/src/filters.cpp b/src/filters.cpp
new file mode 100644
index 0000000..78f3ce4
--- /dev/null
+++ b/src/filters.cpp
@@ -0,0 +1,74 @@
+#include <ctime>
+#include <sstream>
+#include <string>
+#include <nlohmann/json.hpp>
+
+#include "nostr.hpp"
+
+using nlohmann::json;
+using std::invalid_argument;
+using std::stringstream;
+using std::string;
+using std::time;
+
+namespace nostr
+{
+string Filters::serialize()
+{
+    try
+    {
+        this->validate();
+    } 
+    catch (const invalid_argument& e)
+    {
+        throw e;
+    }
+
+    json j = {
+        {"ids", this->ids},
+        {"authors", this->authors},
+        {"kinds", this->kinds},
+        {"since", this->since},
+        {"until", this->until},
+        {"limit", this->limit}
+    };
+    
+    for (auto& tag : this->tags)
+    {
+        stringstream jss;
+        jss << "#" << tag.first;
+        string js = jss.str();
+
+        j[js] = tag.second;
+    }
+
+    return j.dump();
+};
+
+void Filters::validate()
+{
+    bool hasLimit = this->limit > 0;
+    if (!hasLimit)
+    {
+        throw invalid_argument("Filters::validate: The limit must be greater than 0.");
+    }
+
+    bool hasUntil = this->until > 0;
+    if (!hasUntil)
+    {
+        this->until = time(nullptr);
+    }
+
+    bool hasIds = this->ids.size() > 0;
+    bool hasAuthors = this->authors.size() > 0;
+    bool hasKinds = this->kinds.size() > 0;
+    bool hasTags = this->tags.size() > 0;
+
+    bool hasFilter = hasIds || hasAuthors || hasKinds || hasTags;
+
+    if (!hasFilter)
+    {
+        throw invalid_argument("Filters::validate: At least one filter must be set.");
+    }
+};
+} // namespace nostr