#define MICHLIB_NOSOURCE
#include "copcat.h"
#include "GPL.h"
#include "mirrorfuncs.h"

const MString CopernicusCatalog::caturl = "https://stac.marine.copernicus.eu/metadata/catalog.stac.json";

CopernicusCatalog::CopernicusCatalog()
{
 // Cache
 auto oldprefix = michlib::GPL.UsePrefix("COPERNICUS");
 cache.reset(CreateCache(michlib::GPL.ParameterSValue("Cache", "")));
 michlib::GPL.UsePrefix(oldprefix);
 if(!cache)
 {
  michlib::errmessage("Can't init cache");
  cache.reset(new FakeCache);
 }

 GetCatalog();
}

Error CopernicusCatalog::GetCatalog()
{
 if(Valid()) return Error();
 auto ret = GetJSON(caturl);
 if(ret)
  catalog = ret.Value();
 else
  return ret.Add("CopernicusCatalog::GetCatalog", "can't download catalog");
 return Error();
}

RetVal<std::vector<MString>> CopernicusCatalog::ProductList() const
{
 static const MString pref = "CopernicusCatalog::ProductList";

 if(!Valid()) return {pref, "no catalog"};

 const auto& links = catalog["links"];
 if(links.type() != Json::arrayValue) return {pref, "no \"links\" section in the catalog"};

 std::vector<MString> out;
 for(Json::ArrayIndex i = 0; i < links.size(); i++)
 {
  const auto& rel  = links[i]["rel"];
  const auto& titl = links[i]["title"];

  if(rel.type() == Json::stringValue && titl.type() == Json::stringValue && rel.asString() == "child") out.emplace_back(titl.asString().c_str());
 }
 return out;
}

RetVal<MString> CopernicusCatalog::ProductURL(const MString& prod) const
{
 static const MString pref = "CopernicusCatalog::ProductURL";

 if(!Valid()) return {pref, "no catalog"};

 const auto& links = catalog["links"];
 if(links.type() != Json::arrayValue) return {pref, "no \"links\" section in the catalog"};

 for(Json::ArrayIndex i = 0; i < links.size(); i++)
 {
  const auto& titl = links[i]["title"];
  const auto& href = links[i]["href"];
  if(titl.type() == Json::stringValue && href.type() == Json::stringValue && titl.asString().c_str() == prod) return DirName(caturl) + "/" + MString(href.asString().c_str());
 }
 return {pref, "unknown product: " + prod};
}

RetVal<std::vector<MString>> CopernicusCatalog::DatasetList(const MString& prod) const
{
 static const MString pref = "CopernicusCatalog::DatasetList";

 MString url;
 {
  auto ret = ProductURL(prod);
  if(!ret) return ret.Add(pref, "Can't get url for the product " + prod);
  url = ret.Value();
 }

 auto ret = GetJSON(url);
 if(!ret) return ret.Add(pref, "Can't download product " + prod);

 const auto& links = ret.Value()["links"];
 if(links.type() != Json::arrayValue) return {pref, "no \"links\" section in the product " + prod + " description"};

 std::vector<MString> out;
 for(Json::ArrayIndex i = 0; i < links.size(); i++)
 {
  const auto& rel  = links[i]["rel"];
  const auto& titl = links[i]["title"];

  if(rel.type() == Json::stringValue && titl.type() == Json::stringValue && rel.asString() == "item") out.emplace_back(titl.asString().c_str());
 }
 return out;
}

RetVal<MString> CopernicusCatalog::DatasetURL(const MString& prod, const MString& dataset) const
{
 static const MString pref = "CopernicusCatalog::DatasetURL";

 MString url;
 {
  auto ret = ProductURL(prod);
  if(!ret) return ret.Add(pref, "Can't get url for the product " + prod);
  url = ret.Value();
 }

 auto ret = GetJSON(url);
 if(!ret) return ret.Add(pref, "Can't download product " + prod);

 const auto& links = ret.Value()["links"];
 if(links.type() != Json::arrayValue) return {pref, "no \"links\" section in the product " + prod + " description"};

 for(Json::ArrayIndex i = 0; i < links.size(); i++)
 {
  const auto& titl = links[i]["title"];
  const auto& href = links[i]["href"];
  if(titl.type() == Json::stringValue && href.type() == Json::stringValue && titl.asString().c_str() == dataset) return DirName(url) + "/" + MString(href.asString().c_str());
 }
 return {pref, "unknown dataset: " + dataset};
}

RetVal<MString> CopernicusCatalog::AssetURL(const MString& prod, const MString& dataset, const MString& asset) const
{
 static const MString pref = "CopernicusCatalog::AssetURL";

 MString url;
 {
  auto ret = DatasetURL(prod, dataset);
  if(!ret) return ret.Add(pref, "Can't get url for the dataset " + dataset);
  url = ret.Value();
 }

 auto ret = GetJSON(url);
 if(!ret) return ret.Add(pref, "Can't download dataset " + dataset);

 const auto& href = ret.Value()["assets"][asset.Buf()]["href"];
 if(!href || href.type() != Json::stringValue) return {pref, "href for the asset " + asset + " not found"};
 return MString(href.asString().c_str());
}

RetVal<Json::Value> CopernicusCatalog::GetJSON(const MString& url) const
{
 const static MString pref = "CopernicusCatalog::GetJSON";

 Json::Reader reader;
 Json::Value  obj;
 MString      content;

 auto [val, suc] = cache->Get(url);
 if(suc)
  content = std::move(val);
 else
 {
  michlib::message(url + " not found in cache, downloading");
  auto [out, res] = GetUrl(chandle, url);
  if(res != CURLE_OK) return Error(pref, MString("can't download JSON: ") + chandle.Err());
  cache->Put(url, out, 3600);
  content = std::move(out);
 }

 reader.parse(content.Buf(), content.Buf() + content.Len(), obj, false);

 return obj;
}