#include "handlerfeedgenerator.h"
#include "../parser.h"
#include "../revisionrenderer.h"
std::vector<HandlerFeedGenerator::EntryRevisionPair> HandlerFeedGenerator::fetchEntries(
	std::vector<std::string> categories)
{
	auto revisionDao = this->database->createRevisionDao();
	auto pageDao = this->database->createPageDao();

	std::vector<EntryRevisionPair> result;
	QueryOption option;
	option.includeInvisible = false;
	// option.limit = 20;
	
	auto comppage = [](const Page &a, const Page &b) { return a.name < b.name; };
	std::set<Page, decltype(comppage)> members (comppage);
	if(categories.empty())
	{
		auto pages = pageDao->getPageList(option);
		std::copy(pages.begin(), pages.end(), std::inserter(members, members.end()));
	}
	else
	{
		auto categoryDao = this->database->createCategoryDao();
		for(std::string cat : categories)
		{
			if(!categoryDao->find(cat))
			{
				throw std::runtime_error("No such category");
			}
			auto catmembers = categoryDao->fetchMembers(cat, option);
			std::copy(catmembers.begin(), catmembers.end(), std::inserter(members, members.end()));
		}
	}
	for(const Page &member : members)
	{
		auto revision = revisionDao->getRevisionForPage(member.name, 1).value();
		result.push_back({member, revision});
	}
	std::sort(result.begin(), result.end(),
			  [](EntryRevisionPair &a, EntryRevisionPair &b) { return a.second.timestamp > b.second.timestamp; });

	const int maxResults = 20;
	if(result.size() > maxResults)
	{
		result.erase(result.begin() + maxResults - 1, result.end());
	}

	return result;
}

std::string HandlerFeedGenerator::generateAtom(const std::vector<HandlerFeedGenerator::EntryRevisionPair> &entries,
											   std::string filter)
{

	std::stringstream stream;
	// don't care about offset for now especially since "%z" does not return what we need exactly (with ':')
	const std::string dateformat = "%Y-%m-%dT%T";

	time_t newestPublished = 0;
	std::string atomfooter = this->templ->loadResolvedPart("feeds/atomfooter");
	auto revisionDao = this->database->createRevisionDao();
	auto pageDao = this->database->createPageDao();

	std::string subtitle = filter;
	if(utils::trim(filter).empty())
	{
		subtitle = "All pages";
	}

	RevisionRenderer revisionRenderer { *this->templ, *this->database, *this->urlProvider };

	for(const EntryRevisionPair &entry : entries)
	{
		const Page &page = entry.first;
		const Revision &initialRevision = entry.second;
		Revision current = revisionDao->getCurrentForPage(page.name).value();
		std::string url = this->urlProvider->rootUrl() + this->urlProvider->page(page.name);
		if(initialRevision.timestamp > newestPublished)
		{
			newestPublished = initialRevision.timestamp;
		}
		std::string entryPublished = utils::formatLocalDate(initialRevision.timestamp, dateformat) + "Z";
		std::string entryUpdated = utils::formatLocalDate(current.timestamp, dateformat) + "Z";
		std::string entryurl =
			this->urlProvider->combine({this->urlProvider->rootUrl(), this->urlProvider->page(page.name)});
		TemplatePage atomentry = this->templ->getPage("feeds/atomentry");
		atomentry.setVar("entrytitle", utils::html_xss(page.title));
		atomentry.setVar("entryurl", utils::html_xss(entryurl));
		atomentry.setVar("entryid", utils::html_xss(entryurl));
		atomentry.setVar("entrypublished", entryPublished);
		atomentry.setVar("entryupdated", entryUpdated);
		atomentry.setVar("entrycontent", utils::html_xss(revisionRenderer.renderContent(current, page.title)));
		stream << atomentry.render();
	}
	stream << atomfooter;
	TemplatePage atomheader = this->templ->getPage("feeds/atomheader");
	atomheader.setVar("subtitle", subtitle);
	std::string selflink = utils::html_xss(this->urlProvider->atomFeed(filter));
	atomheader.setVar("atomfeeduniqueid", selflink);
	atomheader.setVar("atomselflink", selflink);
	atomheader.setVar("atomfeedupdate", utils::formatLocalDate(newestPublished, dateformat) + "Z");
	return atomheader.render() + stream.str();
}

Response HandlerFeedGenerator::handleRequest(const Request &r)
{
	Response response;
	try
	{
		std::string type = r.get("type");
		std::string categories = r.get("cats");
		if(type == "atom")
		{
			std::string filter = categories;
			Response result;
			result.setStatus(200);
			result.setContentType("application/atom+xml");
			std::string cacheKey = "feed:atom:" + filter;
			auto cached = this->cache->get(cacheKey);
			if(cached)
			{
				result.setBody(cached.value());
			}
			else
			{
				auto entries = fetchEntries(utils::split(categories, ','));
				std::string feed = generateAtom(entries, filter);
				result.setBody(feed);
				this->cache->put(cacheKey, feed);
			}
			response = result;
		}
		else
		{
			return errorResponse("Invalid feed type", "Unknown feed type, try atom", 400);
		}
	}
	catch(std::runtime_error &e)
	{
		Logger::error() << "Error while serving feed: " << e.what();
		return errorResponse("Error", "An error occured while trying to serve the feed", 500);
	}
	return response;
}

bool HandlerFeedGenerator::canAccess(const Permissions &perms)
{
	return true;
}