#include <FastHash.h>

#include "routes.h"
#include "../servehelper.h"
#include "../pixivclient.h"
#include "../hiredis_wrapper.h"

static inline std::optional<std::string> guess_extension(const std::string& path, PixivClient& pixiv_client);

void guess_extension_route(const httplib::Request& req, httplib::Response& res, const Config& config, PixivClient& pixiv_client, Redis* redis) {
    using namespace std::string_literals;

    std::string path = req.matches.str(1);
    std::string cache_key = "pixwhile:i.pximg.net:ext:"s + std::to_string(FastHash(path.data(), path.size(), 0));

    std::optional<std::string> extension = redis
        ? redis->get(cache_key)
        : std::nullopt;
    if (!extension) {
        extension = guess_extension(path, pixiv_client);
        if (!extension) {
            res.status = 500;
            serve_error(req, res, config, "500: Internal Server Error", "Failed to guess file extension for https://i.pximg.net"s + path);
            return;
        }
        if (redis) {
            redis->set(std::move(cache_key), *extension, 24 * 60 * 60);
        }
    }

    serve_redirect(req, res, config, proxy_image_url(req, config, "https://i.pximg.net" + path + '.' + *extension), true);
}

static inline std::optional<std::string> guess_extension(const std::string& path, PixivClient& pixiv_client) {
    auto guess_extension = [&](const char* extension) {
        return pixiv_client.i_pximg_url_valid(path + '.' + extension);
    };

    if (guess_extension("png")) {
        return "png";
    } else if (guess_extension("jpg")) {
        return "jpg";
    } else {
        return std::nullopt;
    }
}