#include "gtest/gtest.h"

#include <mbgl/map/map.hpp>
#include <mbgl/util/image.hpp>
#include <mbgl/util/std.hpp>

#include <mbgl/util/io.hpp>
#include <rapidjson/document.h>
#include <rapidjson/writer.h>
#include <rapidjson/stringbuffer.h>

#include <mbgl/platform/default/headless_view.hpp>
#include <mbgl/platform/default/headless_display.hpp>
#include <mbgl/storage/caching_http_file_source.hpp>

#include "./fixtures/fixture_log.hpp"

#include <dirent.h>
#include <signal.h>
#include <libgen.h>
#ifdef __linux__
#include <sys/prctl.h>
#endif

std::string base_directory;

namespace mbgl {
namespace platform {

std::string defaultCacheDatabase() {
    // Disables the cache.
    return "";
}
}
}

class ServerEnvironment : public ::testing::Environment {
public:
    virtual void SetUp() {
        pid = fork();
        if (pid < 0) {
            throw std::runtime_error("Cannot create web server");
        } else if (pid == 0) {
#ifdef __linux__
            prctl(PR_SET_PDEATHSIG, SIGHUP);
#endif
            const auto executable = base_directory + "bin/server.py";
            const char *port = "2900";
            char *arg[] = { const_cast<char *>(executable.c_str()), const_cast<char *>(port), nullptr };
            int ret = execv(executable.c_str(), arg);
            // This call should not return. In case execve failed, we exit anyway.
            if (ret < 0) {
                fprintf(stderr, "Failed to start server: %s\n", strerror(errno));
            }
            exit(0);
        } else {
            display = std::make_shared<mbgl::HeadlessDisplay>();
        }
    }
    virtual void TearDown() {
        ASSERT_TRUE(pid);
        kill(pid, SIGHUP);
    }

    std::shared_ptr<mbgl::HeadlessDisplay> display;

private:
    pid_t pid = 0;
};


ServerEnvironment* env = nullptr;


GTEST_API_ int main(int argc, char *argv[]) {
    // Note: glibc's dirname() **modifies** the argument and can't handle static strings.
    std::string file { __FILE__ }; file = dirname(const_cast<char *>(file.c_str()));
    if (file[0] == '/') {
        // If __FILE__ is an absolute path, we don't have to guess from the argv 0.
        base_directory = file + "/suite/";
    } else {
        std::string argv0 { argv[0] }; argv0 = dirname(const_cast<char *>(argv0.c_str()));
        base_directory = argv0 + "/" + file + "/suite/";
    }

    testing::InitGoogleTest(&argc, argv);
    env = new ServerEnvironment();
    ::testing::AddGlobalTestEnvironment(env);
    return RUN_ALL_TESTS();
}

void rewriteLocalScheme(rapidjson::Value &value, rapidjson::Document::AllocatorType &allocator) {
    ASSERT_TRUE(value.IsString());
    auto string = std::string { value.GetString(),value.GetStringLength() };
    if (string.compare(0, 8, "local://") == 0) {
        string.replace(0, 8, "http://127.0.0.1:2900/");
        value.SetString(string.data(), string.size(), allocator);
    }
}

class HeadlessTest : public ::testing::TestWithParam<std::string> {};

TEST_P(HeadlessTest, render) {
    using namespace mbgl;

    const std::string& base = GetParam();

    std::string style = util::read_file(base_directory + "tests/" + base + "/style.json");
    std::string info = util::read_file(base_directory + "tests/" + base + "/info.json");

    // Parse style.
    rapidjson::Document styleDoc;
    styleDoc.Parse<0>((const char *const)style.c_str());
    ASSERT_FALSE(styleDoc.HasParseError());
    ASSERT_TRUE(styleDoc.IsObject());

    // Rewrite "local://" to "http://127.0.0.1:2900/".
    if (styleDoc.HasMember("sprite")) {
        rewriteLocalScheme(styleDoc["sprite"], styleDoc.GetAllocator());
    }

    if (styleDoc.HasMember("glyphs")) {
        rewriteLocalScheme(styleDoc["glyphs"], styleDoc.GetAllocator());
    }

    if (styleDoc.HasMember("sources")) {
        auto &sources = styleDoc["sources"];
        ASSERT_TRUE(sources.IsObject());
        for (auto source = sources.MemberBegin(), end = sources.MemberEnd(); source != end; source++) {
            if (source->value.HasMember("tiles")) {
                auto &tiles = source->value["tiles"];
                ASSERT_TRUE(tiles.IsArray());
                for (rapidjson::SizeType i = 0; i < tiles.Size(); i++) {
                    rewriteLocalScheme(tiles[i], styleDoc.GetAllocator());
                }
            }

            if (source->value.HasMember("url")) {
                rewriteLocalScheme(source->value["url"], styleDoc.GetAllocator());
            }
        }
    }

    // Convert the JSON object back into a stringified version.
    rapidjson::StringBuffer buffer;
    rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
    styleDoc.Accept(writer);
    style = buffer.GetString();

    // Parse settings.
    rapidjson::Document infoDoc;
    infoDoc.Parse<0>((const char *const)info.c_str());
    ASSERT_FALSE(infoDoc.HasParseError());
    ASSERT_TRUE(infoDoc.IsObject());

    Log::Set<FixtureLogBackend>();

    for (auto it = infoDoc.MemberBegin(), end = infoDoc.MemberEnd(); it != end; it++) {
        const std::string name {
            it->name.GetString(), it->name.GetStringLength()
        };
        const rapidjson::Value& value = it->value;
        ASSERT_TRUE(value.IsObject());
        if (value.HasMember("center")) ASSERT_TRUE(value["center"].IsArray());

        const std::string actual_image = base_directory + "tests/" + base + "/" + name +  "/actual.png";

        const double zoom = value.HasMember("zoom") ? value["zoom"].GetDouble() : 0;
        const double bearing = value.HasMember("bearing") ? value["bearing"].GetDouble() : 0;
        const double latitude = value.HasMember("center") ? value["center"][rapidjson::SizeType(0)].GetDouble() : 0;
        const double longitude = value.HasMember("center") ? value["center"][rapidjson::SizeType(1)].GetDouble() : 0;
        const unsigned int width = value.HasMember("width") ? value["width"].GetUint() : 512;
        const unsigned int height = value.HasMember("height") ? value["height"].GetUint() : 512;
        const unsigned int pixelRatio = value.HasMember("pixelRatio") ? value["pixelRatio"].GetUint() : 1;

        std::vector<std::string> classes;
        if (value.HasMember("classes")) {
            const rapidjson::Value& js_classes = value["classes"];
            ASSERT_TRUE(js_classes.IsArray());
            for (rapidjson::SizeType i = 0; i < js_classes.Size(); i++) {
                const rapidjson::Value& js_class = js_classes[i];
                ASSERT_TRUE(js_class.IsString());
                classes.push_back({ js_class.GetString(), js_class.GetStringLength() });
            }
        }

        HeadlessView view(env->display);
        CachingHTTPFileSource fileSource(platform::defaultCacheDatabase());
        Map map(view, fileSource);

        map.setStyleJSON(style, base_directory);
        map.setAppliedClasses(classes);

        view.resize(width, height, pixelRatio);
        map.resize(width, height, pixelRatio);
        map.setLonLatZoom(longitude, latitude, zoom);
        map.setBearing(bearing);


        // Run the loop. It will terminate when we don't have any further listeners.
        map.run();

        const unsigned int w = width * pixelRatio;
        const unsigned int h = height * pixelRatio;

        auto pixels = view.readPixels();

        const std::string image = util::compress_png(w, h, pixels.get());
        util::write_file(actual_image, image);
    }
}

INSTANTIATE_TEST_CASE_P(Headless, HeadlessTest, ::testing::ValuesIn([] {
    std::vector<std::string> names;

    DIR *dir = opendir((base_directory + "tests").c_str());
    if (dir == nullptr) {
        return names;
    }

    for (dirent *dp = nullptr; (dp = readdir(dir)) != nullptr;) {
        const std::string name = dp->d_name;
        if (name != "." && name != ".." && name != "index.html") {
            names.push_back(name);
        }
    }

    closedir(dir);

    return names;
}()));