#include <doctest/doctest.h>

#include <light/light.hh>
#include <common/bspinfo.hh>
#include <qbsp/qbsp.hh>
#include <testmaps.hh>

struct testresults_t {
    mbsp_t bsp;
    bspxentries_t bspx;
};

static testresults_t LoadTestmap(const std::filesystem::path &name, std::vector<std::string> extra_args)
{
    auto map_path = std::filesystem::path(testmaps_dir) / name;

    auto bsp_path = fs::path(test_quake2_maps_dir) / name.filename();
    bsp_path.replace_extension(".bsp");

    auto wal_metadata_path = std::filesystem::path(testmaps_dir) / "q2_wal_metadata";

    std::vector<std::string> args{
        "", // the exe path, which we're ignoring in this case
        "-noverbose",
        "-q2bsp",
        "-path",
        wal_metadata_path.string()
    };
    args.push_back(map_path.string());
    args.push_back(bsp_path.string());

    // run qbsp

    InitQBSP(args);
    ProcessFile();

    // run light
    {
        std::vector<std::string> light_args{
            "", // the exe path, which we're ignoring in this case
        };
        for (auto &arg : extra_args) {
            light_args.push_back(arg);
        }
        light_args.push_back(bsp_path.string());

        light_main(light_args);
    }

    // serialize obj
    {
        bspdata_t bspdata;
        LoadBSPFile(bsp_path, &bspdata);

        ConvertBSPFormat(&bspdata, &bspver_generic);

        // write to .json for inspection
        serialize_bsp(bspdata, std::get<mbsp_t>(bspdata.bsp),
            fs::path(qbsp_options.bsp_path).replace_extension(".bsp.json"));

        return {std::move(std::get<mbsp_t>(bspdata.bsp)),
                std::move(bspdata.bspx.entries)};
    }
}

TEST_CASE("-world_units_per_luxel") {
    LoadTestmap("q2_lightmap_custom_scale.map", {"-world_units_per_luxel", "8"});
}

TEST_CASE("emissive cube artifacts") {
    // A cube with surface flags "light", value "100", placed in a hallway.
    //
    // Generates harsh lines on the walls/ceiling due to a hack in `light` allowing
    // surface lights to emit 50% at 90 degrees off their surface normal (when physically it should be 0%).
    //
    // It's wanted in some cases (base1.map sewer lights flush with the wall, desired for them to
    // emit some lights on to their adjacent wall faces.)
    //
    // To disable the behaviour in this case with the cube lighting a hallway we have a entity key:
    //
    //     "_surflight_rescale" "0"
    //
    auto [bsp, bspx] = LoadTestmap("light_q2_emissive_cube.map", {"-threads", "1", "-world_units_per_luxel", "4", "-novanilla"});

    const auto start = qvec3d{1044, -1244, 880};
    const auto end = qvec3d{1044, -1272, 880};

    auto *floor = BSP_FindFaceAtPoint(&bsp, &bsp.dmodels[0], start, {0, 0, 1});
    auto lm_info = BSPX_DecoupledLM(bspx, Face_GetNum(&bsp, floor));

    const faceextents_t extents(*floor, bsp, lm_info.lmwidth, lm_info.lmheight, lm_info.world_to_lm_space);

    // sample the lightmap along the floor, approaching the glowing cube
    // should get brighter
    qvec3b previous_sample{};
    for (int y = start[1]; y >= end[1]; y -= 4) {
        qvec3d pos = start;
        pos[1] = y;

        auto lm_coord = extents.worldToLMCoord(pos);

        auto sample = LM_Sample(&bsp, extents, lm_info.offset, lm_coord);
        CHECK(sample[0] >= previous_sample[0]);

        //logging::print("world: {} lm_coord: {} sample: {} lm size: {}x{}\n", pos, lm_coord, sample, lm_info.lmwidth, lm_info.lmheight);

        previous_sample = sample;
    }
}

TEST_CASE("-novanilla + -world_units_per_luxel")
{
    auto [bsp, bspx] = LoadTestmap("q2_lightmap_custom_scale.map", {"-novanilla", "-world_units_per_luxel", "8"});

    for (auto &face : bsp.dfaces) {
        CHECK(face.lightofs == -1);
    }

    // make sure no other bspx lumps are written
    CHECK(bspx.size() == 1);
    CHECK(bspx.find("DECOUPLED_LM") != bspx.end());

    // make sure all dlightdata bytes are accounted for by the DECOUPLED_LM lump
    // and no extra was written.
    size_t expected_dlightdata_bytes = 0;
    for (auto &face : bsp.dfaces) {
        // count used styles
        size_t face_used_styles = 0;
        for (auto style : face.styles) {
            if (style != 255) {
                ++face_used_styles;
            }
        }

        // count used pixels per style
        auto lm_info = BSPX_DecoupledLM(bspx, Face_GetNum(&bsp, &face));
        const faceextents_t extents(face, bsp, lm_info.lmwidth, lm_info.lmheight, lm_info.world_to_lm_space);
        int samples_per_face = extents.numsamples() * face_used_styles;

        // round up to multiple of 4
        if (samples_per_face % 4) {
            samples_per_face += (4 - (samples_per_face % 4));
        }

        int bytes_per_face = 3 * samples_per_face;
        expected_dlightdata_bytes += bytes_per_face;
    }
    CHECK(bsp.dlightdata.size() == expected_dlightdata_bytes);
}