#include "../tests-private.hpp"
#include "src/tile-constants.hpp"
#include "src/chunk.hpp"
#include "src/path-search.hpp"
#include "../app.hpp"
#include "../imgui-raii.hpp"
#include "floormat/main.hpp"
#include <bitset>
#include <Corrade/Containers/Pointer.h>
#include <Corrade/Containers/GrowableArray.h>
#include <Magnum/Math/Vector2.h>
#include <Magnum/Math/Functions.h>
#include <Magnum/Math/Color.h>

namespace floormat::tests {

namespace {

using namespace floormat::imgui;
using detail_astar::div_factor;
using detail_astar::div_size;
template<typename T> using bbox = typename path_search::bbox<T>;

constexpr auto div_min = -iTILE_SIZE2/2, div_max = TILE_MAX_DIM*iTILE_SIZE2 - iTILE_SIZE2/2;

constexpr uint32_t chunk_dim = TILE_MAX_DIM*uint32_t{div_factor}+1,
                   chunk_nbits = chunk_dim * chunk_dim;
//constexpr auto bbox_size = Vector2ub(iTILE_SIZE2/2);
constexpr auto chunk_size = iTILE_SIZE2*Vector2i(TILE_MAX_DIM);
constexpr auto visited_bits = chunk_dim * chunk_dim *4*4;
constexpr auto div_count = Vector2i{TILE_MAX_DIM * div_factor};

constexpr bbox<Int> bbox_from_pos1(Vector2i center/*, Vector2ui size*/) // from src/dijkstra.cpp
{
    //auto top_left = center - Vector2i(size / 2);
    //auto bottom_right = top_left + Vector2i(size);
    auto bottom_right = center + Vector2i(1);
    //return { top_left, bottom_right };
    return { center, bottom_right };
}

constexpr bbox<Int> bbox_from_pos2(Vector2i pt, Vector2i from/*, Vector2ui size*/) // from src/dijkstra.cpp
{
    auto bb0 = bbox_from_pos1(from/*, size*/);
    auto bb = bbox_from_pos1(pt/*, size*/);
    auto min = Math::min(bb0.min, bb.min);
    auto max = Math::max(bb0.max, bb.max);
    return { min, max };
}

constexpr bbox<Int> make_pos(Vector2i ij, Vector2i from)
{
    auto pos = div_min + div_size * ij;
    auto pos0 = pos + from*div_size;
    return bbox_from_pos2(pos, pos0/*, Vector2ui(div_size)*/);
}

bool check_pos(chunk& c, const std::array<chunk*, 8>& nbs, Vector2i ij, Vector2i from)
{
    auto pos = make_pos(ij, from);
    bool ret = path_search::is_passable_(&c, nbs, Vector2(pos.min), Vector2(pos.max), 0);
    //if (ret) Debug{} << "check" << ij << ij/div_factor << ij % div_factor << pos.min << pos.max << ret;
    return ret;
}

struct pending_s
{
    chunk_coords_ c;
    bool exists : 1 = false;
};

struct result_s
{
    std::bitset<chunk_nbits> is_passable;
    chunk_coords_ c;
    bool exists : 1 = false;
};

struct node_s
{
    Vector2i pos;
};

struct tmp_s
{
    Array<node_s> stack;
    std::bitset<visited_bits> visited;
    std::bitset<chunk_nbits> passable;
    std::array<chunk*, 8> neighbors = {};

    void append(Vector2i pos, int from);
    static Pointer<tmp_s> make();
    void clear();
};

void tmp_s::append(Vector2i pos, int from)
{
    auto i = (uint32_t)pos.y() * chunk_dim + (uint32_t)pos.x();
    if (i >= passable.size())
        return;
    if (passable[i])
        return;
    passable[i] = true;
    auto v = i*4 + (uint32_t)from;
    fm_debug_assert(v < visited.size());
    if (visited[v])
        return;
    visited[v] = true;
    arrayAppend(stack, {pos});
}

Pointer<tmp_s> tmp_s::make()
{
    auto ptr = Pointer<tmp_s>{InPlace};
    arrayResize(ptr->stack, 0);
    arrayReserve(ptr->stack, TILE_COUNT);
    ptr->visited = {};
    ptr->passable = {};
    ptr->neighbors = {};
    return ptr;
}

void tmp_s::clear()
{
    arrayResize(stack, 0);
    visited = {};
    passable = {};
    neighbors = {};
}

struct region_test : base_test
{
    result_s result;
    pending_s pending;
    Pointer<tmp_s> tmp;

    tmp_s& get_tmp();
    void do_region_extraction(world& w, chunk_coords_ coord);

    ~region_test() noexcept override = default;

    bool handle_key(app&, const key_event&, bool) override { return {}; }
    bool handle_mouse_click(app& a, const mouse_button_event& e, bool is_down) override;
    bool handle_mouse_move(app& a, const mouse_move_event& e) override { return {}; }
    void draw_overlay(app& a) override;
    void draw_ui(app&, float) override;
    void update_pre(app&) override {}
    void update_post(app& a) override;
};

tmp_s& region_test::get_tmp()
{
    if (tmp)
        tmp->clear();
    else
        tmp = tmp_s::make();
    return *tmp;
}

void region_test::do_region_extraction(world& w, chunk_coords_ coord)
{
    auto* c = w.at(coord);
    if (!c)
    {
        result.exists = false;
        pending.exists = false;
        return;
    }

    auto& tmp = get_tmp();
    const auto nbs = w.neighbors(coord);

    static_assert(div_count.x() == div_count.y());
    constexpr auto last = div_count - Vector2i{1};
    constexpr Vector2i fours[4] = { {0, 1}, {0, -1}, {1, 0}, {-1, 0} };

    //if (Vector2i from{0, -1}, pos{0, 0}; check_pos(*c, nbs, pos, from)) tmp.append(pos, 0); // bottom

    for (Int i = 0; i < div_count.x(); i++)
    {
        if (Vector2i pos{i, last.y()}; check_pos(*c, nbs, pos, fours[0])) tmp.append(pos, 0); // bottom
        if (Vector2i pos{i, 0};        check_pos(*c, nbs, pos, fours[1])) tmp.append(pos, 1); // top
        if (Vector2i pos{last.x(), i}; check_pos(*c, nbs, pos, fours[2])) tmp.append(pos, 2); // right
        if (Vector2i pos{0, i};        check_pos(*c, nbs, pos, fours[3])) tmp.append(pos, 3); // left
    }
    while (!tmp.stack.isEmpty())
    {
        auto p = tmp.stack.back().pos;
        arrayRemoveSuffix(tmp.stack);
        for (int i = 0; i < 4; i++)
        {
            Vector2i from = fours[i], pos{p - from};
            if ((uint32_t)pos.x() < chunk_dim && (uint32_t)pos.y() < chunk_dim)
                if (check_pos(*c, nbs, pos, from))
                    tmp.append(pos, i);
        }
    }

    result = {
        .is_passable = tmp.passable,
        .c = coord,
        .exists = true,
    };

    Debug{} << "done!" << tmp.passable.count();
}

void region_test::draw_overlay(app& a)
{

}

void region_test::draw_ui(app& a, float width)
{

}

bool region_test::handle_mouse_click(app& a, const mouse_button_event& e, bool is_down)
{
    if (e.button == mouse_button_left && is_down)
    {
        auto& M = a.main();
        auto& w = M.world();
        if (auto pt_ = a.cursor_state().point())
        {
            pending = {
                .c = pt_->chunk3(),
                .exists = true,
            };
            return true;
        }
    }
    else if (e.button == mouse_button_right && is_down)
    {
        pending.exists = false;
        result.exists = false;
    }
    return false;
}

void region_test::update_post(app& a)
{
    if (pending.exists)
    {
        pending.exists = false;
        auto& M = a.main();
        auto& w = M.world();
        do_region_extraction(w, pending.c);
    }
}

} // namespace

Pointer<base_test> tests_data::make_test_region() { return Pointer<region_test>{InPlaceInit}; }

} // namespace floormat::tests