#include "testHarness.h"
#include "vf/SlotAction.h"

#include <array>
#include <string>
#include <vector>

using namespace vf;

namespace {

const CraftingRegistry& sharedRegistry() {
    static CraftingRegistry registry;
    return registry;
}

struct Session {
    ContainerMenu menu;
    CursorStack cursor;
    DragState drag;

    explicit Session(MenuKind kind) : menu(kind, &sharedRegistry()) {}

    SlotActionResult click(ClickKind kind, int slotIndex) {
        return applySlotAction(menu, cursor, drag, clickAt(kind, slotIndex));
    }
    SlotActionResult hotbar(int slotIndex, int button) {
        return applySlotAction(menu, cursor, drag, hotbarSwapAt(slotIndex, button));
    }
};

// The seven items the random walk shuffles around. Tools are in the mix so the
// walk also has stacks that refuse to merge.
const std::array<ItemId, 7> walkItems = {ItemId::Stone,     ItemId::Planks, ItemId::Sand,
                                         ItemId::CoalLump,  ItemId::Apple,  ItemId::IronPickaxe,
                                         ItemId::RawBeef};

struct Ledger {
    std::array<int, 7> counts{};

    void snapshot(const ContainerMenu& menu, const CursorStack& cursor) {
        for (std::size_t i = 0; i < walkItems.size(); ++i) {
            counts[i] = totalAcrossMenuAndCursor(menu, cursor, walkItems[i]);
        }
    }
};

void seedMenu(ContainerMenu& menu, uint32_t& rng) {
    for (int i = 0; i < menu.slotCount(); ++i) {
        if (menu.slot(i).takeOnly) continue;
        if (stackRandom(rng) % 3u == 0u) continue;
        ItemId item = walkItems[stackRandom(rng) % walkItems.size()];
        MetaStack stack = makeStack(item, 1 + static_cast<int>(stackRandom(rng) % 40u));
        if (!menu.canPlace(i, stack)) continue;
        menu.slot(i).cell.insert(stack);
    }
}

SlotAction randomAction(const ContainerMenu& menu, uint32_t& rng) {
    ClickKind kind = static_cast<ClickKind>(stackRandom(rng) %
                                            static_cast<uint32_t>(ClickKind::Count));
    int slotIndex = static_cast<int>(stackRandom(rng) % static_cast<uint32_t>(menu.slotCount()));
    // Every eighth action aims outside the window, which is the only way to
    // reach the throw-away path with a full cursor.
    if (stackRandom(rng) % 8u == 0u) slotIndex = -1;
    if (kind == ClickKind::HotbarSwap) {
        return hotbarSwapAt(slotIndex, static_cast<int>(stackRandom(rng) % 9u));
    }
    return clickAt(kind, slotIndex);
}

struct WalkCoverage {
    int applied = 0;
    int dropped = 0;
    int distinctKindsApplied = 0;
};

WalkCoverage runConservationWalk(MenuKind kind, uint32_t seed, int steps) {
    Session session(kind);
    uint32_t rng = seed;
    seedMenu(session.menu, rng);

    Ledger before;
    before.snapshot(session.menu, session.cursor);

    std::array<int, 7> thrown{};
    std::array<int, static_cast<std::size_t>(ClickKind::Count)> perKind{};
    WalkCoverage coverage;
    for (int step = 0; step < steps; ++step) {
        SlotAction action = randomAction(session.menu, rng);
        SlotActionResult outcome =
            applySlotAction(session.menu, session.cursor, session.drag, action);
        if (outcome.applied) {
            ++coverage.applied;
            ++perKind[static_cast<std::size_t>(action.kind)];
        }
        coverage.dropped += outcome.dropped;
        CHECK_EQ(outcome.created, 0);
        CHECK_EQ(outcome.dropped, static_cast<int>([&] {
                     int sum = 0;
                     for (const MetaStack& lost : outcome.droppedStacks) sum += lost.count;
                     return sum;
                 }()));
        for (const MetaStack& lost : outcome.droppedStacks) {
            for (std::size_t i = 0; i < walkItems.size(); ++i) {
                if (lost.item == walkItems[i]) thrown[i] += lost.count;
            }
        }
    }

    Ledger after;
    after.snapshot(session.menu, session.cursor);
    for (std::size_t i = 0; i < walkItems.size(); ++i) {
        CHECK_EQ(after.counts[i] + thrown[i], before.counts[i]);
    }
    for (int hits : perKind) {
        if (hits > 0) ++coverage.distinctKindsApplied;
    }
    return coverage;
}

} // namespace

VF_TEST(everyClickKindHasAName) {
    for (int i = 0; i < static_cast<int>(ClickKind::Count); ++i) {
        CHECK(std::string(clickKindName(static_cast<ClickKind>(i))) != std::string("unknown"));
    }
}

VF_TEST(aLeftClickPicksUpTheWholeStackAndPutsItDownAgain) {
    Session session(MenuKind::Chest);
    session.menu.slot(0).cell.stack = makeStack(ItemId::Stone, 37);

    SlotActionResult pickup = session.click(ClickKind::Left, 0);
    CHECK(pickup.applied);
    CHECK_EQ(pickup.moved, 37);
    CHECK(pickup.cursorChanged);
    CHECK_EQ(session.cursor.held.count, 37);
    CHECK(session.menu.stackAt(0).empty());

    SlotActionResult drop = session.click(ClickKind::Left, 4);
    CHECK(drop.applied);
    CHECK_EQ(drop.moved, 37);
    CHECK(session.cursor.empty());
    CHECK_EQ(session.menu.stackAt(4).count, 37);

    CHECK(!session.click(ClickKind::Left, 9).applied);
    CHECK(!session.click(ClickKind::Left, 999).applied);
}

VF_TEST(aLeftClickMergesIntoAMatchingStackAndSwapsWithAForeignOne) {
    Session session(MenuKind::Chest);
    session.menu.slot(0).cell.stack = makeStack(ItemId::Sand, 50);
    session.menu.slot(1).cell.stack = makeStack(ItemId::Sand, 60);
    session.menu.slot(2).cell.stack = makeStack(ItemId::Planks, 8);