#include <algorithm>

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

using namespace vf;

namespace {

// Consecutive small seeds share too much structure for a raw xorshift stream,
// so the sampling tests walk a scrambled sequence instead.
uint32_t seedFor(int index) {
    uint32_t mixed = static_cast<uint32_t>(index) + 1u;
    mixed ^= mixed >> 16;
    mixed *= 0x7feb352du;
    mixed ^= mixed >> 15;
    mixed *= 0x846ca68bu;
    mixed ^= mixed >> 16;
    return mixed == 0u ? 1u : mixed;
}

LootContext contextWith(ItemId tool, uint32_t seed) {
    LootContext context;
    context.tool = tool;
    context.seed = seed;
    return context;
}

LootContext enchanted(ItemId tool, EnchantKind kind, int level, uint32_t seed) {
    LootContext context = contextWith(tool, seed);
    addEnchant(context.toolEnchants, kind, level);
    return context;
}

LootContext killContext(bool byPlayer, uint32_t seed) {
    LootContext context = contextWith(ItemId::IronSword, seed);
    context.playerKill = byPlayer;
    return context;
}

bool sameRoll(const LootRoll& left, const LootRoll& right) {
    if (left.items.size() != right.items.size()) return false;
    for (std::size_t i = 0; i < left.items.size(); ++i) {
        if (left.items[i].item != right.items[i].item) return false;
        if (left.items[i].count != right.items[i].count) return false;
        if (left.items[i].durability != right.items[i].durability) return false;
    }
    return true;
}

LootEntry entryOf(ItemId item, uint32_t conditions) {
    LootEntry entry;
    entry.item = item;
    entry.conditions = conditions;
    return entry;
}

LootTable singlePool(const std::vector<LootEntry>& entries, int minRolls = 1, int maxRolls = 1) {
    LootPool pool;
    pool.entries = entries;
    pool.minRolls = minRolls;
    pool.maxRolls = maxRolls;
    LootTable table;
    table.pools.push_back(pool);
    return table;
}

int maxOverSeeds(Block block, const EnchantSet& enchants, ItemId tool, ItemId wanted, int samples) {
    int best = 0;
    for (int i = 0; i < samples; ++i) {
        LootContext context = contextWith(tool, seedFor(i));
        context.toolEnchants = enchants;
        best = std::max(best, rollBlockDrops(block, context).countOf(wanted));
    }
    return best;
}

} // namespace

VF_TEST(theSameSeedAlwaysReproducesTheSameRollAcrossEveryTableFamily) {
    LootContext blockContext = enchanted(ItemId::DiamondPickaxe, EnchantKind::Fortune, 3, 0xabcdef01u);
    CHECK(sameRoll(rollBlockDrops(Block::LapisOre, blockContext),
                   rollBlockDrops(Block::LapisOre, blockContext)));

    LootContext mobContext = killContext(true, 0x1234567u);
    addEnchant(mobContext.toolEnchants, EnchantKind::Looting, 2);
    CHECK(sameRoll(rollMobDrops(LootTable::MobKind::Zombie, mobContext),
                   rollMobDrops(LootTable::MobKind::Zombie, mobContext)));

    LootContext chestContext = contextWith(ItemId::None, 0x55aa33ccu);
    LootRoll first = rollChestContents(LootTable::ChestKind::Dungeon, chestContext);
    LootRoll second = rollChestContents(LootTable::ChestKind::Dungeon, chestContext);
    CHECK(sameRoll(first, second));
    CHECK(first.totalCount() > 0);
}

VF_TEST(differentSeedsPullApartTheContentsOfTheSameChest) {
    LootRoll reference = rollChestContents(LootTable::ChestKind::Dungeon,
                                           contextWith(ItemId::None, seedFor(0)));
    int different = 0;
    for (int i = 1; i < 64; ++i) {
        LootRoll roll = rollChestContents(LootTable::ChestKind::Dungeon,
                                          contextWith(ItemId::None, seedFor(i)));
        if (!sameRoll(reference, roll)) ++different;
    }
    CHECK(different >= 55);
}

VF_TEST(stoneDropsCobblestoneUnlessTheSilkTouchBranchTakesOver) {
    LootContext plain = contextWith(ItemId::StonePickaxe, 7u);
    LootRoll broken = rollBlockDrops(Block::Stone, plain);
    CHECK_EQ(broken.countOf(ItemId::Cobblestone), 1);
    CHECK_EQ(broken.countOf(ItemId::Stone), 0);

    LootContext silk = enchanted(ItemId::StonePickaxe, EnchantKind::SilkTouch, 1, 7u);
    LootRoll harvested = rollBlockDrops(Block::Stone, silk);
    CHECK_EQ(harvested.countOf(ItemId::Stone), 1);
    CHECK_EQ(harvested.countOf(ItemId::Cobblestone), 0);
}

VF_TEST(oresDropTheirRawFormAndSilkTouchDropsTheOreBlockItself) {
    const struct { Block block; ItemId raw; ItemId oreItem; } ores[] = {
        {Block::CoalOre, ItemId::CoalLump, ItemId::CoalOre},
        {Block::IronOre, ItemId::IronOre, ItemId::IronOre},
        {Block::DiamondOre, ItemId::DiamondGem, ItemId::DiamondOre},
        {Block::EmeraldOre, ItemId::EmeraldGem, ItemId::EmeraldOre},
    };
    for (const auto& ore : ores) {
        LootContext plain = contextWith(ItemId::DiamondPickaxe, 31u);
        CHECK_EQ(rollBlockDrops(ore.block, plain).countOf(ore.raw), 1);

        LootContext silk = enchanted(ItemId::DiamondPickaxe, EnchantKind::SilkTouch, 1, 31u);
        LootRoll harvested = rollBlockDrops(ore.block, silk);
        CHECK_EQ(harvested.countOf(ore.oreItem), 1);
        CHECK_EQ(harvested.totalCount(), 1);
    }
}

VF_TEST(fortuneMultipliesOreDropsAndNeverDropsBelowTheBaseYield) {
    EnchantSet bare;
    EnchantSet fortune;
    addEnchant(fortune, EnchantKind::Fortune, 3);

    int worstPlain = 99;
    int worstFortune = 99;
    for (int i = 0; i < 400; ++i) {
        LootContext plain = contextWith(ItemId::DiamondPickaxe, seedFor(i));
        worstPlain = std::min(worstPlain, rollBlockDrops(Block::DiamondOre, plain)
                                              .countOf(ItemId::DiamondGem));

        LootContext lucky = contextWith(ItemId::DiamondPickaxe, seedFor(i));
        lucky.toolEnchants = fortune;
        worstFortune = std::min(worstFortune, rollBlockDrops(Block::DiamondOre, lucky)
                                                  .countOf(ItemId::DiamondGem));
    }
    CHECK_EQ(worstPlain, 1);
    CHECK_EQ(worstFortune, 1);