#include "testHarness.h"

#include "vf/Block.h"
#include "vf/RegionCompact.h"
#include "vf/SaveIntegrity.h"
#include "vf/SaveMigration.h"
#include "vf/WorldBackup.h"

#include <cstdint>
#include <string>
#include <vector>

using namespace vf;

namespace {

Chunk uniformChunk(Block block) {
    Chunk chunk;
    for (int x = 0; x < chunkSize; ++x)
        for (int y = 0; y < chunkSize; ++y)
            for (int z = 0; z < chunkSize; ++z) chunk.set(x, y, z, block);
    return chunk;
}

Chunk texturedChunk(int seed) {
    Chunk chunk;
    for (int x = 0; x < chunkSize; ++x)
        for (int y = 0; y < chunkSize; ++y)
            for (int z = 0; z < chunkSize; ++z) {
                int value = 1 + (x * 7 + y * 5 + z * 3 + seed) % 12;
                chunk.set(x, y, z, static_cast<Block>(value));
            }
    return chunk;
}

SaveChunkRecord buildRecord(const Vec3i& coord, const Chunk& blocks, SaveVersion version) {
    SaveChunkRecord record;
    record.coord = coord;
    record.blocks = blocks;
    if (versionHasLight(version)) record.light = defaultChunkLight(blocks, saveDefaultSkyLight);
    return record;
}

SaveContainer baseContainer() {
    SaveContainer container;
    container.version = SaveVersion::V4;
    container.chunks.push_back(buildRecord({0, 0, 0}, uniformChunk(Block::Stone), SaveVersion::V4));
    container.chunks.push_back(buildRecord({1, 0, 0}, uniformChunk(Block::Dirt), SaveVersion::V4));
    container.chunks.push_back(buildRecord({2, 0, 0}, uniformChunk(Block::Sand), SaveVersion::V4));
    return container;
}

void replaceChunk(SaveContainer& container, const Vec3i& coord, const Chunk& blocks) {
    for (SaveChunkRecord& record : container.chunks) {
        if (!(record.coord == coord)) continue;
        record.blocks = blocks;
        record.light = defaultChunkLight(blocks, saveDefaultSkyLight);
        return;
    }
    container.chunks.push_back(buildRecord(coord, blocks, container.version));
}

void dropChunk(SaveContainer& container, const Vec3i& coord) {
    for (std::size_t i = 0; i < container.chunks.size(); ++i) {
        if (!(container.chunks[i].coord == coord)) continue;
        container.chunks.erase(container.chunks.begin() + static_cast<std::ptrdiff_t>(i));
        return;
    }
}

} // namespace

VF_TEST(aFullBackupRestoresTheExactBytesItCaptured) {
    ByteBuffer save = writeSaveContainer(baseContainer());
    BackupStore store;
    uint32_t id = store.capture(BackupKind::Full, save, 0);
    CHECK(id != 0u);
    CHECK(store.lastFailure().empty());

    RestoreResult restored = store.restore(id);
    CHECK(restored.ok);
    CHECK(restored.failure.empty());
    CHECK(restored.save == save);
    CHECK_EQ(restored.chunksRestored, static_cast<std::size_t>(3));
    CHECK_EQ(restored.chunksFromFull, static_cast<std::size_t>(3));
    CHECK_EQ(restored.chunksFromIncrements, static_cast<std::size_t>(0));
    CHECK_EQ(restored.incrementsApplied, static_cast<std::size_t>(0));
    CHECK_EQ(restored.chain.size(), static_cast<std::size_t>(1));
}

VF_TEST(everyPointOfABackupChainRestoresByteForByte) {
    SaveContainer container = baseContainer();
    ByteBuffer save0 = writeSaveContainer(container);

    replaceChunk(container, {1, 0, 0}, texturedChunk(3));
    ByteBuffer save1 = writeSaveContainer(container);

    replaceChunk(container, {2, 0, 0}, texturedChunk(4));
    replaceChunk(container, {3, 0, 0}, uniformChunk(Block::Gravel));
    ByteBuffer save2 = writeSaveContainer(container);

    dropChunk(container, {0, 0, 0});
    ByteBuffer save3 = writeSaveContainer(container);

    BackupStore store;
    uint32_t id0 = store.capture(BackupKind::Full, save0, 0);
    uint32_t id1 = store.capture(BackupKind::Incremental, save1, 1000);
    uint32_t id2 = store.capture(BackupKind::Incremental, save2, 2000);
    uint32_t id3 = store.capture(BackupKind::Incremental, save3, 3000);
    CHECK(id0 != 0u);
    CHECK(id1 != 0u);
    CHECK(id2 != 0u);
    CHECK(id3 != 0u);

    CHECK(store.restore(id0).save == save0);
    CHECK(store.restore(id1).save == save1);
    CHECK(store.restore(id2).save == save2);
    CHECK(store.restore(id3).save == save3);

    RestoreResult latest = store.restoreLatest();
    CHECK(latest.ok);
    CHECK(latest.save == save3);
    CHECK_EQ(latest.chain.size(), static_cast<std::size_t>(4));
    CHECK_EQ(latest.incrementsApplied, static_cast<std::size_t>(3));
    CHECK_EQ(latest.chunksRestored, static_cast<std::size_t>(3));
    CHECK_EQ(latest.chunksRemoved, static_cast<std::size_t>(1));
}

VF_TEST(anIncrementalKeepsOnlyTheChunksThatMoved) {
    SaveContainer container = baseContainer();
    ByteBuffer save0 = writeSaveContainer(container);
    replaceChunk(container, {1, 0, 0}, texturedChunk(3));
    ByteBuffer save1 = writeSaveContainer(container);
    replaceChunk(container, {2, 0, 0}, texturedChunk(4));
    replaceChunk(container, {3, 0, 0}, uniformChunk(Block::Gravel));
    ByteBuffer save2 = writeSaveContainer(container);
    dropChunk(container, {0, 0, 0});
    ByteBuffer save3 = writeSaveContainer(container);

    BackupStore store;
    uint32_t id0 = store.capture(BackupKind::Full, save0, 0);
    uint32_t id1 = store.capture(BackupKind::Incremental, save1, 1000);
    uint32_t id2 = store.capture(BackupKind::Incremental, save2, 2000);
    uint32_t id3 = store.capture(BackupKind::Incremental, save3, 3000);

    const BackupEntry* full = store.index().find(id0);
    const BackupEntry* first = store.index().find(id1);
    const BackupEntry* second = store.index().find(id2);
    const BackupEntry* third = store.index().find(id3);
    CHECK(full != nullptr);
    CHECK(first != nullptr);
    CHECK(second != nullptr);
    CHECK(third != nullptr);
    if (full == nullptr || first == nullptr || second == nullptr || third == nullptr) return;

    CHECK(full->kind == BackupKind::Full);
    CHECK_EQ(full->stored.size(), static_cast<std::size_t>(3));
    CHECK_EQ(full->state.size(), static_cast<std::size_t>(3));
    CHECK_EQ(full->parentId, static_cast<uint32_t>(0));