ObsidianDragon/tests/fake_lite_backend.h

// DragonX Wallet - ImGui Edition
// Copyright 2024-2026 The Hush Developers
// Released under the GPLv3
//
// Deterministic in-process fake SDXL backend for lite-wallet tests.
//
// Provides a LiteClientBridgeApi whose function pointers return canned JSON and
// track owned-string allocation/free counts, so tests can drive the lite bridge
// (and, from M1 on, the lite services) without a real litelib_* library, network,
// or the DRAGONX_ENABLE_LITE_BACKEND build flag. Build a bridge with:
//
//     auto bridge = dragonx::wallet::LiteClientBridge::fromApi(dragonx::test::makeFakeLiteApi());
//
// Invariant for leak/double-free checks: after a test, g_liteFakeAlloc == g_liteFakeFreed.

#pragma once

#include "wallet/lite_client_bridge.h"

#include <atomic>
#include <chrono>
#include <cstdlib>
#include <cstring>
#include <thread>

namespace dragonx {
namespace test {

// Owned-string accounting (atomic: a detached sync thread may touch these concurrently).
inline std::atomic<long> g_liteFakeAlloc{0};   // owned strings handed to the bridge
inline std::atomic<long> g_liteFakeFreed{0};   // owned strings released via freeString
inline bool g_liteFakeWalletExists = true;
inline bool g_liteFakeServerOnline = true;
inline bool g_liteFakeShutdownCalled = false;
inline std::atomic<bool> g_liteFakeSyncBlock{false};  // when true, the "sync" command blocks
inline std::atomic<bool> g_liteFakeBadBalance{false}; // when true, "balance" returns invalid JSON

inline void resetLiteFakeCounters()
{
    g_liteFakeAlloc = 0;
    g_liteFakeFreed = 0;
    g_liteFakeShutdownCalled = false;
}

inline char* liteFakeDup(const char* s)
{
    char* p = static_cast<char*>(std::malloc(std::strlen(s) + 1));
    std::strcpy(p, s);
    ++g_liteFakeAlloc;
    return p;
}

inline bool liteFakeWalletExists(const char*) { return g_liteFakeWalletExists; }
inline char* liteFakeInitNew(bool, const char*) { return liteFakeDup("{\"result\":\"created\"}"); }
inline char* liteFakeInitFromPhrase(bool, const char*, const char*,
                                    unsigned long long, unsigned long long, bool)
{
    return liteFakeDup("{\"result\":\"restored\"}");
}
inline char* liteFakeInitExisting(bool, const char*) { return liteFakeDup("{\"result\":\"opened\"}"); }
inline char* liteFakeExecute(const char* command, const char* args)
{
    // new-address generation returns a JSON array with the new address (type from args: zs/R).
    if (command && std::strcmp(command, "new") == 0) {
        return liteFakeDup(args && std::strcmp(args, "R") == 0 ? "[\"R1fakenew\"]" : "[\"zs1fakenew\"]");
    }
    // A command named "boom" yields an "Error:"-prefixed response (the bridge's
    // looksLikeError contract maps that to ok=false).
    if (command && std::strcmp(command, "boom") == 0) {
        return liteFakeDup("Error: simulated lite backend failure");
    }
    // Command-appropriate canned responses matching the litelib JSON shapes (see
    // tests/fixtures/lite/result_parsers.json), so the gateway/sync refresh path parses.
    if (command) {
        const char* c = command;
        if (std::strcmp(c, "sync") == 0) {
            // Simulate the real backend's blocking full sync when requested, so tests can
            // verify shutdown doesn't hang on an in-flight sync.
            while (g_liteFakeSyncBlock.load()) std::this_thread::sleep_for(std::chrono::milliseconds(5));
            return liteFakeDup("{\"result\":\"success\"}");
        }
        if (std::strcmp(c, "syncstatus") == 0)  // real backend shape: "syncing" is a string
            return liteFakeDup("{\"syncing\":\"true\",\"synced_blocks\":1000,\"total_blocks\":1000}");
        if (std::strcmp(c, "balance") == 0 && g_liteFakeBadBalance.load())
            return liteFakeDup("not-json");  // simulate a shape/parse failure for one command
        if (std::strcmp(c, "balance") == 0)
            return liteFakeDup("{\"tbalance\":100000000,\"zbalance\":200000000,\"unconfirmed\":50000000,"
                               "\"verified_zbalance\":180000000,\"spendable_zbalance\":170000000}");
        if (std::strcmp(c, "addresses") == 0)
            return liteFakeDup("{\"z_addresses\":[\"zs1fakeaddr\"],\"t_addresses\":[\"R1fakeaddr\"]}");
        if (std::strcmp(c, "notes") == 0)
            return liteFakeDup("{\"unspent_notes\":[],\"utxos\":[],\"pending_notes\":[],\"pending_utxos\":[]}");
        if (std::strcmp(c, "list") == 0)
            return liteFakeDup("[{\"txid\":\"faketx\",\"datetime\":1700000000,\"block_height\":990,"
                               "\"unconfirmed\":false,\"address\":\"zs1fakeaddr\",\"amount\":150000000,\"memo\":\"\"}]");
        if (std::strcmp(c, "height") == 0) return liteFakeDup("{\"height\":1000}");
        if (std::strcmp(c, "info") == 0)
            return liteFakeDup("{\"chain_name\":\"main\",\"version\":\"sdxl-fake\",\"latest_block_height\":1000}");
    }
    // Default for any other/unknown command.
    return liteFakeDup("{\"version\":\"sdxl-fake\"}");
}
inline void liteFakeFree(char* v)
{
    if (v) {
        ++g_liteFakeFreed;
        std::free(v);
    }
}
inline bool liteFakeServerOnline(const char*) { return g_liteFakeServerOnline; }
inline void liteFakeShutdown() { g_liteFakeShutdownCalled = true; }

inline dragonx::wallet::LiteClientBridgeApi makeFakeLiteApi()
{
    dragonx::wallet::LiteClientBridgeApi api;
    api.walletExists = &liteFakeWalletExists;
    api.initializeNew = &liteFakeInitNew;
    api.initializeNewFromPhrase = &liteFakeInitFromPhrase;
    api.initializeExisting = &liteFakeInitExisting;
    api.execute = &liteFakeExecute;
    api.freeString = &liteFakeFree;
    api.checkServerOnline = &liteFakeServerOnline;
    api.shutdown = &liteFakeShutdown;
    return api;
}

} // namespace test
} // namespace dragonx