// SPDX-License-Identifier: LGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

import std;
import Crafter.Build;
namespace fs = std::filesystem;
using namespace Crafter;

// A WASI sysroot without exception support has to stop a wasm build with one
// line that says so. wasm builds compile with -fwasm-exceptions and link the
// libc++ and libunwind that wasi-sdk 33 and later ship under lib/<triple>/eh;
// a sysroot that lacks them (an older wasi-sdk, one built without its
// exceptions option) otherwise compiles and then fails the first link with
// "unable to find library -lunwind", which does not say why it was asked
// for. A sysroot that is not there at all, or has nothing for the target,
// gets a message of its own rather than that one. The checks run before
// anything is made, so a refused build leaves no bin/ behind, and they need
// no working wasm toolchain.
//
// A scratch sysroot is taken through these states: missing; without
// lib/wasm32-wasip1; without libunwind, for an executable and for a static
// library, which links nothing and passes; with libunwind under eh/; with
// libunwind in the triple's own directory, which the driver searches after
// eh/. The cases that pass the check fail later on the sysroot's empty std
// module source, which is not what is under test. The cache is redirected
// into the scratch directory as well: the std PCM cache is not keyed on the
// sysroot, and a PCM built from the fake source must not land where the real
// wasm tests read theirs.

extern "C" int setenv(const char* name, const char* value, int overwrite);

namespace {
    std::int32_t failures = 0;

    void Check(bool cond, std::string_view msg) {
        if (!cond) {
            std::println(std::cerr, "FAIL: {}", msg);
            ++failures;
        }
    }

    BuildResult BuildAgainst(const fs::path& project, const fs::path& sysroot, ConfigurationType type = ConfigurationType::Executable) {
        Configuration app;
        app.path = project;
        app.name = "hello";
        app.outputName = "hello";
        app.target = "wasm32-wasip1";
        app.sysroot = sysroot.string();
        app.type = type;
        std::array<fs::path, 0> ifaces = {};
        std::array<fs::path, 1> impls = { "main" };
        app.GetInterfacesAndImplementations(ifaces, impls);
        std::unordered_map<fs::path, std::shared_future<BuildResult>> depResults;
        std::mutex depMutex;
        return Build(app, depResults, depMutex);
    }
}

int main() {
    // Build() reports a missing compiler before it gets to the sysroot.
    if (const Toolchain& tc = GetToolchain(); !tc.error.empty()) {
        std::println(std::cerr, "SKIP: {}", tc.error);
        return 77;
    }

    const fs::path scratch = fs::temp_directory_path() / "crafter-build-wasi-sysroot-without-exceptions";
    fs::remove_all(scratch);
    fs::create_directories(scratch);
    setenv("XDG_CACHE_HOME", (scratch / "cache").c_str(), 1);
    const fs::path project = scratch / "project";
    fs::copy(fs::current_path() / "tests" / "WasiSysrootWithoutExceptions" / "fixture", project, fs::copy_options::recursive);

    const fs::path sysroot = scratch / "sysroot";
    const fs::path libDir = sysroot / "lib" / "wasm32-wasip1";
    {
        const BuildResult r = BuildAgainst(project, sysroot);
        Check(r.result.contains(std::format("no WASI sysroot at {}", sysroot.string())), std::format("a missing sysroot is named as missing: {}", r.result));
    }

    fs::create_directories(sysroot / "share" / "libc++" / "v1");
    std::ofstream(sysroot / "share" / "libc++" / "v1" / "std.cppm");
    {
        const BuildResult r = BuildAgainst(project, sysroot);
        Check(r.result.contains(std::format("has nothing for wasm32-wasip1 (no {})", libDir.string())), std::format("a sysroot without the target's directory says so: {}", r.result));
    }

    fs::create_directories(libDir / "eh");
    constexpr std::string_view missing = "has no C++ exception support";
    {
        const BuildResult r = BuildAgainst(project, sysroot);
        Check(r.result.contains(missing), std::format("without libunwind the build stops on the sysroot: {}", r.result));
        Check(r.result.contains((libDir / "eh" / "libunwind.a").string()), std::format("the message names the library it looked for: {}", r.result));
        Check(!fs::exists(project / "bin") && !fs::exists(project / "build"), "a refused build leaves no bin/ or build/ behind");
    }
    Check(!BuildAgainst(project, sysroot, ConfigurationType::LibraryStatic).result.contains(missing), "a static library links nothing and passes without libunwind");

    std::ofstream(libDir / "eh" / "libunwind.a");
    Check(!BuildAgainst(project, sysroot).result.contains(missing), "libunwind under eh/ passes the check");

    fs::remove(libDir / "eh" / "libunwind.a");
    std::ofstream(libDir / "libunwind.a");
    Check(!BuildAgainst(project, sysroot).result.contains(missing), "libunwind in the triple's directory passes the check");

    fs::remove_all(scratch);
    if (failures > 0) {
        std::println(std::cerr, "{} assertions failed", failures);
        return 1;
    }
    return 0;
}