// 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 GitProject or LocalProject without `.args` forwards the args of the
// project file that declares it: both specs default their args to
// ProjectArgs(). Before that default, every project.cpp with a sibling
// dependency copied its span into a std::vector<std::string> for each spec,
// and a spec that missed the copy built its sibling with none of the
// project's flags: for the host while the project cross-compiled, and in
// release while the project built --debug. The fixture is a chain
// app -> lib -> leaf of LocalProjects; app also loads lib with an empty and
// with a replaced list, and checks the GitProjectSpec default itself, which
// a clone would need a repository for. A spec made at namespace scope gets
// no args: made while dlopen runs the file's static initialisers, which
// happens on its first load only, it would otherwise keep that load's args
// for every later one.
namespace {
    std::int32_t Failures = 0;

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

    // The single sibling lib, static and leaf declare, or nullptr.
    const Configuration* OnlyDependency(const Configuration& cfg) {
        return cfg.dependencies.size() == 1 ? cfg.dependencies[0] : nullptr;
    }

    // What a sibling was loaded with, as ApplyStandardArgs split it up:
    // --debug into cfg.debug, the uninterpreted rest into cfg.projectArgs.
    // Printed either way, so a failure says which args the sibling read.
    void CheckLoaded(const Configuration* cfg, bool debug, const std::vector<std::string>& rest, std::string_view what) {
        if (!cfg) {
            Check(false, std::format("{} (no such configuration)", what));
            return;
        }
        Check(cfg->debug == debug && cfg->projectArgs == rest, std::format("{} (debug {}, projectArgs {})", what, cfg->debug, cfg->projectArgs));
    }
}

int main() {
    const fs::path installedHome = GetCrafterBuildHome();
    if (!fs::exists(installedHome / "Crafter.Build.cppm")) {
        std::println(std::cerr, "SKIP: no module sources at {}", installedHome.string());
        return 77;
    }

    // Staged because LoadProject drops a build/ tree next to every project
    // file it compiles.
    const fs::path fixture = fs::current_path() / "tests" / "ProjectArgs" / "fixture";
    const fs::path scratch = fs::temp_directory_path() / "crafter-build-project-args";
    std::error_code ec;
    fs::remove_all(scratch, ec);
    fs::create_directories(scratch);
    fs::copy(fixture, scratch, fs::copy_options::recursive);

    Check(ProjectArgs().empty(), "no project args outside a project file");

    // Loaded from the project's own directory, as crafter-build runs it: the
    // fixture's LocalProject paths are relative to the working directory.
    const fs::path cwd = fs::current_path();
    fs::current_path(scratch / "app");
    std::array<std::string_view, 2> args = { "--debug", "--flavor=x" };
    const std::vector<std::string> flavor = { "--flavor=x" };
    const std::vector<std::string> only = { "--only" };
    try {
        Configuration cfg = LoadProject("project.cpp", args);
        Check(std::ranges::contains(cfg.compileFlags, "-DGIT_DEFAULT=1"), "a GitProjectSpec's args default to the project's own");
        Check(cfg.dependencies.size() == 4, std::format("the project declared its four siblings (got {})", cfg.dependencies.size()));
        if (cfg.dependencies.size() == 4) {
            const Configuration* inherited = cfg.dependencies[0];
            const Configuration* none = cfg.dependencies[1];
            const Configuration* replaced = cfg.dependencies[2];
            const Configuration* fromStatic = cfg.dependencies[3];
            CheckLoaded(inherited, true, flavor, "a LocalProject without .args gets the project's args");
            CheckLoaded(none, false, {}, "`.args = {}` forwards nothing");
            CheckLoaded(replaced, false, only, "an explicit list replaces the args rather than adding to them");
            Check(inherited != none && inherited != replaced && none != replaced, "each list loads its own configuration");

            // One sibling further down, the same default passes on what the
            // middle project was given, not what the top one was.
            CheckLoaded(OnlyDependency(*inherited), true, flavor, "the project's args reach its sibling's sibling");
            CheckLoaded(OnlyDependency(*none), false, {}, "a sibling loaded with nothing passes nothing on");
            CheckLoaded(OnlyDependency(*replaced), false, only, "a sibling passes on the list it was given");

            CheckLoaded(fromStatic, true, flavor, "the sibling with a namespace-scope spec is itself loaded with the args");
            CheckLoaded(OnlyDependency(*fromStatic), false, {}, "a spec made at namespace scope forwards nothing");
        }
    } catch (const std::exception& e) {
        fs::current_path(cwd);
        std::println(std::cerr, "FAIL: LoadProject threw: {}", e.what());
        return 1;
    }
    fs::current_path(cwd);

    Check(ProjectArgs().empty(), "no project args once the project file has returned");
    return Failures > 0 ? 1 : 0;
}