import std;
import Crafter.Build;
using namespace Crafter;

// POSIX env helpers — libc++ exports only std::getenv via `import std`, so
// forward-declare the setters we need against the C library directly. The
// test only runs on POSIX hosts (the project.cpp gates new tests by
// x86_64-pc-linux-gnu) so we don't need a Windows alternative here.
extern "C" int setenv(const char* name, const char* value, int overwrite);
extern "C" int unsetenv(const char* name);

namespace {
    int failures = 0;

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

// Pure-data tests for TestRunner factories. No tests are actually executed;
// we just confirm the routing tables in ForTarget / FromSpec / FromEnv.
int main() {
    // FromSpec: empty -> nullopt; recognized -> populated; garbage -> throws.
    {
        auto empty = TestRunner::FromSpec("");
        Check(!empty.has_value(), "FromSpec(\"\") returns nullopt");
    }
    {
        auto local = TestRunner::FromSpec("local");
        Check(local.has_value() && local->IsLocal(), "FromSpec(\"local\") returns Local");
        Check(local.has_value() && local->name == "local", "Local name is 'local'");
    }
    {
        auto cmd = TestRunner::FromSpec("cmd:wasmtime");
        Check(cmd.has_value(), "FromSpec(\"cmd:wasmtime\") returns a runner");
        Check(cmd.has_value() && cmd->name == "cmd:wasmtime", "Cmd name carries the binary");
        Check(cmd.has_value() && cmd->exec.find("wasmtime") != std::string::npos, "Cmd exec carries the binary");
        Check(cmd.has_value() && !cmd->probe.empty(), "Cmd probe is set so harness can detect missing tools");
    }
    {
        bool threw = false;
        try {
            (void)TestRunner::FromSpec("garbage");
        } catch (const std::exception&) {
            threw = true;
        }
        Check(threw, "FromSpec rejects unrecognized non-empty specs");
    }

    // ForTarget routing.
    {
        Configuration cfg;
        cfg.target = HostTarget();
        TestRunner r = TestRunner::ForTarget(cfg);
        Check(r.IsLocal(), "ForTarget(host) is Local");
    }
    {
        Configuration cfg;
        cfg.target = "wasm32-wasip1";
        TestRunner r = TestRunner::ForTarget(cfg);
        Check(r.name == "cmd:wasmtime", "ForTarget(wasm32-wasip1) routes through wasmtime");
    }
    {
        Configuration cfg;
        cfg.target = "aarch64-linux-gnu";
        TestRunner r = TestRunner::ForTarget(cfg);
        Check(r.name == "cmd:qemu-aarch64", "ForTarget(aarch64-linux-gnu) routes through qemu-aarch64");
    }
    {
        Configuration cfg;
        cfg.target = "i686-linux-gnu";
        TestRunner r = TestRunner::ForTarget(cfg);
        Check(r.name == "cmd:qemu-i386", "ForTarget(i686-linux-gnu) rewrites arch to i386");
    }
    {
        // Sysroot propagates to QEMU_LD_PREFIX so the dynamic linker is reachable.
        Configuration cfg;
        cfg.target = "aarch64-linux-gnu";
        cfg.sysroot = "/opt/alarm-sysroot";
        TestRunner r = TestRunner::ForTarget(cfg);
        Check(r.exec.find("QEMU_LD_PREFIX=/opt/alarm-sysroot") != std::string::npos,
            "ForTarget propagates sysroot to QEMU_LD_PREFIX");
    }
    {
        // From a Linux host the only sensible way to run x86_64-w64-mingw32 is wine.
        Configuration cfg;
        cfg.target = "x86_64-w64-mingw32";
        TestRunner r = TestRunner::ForTarget(cfg);
        if (HostTarget().find("linux") != std::string::npos) {
            Check(r.name == "wine", "ForTarget(mingw) on Linux host uses wine");
        }
    }

    // FromEnv: when the env var is set, it wins over the fallback.
    {
        // Use a unique fake triple so we don't stomp on a real env var the
        // CI/dev shell may have set.
        const char* name = "CRAFTER_BUILD_RUNNER_fake_target_for_unit_test";
        setenv(name, "cmd:fake-tool", 1);
        TestRunner r = TestRunner::FromEnv("fake-target-for-unit-test", TestRunner::Local());
        Check(r.name == "cmd:fake-tool", "FromEnv reads CRAFTER_BUILD_RUNNER_<target>");
        unsetenv(name);
        TestRunner fallback = TestRunner::FromEnv("fake-target-for-unit-test", TestRunner::Local());
        Check(fallback.IsLocal(), "FromEnv falls back when env var is unset");
    }

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