// Unit test for the DPI -> UI scale math (common/include/coop/dpi.hpp): the 96-DPI baseline, common
// Windows scalings, the zero-DPI fallback, clamping at both ends, and the default-font pixel-size
// derivation. Pure math -- no window, no ImGui -- so it's the reasonably-testable slice of the
// per-monitor DPI feature (the actual awareness + font rasterization are verified by hand).
#include <cmath>
#include <cstdio>

#include "coop/dpi.hpp"

using namespace coop;

namespace {
int g_failures = 0;
void check(bool ok, const char* what)
{
	std::printf("%s %s\n", ok ? "  ok:" : "FAIL:", what);
	if (!ok) {
		++g_failures;
	}
}
bool approx(float a, float b)
{
	return std::fabs(a - b) < 1e-4f;
}
} // namespace

int main()
{
	// Baseline and the common Windows display scalings.
	check(approx(dpi_scale_from(96), 1.0f), "96 DPI -> 1.0 (100%)");
	check(approx(dpi_scale_from(120), 1.25f), "120 DPI -> 1.25 (125%)");
	check(approx(dpi_scale_from(144), 1.5f), "144 DPI -> 1.5 (150%)");
	check(approx(dpi_scale_from(192), 2.0f), "192 DPI -> 2.0 (200%)");

	// A zero / unknown DPI falls back to the 96 baseline (never 0 -> a zero-size font).
	check(approx(dpi_scale_from(0), 1.0f), "0 DPI -> 1.0 fallback");

	// Clamping: never below 100%, and capped at the max for an absurd report.
	check(approx(dpi_scale_from(48), kMinUiScale), "48 DPI clamps up to the min UI scale");
	check(approx(dpi_scale_from(100000), kMaxUiScale), "absurd DPI clamps to the max UI scale");

	// Font size scales from the single named base constant, matching ImGui's 13px default at 100%.
	check(approx(kBaseFontPx, 13.0f), "base font px is ImGui's 13px default");
	check(approx(scaled_font_px(96), 13.0f), "font px at 100% == base");
	check(approx(scaled_font_px(144), 19.5f), "font px at 150% == 13 * 1.5");
	check(approx(scaled_font_px(0), kBaseFontPx), "font px at unknown DPI == base (fallback)");

	std::printf(g_failures == 0 ? "PASS dpi_test\n" : "FAILED dpi_test (%d)\n", g_failures);
	return g_failures == 0 ? 0 : 1;
}