use crate::mem::phys::BitmapFrameAllocator;

crate::kernel_test!(
    fn allocate_returns_aligned_nonzero() {
        let alloc = BitmapFrameAllocator;
        let frame = alloc.allocate().expect("allocation failed");
        let addr = frame.phys_addr().as_u64();
        assert!(addr != 0, "allocated frame has zero address");
        assert!(
            addr.is_multiple_of(4096),
            "frame not page-aligned: {:#x}",
            addr
        );
    }
);

crate::kernel_test!(
    fn allocate_then_free_restores_count() {
        let before = BitmapFrameAllocator::free_frames();
        let frame = BitmapFrameAllocator.allocate().expect("allocation failed");
        assert_eq!(
            BitmapFrameAllocator::free_frames(),
            before - 1,
            "free count did not decrease"
        );
        drop(frame);
        assert_eq!(
            BitmapFrameAllocator::free_frames(),
            before,
            "free count did not restore after drop"
        );
    }
);

crate::kernel_test!(
    fn bitmap_invariant_holds() {
        let total = BitmapFrameAllocator::total_frames();
        let used = BitmapFrameAllocator::used_frames();
        let free = BitmapFrameAllocator::free_frames();
        assert_eq!(
            used + free,
            total,
            "invariant broken: used({}) + free({}) != total({})",
            used,
            free,
            total
        );
    }
);

crate::kernel_test!(
    fn write_and_readback_through_hhdm() {
        let frame = BitmapFrameAllocator.allocate().expect("allocation failed");
        let virt = crate::mem::addr::phys_to_virt(frame.phys_addr());
        let ptr: *mut u64 = virt.as_mut_ptr();
        let pattern: u64 = 0xA5A5_5A5A_DEAD_BEEF;
        unsafe { ptr.write_volatile(pattern) };
        let readback = unsafe { ptr.read_volatile() };
        assert_eq!(readback, pattern, "write/readback mismatch through HHDM");
    }
);