#include <socks/types.h>
#include <socks/vm.h>
#include <string.h>
#include <stdio.h>
#include <inttypes.h>
#include <stdlib.h>

static void convert_region_to_blocks(vm_zone_t *zone, phys_addr_t base, phys_addr_t limit, int reserved)
{
	size_t block_frames = vm_bytes_to_pages(limit - base);
	printf("adding region %08zx-%08zx (%zu frames) to zone %s\n", base, limit, block_frames, zone->z_name);
	int reset_order = 0;

	for (int order = VM_PAGE_MAX_ORDER; order >= VM_PAGE_MIN_ORDER; ) {
		size_t order_frames = vm_page_order_to_pages(order);
		vm_alignment_t order_alignment = vm_page_order_to_alignment(order);

		if (order_frames > block_frames) {
			order--;
			continue;
		}

		if (!VM_CHECK_ALIGN(base, order_alignment)) {
			reset_order = 1;
			order--;
			continue;
		}
		
		printf("%s: %zu %s pages at %08" PRIxPTR "\n",
		       zone->z_name,
		       order_frames,
		       reserved == 1 ? "reserved" : "free",
		       base);
		
		base += order_frames * VM_PAGE_SIZE;
		block_frames -= order_frames;

		if (reset_order) {
			order = VM_PAGE_MAX_ORDER;
			reset_order = 0;
		} else {
			order--;
		}

		if (base > limit) {
			printf("too many pages created!\n");
			abort();
		} 

		if (base == limit) {
			break;
		}
	}
}

void vm_zone_init(vm_zone_t *z, const char *name, uintptr_t base, uintptr_t limit)
{
	printf("initialising zone %s (%08zx-%08zx)\n", name, base, limit);
	memset(z, 0x0, sizeof *z);
	z->z_name = name;

	phys_addr_t block_start = base, block_end = base;
	int this_page_reserved = 0, last_page_reserved = -1;
	for (uintptr_t i = base; i < limit; i += VM_PAGE_SIZE) {
		vm_page_t *pg = vm_page_get(i);
		if (!pg) {
			break;
		}
		
		this_page_reserved = (pg->p_flags & VM_PAGE_RESERVED) ? 1 : 0;

		if (last_page_reserved == -1) {
			last_page_reserved = this_page_reserved;
		}

		if (this_page_reserved == last_page_reserved) {
			block_end = i;
			continue;
		}

		convert_region_to_blocks(z, block_start, i, this_page_reserved);

		block_start = i;
		last_page_reserved = this_page_reserved;
	}

	if (block_start != block_end) {
		convert_region_to_blocks(z, block_start, block_end, this_page_reserved);
	}
}