#include "arch/x86_64/syscall/wrappers.h"
#include "arch/x86_64/syscall.h"
#include "arch/x86_64/page.h"
#include <stddef.h>
#include "error.h"
#include "lock.h"
#include "string.h"
#include "memory.h"
#include "print.h"

static int
s_handle_invoke_mapping_exists(
        objdir_t *root_dir, 
        objdir_entry_t *target_entry, 
        uint8_t *payload, 
        size_t payload_at
        )
{
    pmle_t *pml4 = (pmle_t*)vmem_phys_tovirt(target_entry->data);
    pmle_t *target_pml;
    uint8_t target_depth;
    SYSCALL_PAYLOAD_TAKEPML(payload, payload_at, pml4, target_depth, target_pml);
    if(target_pml == NULL || !target_pml->p) return KE_DNE;

#ifdef DBG_SYSCALL
    klogf("pml d%i %p from %p exists\n", target_depth, target_pml, pml4);
#endif
    return 0;
}

static int
s_handle_invoke_mapping_map(
        objdir_t *root_dir, 
        objdir_entry_t *target_entry, 
        uint8_t *payload, 
        size_t payload_at
        )
{
    pmle_t *pml4 = (pmle_t*)vmem_phys_tovirt(target_entry->data);
    pmle_t *target_pml;
    uint8_t target_depth;
    SYSCALL_PAYLOAD_TAKEPML(payload, payload_at, pml4, target_depth, target_pml);
    if(target_pml == NULL) return KE_DNE;

    size_t untyped_pathw;
    objdir_entry_t *untyped_entry;
    SYSCALL_PAYLOAD_TAKEOBJ(payload, payload_at, untyped_pathw, untyped_entry);
    
    if(untyped_entry->type != KO_MEMORY_UNTYPED) return KE_BADOBJ;
    mtx_acquire(&untyped_entry->lock);

    if((untyped_entry->data & 0xFFF) != 0) {
        mtx_release(&untyped_entry->lock);
        return KE_ALIGN;
    }

    uintptr_t untyped_phys = untyped_entry->data;
    size_t *untyped = ko_entry_data(untyped_entry);
    size_t untyped_size = *untyped;
    if(untyped_size != 0x1000) {
        mtx_release(&untyped_entry->lock);
        return KE_BADSIZE;
    }
    
    target_pml->value = untyped_phys | PAGE_RW | PAGE_US | PAGE_PRESENT;
    __asm__ volatile("invlpg (%0)":: "r"(untyped): "memory");

    if(target_depth != 3) {
        memset(untyped, 0, 0x1000);
    }
    untyped_entry->type = KO_NONE;
#ifdef DBG_SYSCALL
    klogf("map %p[%i] to %p[%i]\n", untyped_phys, target_depth, target_pml, ((uintptr_t)target_pml & 0xFFF) / 8);
#endif

    mtx_release(&untyped_entry->lock);
    return 0;
}

static int
s_handle_invoke_mapping_unmap(
        objdir_t *root_dir, 
        objdir_entry_t *target_entry, 
        uint8_t *payload, 
        size_t payload_at
        )
{
    pmle_t *pml4 = (pmle_t*)vmem_phys_tovirt(target_entry->data);
    pmle_t *target_pml;
    uint8_t target_depth;
    SYSCALL_PAYLOAD_TAKEPML(payload, payload_at, pml4, target_depth, target_pml);
    if(target_pml == NULL || !target_pml->p) return KE_DNE;
   
    if(target_depth != 3) {
        for(pmli_t i = 0; i < 512; i++) {
            if(target_pml[i].p) return KE_FULL;
        }
    }

    target_pml->p = false;

    objdir_entry_t *dest_entry;
    size_t dest_pathw;
    SYSCALL_PAYLOAD_TAKEOBJ(payload, payload_at, dest_pathw, dest_entry);

    if(dest_entry->type != KO_NONE) return KE_FULL;
    uintptr_t pmle_addr = target_pml->paddr << 12;
    size_t *untyped = vmem_phys_tovirt(pmle_addr);
    __asm__ volatile("invlpg (%0)":: "r"(untyped): "memory");

    *untyped = 0x1000;
    dest_entry->type = KO_MEMORY_UNTYPED;
    dest_entry->data = pmle_addr;

#ifdef DBG_SYSCALL
    klogf("unmap %p[%i] to untyped %p\n", target_pml, 3 - target_depth, pmle_addr);
#endif
    return 0;
}

static int (*s_invoke_handles[])(objdir_t*, objdir_entry_t*, uint8_t*, size_t) = {
    [INVOKE_MAPPING_EXISTS] = s_handle_invoke_mapping_exists,
    [INVOKE_MAPPING_MAP] = s_handle_invoke_mapping_map,
    [INVOKE_MAPPING_UNMAP] = s_handle_invoke_mapping_unmap
};

static size_t s_invoke_handles_count = sizeof(s_invoke_handles) / sizeof(void*);

int
syscall_handle_invoke_mapping(
        objdir_t *root_dir, 
        objdir_entry_t *target, 
        uint8_t *payload, 
        size_t payload_at
        )
{
    uint8_t funcid;
    SYSCALL_PAYLOAD_TAKEL(payload, payload_at, funcid, uint8_t);

    if(funcid >= s_invoke_handles_count) return KE_BADFUNC;
    int r = s_invoke_handles[funcid](root_dir, target, payload, payload_at);
#ifdef DBG_SYSCALL
    klogf("Call returns %i\n", r);
#endif
    return r;
}