#include "arch/x86_64/hal/obj.h"
#include "proc/process.h"
#include "jove.h"
#include "lib/printf.h"
#include "sys/objdir.h"
#include "syscall.h"

int
s_syscall_objdir_objtype(
        jove_owned_obj_t *objdir,
        jove_owned_obj_t *target_dir,
        size_t payload_size,
        void *payload_data)
{
    size_t bytes_needed = 2;
    CHECK_TOOSMALL(bytes_needed, payload_size, "Message is too small for payload.");

    uint16_t local_idx = *((uint16_t*)payload_data);

    if(local_idx > OBJDIR_ENTRIES) {
        kprintf("%s: Object index is out of bounds (>= 512)\n", __func__);
        return EOOB;
    }

    jove_obj_t local_obj = objdir_peeklocal(target_dir, local_idx);
    return obj_peektype(local_obj);
}

static int
s_syscall_objdir_swap(jove_owned_obj_t *target_obj,
        lockstack_t *lockstack,
        jove_owned_obj_t *rootdir,
        size_t bytes_left,
        void *payload_data)
{
    size_t bytes_needed = sizeof(struct syscall_objdir_swap);
    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for payload.");

    struct syscall_objdir_swap *payload = payload_data;
    bytes_needed += payload->other_path_length * sizeof(objpath_part_t);
    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for other path.");

    jove_owned_obj_t *obj_a = lockstack_push(lockstack, objdir_trygetlocal(target_obj, payload->index));
    if(obj_a == NULL) {
        klogf("Getting local object %i failed : %s\n",
                payload->index, errstr(errno));
        return -errno;
    }
    jove_perm_obj_t objdir_b = link_try_traverse_objdir(rootdir, lockstack,
            payload->other_path_length - 1, payload->other_path);
    if(objdir_b.obj == NULL) {
        klogf("Getting object %P failed : %s\n",
                payload->other_path, payload->other_path_length, errstr(errno));
        return -errno;
    }

    CHECK_OBJPERM(objdir_b, SYSCALL_PERM_OBJDIR_SWAP_TGT, "Other object is missing permission");
    jove_owned_obj_t *obj_b = lockstack_push(lockstack, 
            objdir_trygetlocal(objdir_b.obj, payload->other_path[payload->other_path_length-1]));
    if(obj_b == NULL) {
        klogf("Getting object %P failed : %s\n",
                payload->other_path, payload->other_path_length, errstr(errno));
        return -errno;
    }

    objdir_swapobj(obj_a, obj_b);
    return 0;
}

static int
s_syscall_objdir_link(jove_owned_obj_t *target_obj,
        lockstack_t *lockstack,
        jove_owned_obj_t *rootdir_obj,
        size_t bytes_left,
        void *payload_data)
{
    size_t bytes_needed = sizeof(struct syscall_objdir_link);
    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for payload");

    struct syscall_objdir_link *payload = payload_data;
    bytes_needed += payload->other_path_length * sizeof(objpath_part_t);
    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for other object");

    jove_owned_obj_t *link_obj = lockstack_push(lockstack, objdir_trygetlocal(target_obj, payload->index));
    if(link_obj == NULL) {
        klogf("Getting local object %i failed : %s\n", payload->index, errstr(errno));
        return -errno;
    }
    CHECK_OBJTYPE(link_obj, JOVE_OBJ_LINK, "Local object is not a link object");
    
    jove_perm_obj_t dest_obj = link_try_traverse_objdir(rootdir_obj, lockstack,
            payload->other_path_length, payload->other_path);
    if(dest_obj.obj == NULL) {
        klogf("Getting destination object %P failed : %s\n",
                payload->other_path, payload->other_path_length, errstr(errno));
        return -errno;
    }
    
    if(obj_gettype(dest_obj.obj) != JOVE_OBJ_NONE) {
        klogf("Destination object %P is not empty\n",
                payload->other_path, payload->other_path_length);
        return -EFULL;
    }
    CHECK_OBJPERM(dest_obj, SYSCALL_PERM_OBJDIR_LINK_TGT, "Destination object is missing permissions");
    return link_dup(link_obj, dest_obj.obj);
}

int
_syscall_handle_objdir(syscall_context_t *ctx)
{
    switch(ctx->header->callid) {
        case SYSCALL_OBJDIR_OBJTYPE:
            if(ctx->target.permissions & SYSCALL_PERM_OBJDIR_OBJTYPE)
                return s_syscall_objdir_objtype(
                        ctx->objdir, ctx->target.obj, ctx->bytes_left, ctx->payload);
            return -EPERM;

        case SYSCALL_OBJDIR_SWAP:
            if(ctx->target.permissions & SYSCALL_PERM_OBJDIR_SWAP)
                return s_syscall_objdir_swap(ctx->target.obj,
                        &ctx->lockstack, ctx->objdir, ctx->bytes_left, ctx->payload);
            return -EPERM;
        
        case SYSCALL_OBJDIR_LINK:
            if(ctx->target.permissions & SYSCALL_PERM_OBJDIR_LINK)
                return s_syscall_objdir_link(ctx->target.obj,
                        &ctx->lockstack, ctx->objdir, ctx->bytes_left, ctx->payload);
            return -EPERM;

        default:
            return -EBADCALL;
    }
}