#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_obj_t *objdir,
        jove_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 (%i >= 512)\n", __func__, local_idx);
        return EOOB;
    }

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

static int
s_syscall_objdir_swap(lockstack_t *lockstack,
                      jove_obj_t *rootdir,
                      size_t bytes_left,
                      void *payload_data)
{
    //Verify the message is big enough for the payload.
    size_t bytes_needed = sizeof(struct syscall_objdir_swap);
    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for payload.");

    //Verify the message is big enough for the other path.
    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.");

    //Verify the object pointed to in the entry exists.
    jove_obj_t *target = lockstack_pop(lockstack);
    jove_owned_obj_t *obj_a = lockstack_push(lockstack, objdir_getlocal(target, payload->index));
    if(obj_a == NULL) {
        klogf("Getting local object %i failed : %s\n",
                payload->index, errstr(errno));
        return -errno;
    }

    //Verify the second object directory exists.
    jove_perm_obj_t objdir_b = link_traverse_objdir(rootdir, payload->other_path_length - 1, payload->other_path);
    if(objdir_b.obj == NULL) {
        obj_release(objdir_b.obj);
        klogf("Getting object %P failed : %s\n",
                payload->other_path, payload->other_path_length, errstr(errno));
        return -errno;
    }
    
    //Verify the second object directory has the correct permissions.
    CHECK_OBJPERM(objdir_b, SYSCALL_PERM_OBJDIR_SWAP_TGT, "Other object is missing permission");

    //Verify the second object exists.
    jove_owned_obj_t *obj_b = lockstack_push(lockstack, 
            objdir_getlocal_locked(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_obj_t *rootdir_obj,
        size_t bytes_left,
        void *payload_data)
{
    //Verify the message is big enough for the payload.
    size_t bytes_needed = sizeof(struct syscall_objdir_link);
    CHECK_TOOSMALL(bytes_needed, bytes_left, "Message too small for payload");

    //Verify the message is big enough for the second path.
    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");

    //Verify the objdir index is a valid object.
    jove_owned_obj_t *link_obj = lockstack_push(lockstack, objdir_getlocal_locked(target_obj, payload->index));
    if(link_obj == NULL) {
        klogf("Getting local object %i failed : %s\n", payload->index, errstr(errno));
        return -errno;
    }

    //Verify that the link object is infact a link object.
    CHECK_OBJTYPE(link_obj, JOVE_OBJ_LINK, "Local object is not a link object");
    
    jove_perm_obj_t dest_obj = link_traverse_objdir(rootdir_obj, payload->other_path_length, payload->other_path);
    lockstack_push(lockstack, dest_obj.obj);

    //Verify the destination path exists.
    if(dest_obj.obj == NULL) {
        klogf("Getting destination object %P failed : %s\n",
                payload->other_path, payload->other_path_length, errstr(errno));
        return -errno;
    }
    
    //Verify the destination path is empty.
    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;
    }
    //Verify the destination path has the correct permissions.
    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, lockstack_pop(&ctx->lockstack), 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->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;
    }
}