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

int
_syscall_handle_generic(
        jove_owned_obj_t *pcb_obj,
        jove_owned_obj_t *objdir,
        jove_owned_obj_t *message_obj,
        jove_owned_obj_t *target_obj,
        struct syscall_header *header,
        size_t bytes_left,
        void *payload)
{
    pcb_t *pcb = obj_deref(pcb_obj);
    kprintf("syscall: Process %i encountered stub syscall on object %P\n", pcb_pid(pcb), header->path, header->pathlen);
    return EBADOBJ;
}

static const syscall_handle_t s_syscall_handles[128] = {
    [JOVE_OBJ_NONE] = NULL,
    [JOVE_OBJ_UNTYPED] = _syscall_handle_generic,
    [JOVE_OBJ_OBJDIR] = _syscall_handle_generic,
    [JOVE_OBJ_PAGEDIR] = _syscall_handle_generic,
    [JOVE_OBJ_PROCESSOR] = _syscall_handle_generic,
    [JOVE_OBJ_PROCESS] = _syscall_handle_generic,
    [JOVE_OBJ_PAGEFRAME] = _syscall_handle_generic,
    [JOVE_OBJ_INITRD_FILE] = _syscall_handle_generic,
    [JOVE_OBJ_FRAMEBUFFER] = _syscall_handle_generic,
    [JOVE_OBJ_VIRTTERM] = _syscall_handle_generic,
    [JOVE_OBJ_MESSAGE] = _syscall_handle_generic,
};

int
syscall_handler(uintmax_t message_path_raw, uint16_t message_pathlen)
{
    uint16_t *message_path = (uint16_t*)&message_path_raw;
    if(message_pathlen > sizeof(uintmax_t) >> 1) {
        return EBADPATH;
    }

    jove_owned_obj_t *pcb_obj = process_current();
    pcb_t *pcb = obj_deref(pcb_obj);

    jove_owned_obj_t *objdir = pcb_rootdir(pcb);
    kprintf("Syscall: %p : %P \n", objdir, message_path, message_pathlen);

    jove_owned_obj_t *message_obj = objdir_getobj(objdir, message_path, message_pathlen);
    if(message_obj == 0) {
        obj_release(objdir);
        obj_release(pcb_obj);
        return errno;
    }

#define SYSCALL_MIDWAY_CLEANUP \
    obj_release(message_obj); \
    obj_release(objdir); \
    obj_release(pcb_obj)

    if(obj_gettype(message_obj) != JOVE_OBJ_MESSAGE) {
        kprintf("syscall: Process %i tried to call syscall with invalid object: %P\n", pcb_pid(pcb), message_path, message_pathlen);
        SYSCALL_MIDWAY_CLEANUP;
        return EBADOBJ;
    }

    size_t messagelen = message_len(message_obj);
    void *messagedata = message_data(message_obj);
    struct syscall_header *header = messagedata;

    size_t header_bytes = sizeof(struct syscall_header) + header->pathlen * 2;
    int bytes_left = messagelen - header_bytes;
    kprintf("syscall: Payload %p len %i\n", messagedata, header->pathlen);
    if(bytes_left < 0) {
        //Target path exceeds message length.
        kprintf("syscall: Process %i tried to call syscall with OOB target path.\n", pcb_pid(pcb));
        SYSCALL_MIDWAY_CLEANUP;
        return EBADPATH;
    }
    jove_owned_obj_t *target = objdir_getobj(objdir, header->path, header->pathlen);
    if(target == 0) {
        //Could not find payload target in pcb rootdir.
        kprintf("syscall: Process %i tried to call syscall with bad target path %P\n", 
                pcb_pid(pcb), header->path, header->pathlen);
        SYSCALL_MIDWAY_CLEANUP;
        return errno;
    }
    int sysret = 0;

    uint8_t target_type = obj_gettype(target);
    if(target_type > 0x7F) {
        sysret = syscall_handle_arch(pcb_obj, objdir, message_obj, target,
                header, bytes_left, messagedata + header_bytes);
    }else{
        syscall_handle_t call_handle = s_syscall_handles[obj_gettype(target)];
        if(call_handle == NULL) {
            kprintf("syscall: Process %i tried to call syscall on object %P which doesn't support syscalls!\n",
                    pcb_pid(pcb), header->path, header->pathlen);
            sysret = EBADOBJ;
        }else 
            sysret = call_handle(pcb_obj, objdir, message_obj, target, 
                header, bytes_left, message_data + header_bytes);
    }

    obj_release(target);
    SYSCALL_MIDWAY_CLEANUP;
    return sysret;
}