import drivers.serial.uart.serial as serial
import services.desktop as desktop
import drivers.fs.fat32.fat32 as fat32
import drivers.fs.fat32.fat32_types as fat32_types
import sched.sched as sched
import sched.process as process
import viperlib
import string
import mm.mm as mm
import paging.paging as paging
import execrunner.elf as elf


define CREATE_WINDOW = 1
define DRAW_TEXT     = 2
define EXIT          = 3
define OPEN          = 4
define CLOSE         = 5
define READ          = 6
define WRITE         = 7
define SEEK          = 8
define TELL          = 9
define SIZE          = 10
define MKDIR         = 11
define REMOVE        = 12
define OPENDIR       = 13
define READDIR       = 14
define CLOSEDIR      = 15
define STAT          = 16
define WAIT_WINDOW   = 17
define SERIAL_PUTS   = 18
define LOAD_SO       = 19
define SO_CALL1      = 20
define GET_WINBUF    = 21
define WIN_FLUSH     = 22
define POLL_EVENT    = 23
define SET_CURSOR    = 24
define YIELD         = 25
define SET_TITLE     = 26
define SET_GEOMETRY  = 27
define SPAWN         = 28
define MMAP          = 29
define MUNMAP        = 30
define SET_RESIZABLE = 31
define GET_WIN_SIZE  = 32
define THREAD_CREATE = 33
define THREAD_EXIT   = 34

define IA32_EFER  = 0xC0000080
define IA32_STAR  = 0xC0000081
define IA32_LSTAR = 0xC0000082
define IA32_FMASK = 0xC0000084

def wrmsr(msr: uint32, val: uint64):
    lo: uint32 = uint32(val & 0xFFFFFFFF)
    hi: uint32 = uint32(val >> 32)
    __asm__(f"""mov ecx, {asminp(msr, ASM_DESCR.REG_ANY)}
              mov eax, {asminp(lo, ASM_DESCR.REG_ANY)}
              mov edx, {asminp(hi, ASM_DESCR.REG_ANY)}
              wrmsr""",
          op=[ASM_DESCR.CLOBBER_RCX, ASM_DESCR.CLOBBER_RAX, ASM_DESCR.CLOBBER_RDX])

def rdmsr(msr: uint32) -> uint64:
    lo: uint32
    hi: uint32
    # rdmsr 固定写 EDX:EAX；out 绑定 + CLOBBER_RAX/RDX 冲突会导致 lo/hi
    # 分配到非 EAX/EDX 读到垃圾。显式 mov 到输出寄存器（与 asm.inb 修复同模式）。
    __asm__(f"""mov ecx, {asminp(msr, ASM_DESCR.REG_ANY)}
              rdmsr
              mov {asmout(lo, ASM_DESCR.OUTPUT_REG)}, eax
              mov {asmout(hi, ASM_DESCR.OUTPUT_REG)}, edx""",
          out=[asmout(lo, ASM_DESCR.OUTPUT_REG), asmout(hi, ASM_DESCR.OUTPUT_REG)],
          op=[ASM_DESCR.CLOBBER_RCX, ASM_DESCR.CLOBBER_RAX, ASM_DESCR.CLOBBER_RDX])
    return uint64(lo) | (uint64(hi) << 32)

def _current_proc() -> process.Process*:
    return process.ProcessManager.current()

def _fd_alloc(p: process.Process*) -> int:
    for i in range(process.PROC_MAX_FDS):
        if not p.fd_used[i]:
            p.fd_used[i] = 1
            return i
    return -1

def _fd_free(p: process.Process*, fd: int):
    if fd >= 0 and fd < process.PROC_MAX_FDS:
        p.fd_used[fd] = None
        p.fd_table[fd] = None

def _dir_alloc(p: process.Process*) -> int:
    for i in range(process.PROC_MAX_DIRS):
        if not p.dir_used[i]:
            p.dir_used[i] = 1
            return i
    return -1

def _dir_free(p: process.Process*, dd: int):
    if dd >= 0 and dd < process.PROC_MAX_DIRS:
        p.dir_used[dd] = None
        p.dir_table[dd] = None

def CREATE_WINDOW(x: int, y: int, w: int, h: int, title: const str, style: int) -> int:
    desktop.set_app_pid(process.current())
    return desktop.create(x, y, w, h, title, style)

def DRAW_TEXT(win_id: int, x: int, y: int, text: const str, color: uint32) -> int:
    return desktop.draw_text(win_id, x, y, text, color)

def EXIT(code: int) -> int:
    serial.puts("[syscall] exit called\n")
    desktop.destroy_by_pid(process.current())
    return 0

def WAIT_WINDOW(win_id: int) -> int:
    while desktop.is_active(win_id):
        sched.Scheduler.try_reschedule()
    return 0

def SERIAL_PUTS(str_ptr: str) -> int:
    s: const str = str_ptr
    serial.puts(s)
    return 0

_loaded_so_base: rawptr = None
_loaded_so_path: [64]char

def LOAD_SO(path_ptr: str) -> uint64:
    global _loaded_so_base
    path: const str = path_ptr
    serial.puts("[so] loading: ")
    serial.puts(path)
    serial.puts("\n")
    base: rawptr = elf.load_so(path)
    if base is not None:
        _loaded_so_base = base
        for i in range(63):
            ch: char = path[i]
            _loaded_so_path[i] = ch
            if ch == 0: break
        _loaded_so_path[63] = 0
        return uint64(base)
    return 0

def SO_CALL1(sym_name_ptr: str, arg1: rawptr) -> int:
    if _loaded_so_base is None: return -1
    sym_name: const str = sym_name_ptr
    fn: rawptr = elf.get_so_symbol(_loaded_so_base, sym_name, &_loaded_so_path[0])
    if fn is None:
        serial.puts("[so] symbol not found\n")
        return -2
    __asm__(f"""mov rdi, {asminp(arg1, ASM_DESCR.REG_ANY)}
            call {asminp(fn, ASM_DESCR.REG_ANY)}""",
          op=[ASM_DESCR.CLOBBER_MEMORY, ASM_DESCR.CLOBBER_RAX,
              ASM_DESCR.CLOBBER_RCX, ASM_DESCR.CLOBBER_RDX,
              ASM_DESCR.CLOBBER_RDI, ASM_DESCR.CLOBBER_RSI,
              ASM_DESCR.CLOBBER_R8, ASM_DESCR.CLOBBER_R9,
              ASM_DESCR.CLOBBER_R10, ASM_DESCR.CLOBBER_R11])
    serial.puts("[so] call returned\n")
    return 0

def GET_WINBUF(win_id: int) -> uint64:
    buf: rawptr = desktop.get_fb(win_id)
    if buf is None:
        return 0
    return uint64(buf)

def WIN_FLUSH(win_id: int, src: rawptr) -> int:
    """把 app 的**用户缓冲**内容拷进窗口的内核后备缓冲，再上屏。

    旧设计由 GET_WINBUF 把内核缓冲地址直接交给用户态，而那片页 U=0 → app 一画就 #PF(err=0x7)。
    现在 app 画在自己的用户缓冲（MMAP 分配）里，由这里 memcpy 进窗口缓冲。
    """
    if src is None: return -1
    dst: rawptr = desktop.get_fb(win_id)      # 可能按 resize 重建 → 先取指针
    n: int = desktop.get_fb_bytes(win_id)     # 再取尺寸，保证与刚取的指针一致
    if dst is None or n <= 0: return -1
    string.memcpy(dst, src, n)
    desktop.flush(win_id)
    return 0

def SET_CURSOR(win_id: int, cursor_t: int) -> int:
    desktop.set_cursor_type(win_id, cursor_t)
    return 0

def OPEN(path_ptr: str, mode: uint32) -> int:
    p: process.Process* = _current_proc()
    path: const str = path_ptr
    fat32.lock()
    fp: rawptr = fat32.open(path, uint8(mode))
    if not fp:
        fat32.unlock()
        return -1
    fd: int = _fd_alloc(p)
    if fd < 0:
        fat32.close(fp)
        fat32.unlock()
        return -1
    p.fd_table[fd] = fp
    fat32.unlock()
    return fd

def CLOSE(fd: int) -> int:
    p: process.Process* = _current_proc()
    if fd < 0 or fd >= process.PROC_MAX_FDS:
        return int(fat32_types.FRESULT.FR_INVALID_OBJECT)
    fp: rawptr = p.fd_table[fd]
    if not fp:
        return int(fat32_types.FRESULT.FR_INVALID_OBJECT)
    fat32.lock()
    res: int = int(fat32.close(fp))
    fat32.unlock()
    _fd_free(p, fd)
    return res

def READ(fd: int, buf_ptr: rawptr, count: uint32) -> int:
    p: process.Process* = _current_proc()
    if fd < 0 or fd >= process.PROC_MAX_FDS:
        return -1
    fp: rawptr = p.fd_table[fd]
    if not fp:
        return -1
    fat32.lock()
    br: uint32 = fat32.read(fp, buf_ptr, count)
    fat32.unlock()
    return int(br)

def WRITE(fd: int, buf_ptr: rawptr, count: uint32) -> int:
    p: process.Process* = _current_proc()
    if fd < 0 or fd >= process.PROC_MAX_FDS:
        return -1
    fp: rawptr = p.fd_table[fd]
    if not fp:
        return -1
    fat32.lock()
    bw: uint32 = fat32.write(fp, buf_ptr, count)
    fat32.unlock()
    return int(bw)

def SEEK(fd: int, offset: uint32) -> int:
    p: process.Process* = _current_proc()
    if fd < 0 or fd >= process.PROC_MAX_FDS:
        return int(fat32_types.FRESULT.FR_INVALID_OBJECT)
    fp: rawptr = p.fd_table[fd]
    if not fp:
        return int(fat32_types.FRESULT.FR_INVALID_OBJECT)
    fat32.lock()
    r: int = int(fat32.seek(fp, offset))
    fat32.unlock()
    return r

def TELL(fd: int) -> uint32:
    p: process.Process* = _current_proc()
    if fd < 0 or fd >= process.PROC_MAX_FDS:
        return 0
    fp: rawptr = p.fd_table[fd]
    if not fp:
        return 0
    fat32.lock()
    pos: uint32 = fat32.tell(fp)
    fat32.unlock()
    return pos

def fsize(fd: int) -> uint32:
    p: process.Process* = _current_proc()
    if fd < 0 or fd >= process.PROC_MAX_FDS:
        return 0
    fp: rawptr = p.fd_table[fd]
    if not fp:
        return 0
    fat32.lock()
    sz: uint32 = fat32.size(fp)
    fat32.unlock()
    return sz

def MKDIR(path_ptr: str) -> int:
    path: const str = path_ptr
    fat32.lock()
    r: int = int(fat32.mkdir(path))
    fat32.unlock()
    return r

def REMOVE(path_ptr: str) -> int:
    path: const str = path_ptr
    fat32.lock()
    r: int = int(fat32.remove(path))
    fat32.unlock()
    return r

def OPENdir(path_ptr: str) -> int:
    p: process.Process* = _current_proc()
    path: const str = path_ptr
    dd: int = _dir_alloc(p)
    if dd < 0:
        return -1
    dp: fat32_types.dirobj* = &p.dir_pool[dd]
    fat32.lock()
    res: int = int(fat32.opendir(path, dp))
    fat32.unlock()
    if res != 0:
        _dir_free(p, dd)
        return -1
    p.dir_table[dd] = rawptr(uint64(dp))
    return dd

def READdir(dd: int, info_ptr: rawptr) -> int:
    p: process.Process* = _current_proc()
    if dd < 0 or dd >= process.PROC_MAX_DIRS:
        return int(fat32_types.FRESULT.FR_INVALID_OBJECT)
    dp: rawptr = p.dir_table[dd]
    if not dp:
        return int(fat32_types.FRESULT.FR_INVALID_OBJECT)
    info: fat32_types.fileinfo* = info_ptr
    fat32.lock()
    r: int = int(fat32.readdir(dp, info))
    fat32.unlock()
    return r

def CLOSEdir(dd: int) -> int:
    p: process.Process* = _current_proc()
    if dd < 0 or dd >= process.PROC_MAX_DIRS:
        return int(fat32_types.FRESULT.FR_INVALID_OBJECT)
    dp: rawptr = p.dir_table[dd]
    if not dp:
        return int(fat32_types.FRESULT.FR_INVALID_OBJECT)
    fat32.lock()
    fat32.closedir(dp)
    fat32.unlock()
    _dir_free(p, dd)
    return 0

def STAT(path_ptr: str, info_ptr: rawptr) -> int:
    path: const str = path_ptr
    info: fat32_types.fileinfo* = info_ptr
    fat32.lock()
    r: int = int(fat32.stat(path, info))
    fat32.unlock()
    return r

def SPAWN(path_ptr: str, blocking: int) -> int:
    path: const str = path_ptr
    pid: int = elf.spawn_elf(path)
    if pid < 0:
        return pid
    if blocking:
        p: process.Process* = process.ProcessManager.get_process(pid)
        if p:
            while p.state != process.PROC_DONE:
                sched.Scheduler.try_reschedule()
    return pid

define USER_HEAP_BASE = 0x20000000

def MMAP(size: uint64) -> uint64:
    p: process.Process* = _current_proc()
    if size == 0: return 0
    aligned_size: uint64 = (size + 4095) & ~uint64(4095)
    if p.heap_start == 0:
        p.heap_start = USER_HEAP_BASE
    heap_end: uint64 = p.heap_start + p.heap_size
    new_end: uint64 = heap_end + aligned_size
    for va in range(heap_end, new_end, 4096):
        phys_page: rawptr = mm.malloc(4096)
        if phys_page is None: return 0
        paging.MapPage(va, uint64(phys_page), paging.PTE_PRESENT | paging.PTE_WRITABLE | paging.PTE_USER)
    p.heap_size = p.heap_size + aligned_size
    return heap_end

def MUNMAP(ptr: uint64, size: uint64) -> int:
    return 0

extern def syscall_entry()

export def syscall_handler(num: uint64, arg1: uint64, arg2: uint64, arg3: uint64, arg4: uint64, arg5: uint64, arg6: uint64) -> uint64:
    n: int = int(num)
    if n == CREATE_WINDOW:
        title_ptr: str = str(arg5)
        return uint64(CREATE_WINDOW(int(arg1), int(arg2), int(arg3), int(arg4), title_ptr, int(arg6)))
    elif n == DRAW_TEXT:
        text_ptr: str = str(arg4)
        return uint64(DRAW_TEXT(int(arg1), int(arg2), int(arg3), text_ptr, uint32(arg5)))
    elif n == EXIT:
        return uint64(EXIT(int(arg1)))
    elif n == OPEN:
        path_ptr: str = str(arg1)
        return uint64(OPEN(path_ptr, uint32(arg2)))
    elif n == CLOSE:
        return uint64(CLOSE(int(arg1)))
    elif n == READ:
        buf_ptr: rawptr = rawptr(arg2)
        return uint64(READ(int(arg1), buf_ptr, uint32(arg3)))
    elif n == WRITE:
        buf_ptr: rawptr = rawptr(arg2)
        return uint64(WRITE(int(arg1), buf_ptr, uint32(arg3)))
    elif n == SEEK:
        return uint64(SEEK(int(arg1), uint32(arg2)))
    elif n == TELL:
        return uint64(TELL(int(arg1)))
    elif n == SIZE:
        return uint64(fsize(int(arg1)))
    elif n == MKDIR:
        path_ptr: str = str(arg1)
        return uint64(MKDIR(path_ptr))
    elif n == REMOVE:
        path_ptr: str = str(arg1)
        return uint64(REMOVE(path_ptr))
    elif n == OPENDIR:
        path_ptr: str = str(arg1)
        return uint64(OPENdir(path_ptr))
    elif n == READDIR:
        info_ptr: rawptr = rawptr(arg2)
        return uint64(READdir(int(arg1), info_ptr))
    elif n == CLOSEDIR:
        return uint64(CLOSEdir(int(arg1)))
    elif n == STAT:
        path_ptr: str = str(arg1)
        info_ptr: rawptr = rawptr(arg2)
        return uint64(STAT(path_ptr, info_ptr))
    elif n == WAIT_WINDOW:
        if int(arg2) == 1:
            return uint64(desktop.is_active(int(arg1)))
        elif int(arg2) == 2:
            sched.Scheduler.try_reschedule()
            return 0
        return uint64(WAIT_WINDOW(int(arg1)))
    elif n == SERIAL_PUTS:
        str_ptr_sp: str = str(arg1)
        return uint64(SERIAL_PUTS(str_ptr_sp))
    elif n == LOAD_SO:
        path_ptr_so: rawptr = rawptr(arg1)
        return LOAD_SO(path_ptr_so)
    elif n == SO_CALL1:
        sym_ptr: rawptr = rawptr(arg1)
        return uint64(SO_CALL1(sym_ptr, rawptr(arg2)))
    elif n == GET_WINBUF:
        return GET_WINBUF(int(arg1))
    elif n == WIN_FLUSH:
        return uint64(WIN_FLUSH(int(arg1), rawptr(arg2)))
    elif n == POLL_EVENT:
        buf_ptr_ev: rawptr = rawptr(arg1)
        caller_pid_ev: int = process.current()
        return uint64(desktop.poll_event(buf_ptr_ev, caller_pid_ev))
    elif n == SET_CURSOR:
        desktop.set_cursor_type(int(arg1), int(arg2))
        return 0
    elif n == YIELD:
        sched.Scheduler.try_reschedule()
        return 0
    elif n == SET_TITLE:
        title_ptr_st: rawptr = rawptr(arg2)
        return uint64(desktop.set_title(int(arg1), title_ptr_st))
    elif n == SET_GEOMETRY:
        return uint64(desktop.set_geometry(int(arg1), int(arg2), int(arg3), int(arg4), int(arg5)))
    elif n == SET_RESIZABLE:
        return uint64(desktop.set_resizable(int(arg1), int(arg2), int(arg3)))
    elif n == GET_WIN_SIZE:
        return uint64(desktop.get_size(int(arg1)))
    elif n == SPAWN:
        path_ptr_sp: rawptr = rawptr(arg1)
        return uint64(SPAWN(path_ptr_sp, int(arg2)))
    elif n == MMAP:
        return MMAP(arg1)
    elif n == MUNMAP:
        return uint64(MUNMAP(arg1, arg2))
    elif n == THREAD_CREATE:
        func_ptr: rawptr = rawptr(arg1)
        arg_ptr: rawptr = rawptr(arg2)
        cur_pid: int = process.current()
        # app 传进来的是**用户地址**：必须用 create_user_thread（独立用户栈 + 独立内核栈、
        # 走 drop_to_user_mode 进 Ring 3），不能用 create_thread 在 Ring 0 直接 call。
        th: sched.Thread* = sched.Scheduler.create_user_thread(cur_pid, func_ptr, arg_ptr)
        if th is None: return uint64(0xFFFFFFFFFFFFFFFF)
        p: process.Process* = process.ProcessManager.get_process(cur_pid)
        if p:
            p.addThread(th.tid)
        return uint64(th.tid)
    elif n == THREAD_EXIT:
        # 用户线程显式退出（回收用户栈等资源后让出，永不返回）。
        sched.Scheduler.exit_current_thread()
        return 0
    return 0

def init():
    efer: uint64 = rdmsr(IA32_EFER)
    efer = efer | 1
    wrmsr(IA32_EFER, efer)
    star_val: uint64 = (uint64(0x08) << 32) | (uint64(0x1B) << 48)
    wrmsr(IA32_STAR, star_val)
    wrmsr(IA32_LSTAR, uint64(syscall_entry))
    wrmsr(IA32_FMASK, 0x200)
    serial.puts("[syscall] MSR init done\n")