import vpsdk.devfs as devfs
import vpsdk.desk as desk
import vpsdk.process as process
from stdint import *
import viperlib
import desk_server


def _dbg(msg: const str):
    # S4：改走 /dev/serial0（SERIAL_PUTS 私有 syscall 已删除）
    devfs.serial_puts(msg)


@__attribute__(section(".text.startup"), aligned(16))
export def _start() -> int:
    _dbg("[explorer] start\n")

    # 1) 打开 framebuffer 设备，问几何，再映射成线性地址
    fb_fd: int = devfs.fb_open()
    if fb_fd < 0:
        _dbg("[explorer] open /dev/fb0 FAILED\n")
        process.exit(1)
        return 0

    # fb_get_info 改为出参 + 返回码：必须判返回码，否则拿到的是"未写入的残留"
    # （旧写法按值返回 FbInfo，只见前 16 字节有效 ⇒ size/phys 打出垃圾）。
    info: devfs.FbInfo
    _fb_ret: int = devfs.fb_get_info(fb_fd, &info)
    if _fb_ret != 0:
        _dbg("[explorer] FB_GET_INFO FAILED\n")
        process.exit(1)
        return 0

    buf: [160]char
    viperlib.snprintf(&buf, 160,
        "[explorer] fb %ux%u pitch=%u fmt=%u size=%lu phys=0x%lx\n",
        info.width, info.height, info.pitch, info.format, info.size, info.phys)
    _dbg(&buf)

    if info.pitch == 0 or info.size == 0:
        # 几何为 0 ⇒ 内核侧登记/回填没成功（例如注册时传进去的 width/height 是 0）。
        # 继续走只会以 pitch=0 画崩，这里 fail-fast 并把原因说清楚。
        _dbg("[explorer] fb geometry invalid (pitch/size=0)\n")
        process.exit(1)
        return 0

    fb_va: uint64 = devfs.fb_map(fb_fd, info.size)
    if fb_va == 0:
        _dbg("[explorer] mmap /dev/fb0 FAILED\n")
        process.exit(1)
        return 0

    buf2: [96]char
    viperlib.snprintf(&buf2, 96, "[explorer] fb mapped at 0x%lx\n", fb_va)
    _dbg(&buf2)

    # 2) 屏幕几何/映射地址已打印（上面两行），像素通路由此验证；真正的绘制在服务端。
    fb: uint32* = uint32*(fb_va)

    # 4) 输入设备可达性：能 open 到就说明 /dev/* 通路已打通
    #    （真正读事件、接管窗口合成放到 S3 —— 内核桌面此刻还在抢同一个 PS/2 口）。
    kfd: int = devfs.kbd_open()
    mfd: int = devfs.mouse_open()
    buf3: [96]char
    viperlib.snprintf(&buf3, 96, "[explorer] input: kbd=%d mouse=%d\n", kfd, mfd)
    _dbg(&buf3)

    # 5) 挂上 /dev/desk 共享区并格式化 —— explorer 是图形壳，共享区由它初始化，
    #    app 侧只 desk_ready() 校验。这里先把头打出来证明 IPC 底座可用。
    desk_fd: int = desk.desk_open()
    if desk_fd < 0:
        _dbg("[explorer] open /dev/desk FAILED\n")
        process.exit(1)
        return 0
    shm: uint64 = desk.desk_map(desk_fd)
    if shm == 0:
        _dbg("[explorer] mmap /dev/desk FAILED\n")
        process.exit(1)
        return 0
    desk.desk_format(shm, info.width, info.height, info.pitch)
    hdr: desk.DeskHeader* = desk.DeskHeader*(shm + desk.desk_header_off())
    buf4: [144]char
    viperlib.snprintf(&buf4, 144,
        "[explorer] desk shm=0x%lx ready=%d slot=%lu arena=%u\n",
        shm, hdr.ready, uint64(desk.desk_slot_size()), hdr.arena_off)
    _dbg(&buf4)

    # 6) 进入窗口服务端主循环（永不返回）：请求环 + 输入 + 合成。
    srv: desk_server.DeskServer = desk_server.DeskServer()
    srv.init(fb, int(info.width), int(info.height), int(info.pitch), info.format, shm, kfd, mfd, fb_fd)
    _dbg("[explorer] desk server running\n")
    srv.serve()
    return 0