/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2021.12.07     linzhenxing      first version
 */
#include <rtthread.h>
#include <tty.h>
#include <tty_ldisc.h>

#define DBG_TAG               "PTY"
#ifdef RT_TTY_DEBUG
#define DBG_LVL               DBG_LOG
#else
#define DBG_LVL               DBG_INFO
#endif /* RT_TTY_DEBUG */
#include <rtdbg.h>

#define PTY_PTS_SIZE 10
static struct tty_struct ptm_driver;
static struct tty_struct pts_drivers[PTY_PTS_SIZE];
static int pts_index = 0;

static int pts_register(struct tty_struct *ptm_drv, struct tty_struct *pts_drv, int pts_index);

/* check free pts device */
static struct tty_struct *find_freepts(void)
{
    for(int i = 0; i < PTY_PTS_SIZE; i++)
    {
        if (pts_drivers[i].init_flag == TTY_INIT_FLAG_NONE)
        {
            pts_drivers[i].init_flag = TTY_INIT_FLAG_ALLOCED;
            return &pts_drivers[i];
        }
    }
    return RT_NULL;
}

/* Set the lock flag on a pty */
static int pty_set_lock(struct tty_struct *tty, int *arg)
{
    int val = *arg;

    if (val)
    {
        tty->pts_lock = val;
    }
    else
    {
        tty->pts_lock = val;
    }
    return 0;
}

static int pty_get_lock(struct tty_struct *tty, int *arg)
{
    *arg = tty->pts_lock;
    return 0;
}

static int pty_get_index(struct tty_struct *tty, int *arg)
{
    *arg = tty->index;
    return 0;
}
/* RT-Thread Device Interface */
/*
 * This function initializes console device.
 */
static rt_err_t pty_device_init(struct rt_device *dev)
{
    rt_err_t result = RT_EOK;
    int level = 0;
    struct tty_struct *tty = RT_NULL;
    RT_ASSERT(dev != RT_NULL);

    tty = (struct tty_struct *)dev;
    level = rt_hw_interrupt_disable();
    RT_ASSERT(tty->init_flag == TTY_INIT_FLAG_REGED);
    tty->init_flag = TTY_INIT_FLAG_INITED;
    rt_hw_interrupt_enable(level);
    return result;
}

static rt_err_t pty_device_open(struct rt_device *dev, rt_uint16_t oflag)
{
    rt_err_t result = RT_EOK;
    return result;
}

static rt_err_t pty_device_close(struct rt_device *dev)
{
    rt_err_t result = RT_EOK;
    struct tty_struct *tty = (struct tty_struct*)dev;
    //struct tty_struct *to = RT_NULL;

    if (tty->subtype == PTY_TYPE_MASTER)
    {
        // to = tty->other_struct;
        // to->init_flag = TTY_INIT_FLAG_NONE;
        // to->other_struct = RT_NULL;
        // to->foreground = RT_NULL;
        // to->index = -1;
        // tty_ldisc_kill(to);
        // tty->other_struct = RT_NULL;
    }
    else
    {
        // to = tty->other_struct;
        // to->other_struct = RT_NULL;
        // tty->init_flag = TTY_INIT_FLAG_NONE;
        // tty->other_struct = RT_NULL;
        // tty->foreground = RT_NULL;
        // tty->index = -1;
        // tty->other_struct = RT_NULL;
        // tty_ldisc_kill(tty);
    }

    return result;
}

static rt_size_t pty_device_read(struct rt_device *dev,
        rt_off_t          pos,
        void             *buffer,
        rt_size_t         size)
{
    rt_size_t len = 0;

    return len;
}

static rt_size_t pty_device_write(struct rt_device *dev,
        rt_off_t          pos,
        const void       *buffer,
        rt_size_t         size)
{
    rt_base_t level = 0;
    rt_size_t len = 0;
    struct tty_struct *tty = RT_NULL;
    struct tty_struct *to = RT_NULL;

    tty = (struct tty_struct *)dev;
    RT_ASSERT(tty != RT_NULL);
    RT_ASSERT(tty->init_flag == TTY_INIT_FLAG_INITED);
    to = tty->other_struct;
    level = rt_hw_interrupt_disable();

    if (to->ldisc->ops->receive_buf)
    {
        len = to->ldisc->ops->receive_buf(to, (char *)buffer, size);
    }
    rt_hw_interrupt_enable(level);

    return len;
}

static rt_err_t  pty_device_control(rt_device_t dev, int cmd, void *args)
{
    struct tty_struct *tty = (struct tty_struct *)dev;

    switch (cmd)
    {
    case TIOCSPTLCK: /* Set PT Lock (disallow slave open) */
        return pty_set_lock(tty, (int *)args);
    case TIOCGPTLCK: /* Get PT Lock status */
        return pty_get_lock(tty, (int *)args);
    case TIOCGPTN: /* Get PT Number */
        return pty_get_index(tty, (int *)args);
    }

    return -ENOIOCTLCMD;
}

static int ptmx_open(struct dfs_fd *fd)
{
    int ret = 0;
    struct tty_struct *tty = RT_NULL;
    struct tty_struct *pts_drv = RT_NULL;
    struct tty_ldisc *ld = RT_NULL;
    struct rt_lwp *lwp = RT_NULL;
    struct rt_wqueue *wq = RT_NULL;

    tty = (struct tty_struct *)fd->vnode->data;
    RT_ASSERT(tty != RT_NULL);

    pts_drv = find_freepts();
    if (pts_drv == RT_NULL)
    {
        LOG_E("free pts driver find fail\n");
        return -1;
    }
    ret = pts_register(tty, pts_drv, pts_index);
    if (ret < 0)
    {
        LOG_E("pts register fail\n");
        rt_free(pts_drv);
        return -1;
    }
    pts_index++;
    lwp = (struct rt_lwp *)(rt_thread_self()->lwp);
    wq = wait_queue_get(lwp, tty);
    pts_drv->wait_queue = *wq;
    tty->other_struct = pts_drv;
    ld = tty->ldisc;
    if (ld->ops->open)
    {
        ret = ld->ops->open(fd);
    }

    return ret;
}
#ifdef RT_USING_DEVICE_OPS
const static struct rt_device_ops pty_device_ops =
{
    pty_device_init,
    pty_device_open,
    pty_device_close,
    pty_device_read,
    pty_device_write,
    pty_device_control,
};
#endif /* RT_USING_DEVICE_OPS */
static struct dfs_file_ops pts_fops;
static struct dfs_file_ops ptmx_fops;
static int pts_register(struct tty_struct *ptm_drv, struct tty_struct *pts_drv, int pts_index)
{
    rt_err_t ret = RT_EOK;
    rt_base_t level = 0;
    struct rt_device *device = RT_NULL;
    char name[20];

    RT_ASSERT(ptm_drv!=RT_NULL);
    level = rt_hw_interrupt_disable();

    if (pts_drv->init_flag != TTY_INIT_FLAG_ALLOCED)
    {
        LOG_E("pts%d has been registered\n", pts_index);
        ret = (-RT_EBUSY);
        goto _exit;
    }

    device = &pts_drv->parent;
    device->type    = RT_Device_Class_Char;
#ifdef RT_USING_DEVICE_OPS
    device->ops     = &pty_device_ops;
#else
    device->init    = pty_device_init;
    device->open    = pty_device_open;
    device->close   = pty_device_close;
    device->read    = pty_device_read;
    device->write   = pty_device_write;
    device->control = pty_device_control;
#endif /* RT_USING_DEVICE_OPS */

    rt_snprintf(name, sizeof(name), "pts%d", pts_index);
    ret = rt_device_register(device, name, RT_DEVICE_FLAG_RDWR);
    if (ret != RT_EOK)
    {
        LOG_E("pts%d register failed\n", pts_index);
        ret = -RT_EIO;
        goto _exit;
    }

#ifdef RT_USING_POSIX_DEVIO
    /* set fops */
    tty_set_fops(&pts_fops);
    device->fops = &pts_fops;
#endif

    pts_drv->type = TTY_DRIVER_TYPE_PTY;
    pts_drv->subtype = PTY_TYPE_SLAVE;

    pts_drv->pgrp = -1;
    pts_drv->session = -1;
    pts_drv->foreground = RT_NULL;
    pts_drv->index = pts_index;
    pts_drv->pts_lock = 1;
    rt_wqueue_init(&pts_drv->wait_queue);

    tty_ldisc_init(pts_drv);

extern struct termios tty_std_termios;
    pts_drv->init_termios = tty_std_termios;
    pts_drv->init_termios.c_cflag = B38400 | CS8 | CREAD;
    pts_drv->init_termios.c_lflag |= ICANON;
    pts_drv->init_termios.__c_ispeed = 38400;
    pts_drv->init_termios.__c_ospeed = 38400;

    pts_drv->other_struct = ptm_drv;

    pts_drv->init_flag = TTY_INIT_FLAG_REGED;
_exit:
    rt_hw_interrupt_enable(level);

    return ret;
}

static int ptmx_register(void)
{
    rt_base_t level = 0;
    rt_err_t ret = RT_EOK;
    struct rt_device *device = RT_NULL;
    struct tty_struct *ptm_drv = &ptm_driver;

    level = rt_hw_interrupt_disable();
    RT_ASSERT(ptm_drv->init_flag == TTY_INIT_FLAG_NONE);
    
    device = &(ptm_drv->parent);

    device->type = RT_Device_Class_Char;

#ifdef RT_USING_DEVICE_OPS
    device->ops     = &pty_device_ops;
#else
    device->init    = pty_device_init;
    device->open    = pty_device_open;
    device->close   = pty_device_close;
    device->read    = pty_device_read;
    device->write   = pty_device_write;
    device->control = pty_device_control;
#endif /* RT_USING_DEVICE_OPS */

    ret = rt_device_register(device, "ptmx", RT_DEVICE_FLAG_RDWR);
    if (ret != RT_EOK)
    {
        LOG_E("ptmx register fail\n");
        ret = -RT_EIO;
        goto _exit;
    }

#ifdef RT_USING_POSIX_DEVIO
    /* set fops */
    tty_set_fops(&ptmx_fops);
    ptmx_fops.open = ptmx_open;
    device->fops = &ptmx_fops;
#endif

    ptm_drv->type = TTY_DRIVER_TYPE_PTY;
    ptm_drv->subtype = PTY_TYPE_MASTER;
    ptm_drv->head = rt_calloc(1, sizeof(struct tty_node));
    if (!ptm_drv->head)
    {
        return -RT_ENOMEM;
    }
    tty_initstack(ptm_drv->head);

    rt_spin_lock_init(&ptm_drv->spinlock);
    ptm_drv->pgrp = -1;
    ptm_drv->session = -1;
    ptm_drv->foreground = RT_NULL;
    rt_wqueue_init(&ptm_drv->wait_queue);

    tty_ldisc_init(ptm_drv);

extern struct termios tty_std_termios;
    ptm_drv->init_termios.c_iflag = 0;
    ptm_drv->init_termios.c_oflag = 0;
    ptm_drv->init_termios.c_cflag = B38400 | CS8 | CREAD;
    ptm_drv->init_termios.c_lflag = 0;
    ptm_drv->init_termios.__c_ispeed = 38400;
    ptm_drv->init_termios.__c_ospeed = 38400;

    ptm_drv->init_flag = TTY_INIT_FLAG_REGED;

_exit:
    rt_hw_interrupt_enable(level);

    return ret;
}
INIT_DEVICE_EXPORT(ptmx_register);