// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <linux/ctype.h>	/* for isdigit() and friends */
#include <linux/fs.h>
#include <linux/mm.h>		/* for verify_area */
#include <linux/errno.h>	/* for -EBUSY */
#include <linux/ioport.h>	/* for check_region, request_region */
#include <linux/interrupt.h>
#include <linux/delay.h>	/* for loops_per_sec */
#include <linux/kmod.h>
#include <linux/jiffies.h>
#include <linux/uaccess.h>	/* for copy_from_user */
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/kthread.h>

#include "spk_priv.h"
#include "speakup.h"
#include "serialio.h"

static LIST_HEAD(synths);
struct spk_synth *synth;
char spk_pitch_buff[32] = "";
static int module_status;
bool spk_quiet_boot;

struct speakup_info_t speakup_info = {
	/*
	 * This spinlock is used to protect the entire speakup machinery, and
	 * must be taken at each kernel->speakup transition and released at
	 * each corresponding speakup->kernel transition.
	 *
	 * The progression thread only interferes with the speakup machinery
	 * through the synth buffer, so only needs to take the lock
	 * while tinkering with the buffer.
	 *
	 * We use spin_lock/trylock_irqsave and spin_unlock_irqrestore with this
	 * spinlock because speakup needs to disable the keyboard IRQ.
	 */
	.spinlock = __SPIN_LOCK_UNLOCKED(speakup_info.spinlock),
	.flushing = 0,
};
EXPORT_SYMBOL_GPL(speakup_info);

static int do_synth_init(struct spk_synth *in_synth);

/*
 * Main loop of the progression thread: keep eating from the buffer
 * and push to the serial port, waiting as needed
 *
 * For devices that have a "full" notification mechanism, the driver can
 * adapt the loop the way they prefer.
 */
static void _spk_do_catch_up(struct spk_synth *synth, int unicode)
{
	u16 ch;
	unsigned long flags;
	unsigned long jiff_max;
	struct var_t *delay_time;
	struct var_t *full_time;
	struct var_t *jiffy_delta;
	int jiffy_delta_val;
	int delay_time_val;
	int full_time_val;
	int ret;

	jiffy_delta = spk_get_var(JIFFY);
	full_time = spk_get_var(FULL);
	delay_time = spk_get_var(DELAY);

	spin_lock_irqsave(&speakup_info.spinlock, flags);
	jiffy_delta_val = jiffy_delta->u.n.value;
	spin_unlock_irqrestore(&speakup_info.spinlock, flags);

	jiff_max = jiffies + jiffy_delta_val;
	while (!kthread_should_stop()) {
		spin_lock_irqsave(&speakup_info.spinlock, flags);
		if (speakup_info.flushing) {
			speakup_info.flushing = 0;
			spin_unlock_irqrestore(&speakup_info.spinlock, flags);
			synth->flush(synth);
			continue;
		}
		if (!unicode)
			synth_buffer_skip_nonlatin1();
		if (synth_buffer_empty()) {
			spin_unlock_irqrestore(&speakup_info.spinlock, flags);
			break;
		}
		ch = synth_buffer_peek();
		set_current_state(TASK_INTERRUPTIBLE);
		full_time_val = full_time->u.n.value;
		spin_unlock_irqrestore(&speakup_info.spinlock, flags);
		if (ch == '\n')
			ch = synth->procspeech;
		if (unicode)
			ret = synth->io_ops->synth_out_unicode(synth, ch);
		else
			ret = synth->io_ops->synth_out(synth, ch);
		if (!ret) {
			schedule_timeout(msecs_to_jiffies(full_time_val));
			continue;
		}
		if (time_after_eq(jiffies, jiff_max) && (ch == SPACE)) {
			spin_lock_irqsave(&speakup_info.spinlock, flags);
			jiffy_delta_val = jiffy_delta->u.n.value;
			delay_time_val = delay_time->u.n.value;
			full_time_val = full_time->u.n.value;
			spin_unlock_irqrestore(&speakup_info.spinlock, flags);
			if (synth->io_ops->synth_out(synth, synth->procspeech))
				schedule_timeout(
					msecs_to_jiffies(delay_time_val));
			else
				schedule_timeout(
					msecs_to_jiffies(full_time_val));
			jiff_max = jiffies + jiffy_delta_val;
		}
		set_current_state(TASK_RUNNING);
		spin_lock_irqsave(&speakup_info.spinlock, flags);
		synth_buffer_getc();
		spin_unlock_irqrestore(&speakup_info.spinlock, flags);
	}
	synth->io_ops->synth_out(synth, synth->procspeech);
}

void spk_do_catch_up(struct spk_synth *synth)
{
	_spk_do_catch_up(synth, 0);
}
EXPORT_SYMBOL_GPL(spk_do_catch_up);

void spk_do_catch_up_unicode(struct spk_synth *synth)
{
	_spk_do_catch_up(synth, 1);
}
EXPORT_SYMBOL_GPL(spk_do_catch_up_unicode);

void spk_synth_flush(struct spk_synth *synth)
{
	synth->io_ops->flush_buffer(synth);
	synth->io_ops->synth_out(synth, synth->clear);
}
EXPORT_SYMBOL_GPL(spk_synth_flush);

unsigned char spk_synth_get_index(struct spk_synth *synth)
{
	return synth->io_ops->synth_in_nowait(synth);
}
EXPORT_SYMBOL_GPL(spk_synth_get_index);

int spk_synth_is_alive_nop(struct spk_synth *synth)
{
	synth->alive = 1;
	return 1;
}
EXPORT_SYMBOL_GPL(spk_synth_is_alive_nop);

int spk_synth_is_alive_restart(struct spk_synth *synth)
{
	if (synth->alive)
		return 1;
	if (synth->io_ops->wait_for_xmitr(synth) > 0) {
		/* restart */
		synth->alive = 1;
		synth_printf("%s", synth->init);
		return 2; /* re-enabled */
	}
	pr_warn("%s: can't restart synth\n", synth->long_name);
	return 0;
}
EXPORT_SYMBOL_GPL(spk_synth_is_alive_restart);

static void thread_wake_up(struct timer_list *unused)
{
	wake_up_interruptible_all(&speakup_event);
}

static DEFINE_TIMER(thread_timer, thread_wake_up);

void synth_start(void)
{
	struct var_t *trigger_time;

	if (!synth->alive) {
		synth_buffer_clear();
		return;
	}
	trigger_time = spk_get_var(TRIGGER);
	if (!timer_pending(&thread_timer))
		mod_timer(&thread_timer, jiffies +
			msecs_to_jiffies(trigger_time->u.n.value));
}

void spk_do_flush(void)
{
	if (!synth)
		return;

	speakup_info.flushing = 1;
	synth_buffer_clear();
	if (synth->alive) {
		if (spk_pitch_shift) {
			synth_printf("%s", spk_pitch_buff);
			spk_pitch_shift = 0;
		}
	}
	wake_up_interruptible_all(&speakup_event);
	wake_up_process(speakup_task);
}

void synth_write(const char *_buf, size_t count)
{
	const unsigned char *buf = (const unsigned char *) _buf;

	while (count--)
		synth_buffer_add(*buf++);
	synth_start();
}

/* Consume one utf-8 character from buf (that contains up to count bytes),
 * returns the unicode codepoint if valid, -1 otherwise.
 * In all cases, returns the number of consumed bytes in *consumed,
 * and the minimum number of bytes that would be needed for the next character
 * in *want.
 */
s32 synth_utf8_get(const char *buf, size_t count, size_t *consumed, size_t *want)
{
	unsigned char c = buf[0];
	int nbytes = 8 - fls(c ^ 0xff);
	u32 value;
	size_t i;

	switch (nbytes) {
	case 8: /* 0xff */
	case 7: /* 0xfe */
	case 1: /* 0x80 */
		/* Invalid, drop */
		*consumed = 1;
		*want = 1;
		return -1;

	case 0:
		/* ASCII, take as such */
		*consumed = 1;
		*want = 1;
		return c;

	default:
		/* 2..6-byte UTF-8 */

		if (count < nbytes) {
			/* We don't have it all */
			*consumed = 0;
			*want = nbytes;
			return -1;
		}

		/* First byte */
		value = c & ((1u << (7 - nbytes)) - 1);

		/* Other bytes */
		for (i = 1; i < nbytes; i++) {
			c = buf[i];
			if ((c & 0xc0) != 0x80)	{
				/* Invalid, drop the head */
				*consumed = i;
				*want = 1;
				return -1;
			}
			value = (value << 6) | (c & 0x3f);
		}

		*consumed = nbytes;
		*want = 1;
		return value;
	}
}

void synth_writeu(const char *buf, size_t count)
{
	size_t i, consumed, want;

	/* Convert to u16 */
	for (i = 0; i < count; i++) {
		s32 value;

		value = synth_utf8_get(buf + i, count - i, &consumed, &want);
		if (value == -1) {
			/* Invalid or incomplete */

			if (want > count - i)
				/* We don't have it all, stop */
				count = i;

			continue;
		}

		if (value < 0x10000)
			synth_buffer_add(value);
	}

	synth_start();
}

void synth_printf(const char *fmt, ...)
{
	va_list args;
	unsigned char buf[160];
	int r;

	va_start(args, fmt);
	r = vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);
	if (r > sizeof(buf) - 1)
		r = sizeof(buf) - 1;

	synth_writeu(buf, r);
}
EXPORT_SYMBOL_GPL(synth_printf);

void synth_putwc(u16 wc)
{
	synth_buffer_add(wc);
}
EXPORT_SYMBOL_GPL(synth_putwc);

void synth_putwc_s(u16 wc)
{
	synth_buffer_add(wc);
	synth_start();
}
EXPORT_SYMBOL_GPL(synth_putwc_s);

void synth_putws(const u16 *buf)
{
	const u16 *p;

	for (p = buf; *p; p++)
		synth_buffer_add(*p);
}
EXPORT_SYMBOL_GPL(synth_putws);

void synth_putws_s(const u16 *buf)
{
	synth_putws(buf);
	synth_start();
}
EXPORT_SYMBOL_GPL(synth_putws_s);

static int index_count;
static int sentence_count;

void spk_reset_index_count(int sc)
{
	static int first = 1;

	if (first)
		first = 0;
	else
		synth->get_index(synth);
	index_count = 0;
	sentence_count = sc;
}

int synth_supports_indexing(void)
{
	if (synth->get_index)
		return 1;
	return 0;
}

void synth_insert_next_index(int sent_num)
{
	int out;

	if (synth->alive) {
		if (sent_num == 0) {
			synth->indexing.currindex++;
			index_count++;
			if (synth->indexing.currindex >
					synth->indexing.highindex)
				synth->indexing.currindex =
					synth->indexing.lowindex;
		}

		out = synth->indexing.currindex * 10 + sent_num;
		synth_printf(synth->indexing.command, out, out);
	}
}

void spk_get_index_count(int *linecount, int *sentcount)
{
	int ind = synth->get_index(synth);

	if (ind) {
		sentence_count = ind % 10;

		if ((ind / 10) <= synth->indexing.currindex)
			index_count = synth->indexing.currindex - (ind / 10);
		else
			index_count = synth->indexing.currindex
				- synth->indexing.lowindex
				+ synth->indexing.highindex - (ind / 10) + 1;
	}
	*sentcount = sentence_count;
	*linecount = index_count;
}

static struct resource synth_res;

int synth_request_region(unsigned long start, unsigned long n)
{
	struct resource *parent = &ioport_resource;

	memset(&synth_res, 0, sizeof(synth_res));
	synth_res.name = synth->name;
	synth_res.start = start;
	synth_res.end = start + n - 1;
	synth_res.flags = IORESOURCE_BUSY;
	return request_resource(parent, &synth_res);
}
EXPORT_SYMBOL_GPL(synth_request_region);

int synth_release_region(unsigned long start, unsigned long n)
{
	return release_resource(&synth_res);
}
EXPORT_SYMBOL_GPL(synth_release_region);

struct var_t synth_time_vars[] = {
	{ DELAY, .u.n = {NULL, 100, 100, 2000, 0, 0, NULL } },
	{ TRIGGER, .u.n = {NULL, 20, 10, 2000, 0, 0, NULL } },
	{ JIFFY, .u.n = {NULL, 50, 20, 200, 0, 0, NULL } },
	{ FULL, .u.n = {NULL, 400, 200, 60000, 0, 0, NULL } },
	{ FLUSH, .u.n = {NULL, 4000, 10, 4000, 0, 0, NULL } },
	V_LAST_VAR
};

/* called by: speakup_init() */
int synth_init(char *synth_name)
{
	int ret = 0;
	struct spk_synth *tmp, *synth = NULL;

	if (!synth_name)
		return 0;

	if (strcmp(synth_name, "none") == 0) {
		mutex_lock(&spk_mutex);
		synth_release();
		mutex_unlock(&spk_mutex);
		return 0;
	}

	mutex_lock(&spk_mutex);
	/* First, check if we already have it loaded. */
	list_for_each_entry(tmp, &synths, node) {
		if (strcmp(tmp->name, synth_name) == 0)
			synth = tmp;
	}

	/* If we got one, initialize it now. */
	if (synth)
		ret = do_synth_init(synth);
	else
		ret = -ENODEV;
	mutex_unlock(&spk_mutex);

	return ret;
}

/* called by: synth_add() */
static int do_synth_init(struct spk_synth *in_synth)
{
	struct var_t *var;

	synth_release();
	if (in_synth->checkval != SYNTH_CHECK)
		return -EINVAL;
	synth = in_synth;
	synth->alive = 0;
	pr_warn("synth probe\n");
	if (synth->probe(synth) < 0) {
		pr_warn("%s: device probe failed\n", in_synth->name);
		synth = NULL;
		return -ENODEV;
	}
	synth_time_vars[0].u.n.value =
		synth_time_vars[0].u.n.default_val = synth->delay;
	synth_time_vars[1].u.n.value =
		synth_time_vars[1].u.n.default_val = synth->trigger;
	synth_time_vars[2].u.n.value =
		synth_time_vars[2].u.n.default_val = synth->jiffies;
	synth_time_vars[3].u.n.value =
		synth_time_vars[3].u.n.default_val = synth->full;
	synth_time_vars[4].u.n.value =
		synth_time_vars[4].u.n.default_val = synth->flush_time;
	synth_printf("%s", synth->init);
	for (var = synth->vars;
		(var->var_id >= 0) && (var->var_id < MAXVARS); var++)
		speakup_register_var(var);
	if (!spk_quiet_boot)
		synth_printf("%s found\n", synth->long_name);
	if (synth->attributes.name &&
	    sysfs_create_group(speakup_kobj, &synth->attributes) < 0)
		return -ENOMEM;
	synth_flags = synth->flags;
	wake_up_interruptible_all(&speakup_event);
	if (speakup_task)
		wake_up_process(speakup_task);
	return 0;
}

void synth_release(void)
{
	struct var_t *var;
	unsigned long flags;

	if (!synth)
		return;
	spin_lock_irqsave(&speakup_info.spinlock, flags);
	pr_info("releasing synth %s\n", synth->name);
	synth->alive = 0;
	timer_delete(&thread_timer);
	spin_unlock_irqrestore(&speakup_info.spinlock, flags);
	if (synth->attributes.name)
		sysfs_remove_group(speakup_kobj, &synth->attributes);
	for (var = synth->vars; var->var_id != MAXVARS; var++)
		speakup_unregister_var(var->var_id);
	synth->release(synth);
	synth = NULL;
}

/* called by: all_driver_init() */
int synth_add(struct spk_synth *in_synth)
{
	int status = 0;
	struct spk_synth *tmp;

	mutex_lock(&spk_mutex);

	list_for_each_entry(tmp, &synths, node) {
		if (tmp == in_synth) {
			mutex_unlock(&spk_mutex);
			return 0;
		}
	}

	if (in_synth->startup)
		status = do_synth_init(in_synth);

	if (!status)
		list_add_tail(&in_synth->node, &synths);

	mutex_unlock(&spk_mutex);
	return status;
}
EXPORT_SYMBOL_GPL(synth_add);

void synth_remove(struct spk_synth *in_synth)
{
	mutex_lock(&spk_mutex);
	if (synth == in_synth)
		synth_release();
	list_del(&in_synth->node);
	module_status = 0;
	mutex_unlock(&spk_mutex);
}
EXPORT_SYMBOL_GPL(synth_remove);

struct spk_synth *synth_current(void)
{
	return synth;
}
EXPORT_SYMBOL_GPL(synth_current);

u16 spk_punc_masks[] = { 0, SOME, MOST, PUNC, PUNC | B_SYM };