/***************************************************************************
 *   Copyright (C) 05/2011 by Olaf Rempel                                  *
 *   razzor@kopf-tisch.de                                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>

#include "event.h"
#include "lcd.h"
#include "list.h"
#include "logging.h"

#define _LCD_DEBUG	0
#define _LCD_DUMMY	1

#define LCD_SCROLL_SPEED	750				/* 750ms */
#define LCD_RESET_TIMEOUT	250				/* 250ms */
#define LCD_RESET_RETRY_TIMEOUT	10000				/* 10s */

#define A125_CMD_GETBUTTON	{ 0x4D, 0x06 }			// not tried
#define A125_CMD_SETLINE	{ 0x4D, 0x0C, 0x00, 0x10 }	// [2] is line, append 16 chars
#define A125_CMD_CLEAR		{ 0x4D, 0x0D }			// works, but slow
#define A125_CMD_BACKLIGHT	{ 0x4D, 0x5E, 0x00 }		// [2] is on/off
#define A125_CMD_RESET		{ 0x4D, 0xFF }

#define A125_EVENT_ID		{ 0x53, 0x01 }			// never seen
#define A125_EVENT_BUTTON1	{ 0x53, 0x05, 0x00, 0x01 }
#define A125_EVENT_BUTTON2	{ 0x53, 0x05, 0x00, 0x02 }
#define A125_EVENT_VERSION	{ 0x53, 0x08 }			// never seen
#define A125_EVENT_ACTINFO	{ 0x53, 0xAA }
#define A125_EVENT_INVALID	{ 0x53, 0xFB }			// never seen

struct lcdpage {
	struct list_head list;
	int priority;

	int (*callback)(struct lcddev *dev, int event, void *privdata);
	void *privdata;
};

enum lcdstate {
	LCD_STATE_NOT_INITIALIZED = 0x00,
	LCD_STATE_INITIALIZING,
	LCD_STATE_INITIALIZING_FAILED,
	LCD_STATE_READY,
};

struct lcddev {
	int fd;
#if (_LCD_DUMMY)
	struct event_fd *fakedevice_event;
#endif /* (_LCD_DUMMY) */
	struct termios oldtio;

	enum lcdstate state;

	int backlight_enabled;
	int backlight_timeout_ms;

	struct list_head page_list;
	struct lcdpage *current_page;

	const char *line_data[2];
	int line_length[2];
	int scroll_pos;

	int update_ms;

	struct event_fd *read_event;
	struct event_timeout *reset_timeout;
	struct event_timeout *backlight_timeout;
	struct event_timeout *scroll_timeout;
	struct event_timeout *update_timeout;
};

static void lcd_pagecallback(struct lcddev *dev, int event);

void lcd_close(struct lcddev *dev)
{
	if (dev->current_page) {
		dev->current_page->callback(dev, LCDPAGE_EVENT_EXIT, dev->current_page->privdata);
		dev->current_page = NULL;
	}

	struct lcdpage *search, *tmp;
	list_for_each_entry_safe(search, tmp, &dev->page_list, list) {
		free(search);
	}

	if (dev->reset_timeout) {
		event_remove_timeout(dev->reset_timeout);
		dev->reset_timeout = NULL;
	}

	if (dev->backlight_timeout) {
		event_remove_timeout(dev->backlight_timeout);
		dev->backlight_timeout = NULL;
	}

	if (dev->update_timeout) {
		event_remove_timeout(dev->update_timeout);
		dev->update_timeout = NULL;
	}

	if (dev->scroll_timeout) {
		event_remove_timeout(dev->scroll_timeout);
		dev->scroll_timeout = NULL;
	}

	if (dev->read_event) {
		event_remove_fd(dev->read_event);
		dev->read_event = NULL;
	}

#if (_LCD_DUMMY)
	if (dev->fakedevice_event != NULL) {
		int fd = event_get_fd(dev->fakedevice_event);
		event_remove_fd(dev->fakedevice_event);
		dev->fakedevice_event = NULL;
		close(fd);

	} else
#endif /* (_LCD_DUMMY) */
	{
		tcsetattr(dev->fd, TCSANOW, &dev->oldtio);
	}

	close(dev->fd);
	free(dev);
}

static int lcd_realdevice_open(struct lcddev *dev, const char *device)
{
	dev->fd = open(device, O_RDWR | O_NOCTTY);
	if (dev->fd < 0) {
		log_print(LOG_ERROR, "%s(): failed to open '%s'", __FUNCTION__, device);
		return -1;
	}

	if (fcntl(dev->fd, F_SETFD, FD_CLOEXEC) < 0) {
		log_print(LOG_ERROR, "%s(): fcntl(FD_CLOEXEC)", __FUNCTION__);
		close(dev->fd);
		return -1;
	}

	tcgetattr(dev->fd, &dev->oldtio);

	struct termios newtio;
	memset(&newtio, 0, sizeof(newtio));
	newtio.c_iflag |= IGNBRK;
	newtio.c_lflag &= ~(ISIG | ICANON | ECHO);
	newtio.c_cflag = B1200 | CS8 | CLOCAL | CREAD;
	newtio.c_cc[VMIN] = 1;
	newtio.c_cc[VTIME] = 0;
	cfsetospeed(&newtio, B1200);
	cfsetispeed(&newtio, B1200);

	int err = tcsetattr(dev->fd, TCSAFLUSH, &newtio);
	if (err < 0) {
		log_print(LOG_ERROR, "%s(): failed to set termios", __FUNCTION__);
		close(dev->fd);
		return -1;
	}

	return 0;
}

#if (_LCD_DUMMY)
static int lcd_fakedevice_reply(int fd, void *privdata)
{
	struct lcddev *dev = (struct lcddev *)privdata;
	char buf[32];

	if (read(fd, buf, sizeof(buf)) <= 0) {
		dev->fakedevice_event = NULL;
		return -1;
	}

	char reset_expect[] = A125_CMD_RESET;
	if (memcmp(buf, reset_expect, sizeof(reset_expect)) == 0) {
		char actinfo_cmd[] = A125_EVENT_ACTINFO;
		write(fd, actinfo_cmd, sizeof(actinfo_cmd));
	}

	return 0;
}

static int lcd_fakedevice_open(struct lcddev *dev)
{
	int fd[2];

	if (socketpair(AF_LOCAL, SOCK_STREAM, 0 , fd) < 0) {
		log_print(LOG_ERROR, "%s(): socketpair() failed", __FUNCTION__);
		return -1;
	}

	if (fcntl(fd[0], F_SETFD, FD_CLOEXEC) < 0) {
		log_print(LOG_ERROR, "%s(): fcntl(FD_CLOEXEC)", __FUNCTION__);
		close(fd[0]);
		close(fd[1]);
		return -1;
	}

	if (fcntl(fd[1], F_SETFD, FD_CLOEXEC) < 0) {
		log_print(LOG_ERROR, "%s(): fcntl(FD_CLOEXEC)", __FUNCTION__);
		close(fd[0]);
		close(fd[1]);
		return -1;
	}

	dev->fd = fd[0];
	dev->fakedevice_event = event_add_readfd(NULL, fd[1], lcd_fakedevice_reply, dev);
	return 0;
}
#endif /* (_LCD_DUMMY) */

#if (_LCD_DEBUG > 1)
static void lcd_dump(const char *prefix, int len, int size, const char *data)
{
	int i;
	int pos = 0;
	char buf[256];

	for (i = 0; i < len; i++) {
		pos += snprintf(buf, sizeof(buf) - pos, "0x%X ", (unsigned char)data[i]);
	}

	log_print(LOG_DEBUG, "%s:[%d/%d]: %s", prefix, len, size, buf);
}
#endif /* (_LCD_DEBUG > 1) */

static int lcd_read(struct lcddev *dev, const char *buf, int len)
{
	int retval = 0, cnt = 0;
	while (cnt < len) {
		retval = read(dev->fd, (char *)buf + cnt, len - cnt);
		if (retval <= 0)
			break;

		cnt += retval;
	}
#if (_LCD_DEBUG > 1)
	lcd_dump(__FUNCTION__, cnt, len, buf);
#endif /* (_LCD_DEBUG > 1) */
	return (cnt != 0) ? cnt : retval;
}

static int lcd_write(struct lcddev *dev, char *buf, int len)
{
	int retval = write(dev->fd, buf, len);

#if (_LCD_DEBUG > 1)
	lcd_dump(__FUNCTION__, retval, len, buf);
#endif /* (_LCD_DEBUG > 1) */
	return retval;
}

static void lcd_reset(struct lcddev *dev);

static int lcd_reset_retry_timeout_cb(int timerid, void *privdata)
{
	struct lcddev *dev = (struct lcddev *)privdata;
	dev->reset_timeout = NULL;

	lcd_reset(dev);
	return -1; /* singleshot */
}

static int lcd_reset_timeout_cb(int timerid, void *privdata)
{
	struct lcddev *dev = (struct lcddev *)privdata;

	log_print(LOG_ERROR, "failed to initalize LCD");
	dev->state = LCD_STATE_INITIALIZING_FAILED;

	dev->reset_timeout = event_add_timeout_ms(LCD_RESET_RETRY_TIMEOUT, lcd_reset_retry_timeout_cb, 0, dev);

	return -1; /* singleshot */
}

static void lcd_reset(struct lcddev *dev)
{
#if (_LCD_DEBUG > 0)
	log_print(LOG_DEBUG, "%s()", __FUNCTION__);
#endif /* (_LCD_DEBUG > 0) */

	char cmd[] = A125_CMD_RESET;
	lcd_write(dev, cmd, sizeof(cmd));

	/* force next backlight command */
	dev->backlight_enabled = -1;

	dev->state = LCD_STATE_INITIALIZING;

	dev->reset_timeout = event_add_timeout_ms(LCD_RESET_TIMEOUT, lcd_reset_timeout_cb, 0, dev);
}

static int lcd_backlight(struct lcddev *dev, int enable)
{
	if (dev->state != LCD_STATE_READY)
		return -1;

#if (_LCD_DEBUG > 0)
	log_print(LOG_DEBUG, "%s(%d)", __FUNCTION__, enable);
#endif /* (_LCD_DEBUG > 0) */

	if (dev->backlight_enabled != enable) {
		char cmd[] = A125_CMD_BACKLIGHT;

		cmd[2] = (enable) ? 0x01 : 0x00;
		lcd_write(dev, cmd, sizeof(cmd));

		dev->backlight_enabled = enable;
	}

	return 0;
}

static int lcd_backlight_timeout_cb(int timerid, void *privdata)
{
	struct lcddev *dev = (struct lcddev *)privdata;
	dev->backlight_timeout = NULL;

	lcd_set_backlight(dev, 0);

	return -1; /* singleshot */
}

int lcd_set_backlight(struct lcddev *dev, int enable)
{
	if (dev->backlight_timeout != NULL) {
		event_remove_timeout(dev->backlight_timeout);
		dev->backlight_timeout = NULL;
	}

	if (!enable) {
		lcd_pagecallback(dev, LCDPAGE_EVENT_BACKLIGHT);

		/* callback re-enabled backlight */
		if (dev->backlight_timeout != NULL) {
			return 0;
		}
	}

	int retval = lcd_backlight(dev, enable);

	if (enable) {
		/* start backlight timeout */
		dev->backlight_timeout = event_add_timeout_ms(dev->backlight_timeout_ms, lcd_backlight_timeout_cb, 0, dev);

	} else {
		/* disable updates (display is not visible) */
		if (dev->update_timeout != NULL) {
			event_remove_timeout(dev->update_timeout);
			dev->update_timeout = NULL;
		}

		/* disable scrolling (display is not visible) */
		if (dev->scroll_timeout != NULL) {
			event_remove_timeout(dev->scroll_timeout);
			dev->scroll_timeout = NULL;
		}
	}

	return retval;
}

static int lcd_update_timeout_cb(int timerid, void *privdata)
{
	struct lcddev *dev = (struct lcddev *)privdata;

	dev->update_timeout = NULL;
	lcd_pagecallback(dev, LCDPAGE_EVENT_UPDATE);

	return -1; /* singleshot */
}

static void lcd_update_start(struct lcddev *dev, int update_ms)
{
	dev->update_ms = update_ms;

	if (dev->update_timeout != NULL) {
		event_remove_timeout(dev->update_timeout);
		dev->update_timeout = NULL;
	}

	if (update_ms > 0) {
		dev->update_timeout = event_add_timeout_ms(update_ms, lcd_update_timeout_cb, 0, dev);
	}
}

static int lcd_read_cb(int fd, void *privdata)
{
	struct lcddev *dev = (struct lcddev *)privdata;

	char buf[4];
	int size = (dev->state != LCD_STATE_INITIALIZING) ? sizeof(buf) : 2;
	int len = lcd_read(dev, buf, size);

	if (dev->state == LCD_STATE_INITIALIZING) {
		char expect[] = A125_EVENT_ACTINFO;

		if (len != sizeof(expect))
			return 0;

		if (memcmp(buf, expect, sizeof(expect)) == 0) {
			event_remove_timeout(dev->reset_timeout);
			dev->reset_timeout = NULL;

			dev->state = LCD_STATE_READY;

			/* trigger application to set data */
			lcd_pagecallback(dev, LCDPAGE_EVENT_ENTER);
		}

	} else if (dev->state == LCD_STATE_READY) {
		char expect1[] = A125_EVENT_BUTTON1;
		char expect2[] = A125_EVENT_BUTTON2;

		if (len != sizeof(expect1) && len != sizeof(expect2))
			return 0;

		if (memcmp(buf, expect1, sizeof(buf)) == 0) {
			lcd_pagecallback(dev, LCDPAGE_EVENT_BUTTON1);

		} else if (memcmp(buf, expect2, sizeof(buf)) == 0) {
			lcd_pagecallback(dev, LCDPAGE_EVENT_BUTTON2);
		}
	}

	return 0;
}

static int lcd_setline(struct lcddev *dev, int line, int len, const char *buf)
{
	if (dev->state != LCD_STATE_READY)
		return -1;

	char cmd[20 +1] = A125_CMD_SETLINE;
	cmd[2] = line;

	memset(cmd +4, ' ', 16);
	memcpy(cmd +4, buf, (len > 16) ? 16 : len);
	cmd[20] = '\0';

#if (_LCD_DEBUG > 0)
	log_print(LOG_DEBUG, "%s(%d, '%-16s')", __FUNCTION__, line, cmd +4);
#endif /* (_LCD_DEBUG > 0) */

	lcd_write(dev, cmd, 20);
	return 0;
}

static int lcd_scroll_timeout_cb(int timerid, void *privdata)
{
	struct lcddev *dev = (struct lcddev *)privdata;
	int i, reset_pos = 0;

	for (i = 0; i < 2; i++) {
		int line_pos = dev->scroll_pos;
		if (line_pos < 0)
			line_pos = 0;

		/* mark line as complete if one space is visible after message */
		if ((dev->line_length[i] - line_pos) <= 15) {
			reset_pos++;
		}

		/* do not scroll further if message is not visible */
		if ((dev->line_length[i] - line_pos) < 0) {
			line_pos = dev->line_length[i];
		}

		lcd_setline(dev, i, dev->line_length[i] - line_pos, dev->line_data[i] + line_pos);
	}

	dev->scroll_pos++;

	if (reset_pos == 2)
		dev->scroll_pos = -1;

	/* periodic */
	return 0;
}

static void lcd_scroll_start(struct lcddev *dev)
{
	if (dev->scroll_timeout != NULL) {
		event_remove_timeout(dev->scroll_timeout);
		dev->scroll_timeout = NULL;
	}

	if ((dev->line_length[0] > 16) || (dev->line_length[1] > 16)) {
		dev->scroll_timeout = event_add_timeout_ms(LCD_SCROLL_SPEED, lcd_scroll_timeout_cb, 0, dev);
	}
}

int lcd_setlines(struct lcddev *dev, const char *line1, const char *line2)
{
	int i;
	int line_length[2] = { 0, 0 };
	const char *line[2] = { line1, line2 };

	for (i = 0; i < 2; i++) {
		if (line[i] != NULL) {
			line_length[i] = strlen(line[i]);

			if ((line_length[i] == dev->line_length[i]) && (dev->line_data[i] != NULL)) {
				if (memcmp(line[i], dev->line_data[i], line_length[i]) == 0) {
					/* same data, no update needed */
					continue;
				}
			}
		}

		if (dev->line_data[i] != NULL) {
			free((void *)dev->line_data[i]);
			dev->line_data[i] = NULL;
		}

		if (line[i] != NULL) {
			dev->line_data[i] = strdup(line[i]);
		}
		dev->line_length[i] = line_length[i];

		if (dev->backlight_enabled) {
			lcd_setline(dev, i, dev->line_length[i], dev->line_data[i]);

			dev->scroll_pos = 0;
			lcd_scroll_start(dev);
		}
	}

	return 0;
}

static void lcd_pagecallback(struct lcddev *dev, int event)
{
	if (dev->state != LCD_STATE_READY) {
		return;
	}

	if (dev->current_page == NULL) {
		if (list_empty(&dev->page_list)) {
			return;
		}

		dev->current_page = list_entry(dev->page_list.next, struct lcdpage, list);
	}

	if ((dev->backlight_enabled == 0x00) && ((event == LCDPAGE_EVENT_BUTTON1) || (event == LCDPAGE_EVENT_BUTTON2))) {
		lcd_set_backlight(dev, 1);

		event = LCDPAGE_EVENT_UPDATE;

		/* restart scrolling if needed */
		lcd_scroll_start(dev);
	}

	int next;
	do {
#if (_LCD_DEBUG > 0)
		log_print(LOG_DEBUG, "%s: cb(%p, 0x%x)", __FUNCTION__, dev->current_page, event);
#endif
		int retval = dev->current_page->callback(dev, event, dev->current_page->privdata);
#if (_LCD_DEBUG > 0)
		log_print(LOG_DEBUG, "%s: cb(%p, 0x%x) => 0x%x", __FUNCTION__, dev->current_page, event, retval);
#endif

		next = (retval == LCDPAGE_COMMAND_NEXT);
		if (next) {
			struct lcdpage *page = dev->current_page;

			if (page->list.next != &dev->page_list) {
				page = list_entry(page->list.next, struct lcdpage, list);
			} else {
				page = list_entry(page->list.next->next, struct lcdpage, list);
			}

			/* no other page ready */
			if (page == dev->current_page) {
				break;
			}

			/* remove update interval for next page */
			if (dev->update_timeout != NULL) {
				event_remove_timeout(dev->update_timeout);
				dev->update_timeout = NULL;
			}

			/* remove scroll interval for next page */
			if (dev->scroll_timeout != NULL) {
				event_remove_timeout(dev->scroll_timeout);
				dev->scroll_timeout = NULL;
			}

			dev->current_page->callback(dev, LCDPAGE_EVENT_EXIT, dev->current_page->privdata);
			dev->current_page = page;
			event = LCDPAGE_EVENT_ENTER;

		/* retval is update interval */
		} else if ((event != LCDPAGE_EVENT_BACKLIGHT) && (event != LCDPAGE_EVENT_EXIT)) {
			lcd_update_start(dev, retval);
		}
	} while (next);
}

int lcd_addpage_cb(struct lcddev *dev,
		   int priority,
		   int (*event_callback)(struct lcddev *dev, int event, void *privdata),
		   void *event_privdata)
{
	struct lcdpage *page = malloc(sizeof(struct lcdpage));
	if (page == NULL) {
		log_print(LOG_ERROR, "%s(): out of memory", __FUNCTION__);
		return -1;
	}

	page->priority = priority;
	page->callback = event_callback;
	page->privdata = event_privdata;

	int inserted = 0;
	struct lcdpage *search;
	list_for_each_entry(search, &dev->page_list, list) {
		if (page->priority > search->priority) {
			list_add_tail(&page->list, &search->list);
			inserted = 1;
			break;
		}
	}

	if (!inserted) {
		list_add_tail(&page->list, &dev->page_list);
	}

	if (dev->current_page == NULL) {
		lcd_pagecallback(dev, LCDPAGE_EVENT_ENTER);
	}

	return 0;
}

struct lcddev * lcd_open(const char *devicename, int backlight_timeout)
{
	struct lcddev *dev = malloc(sizeof(struct lcddev));
	if (dev == NULL) {
		log_print(LOG_ERROR, "%s(): out of memory", __FUNCTION__);
		return NULL;
	}

	memset(dev, 0, sizeof(struct lcddev));

	INIT_LIST_HEAD(&dev->page_list);

	int retval;
#if (_LCD_DUMMY)
	if (strncmp(devicename, "dummy", 5) == 0) {
		retval = lcd_fakedevice_open(dev);
	} else
#endif /* (_LCD_DUMMY) */
	{
		retval = lcd_realdevice_open(dev, devicename);
	}

	if (retval < 0) {
		free(dev);
		return NULL;
	}

	dev->read_event = event_add_readfd(NULL, dev->fd, lcd_read_cb, dev);
	dev->backlight_timeout_ms = backlight_timeout * 1000;

	lcd_reset(dev);
	return dev;
}