// epson.c: Epson ESC/I device backend
// This file is part of scanbuttond.
// Copyleft )c( 2004-2006 by Bernhard Stiftner
//
// 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., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// Thanks to:
//  - James Gilliland (Epson CX3200 support)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <syslog.h>
#include "scanbuttond/scanbuttond.h"
#include "scanbuttond/libusbi.h"
#include "epson.h"

#define	ESC        	0x1B		/* ASCII value for ESC */

static char* backend_name = "Epson USB";

#define NUM_SUPPORTED_USB_DEVICES 15

static int supported_usb_devices[NUM_SUPPORTED_USB_DEVICES][3] = {
	// vendor, product, num_buttons
	{ 0x04B8, 0x0107, 1 },	// Epson Expression 1600
	{ 0x04B8, 0x010E, 1 },	// Epson Expression 1680
	{ 0x04B8, 0x0103, 1 },	// Epson Perfection 610
	{ 0x04B8, 0x0101, 3 },	// Epson Perfection 636U
	{ 0x04B8, 0x010C, 3 },	// Epson Perfection 640
	{ 0x04B8, 0x0104, 1 },	// Epson Perfection 1200U
	{ 0x04B8, 0x010B, 3 },	// Epson Perfection 1240
	{ 0x04B8, 0x010A, 1 },	// Epson Perfection 1640
	{ 0x04B8, 0x0110, 4 },	// Epson Perfection 1650
	{ 0x04B8, 0x011E, 4 },	// Epson Perfection 1660
	{ 0x04B8, 0x011B, 4 },	// Epson Perfection 2400
	{ 0x04B8, 0x0112, 1 },	// Epson Perfection 2450
	{ 0x04B8, 0x011C, 1 },	// Epson Perfection 3200
	{ 0x04B8, 0x0802, 1 },	// Epson CX3200 (note: is the button number
				// really correct?)
	{ 0x04B8, 0x0106, 1 }   // Epson Stylus Scan 2500
};

static char* usb_device_descriptions[NUM_SUPPORTED_USB_DEVICES][2] = {
	{ "Epson", "Expression 1600"},
	{ "Epson", "Expression 1680"},
	{ "Epson", "Perfection 610"},
	{ "Epson", "Perfection 636U"},
	{ "Epson", "Perfection 640"},
	{ "Epson", "Perfection 1200U"},
	{ "Epson", "Perfection 1240"},
	{ "Epson", "Perfection 1640"},
	{ "Epson", "Perfection 1650"},
	{ "Epson", "Perfection 1660"},
	{ "Epson", "Perfection 2400"},
	{ "Epson", "Perfection 2450"},
	{ "Epson", "Perfection 3200"},
	{ "Epson", "Stylus CX3200"},
	{ "Epson", "Stylus Scan 2500"}
};


static libusb_handle_t* libusb_handle;
static scanner_t* epson_scanners = NULL;


// returns -1 if the scanner is unsupported, or the index of the
// corresponding vendor-product pair in the supported_usb_devices array.
int epson_match_libusb_scanner(libusb_device_t* device)
{
	int index;
	for (index = 0; index < NUM_SUPPORTED_USB_DEVICES; index++) {
		if (supported_usb_devices[index][0] == device->vendorID &&
				  supported_usb_devices[index][1] == device->productID) {
			break;
		}
	}
	if (index >= NUM_SUPPORTED_USB_DEVICES) return -1;
	return index;
}


void epson_attach_libusb_scanner(libusb_device_t* device)
{
	const char* descriptor_prefix = "epson:libusb:";
	int index = epson_match_libusb_scanner(device);
	if (index < 0) return; // unsupported
	scanner_t* scanner = (scanner_t*)malloc(sizeof(scanner_t));
	scanner->vendor = usb_device_descriptions[index][0];
	scanner->product = usb_device_descriptions[index][1];
	scanner->connection = CONNECTION_LIBUSB;
	scanner->internal_dev_ptr = (void*)device;
	scanner->lastbutton = 0;
	scanner->sane_device = (char*)malloc(strlen(device->location) + 
		strlen(descriptor_prefix) + 1);
	strcpy(scanner->sane_device, descriptor_prefix);
	strcat(scanner->sane_device, device->location);
	scanner->num_buttons = supported_usb_devices[index][2];
	scanner->is_open = 0;
	scanner->next = epson_scanners;
	epson_scanners = scanner;
}


void epson_detach_scanners(void)
{
	scanner_t* next;
	while (epson_scanners != NULL) {
		next = epson_scanners->next;
		free(epson_scanners->sane_device);
		free(epson_scanners);
		epson_scanners = next;
	}
}


void epson_scan_devices(libusb_device_t* devices)
{
	int index;
	libusb_device_t* device = devices;
	while (device != NULL) {
		index = epson_match_libusb_scanner(device);
		if (index >= 0)
			epson_attach_libusb_scanner(device);
		device = device->next;
	}
}


int epson_init_libusb(void)
{
	libusb_device_t* devices;

	libusb_handle = libusb_init();
	devices = libusb_get_devices(libusb_handle);
	epson_scan_devices(devices);
	return 0;
}


const char* scanbtnd_get_backend_name(void)
{
	return backend_name;
}


int scanbtnd_init(void)
{
	epson_scanners = NULL;

	syslog(LOG_INFO, "epson-backend: init");
	return epson_init_libusb();
}


int scanbtnd_rescan(void)
{
	libusb_device_t *devices;

	epson_detach_scanners();
	epson_scanners = NULL;
	libusb_rescan(libusb_handle);
	devices = libusb_get_devices(libusb_handle);
	epson_scan_devices(devices);
	return 0;
}


const scanner_t* scanbtnd_get_supported_devices(void)
{
	return epson_scanners;
}


int scanbtnd_open(scanner_t* scanner)
{
	int result = -ENOSYS;
	if (scanner->is_open)
		return -EINVAL;
	switch (scanner->connection) {
		case CONNECTION_LIBUSB:
			// if devices have been added/removed, return -ENODEV to
			// make scanbuttond update its device list
			if (libusb_get_changed_device_count() != 0)
				return -ENODEV;
			result = libusb_open((libusb_device_t*)scanner->internal_dev_ptr);
			break;
	}
	if (result == 0)
		scanner->is_open = 1;
	return result;
}


int scanbtnd_close(scanner_t* scanner)
{
	int result = -ENOSYS;
	if (!scanner->is_open)
		return -EINVAL;
	switch (scanner->connection) {
		case CONNECTION_LIBUSB:
			result = libusb_close((libusb_device_t*)scanner->internal_dev_ptr);
			break;
	}
	if (result == 0)
		scanner->is_open = 0;
	return result;
}


int epson_read(scanner_t* scanner, void* buffer, int bytecount)
{
	switch (scanner->connection) {
		case CONNECTION_LIBUSB:
			return libusb_read((libusb_device_t*)scanner->internal_dev_ptr, 
				buffer, bytecount);
			break;
	}
	return -1;
}


int epson_write(scanner_t* scanner, void* buffer, int bytecount)
{
	switch (scanner->connection) {
		case CONNECTION_LIBUSB:
			return libusb_write((libusb_device_t*)scanner->internal_dev_ptr, 
				buffer, bytecount);
			break;
	}
	return -1;
}


void epson_flush(scanner_t* scanner)
{
	switch (scanner->connection) {
		case CONNECTION_LIBUSB:
			libusb_flush((libusb_device_t*)scanner->internal_dev_ptr);
			break;
	}
}


int scanbtnd_get_button(scanner_t* scanner)
{
	#define BUFFER_SIZE 16
	unsigned char bytes[BUFFER_SIZE];
	int rcv_len;
	int num_bytes;

	bytes[0] = ESC;
	bytes[1] = '!';
	bytes[2] = '\0';

	if (!scanner->is_open)
		return -EINVAL;

	num_bytes = epson_write(scanner, (void*)bytes, 2);
	if (num_bytes != 2) {
		syslog(LOG_WARNING, "epson-backend: communication error: "
			"write length:%d (expected:%d)", num_bytes, 2);
		epson_flush(scanner); 
		return 0;
	}
	num_bytes = epson_read(scanner, (void*)bytes, 4);
	if (num_bytes != 4) {
		syslog(LOG_WARNING, "epson-backend: communication error: "
			"read length:%d (expected:%d)", num_bytes, 4);
		epson_flush(scanner);
		return 0;
	}
	rcv_len = bytes[3] << 8 | bytes[2];
	num_bytes = epson_read(scanner, (void*)bytes, MAX(rcv_len, BUFFER_SIZE));
	if (num_bytes != rcv_len) {
		syslog(LOG_WARNING, "epson-backend: communication error: "
			"read length:%d (expected:%d)", num_bytes, MAX(rcv_len, BUFFER_SIZE));
		epson_flush(scanner);
		return 0;
	}
	return bytes[0];
}


const char* scanbtnd_get_sane_device_descriptor(scanner_t* scanner)
{
	return scanner->sane_device;
}


int scanbtnd_exit(void)
{
	syslog(LOG_INFO, "epson-backend: exit");
	epson_detach_scanners();
	libusb_exit(libusb_handle);
	return 0;
}