/*********************************************************************
 *
 *   LPC ISP - Utility functions
 *
 *
 *  Copyright (C) 2012 Nathael Pajani <nathael.pajani@nathael.net>
 *
 *  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 3 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, see <http://www.gnu.org/licenses/>.
 *
 *********************************************************************/


#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>

#include <unistd.h> /* for open, close */
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>

#include <string.h> /* memcpy */

#include <termios.h> /* serial */
#include <ctype.h>


#define FILE_CREATE_MODE (S_IRUSR | S_IWUSR | S_IRGRP)

extern int trace_on;

/* display data as in hexdump -C :
   00000000  7f 45 4c 46 02 01 01 00  00 00 00 00 00 00 00 00  |.ELF............|
 */
void isp_dump(const unsigned char* buf, unsigned int buf_size)
{
	unsigned int count = 0;
	char pass = 0;
	if (buf_size == 0) {
		return;
	}
	while ((count < buf_size) || (pass == 0)) {
		if (count == buf_size) {
			while (count & 0x0F) {
				printf("   ");
				count++;
			}
			pass = 1;
			count -= 0x10;
		}
		if ((count % 0x10) == 0) {
			if (pass == 0) {
				printf(" %08x  ", count);
			} else {
				printf(" |");
			}
		}
		if (pass == 0) {
			printf("%02x ", buf[count]);
		} else {
			if (isgraph((int)buf[count])) {
				printf("%c", buf[count]);
			} else {
				printf(".");
			}
		}
		count++;
		if ((count % 0x10) == 0) {
			if (pass == 0) {
				count -= 0x10;
			} else {
				if (count == buf_size) {
					break; /* prevent infinite loop */
				}
				printf("|\n");
			}
			pass = !pass;
		}
	}
	printf("|\n");
}


/* ---- Serial utility functions ---------------------------------------------------*/

static int serial_fd = -1;

/* Open the serial device and set it up.
 * Returns 0 on success, negativ value on error.
 * Actal setup is done according to LPC11xx user's manual.
 * Only baudrate can be changed using command line option.
 */
int isp_serial_open(int baudrate, char* serial_device)
{
	struct termios tio;

	if (serial_device == NULL) {
		printf("No serial device given on command line\n");
		return -2;
	}

	/* Open serial port */
	serial_fd = open(serial_device, O_RDWR | O_NONBLOCK);
	if (serial_fd < 0) {
		perror("Unable to open serial_device");
		printf("Tried to open \"%s\".\n", serial_device);
		return -1;
	}
	/* Setup serial port */
	memset(&tio, 0, sizeof(tio));
	tio.c_iflag = IXON | IXOFF;  /* See section 21.4.4 of LPC11xx user's manual (UM10398) */
	tio.c_cflag = CS8 | CREAD | CLOCAL;  /* 8n1, see termios.h for more information */
	tio.c_cc[VMIN] = 1;
	tio.c_cc[VTIME] = 5;
	cfsetospeed(&tio, baudrate);
	cfsetispeed(&tio, baudrate);
	tcsetattr(serial_fd, TCSANOW, &tio);

	return 0;
}

void isp_serial_close(void)
{
	close(serial_fd);
}

/* Simple write() wrapper, with trace if enabled */
int isp_serial_write(const char* buf, unsigned int buf_size)
{
	int nb = 0;

	if (trace_on) {
		printf("Sending %d octet(s) :\n", buf_size);
		isp_dump((unsigned char*)buf, buf_size);
	}
	nb = write(serial_fd, buf, buf_size);
	if (nb <= 0) {
		perror("Serial write error");
		return -1;
	}
	return nb;
}

static char next_read_char = 0;
void isp_serial_empty_buffer()
{
	int nb = 0;
	char unused = 0;
	unsigned int loops = 0; /* Used to create a timeout */

	do {
		nb = read(serial_fd, &unused, 1);
		if (nb < 0) {
			if ((errno == EAGAIN) || (errno == EWOULDBLOCK)) {
				if (loops++ > 100) {
					break; /* timeout at 500ms */
				}
				usleep( 5000 );
				continue;
			}
			perror("Serial read error");
			return;
		} else if (nb == 0) {
			printf("serial_read: end of file !!!!\n");
			return;
		}
	} while ((unused != '\r') && (unused != '\n'));

	/* This should be improved by reading ALL \r and \n */
	if (unused == '\r') {
		nb = read(serial_fd, &unused, 1);
	}
	if (unused == '\n') {
		return;
	}
	next_read_char = unused;
}

/* Try to read at least "min_read" characters from the serial line.
 * Returns -1 on error, 0 on end of file, or read count otherwise.
 */
int isp_serial_read(char* buf, unsigned int buf_size, unsigned int min_read)
{
	int nb = 0;
	unsigned int count = 0;
	unsigned int loops = 0; /* Used to create a timeout */

	if (min_read > buf_size) {
		printf("serial_read: buffer too small for min read value.\n");
		return -3;
	}
	if (next_read_char != 0) {
		buf[count++] = next_read_char;
		next_read_char = 0;
	}

	do {
		nb = read(serial_fd, &buf[count], (buf_size - count));
		if (nb < 0) {
			if ((errno == EAGAIN) || (errno == EWOULDBLOCK)) {
				if (loops++ > 100) {
					break; /* timeout at 500ms */
				}
				usleep( 5000 );
				continue;
			}
			perror("Serial read error");
			return -1;
		} else if (nb == 0) {
			printf("serial_read: end of file !!!!\n");
			return 0;
		}
		if (trace_on == 2) {
			isp_dump((unsigned char*)(&buf[count]), nb);
		}
		count += nb;
	} while (count < min_read);

	if (trace_on) {
		printf("Received %d octet(s) :\n", count);
		isp_dump((unsigned char*)buf, count);
	}
	return count;
}


/* ---- UU_Encoding utility functions ----------------------------------------------*/

/* This might have been taken from a lib, but I hate lib dependencies, and installing
 *  a full window manager (or MTA or MUA for instance) for two functions is not an
 *  option */
#define UUENCODE_ADDED_VAL 32
#define LINE_DATA_LENGTH_MAX 45
#define LINE_LENGTH_NULL 96

int isp_uu_encode(char* dest, char* src, unsigned int orig_size)
{
	unsigned int new_size = 0;
	unsigned int pos = 0;

	while (pos < orig_size) {
		unsigned int line_length = orig_size - pos;
		unsigned int i = 0;

		/* Start with line length */
		if (line_length > LINE_DATA_LENGTH_MAX) {
			line_length = LINE_DATA_LENGTH_MAX;
		}
		dest[new_size] = line_length + UUENCODE_ADDED_VAL;
		new_size++;

		/* Encode line */
		while (i < line_length) {
			uint32_t int_triplet = 0;
			int j = 0;

			/* Get original triplet (three bytes) */
			for (j=0; j<3; j++) {
				int_triplet |= ((src[pos + i + j] & 0xFF) << (8 * (2 - j)));
				/* if not enougth data, leave it as nul */
				if ((i + j) > line_length) {
					break;
				}
			}
			for (j=0; j<4; j++) {
				/* Store triplet in four bytes */
				dest[new_size + j] = ((int_triplet >> (6 * (3 - j))) & 0x3F);
				/* Add offset */
				dest[new_size + j] += UUENCODE_ADDED_VAL;
			}
			i += 3;
			new_size += 4;
		}
		pos += line_length;

		/* Add \r\n */
		dest[new_size++] = '\r';
		dest[new_size++] = '\n';
	}
	return new_size;
}

int isp_uu_decode(char* dest, char* src, unsigned int orig_size)
{
	unsigned int new_size = 0;
	unsigned int pos = 0;

	while (pos < orig_size) {
		unsigned int line_length = 0;
		unsigned int i = 0;
		int j = 0;

		/* Read line length */
		line_length = src[pos] - UUENCODE_ADDED_VAL;
		if (src[pos] == LINE_LENGTH_NULL) {
			/* Empty line ? then we are done converting
			 * (should not happen in communication with ISP) */
			return new_size;
		}
		pos++;

		/* Decode line */
		while (i < line_length) {
			char quartet[4];
			uint32_t int_triplet = 0;
			/* copy data */
			memcpy(quartet, &src[pos], 4);
			pos += 4;
			/* Get the original bits */
			for (j=0; j<4; j++) {
				/* Remove the offset added by uuencoding */
				quartet[j] -= UUENCODE_ADDED_VAL;
				int_triplet |= ((quartet[j] & 0x3F) << ((3 - j) * 6));
			}
			/* And store them */
			for (j=2; j>=0; j--) {
				dest[new_size++] = ((int_triplet >> (j * 8)) & 0xFF );
				i++;
				if (i >= line_length) {
					break;
				}
			}
		}

		/* Find next line */
		while ((src[pos] < UUENCODE_ADDED_VAL) && (pos < orig_size))   {
			pos++;
		}
	}
	return new_size;
}



/* ---- File utility functions ----------------------------------------------*/

int isp_buff_to_file(char* data, unsigned int len, char* filename)
{
	int ret = 0;
	int out_fd = -1;

	/* Open file for writing if output is not stdout */
	if (strncmp(filename, "-", strlen(filename)) == 0) {
		out_fd = STDOUT_FILENO;
	} else {
		out_fd = open(filename, (O_WRONLY | O_CREAT | O_TRUNC), FILE_CREATE_MODE);
		if (out_fd <= 0) {
			perror("Unable to open or create file for writing");
			printf("Tried to open \"%s\".\n", filename);
			return -1;
		}
	}

	/* Write data to file */
	ret = write(out_fd, data, len);
	if (ret != (int)len) {
		perror("File write error");
		printf("Unable to write %u bytes of data to file \"%s\", returned %d !",
				len, filename, ret);
		ret = -2;
	}

	/* Close file */
	if (out_fd != STDOUT_FILENO) {
		close(out_fd);
	}

	return ret;
}

int isp_file_to_buff(char* data, unsigned int len, char* filename)
{
	int in_fd = -1;
	unsigned int bytes_read = 0;

	/* Open file for reading if input is not stdin */
	if (strncmp(filename, "-", strlen(filename)) == 0) {
		/* FIXME : set as non blocking ? */
		in_fd = STDIN_FILENO;
	} else {
		in_fd = open(filename, O_RDONLY | O_NONBLOCK);
		if (in_fd <= 0) {
			perror("Unable to open file for reading");
            printf("Tried to open \"%s\".\n", filename);
            return -13;
        }
    }

    /* Read file content */
    do {
        int nb = read(in_fd, &data[bytes_read], (len - bytes_read));
        if (nb < 0) {
            if ((errno == EAGAIN) || (errno == EWOULDBLOCK)) {
                usleep( 50 );
                continue;
            }
            perror("Input file read error");
            if (in_fd != STDIN_FILENO) {
                close(in_fd);
            }
            return -12;
        } else if (nb == 0) {
            /* End of file */
            break;
        }
        bytes_read += nb;
    } while (bytes_read < len);

    if (in_fd != STDIN_FILENO) {
        close(in_fd);
    }

	return bytes_read;
}