/* dla2csv.c - convert dla.xex save files to CSV.
	Rather bloated and slow by Atari standards. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <ctype.h>
#include <sys/types.h>
#include <dirent.h>

#include "dlaver.h"

#define HEIGHT 170
#define WIDTH 256

/* cc65 doesn't fold constants, it won't let us do this:
	#define INBUF_SIZE (WIDTH * HEIGHT)
	...it has to be a *constant*. */
#define INBUF_SIZE 5440

#define STRINGBUF_SIZE 256

/* cc65 doesn't "localize" \b to the Atari backspace character, so: */
#ifdef __ATARI__
	#define BS '\x7e'
#else
	#define BS '\b'
#endif

char inbuf[INBUF_SIZE];
char stringbuf[STRINGBUF_SIZE];
FILE *inf, *outf;

/* We can't use string literal syntax, cc65 "helpfully" turns "\x0a"
	into an Atari 0x9b EOL character. Numeric constants are left alone. */
char a8eol[] = { 0x9b, 0x00, 0x00 };
char uxeol[] = { 0x0a, 0x00, 0x00 };
char mseol[] = { 0x0d, 0x0a, 0x00 };
char *eoltypes[][2] = {
	{ "Atari ($9B)", a8eol },
	{ "Unix (\\n)",  uxeol },
	{ "MS (\\r\\n)", mseol },
	{ NULL, NULL }
};

/* On the Atari, we should show Atari-style error messages, including
	the familiar error number.
	Another reason to do this: on the Atari, perror() says "Bad file number"
	instead of "No space left on device", if the disk fills up due
	to fprintf().
	On modern platforms, just use perror().
 */
#ifdef __ATARI__
	#define PERROR(x) atari_perror(x)
void atari_perror(char *msg) {
	printf("%s: Error %d: %s\n", msg, _oserror, _stroserror(_oserror));
}
#else
	#define PERROR(x) perror(x)
#endif

/* cc65 doesn't play nice with the Break key on the Atari. It
	works as expected during disk I/O, but if you press it while
	printing to stdout or reading from stdin, the program freezes.
	so call disable_break() at startup, then wrap disk I/O in
	enable_break() and disable_break(). */
#ifdef __ATARI__
char get_pokmsk(void) {
	return *((char *)0x10);
}

void set_pokmsk(char value) {
	*((char *)0x10) = *((char *)0xd20e) = value;
}

void enable_break() {
	set_pokmsk(get_pokmsk() | 0x80);
}

void disable_break() {
	set_pokmsk(get_pokmsk() & 0x7f);
}
#else
void enable_break() { } /* no-op */
void disable_break() { } /* no-op */
#endif

/* Read a string from stdin (E: on the Atari).
	Exit on EOF (or Break key on the Atari, except we disable it).
	On Linux, EOF is the ^D character, and this works.
	On the Atari, EOF is ^3... On DOS 2.0S, we end up back at the DUP
	menu... but SpartaDOS 3.2d locks up with a black screen. So don't
	document ctrl-3 as a way to exit the program (too bad), and just
	hope the user never presses it.
 */
void readstring(void) {
	char *result;
	memset(stringbuf, 0, STRINGBUF_SIZE);
	result = fgets(stringbuf, STRINGBUF_SIZE - 1, stdin);
	if(result == NULL) {
		enable_break();
		exit(1);
	}
}

#ifdef __ATARI__
/* Show disk directory, in a 3-column layout.
	drive is an ASCII digit, e.g. 0x31 is drive 1. */
void show_dir(char drive) {
	static char dirspec[16];
	char device = 'D';
	DIR *dir;
	struct dirent *ent;
	int column = 0;

	if(drive == '0') {
		drive++;
		device = 'H';
	}

	sprintf(dirspec, "%c%c:*.*", device, drive);

	if(!(dir = opendir(dirspec))) {
		dirspec[2] = '\0';
		PERROR(dirspec);
		return;
	}

	while((ent = readdir(dir))) {
		printf("%-13s", ent->d_name);
		if(++column == 3) {
			column = 0;
			putchar('\n');
		}
	}

	closedir(dir);
	if(column) putchar('\n');
}
#endif

int prompt_yn(char *prompt, int default_y) {
	char *yn = "y/N";
	if(default_y) yn = "Y/n";

	printf("%s[%s]? ", prompt, yn);
	fflush(stdout);
	readstring();

	switch(stringbuf[0]) {
		case 'y':
		case 'Y':
			return 1;
			break;
		case 'n':
		case 'N':
			return 0;
			break;
		default:
			break;
	}
	return default_y;
}

/* Prompt for a filename, try to open it. If there's an error,
	show error message and retry. Will not return until it
	opens the file. */
FILE *prompt_filename(const char *name, const char *mode) {
	FILE *f = NULL;
	putchar('\n');
	while(f == NULL) {
		printf("%s file: ", name);
		fflush(stdout);
		readstring();
		stringbuf[strlen(stringbuf) - 1] = '\0'; /* kill trailing \n */
		if(strlen(stringbuf) == 0) {
			if(prompt_yn("Exit program", 0)) {
				enable_break();
				exit(0);
			}
			continue;
		}
#ifdef __ATARI__
		/* if the user enters a single digit, show directory of that drive. */
		if(isdigit(stringbuf[0])) {
			show_dir(stringbuf[0]);
			continue;
		}
		/* if there's no device spec (D: or D1: etc), prepend D: */
		if(!strchr(stringbuf, ':')) {
			memmove(stringbuf+2, stringbuf, strlen(stringbuf) + 1);
			stringbuf[0] = 'D';
			stringbuf[1] = ':';
		}
#endif
		enable_break();
		f = fopen(stringbuf, mode);
		disable_break();
		if(!f) PERROR(stringbuf);
	}
	return f;
}

/* Prompt for and read EOL type, retry if needed. Will not return
	until a valid number was entered. */
char *prompt_eol(void) {
	int i;

	putchar('\n');
	for(i = 0; eoltypes[i][0] != NULL; i++) {
		printf("%d:%s  ", i + 1, eoltypes[i][0]);
	}
	putchar('\n');

	i = -1;
	while(i == -1) {
		printf("Line ending type[1]? ");
		fflush(stdout);
		readstring();
		if(stringbuf[0] == '\n') {
			i = 0;
		} else {
			i = stringbuf[0] - 49; /* ASCII 1-3 => 0-2 */
			if(i < 0 || i > 2)
				i = -1;
		}
	}
	return eoltypes[i][1];
}

void backspace3(void) {
	putchar(BS);
	putchar(BS);
	putchar(BS);
}

int main(int argc, char **argv) {
	char *inp, *eol;
	int i, bytes = 0, x, y, xmask, err;

#ifdef __ATARI__
	/* cc65's startup code turns off caps lock. turn it back on,
		since we're typing DOS filenames. in BASIC this would be:
		POKE 702,64 */
	*((char *)0x02be) = 0x40;

	/* also, cc65 sets APPMHI to $bc1f (last byte before the GR.0
		display list). which causes the atari to lock up when Reset
		is pressed. I can't believe this is useful behaviour... */
	*((int *)0x0e) = 0;

	/* clear the screen */
	putchar(0x7d);
#endif

	printf("DLA to CSV converter v" VERSION ".\n");

#ifdef __ATARI__
	printf("\n"
	       "At any filename prompt, you may enter\n"
	       "a number, to get a directory of that\n"
	       "drive.");
	/* be nice to emulator users. 0x31a is HATABS. */
	for(i = 0x31a; i < 0x340; i += 3) {
		if(*((char *)i) == 'H') {
			printf(" Use 0 for \"H:\".");
			break;
		}
	}
	printf("\n\n");
#endif

	while(1) {
		disable_break();
		err = 0;

		/* in case of short read on 2nd or later conversion: */
		memset(inbuf, 0, INBUF_SIZE);

		/* read whole input file into memory */
		inf = prompt_filename("Input DLA", "rb");
		printf("Reading...");
		fflush(stdout);
		enable_break();
		bytes = fread(inbuf, 1, INBUF_SIZE, inf);
		disable_break();
		if(bytes <= 0) {
			PERROR(stringbuf);
			continue;
		}
		printf("Read %d bytes.\n", bytes);

		/* warn if the file size is wrong... */
		if(bytes < INBUF_SIZE) {
			printf("Warning: File too short!\n");
			err = 1;
		} else if(fgetc(inf) != EOF) {
			printf("Warning: File too long!\n");
			err = 1;
		} else {
			printf("File size is OK.\n");
		}
		fclose(inf);

		/* a DLA file never has non-zero bytes at the beginning. */
		for(i = 0; i < 32; i++) {
			if(inbuf[i]) {
				printf("Warning: File doesn't look like a DLA!\n");
				err = 1;
				break;
			}
		}

		/* if anything looks wrong, we shouldn't proceed... but the user
			is boss, so give him the choice to shoot himself in the foot. */
		if(err) {
			if(!prompt_yn("Try to convert anyway", 0))
				continue;
		}

		eol = prompt_eol();

		/* convert in a loop. in case of write error, this allows retry
			without re-reading the input file. */
		i = err = 0;
		while(!i) {
			outf = prompt_filename("Output CSV", "wb");

#ifdef __ATARI__
			printf("Press Ctrl-C to abort conversion.\n");
#endif
			printf("\nConverting...   ");
			fflush(stdout);

			/* CSV file header row (column names) */
			fprintf(outf, "x,y%s", eol);

			/* write output file one line at a time */
			inp = inbuf;
			xmask = 0x80;
			bytes = 0;
			for(y = 0; y < HEIGHT; y++) {
#ifdef __ATARI__
				/* check for ^C */
				if( *((char *)0x2fc) == 0x92 ) {
					printf("User abort!\n");
					fclose(outf);
					remove(stringbuf);
					err = 1;
					*((char *)0x2fc) = 0xff;
					break;
				}
#endif
				backspace3();
				printf("%02d%%", y * 100 / HEIGHT); /* percentage */
				fflush(stdout);
				for(x = 0; x < WIDTH; x++) {
					if(*inp & xmask) {
						if(fprintf(outf, "%d,%d%s", x, y, eol) < 0) {
							putchar('\n');
							PERROR(stringbuf);
							err = 1;
							break;
						}
						bytes++;
					}
					xmask >>= 1;
					if(!xmask) {
						xmask = 0x80;
						inp++;
					}
				}
				if(err) break;
			}
			fclose(outf);
			if(err) {
				if(!prompt_yn("Conversion failed, try again", 1))
					i = 1;
			} else {
				i = 1;
				backspace3();
				printf("100%%\n%d particles.\n", bytes);
			}
		}

		if(!prompt_yn("\nConvert another file", 1))
			break;
	}
	enable_break();
	exit(0);
}