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


#define MAX_WIDTH  20
#define MAX_HEIGHT 12
#define MAX_LINE   8192


int isLegal(char c) {
	int  x;
	char legal[] = { "_# .$@+*" };

	if (c == '-') c = ' ';

	for (x=0; x<(int)strlen(legal); x++) {
		if (legal[x] == c) {
			return x + 1;
		}
	}
	return 0;
}


int main(int argc, char *argv[]) {

	char           puzzle[MAX_WIDTH][MAX_WIDTH];
	char           line[MAX_LINE];  // Ooo!  Look!  Potential buffer overflow!
	char           height;
	unsigned char  width;
	int16_t        x;
	int16_t        y;
	int16_t        count = 0;
	int32_t        bytes = 0;
	FILE          *in;
	FILE          *out;

	if (argc != 3) {
		printf("%s:  [letslogic.txt] [puzzles.dat]\n", argv[0]);
		return 1;
	}

	in = fopen(argv[1], "rt");
	if (!in) {
		printf("Unable to read %s\n", argv[1]);
		return 2;
	}

	out = fopen(argv[2], "wb");
	if (!out) {
		fclose(in);
		printf("Unable to write %s\n", argv[2]);
		return 2;
	}

	// Skip two bytes at the front of the file to later write the puzzle count into.
	fputc(0, out);
	fputc(0, out);
	bytes = 2;

	count  =  0;
	height = -1;
	width  =  0;

	while (fgets(line, MAX_LINE, in)) {
		// Is there anything on this line?
		if (strlen(line) > 0) {
			// Is this a puzzle line?
			if (isLegal(line[0]) > 0) {
				// Got it.  Read this line.
				if (width < strlen(line)) width = strlen(line);
				height++;
				for (x=0; x<width; x++) {
					puzzle[x][(int)height] = line[x];
				}
			} else {
				// Not a puzzle line.  Were we currently reading a puzzle?
				if (height >= 0) {
					// Yep!  Output it!
					if ((width & 1) == 1) {
						// Width must be even - fill new column with zeros.
						for (y=0; y<height; y++) puzzle[width][y] = 0;
						width++;
					}
					fputc(width, out);
					fputc(height + 1, out);
					bytes += 2;
					// Write out the puzzle data, two tiles to a byte.
					for (y=0; y<height; y++) {
						for (x=0; x<width; x+=2) {
							fputc((isLegal(puzzle[x][y]) << 4) + isLegal(puzzle[x + 1][y]), out);
							bytes++;
						}
					}
					// Reset for next pass.
					count++;
					width  =  0;
					height = -1;
					printf("Puzzle %d imported, %d total bytes written.\n", count, bytes);
				}
			}
		}
	}

	// Seek back to the top and write the number of puzzles found.
	fflush(out);
	fseek(out, 0, SEEK_SET);
	fwrite(&count, sizeof(int16_t), 1, out);

	fclose(out);
	fclose(in);

	return 0;
}