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

#define BUFFER_SIZE 240

const int special_tags_count = 3;

const char *special_tags[] = {
	"#HIDE",
	"//HIDE",
	"/*HIDE*/",
};


bool special_tag(char *line) {
	for(int i = 0; i < special_tags_count; i++) {
		if(strncmp(line, special_tags[i], 5) == 0) {
			return true;
		}
	}
	return false;
}

// return whether the first three characters are ```
bool code_block_delimiter(char *line) {
	return (line[0] == '`' && line[1] == '`' && line[2] =='`');
}

int main(int argc, char *argv[]) {
	if(argc < 3) {
		printf("Improper format, use two arguments file in and file out\n"
           "or use three arguments file in file out and parameters "
            "to pass to pandoc\n");
		return -1;
	}

	FILE *in, *out;
	in = fopen(argv[1], "r");
	if(in == NULL) {
		printf("Error opening file\n");
		return -1;
	}

	out = fopen(argv[2], "w");

	char current_line[BUFFER_SIZE], previous_line[BUFFER_SIZE];

	while(fgets(current_line, BUFFER_SIZE, in) != NULL) {

		if(code_block_delimiter(current_line)) {
			// save current line and get next line
			strcpy(previous_line, current_line);
			if(fgets(current_line, BUFFER_SIZE, in) != NULL) {

				// if you get a special tag keep reading until
				// the end of block string ```
				if(special_tag(current_line)) {
					while(fgets(current_line, BUFFER_SIZE, in) != NULL) {
						if(code_block_delimiter(current_line)) {
							break;
						}
					}
				// if you did not get a special tag this is a regular
				// code block, so print the previous line and then
				// then current line
				} else {
					fprintf(out, "%s", previous_line);
					fprintf(out, "%s", current_line);
				}
			}
		} else {
			// regular line, copy to output file
			fprintf(out, "%s", current_line);
		}
	}

	fclose(in);
	fclose(out);

	return 0;
}