#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "yxmllib.h"

#define BUFSIZE 8096

typedef struct buffer {
	int len;
	char *buffer;
} buffer;

buffer *buffer_new() {
	buffer *buf = malloc(sizeof(buffer));
	buf->buffer = malloc(BUFSIZE);
	if (!buf || !buf->buffer) {
		fprintf(stderr, "Could not allocate memory for buffer struct.\n");
		exit(1);
	}
	buf->len = 0;

	return buf;
}

buffer *buffer_reset(buffer *buf) {
	buf->buffer = memset(buf->buffer, 0, BUFSIZE);
	buf->len = 0;

	return buf;
}

buffer *buffer_append(buffer *buf, char *data) {
	for (int i = 0; data[i]; i++) {
		buf->buffer[buf->len] = data[i];
		buf->len++;
	}

	return buf;
}

int process(char *fn, yxml_t *state) {
	size_t filelen;
	char *parsebuffer;
	int intitlegroup, inarticletitle;
	buffer *contentbuf;

	FILE* f = fopen(fn, "rb");
	if (!f) {
		fprintf(stderr, "Could not open %s.", fn);
		perror("Error:");
		return 1;
	}

	// get file size
	fseek(f, 0L, SEEK_END);
	filelen = ftell(f);
	rewind(f);

	parsebuffer = calloc(1, filelen+1);
	if (!parsebuffer) {
		fprintf(stderr, "Could not allocate memory for file %s.\n", fn);
		fclose(f);
		return 1;
	}

	if (fread(parsebuffer, filelen, 1 , f) != 1) {
		fprintf(stderr, "Could not read file into memory for file %s.\n", fn);
		free(parsebuffer);
		fclose(f);
		return 1;
	}

	fclose(f);

	intitlegroup = 0;
	inarticletitle = 0;

	contentbuf = buffer_new();

	yxml_init(state, state+1, BUFSIZE);

	for (; *parsebuffer; parsebuffer++) {
		yxml_ret_t r = yxml_parse(state, *parsebuffer);

		if(r < 0) {
			printf("Parsing error at %s: line %u, byte %lu, offset %lu\n",
					    fn, state->line, state->byte, state->total);
			return 1;
		}

		switch(r) {
			case YXML_ELEMSTART:
				if (!strcmp(state->elem, "title-group")) {
					intitlegroup = 1;
				} else if (!strcmp(state->elem, "article-title") && intitlegroup) {
						printf("%s: ", state->elem);
						inarticletitle = 1;
				}
				break;

			case YXML_CONTENT:
				if (inarticletitle) {
					buffer_append(contentbuf, state->data);
				}
				break;

			case YXML_ELEMEND:
				if (inarticletitle && !strcmp(state->elem, "title-group")) {
					inarticletitle = 0;
					intitlegroup = 0;
					printf("%s\n", contentbuf->buffer);
					buffer_reset(contentbuf);
				}
				break;
		}
  }

	return 0;
}

int main(int argc, char *argv[]) {
	yxml_t *state = malloc(sizeof(yxml_t) + BUFSIZE);

	for (int i = 1; i < argc; i++) {
		process(argv[i], state);
	}

	return 0;
}