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

#include "xml.h"
#include "errhnd.h"

static char* _readline(FILE*);

char*
ReadXMLValue(char *file, char *tag) {
	FILE *f = fopen(file, "r");
	if (f==NULL)
		return NULL;

	char *filetext = (char*)calloc(sizeof(char), 1);
	if (filetext==NULL)
		RaiseErr("calloc() failed");
	char *fileline = malloc(1);
	while ((fileline = _readline(f)) != NULL) {
		int oldlength = strlen(filetext);
		int newlength = oldlength + 2 + strlen(fileline);
		char *newfiletext = (char*)realloc(filetext, newlength);
		if (newfiletext==NULL) {
			free(filetext);
			RaiseErr("realloc() failed");
		}
		filetext = newfiletext;
		strcat(filetext, (char*)"\n");
		strcat(filetext, fileline);
	}

	char *starttag = (char*)calloc(sizeof(char), strlen(tag)+3);
	if (starttag==NULL)
		RaiseErr("calloc() failed");
	starttag[0] = '<';
	strcat(starttag, tag);
	starttag[strlen(starttag)] = '>';

	char *endtag = (char*)calloc(sizeof(char), strlen(tag)+4);
	endtag[0] = '<';
	endtag[1] = '/';
	strcat(endtag, tag);
	endtag[strlen(endtag)] = '>';

	if (strcasestr(filetext, starttag)==NULL)
		return NULL;
	if (strcasestr(filetext, endtag)==NULL)
		return NULL;

	int contentsize = strcasestr(filetext, endtag)-strcasestr(filetext, starttag) - strlen(starttag) + 1;
	char *content = (char*)calloc(sizeof(char), contentsize);
	strncpy(content, strcasestr(filetext, starttag)+strlen(starttag), contentsize-1);
	content[contentsize-1] = 0;

	return content;
}

static char*
_readline(FILE* file) {
	if (!feof(file)) {
		char *line = (char*)malloc(0x20);
		if (line==NULL)
			RaiseErr("calloc() failed");
		line[0] = 0;
		int curchar;
		boolean inTag = bFalse;
		boolean skipToEndTag = bFalse;
		while ((curchar = getc(file)) != '\n' && curchar != EOF) {
			if (curchar == '\r')
				continue;
			if (curchar == '<')
				inTag = bTrue;
			if (curchar == '>') {
				inTag = bFalse;
				skipToEndTag = bFalse;
			}
			if (inTag && skipToEndTag)
				continue;
			if (inTag && curchar == ' ') {
				skipToEndTag = bTrue;
				continue;
			}

			int newlength = strlen(line)+2;
			char *newline = (char*)realloc(line, newlength);
			if (newline==NULL) {
				free(line);
				RaiseErr("realloc() failed");
			}
			line[newlength-2] = curchar;
			line[newlength-1] = 0;
		}
		return line;
	} else {
		return NULL;
	}
}