#include <err.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#ifdef __OpenBSD__
#include <unistd.h>
#else
#define pledge(a,b) 0
#endif

#include "xml.h"

static XMLParser x;
static char tag[256], inputname[256];

static char jschl_vc[256];
static char jschl_answer[256];
static char pass[256];
static char script[4096];

void
xmltagstart(struct xmlparser *x, const char *t, size_t tl)
{
	if (!strcmp(t, "input") || !strcmp(t, "script"))
		snprintf(tag, sizeof(tag), "%s", t);
}

void
xmltagend(struct xmlparser *x, const char *t, size_t tl, int st)
{
	if (!strcmp(tag, "input"))
		inputname[0] = tag[0] = '\0';
	else if (!strcmp(tag, "script"))
		tag[0] = '\0';
}

void
xmlattr(struct xmlparser *x, const char *t, size_t tl,
	const char *a, size_t al, const char *v, size_t vl)
{
	if (strcmp(tag, "input"))
		return;

	if (!strcmp(a, "name")) {
		if (!strcmp(v, "jschl_vc") || !strcmp(v, "pass"))
			snprintf(inputname, sizeof(inputname), "%s", v);
	} else if (inputname[0] && !strcmp(a, "value")) {
		if (!strcmp(inputname, "jschl_vc"))
			snprintf(jschl_vc, sizeof(jschl_vc), "%s", v);
		else if (!strcmp(inputname, "pass"))
			snprintf(pass, sizeof(pass), "%s", v);
	}
}

void
xmlcdata(struct xmlparser *x, const char *d, size_t dl)
{
	char tmp[sizeof(script)];

	if (strcmp(tag, "script"))
		return;

	snprintf(tmp, sizeof(tmp), "%s%s", script, d);
	memcpy(script, tmp, sizeof(script));
}

int
calcvalue(char *script)
{
	char *stopbreaking = "s,t,o,p,b,r,e,a,k,i,n,g,f, ";
	char var[32] = "", key[32] = "", varkey[64] = "";
	char *p, *s;
	int op, pc, cv, nv, v = 0;

	if (!(s = strstr(script, stopbreaking)))
		return v;
	s += strlen(stopbreaking);

	for (p = s; *p; p++) {
		if (*p == '=') {
			*p = '\0';
			snprintf(var, sizeof(var), "%s", s);
			*p = '=';
			break;
		}
	}
	if (!var[0])
		return v;
	if (!(s = strchr(p, '"')))
		return v;
	s++;

	for (p = s; *p; p++) {
		if (*p == '"') {
			*p = '\0';
			snprintf(key, sizeof(key), "%s", s);
			*p = '"';
			break;
		}
	}
	if (!key[0])
		return v;

	snprintf(varkey, sizeof(varkey), "%s.%s", var, key);

	if (!(s = strchr(p, ':')))
		return v;
	s++;

	op = '+';
	while (1) {
//		printf("op: %c\n", op);

		pc = cv = nv = 0;
		for (s = p; *s; s++) {
			if (*s == ';') {
				nv += cv;
//				printf("nv: %d\n", nv);
				break;
			}
			switch (*s) {
			case '(':
				nv += cv;
				cv = 0;
					break;
			case '!':
			case '+':
				if (pc == '!')
					cv++;
				break;
			case ')':
				if (pc == ')')
					break;

//				printf("	cv: %d\n", cv);
				nv *= 10;

				break;
			}
//			printf("		%c\n", *s);
			pc = *s;
		}

		switch (op) {
		case '-': v -= nv; break;
		case '+': v += nv; break;
		case '*': v *= nv; break;
		}

		if (!(s = strstr(p, varkey)))
			return v;
		p = s + strlen(varkey);
		op = *p;
	}

	return v;
}

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

	if (pledge("stdio", NULL) < 0)
		err(1, "pledge");

	if (argc != 2) {
		fprintf(stderr, "%s <hostname>\n", argv[0]);
		return 1;
	}

	x.xmlattr = xmlattr;
	x.xmlcdata = xmlcdata;
	x.xmltagstart = xmltagstart;
	x.xmltagend = xmltagend;
	x.getnext = getchar;

	xml_parse(&x);

	if (!(value = calcvalue(script)))
		return 1;
	value += strlen(argv[1]);
	snprintf(jschl_answer, sizeof(jschl_answer), "%d", value);

	printf("jschl_vc = %s\n", jschl_vc);
	printf("pass = %s\n", pass);
	printf("jschl_answer = %s\n", jschl_answer);
	printf("\n");
	printf("https://%s/cdn-cgi/l/chk_jschl?jschl_vc=%s&pass=%s&jschl_answer=%s\n",
		argv[1], jschl_vc, pass, jschl_answer);

	return 0;
}