/* full of jank */
#include <string.h>
#include <skalibs/env.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/unix-transactional.h>
#include <skalibs/stralloc.h>
#include <skalibs/bytestr.h>
#include <skalibs/buffer.h>
#include <skalibs/skamisc.h>
#include <skalibs/strerr.h>
#include <skalibs/djbunix.h>
#include <skalibs/exec.h>

#include "pdjson.h"

#define MAX(x, y) ((x) > (y) ? (x) : (y))
#define MIN(x, y) ((x) < (y) ? (x) : (y))

#define USAGE "mvwtc id"
#define HTTPOK "HTTP/1.1 200 OK"

void
url_hpn(stralloc *url, stralloc *host, stralloc *path, stralloc *name)
{
	char *afterscheme;
	size_t urli, eohost, lastslash;

	urli = byte_chr(url->s, url->len, '/');
	urli += 2;

	afterscheme = url->s + urli;
	eohost = byte_chr(url->s + urli, url->len - urli, '/');
	stralloc_catb(host, url->s + urli, eohost);
	stralloc_0(host);

	stralloc_cats(path, url->s + urli + eohost);
	stralloc_0(host);

	lastslash = byte_rchr(url->s, url->len, '/');
	stralloc_cats(name, url->s + lastslash + 1);
	stralloc_0(host);
}

/* '\n' → '\0' */
void
sa_nltoz(stralloc *sa)
{
	size_t idx;

	idx = byte_chr(sa->s, sa->len, '\n');
	if (idx < sa->len) {
		sa->s[idx] = '\0';
		sa->len = idx;
	}
}

/* '\0' → '\n' */
void
sa_ztonl(stralloc *sa)
{
	size_t idx;

	idx = byte_chr(sa->s, sa->len, '\0');
	if (idx < sa->len) {
		sa->s[idx] = '\n';
		sa->len = idx + 1;
	}
}

/* img url in sa → url */
int
imgpath(stralloc *url, stralloc *sa)
{
	json_stream j;
	enum json_type t;
	const char *key, *val;

	json_open_buffer(&j, sa->s, sa->len);
	json_set_streaming(&j, 0);

	t = json_next(&j);
	if (t != JSON_OBJECT) {
		json_close(&j);
		return -1;
	}

	while ((t = json_next(&j)) != JSON_DONE) {
		switch (t) {
		case JSON_STRING:
			key = json_get_string(&j, NULL);
			if (!strncmp(key, "post_url", MIN(strlen(key),
							strlen("post_url")))) {
				/* i'm not sure why there need to be two of these */
				t = json_next(&j);
				t = json_next(&j);
				val = json_get_string(&j, NULL);
				url->len = 0;
				stralloc_cats(url, val);
				stralloc_0(url);
				return 0;
			}
			break;
		case JSON_OBJECT_END:
			goto done;
			break;
		}
	}
done:
	return -1;
}

int
http_recv(int fd, stralloc *sa)
{
	char obuf[BUFFER_INSIZE];
	buffer outb = BUFFER_INIT(&buffer_read, fd, obuf, BUFFER_INSIZE);
	if (skagetln(&outb, sa, '\n') < 0)
		return -1;
	if (sa->len < sizeof(HTTPOK) || !strncmp(sa->s, HTTPOK, sizeof(HTTPOK)))
		return -1;
	sa->len = 0;

	/* skip to the end of the header */
	for (;;) {
		if (skagetln(&outb, sa, '\n') < 0)
			return -1;
		if (!strncmp(sa->s, "\r\n", 2)) {
			break;
		}
		sa->len = 0;
	}

	sa->len = 0;
	skagetln(&outb, sa, '\n');
	// todo handle fuckery here
	stralloc_0(sa);

	return 0;
}

int
http_send(int fd, char *id)
{
	char buf[BUFFER_OUTSIZE];

	buffer b = BUFFER_INIT(&buffer_write, fd, buf, BUFFER_OUTSIZE);

	buffer_putsnoflush(&b, "GET /api/links/");
	buffer_putsnoflush(&b, id);
	buffer_putsnoflush(&b, ".json HTTP/1.0\r\n");
	buffer_putsnoflush(&b, "Host: walltaker.joi.how\r\n");
	buffer_putsnoflush(&b, "Connection: close\r\n");
	buffer_putsnoflush(&b, "User-Agent: mvwt\r\n\r\n");
	buffer_flush(&b);

	return 0;
}

int
main(int argc, char *argv[])
{
	stralloc resp = STRALLOC_ZERO;
	stralloc img = STRALLOC_ZERO;
	stralloc currentimg = STRALLOC_ZERO;
	stralloc tmp = STRALLOC_ZERO;
	stralloc imhost = STRALLOC_ZERO;
	stralloc impath = STRALLOC_ZERO;
	stralloc imfile = STRALLOC_ZERO;
	PROG = "mvwtc";

	if (argc != 2)
		strerr_dieusage(100, USAGE);
	
	if (http_send(7, argv[1]) < 0)
		strerr_diefu(111, "send http request");
	if (http_recv(6, &resp) < 0) {
		stralloc_free(&resp);
		strerr_diefu(111, "recieve http response");
	}
	fd_shutdown(7, 1);
	fd_close(7);
	fd_shutdown(6, 0);
	fd_close(6);

	if (imgpath(&img, &resp) < 0) {
		stralloc_free(&img);
		stralloc_free(&resp);
		strerr_dief(111, "json seems mangled");
	}
	stralloc_free(&resp);

	if (opengetlnclose("current", &currentimg, '\n') >= 0) {
		sa_nltoz(&currentimg);
		if (!strncmp(currentimg.s, img.s,
					MIN(currentimg.len, img.len))) {
			/* we don't need to do anything, just exit */
			stralloc_free(&currentimg);
			stralloc_free(&img);
			return 0;
		}
	}

	stralloc_copy(&tmp, &img);
	sa_ztonl(&tmp);
	if (!openwritenclose_suffix6("current", tmp.s, tmp.len, NULL, 0, "~")) {
		stralloc_free(&tmp);
		stralloc_free(&currentimg);
		stralloc_free(&img);
		strerr_diefu(111, "write to current");
	}
	stralloc_free(&tmp);

	url_hpn(&img, &imhost, &impath, &imfile);

	char const *wtimg_argv[] = { "s6-tlsclient", "-N", "--",
		imhost.s, "443", "mvwtimg", imhost.s, impath.s, imfile.s, 0 };

	xexec(wtimg_argv);

	return 111;
}