#include <stdio.h>
#include <string.h>
#include <skalibs/buffer.h>
#include <skalibs/skamisc.h>
#include <skalibs/stralloc.h>
#include <skalibs/strerr.h>
#include <skalibs/djbunix.h>
#include <skalibs/exec.h>

#define USAGE "mvwtimg host path filename"
#define HTTPOK "HTTP/1.1 200 OK"

int
download(int infd, char *path)
{
	int outfd;

	outfd = open_trunc(path);
	if (outfd < 0)
		return -1;

	if (fd_cat(infd, outfd) < 0) {
		fd_close(outfd);
		return -1;
	}

	fd_sync(outfd);
	fd_close(outfd);
	
	return 0;
}

int
fdgetln(int fd, stralloc *sa, int sep)
{
	char s[1];
	ssize_t r;

	sa->len = 0;
	for (;;) {
		r = fd_read(fd, s, 1);
		if (r < 0)
			return -1;
		if (s[0] == EOF)
			break;
		stralloc_append(sa, s[0]);
		if (s[0] == sep)
			break;
	}
	return 0;
}

int
http_recv_header(int fd)
{
	stralloc sa = STRALLOC_ZERO;

	if (fdgetln(fd, &sa, '\n') < 0)
		return -1;
	if (sa.len < sizeof(HTTPOK) || !strncmp(sa.s, HTTPOK, sizeof(HTTPOK)))
		return -1;
	sa.len = 0;

	for (;;) {
		if (fdgetln(fd, &sa, '\n') < 0)
			return -1;
		if (!strncmp(sa.s, "\r\n", 2)) {
			break;
		}
		sa.len = 0;
	}

	stralloc_free(&sa);

	return 0;
}

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

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

	buffer_putsnoflush(&b, "GET ");
	buffer_putsnoflush(&b, path);
	buffer_putsnoflush(&b, " HTTP/1.0\r\n");
	buffer_putsnoflush(&b, "Host: ");
	buffer_putsnoflush(&b, host);
	buffer_putsnoflush(&b, "\r\nConnection: close\r\n");
	buffer_putsnoflush(&b, "User-Agent: mvwt\r\n\r\n");
	buffer_flush(&b);

	return 0;
}

int
main(int argc, char *argv[])
{
	PROG = "mvwtimg";

	if (argc != 4)
		strerr_dieusage(100, USAGE);

	if (http_send(7, argv[2], argv[1]) < 0)
		strerr_diefu(111, "send http request");
	if (http_recv_header(6) < 0)
		strerr_diefu(111, "recieve image header");
	if (download(6, argv[3]) < 0)
		strerr_diefu(111, "downloading and saving image");
	fd_shutdown(7, 1);
	fd_close(7);
	fd_shutdown(6, 0);
	fd_close(6);

	char const *hsetroot_argv[] = { "hsetroot", "-cover", argv[3], 0 };
	xexec(hsetroot_argv);
	return 0;
}