#include <sys/stat.h>
#include <sys/types.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utime.h>

#include "util.h"

static struct feed **feeds;
static char *line;
static size_t linesize;
static struct timespec times[2];
static time_t comparetime;
static unsigned long totalnew;

/* Unescape / decode fields printed by string_print_encoded()
 * "\\" to "\", "\t", to TAB, "\n" to newline. Unrecognised escape sequences
 * are ignored: "\z" etc. */
static void
printcontent(const char *s, FILE *fp)
{
	for (; *s; s++) {
		switch (*s) {
		case '\\':
			switch (*(++s)) {
			case '\0': return; /* ignore */
			case '\\': fputc('\\', fp); break;
			case 't':  fputc('\t', fp); break;
			case 'n':  fputc('\n', fp); break;
			}
			break;
		default:
			fputc((int)*s, fp);
		}
	}
}

/* Unescape / decode fields printed by string_print_encoded()
 * "\\" to "\", "\t", to TAB, "\n" to newline. Unrecognised escape sequences
 * are ignored: "\z" etc. Encode HTML 2.0 / XML 1.0 entities.  */
static void
printcontentxml(const char *s, FILE *fp)
{
	for (; *s; s++) {
		switch (*s) {
		case '\\':
			switch (*(++s)) {
			case '\0': return; /* ignore */
			case '\\': fputc('\\', fp); break;
			case 't':  fputc('\t', fp); break;
			case 'n':  fputc('\n', fp); break;
			}
			break;
		/* XML entities */
		case '<':  fputs("&lt;",   fp); break;
		case '>':  fputs("&gt;",   fp); break;
		case '\'': fputs("&#39;",  fp); break;
		case '&':  fputs("&amp;",  fp); break;
		case '"':  fputs("&quot;", fp); break;
		default:   fputc((int)*s, fp);
		}
	}
}

/* normalize path names, transform to lower-case and replace non-alpha and
 * non-digit with '-' */
static size_t
normalizepath(const char *path, char *buf, size_t bufsiz)
{
	size_t i, r = 0;

	for (i = 0; *path && i < bufsiz; path++) {
		if (isalpha((int)*path) || isdigit((int)*path)) {
			buf[i++] = tolower((int)*path);
			r = 0;
		} else {
			/* don't repeat '-', don't start with '-' */
			if (!r && i)
				buf[i++] = '-';
			r++;
		}
	}
	/* remove trailing '-' */
	for (; i > 0 && (buf[i - 1] == '-'); i--)
		;

	if (bufsiz > 0)
		buf[i] = '\0';

	return i;
}

static void
printfeed(FILE *fpitems, FILE *fpin, struct feed *f)
{
	char dirpath[PATH_MAX], filepath[PATH_MAX];
	char *fields[FieldLast], *feedname, name[128];
	ssize_t linelen;
	FILE *fpcontent = NULL;
	unsigned int isnew;
	struct tm *tm;
	time_t parsedtime;
	int fd, r;

	if (f->name[0])
		feedname = f->name;
	else
		feedname = "unnamed";

	/* make directory for feedname */
	if (!normalizepath(feedname, name, sizeof(name)))
		return;

	strlcpy(dirpath, name, sizeof(dirpath));

	/* error creating directory and it doesn't exist. */
	if (mkdir(dirpath, S_IRWXU | S_IRWXG | S_IRWXO) == -1 && errno != EEXIST)
		err(1, "mkdir: %s", dirpath);

	/* menu if not unnamed */
	if (f->name[0]) {
		fputs("<h2 id=\"", fpitems);
		xmlencode(f->name, fpitems);
		fputs("\"><a href=\"#", fpitems);
		xmlencode(f->name, fpitems);
		fputs("\">", fpitems);
		xmlencode(f->name, fpitems);
		fputs("</a></h2>\n", fpitems);
	}

	while ((linelen = getline(&line, &linesize, fpin)) > 0) {
		if (line[linelen - 1] == '\n')
			line[--linelen] = '\0';
		if (!parseline(line, fields))
			break;

		parsedtime = 0;
		if (strtotime(fields[FieldUnixTimestamp], &parsedtime))
			continue;
		if (!(tm = localtime(&parsedtime)))
			err(1, "localtime");

		if (!normalizepath(fields[FieldTitle], name, sizeof(name)))
			continue;

		r = snprintf(filepath, sizeof(filepath), "%s/%s-%lld.html",
		             dirpath, name, (long long)parsedtime);
		if (r == -1 || (size_t)r >= sizeof(filepath))
			errx(1, "snprintf: path truncation: '%s/%s-%lld.html'",
			        dirpath, name, (long long)parsedtime);

		/* content file doesn't exist yet and has error? */
		if ((fd = open(filepath, O_CREAT | O_EXCL | O_WRONLY,
		               S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)) == -1) {
			if (errno != EEXIST)
				err(1, "open: %s", filepath);
		} else {
			if (!(fpcontent = fdopen(fd, "wb")))
				err(1, "fdopen: %s", filepath);
			fputs("<html><head>"
			      "<link rel=\"stylesheet\" type=\"text/css\" href=\"../../style.css\" />"
			      "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\" />"
			      "</head>\n<body class=\"frame\">"
			      "<div class=\"content\"><h2>", fpcontent);

			if (fields[FieldLink][0]) {
				fputs("<a href=\"", fpcontent);
				xmlencode(fields[FieldLink], fpcontent);
				fputs("\">", fpcontent);
			}
			xmlencode(fields[FieldTitle], fpcontent);
			if (fields[FieldLink][0])
				fputs("</a>", fpcontent);
			fputs("</h2>", fpcontent);

			/* NOTE: this prints the raw HTML of the feed, this is
			 * potentially dangerous, it is left up to the
			 * user / browser to trust a feed it's HTML content. */
			if (!strcmp(fields[FieldContentType], "html")) {
				printcontent(fields[FieldContent], fpcontent);
			} else {
				/* plain-text, wrap with <pre> */
				fputs("<pre>", fpcontent);
				printcontentxml(fields[FieldContent], fpcontent);
				fputs("</pre>", fpcontent);
			}
			fputs("</div></body></html>\n", fpcontent);

			/* set modified and access time of file to time of item. */
			if (parsedtime) {
				/* flush writes before setting atime and mtime
				   else the remaining (buffered) write can occur at
				   fclose() and overwrite our time again. */
				fflush(fpcontent);

				times[0].tv_sec = parsedtime;
				times[1].tv_sec = parsedtime;

				if (futimens(fd, times) == -1)
					err(1, "futimens");
			}
			fclose(fpcontent);
		}

		isnew = (parsedtime >= comparetime) ? 1 : 0;
		totalnew += isnew;
		f->totalnew += isnew;
		f->total++;

		fprintf(fpitems, "%04d-%02d-%02d&nbsp;%02d:%02d ",
		        tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
		        tm->tm_hour, tm->tm_min);

		if (isnew)
			fputs("<b><u>", fpitems);
		fputs("<a href=\"", fpitems);
		fputs(filepath, fpitems);
		fputs("\" target=\"content\">", fpitems);
		xmlencode(fields[FieldTitle], fpitems);
		fputs("</a>", fpitems);
		if (isnew)
			fputs("</u></b>", fpitems);
		fputs("\n", fpitems);
	}
}

int
main(int argc, char *argv[])
{
	FILE *fpindex, *fpitems, *fpmenu, *fp;
	char *name;
	int i, showsidebar = (argc > 1);
	struct feed *f;

	if (pledge("stdio rpath wpath cpath fattr", NULL) == -1)
		err(1, "pledge");

	if (!(feeds = calloc(argc, sizeof(struct feed *))))
		err(1, "calloc");

	if ((comparetime = time(NULL)) == -1)
		err(1, "time");
	/* 1 day is old news */
	comparetime -= 86400;

	/* write main index page */
	if (!(fpindex = fopen("index.html", "wb")))
		err(1, "fopen: index.html");
	if (!(fpmenu = fopen("menu.html", "wb")))
		err(1, "fopen: menu.html");
	if (!(fpitems = fopen("items.html", "wb")))
		err(1, "fopen: items.html");
	fputs("<html><head><link rel=\"stylesheet\" type=\"text/css\" href=\"../style.css\" />"
	      "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\" /></head>"
	      "<body class=\"frame\"><div id=\"items\"><pre>", fpitems);

	if (argc == 1) {
		if (!(feeds[0] = calloc(1, sizeof(struct feed))))
			err(1, "calloc");
		feeds[0]->name = "";
		printfeed(fpitems, stdin, feeds[0]);
	} else {
		for (i = 1; i < argc; i++) {
			if (!(feeds[i - 1] = calloc(1, sizeof(struct feed))))
				err(1, "calloc");
			name = ((name = strrchr(argv[i], '/'))) ? name + 1 : argv[i];
			feeds[i - 1]->name = name;

			if (!(fp = fopen(argv[i], "r")))
				err(1, "fopen: %s", argv[i]);
			printfeed(fpitems, fp, feeds[i - 1]);
			if (ferror(fp))
				err(1, "ferror: %s", argv[i]);
			fclose(fp);
		}
	}
	fputs("</pre>\n</div></body>\n</html>\n", fpitems); /* div items */

	if (showsidebar) {
		fputs("<html><head>"
		      "<link rel=\"stylesheet\" type=\"text/css\" href=\"../style.css\" />\n"
		      "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\" />\n"
		      "</head><body class=\"frame\"><div id=\"sidebar\">", fpmenu);

		for (i = 1; i < argc; i++) {
			f = feeds[i - 1];
			if (f->totalnew)
				fputs("<a class=\"n\" href=\"items.html#", fpmenu);
			else
				fputs("<a href=\"items.html#", fpmenu);
			xmlencode(f->name, fpmenu);
			fputs("\" target=\"items\">", fpmenu);
			if (f->totalnew > 0)
				fputs("<b><u>", fpmenu);
			xmlencode(f->name, fpmenu);
			fprintf(fpmenu, " (%lu)", f->totalnew);
			if (f->totalnew > 0)
				fputs("</u></b>", fpmenu);
			fputs("</a><br/>\n", fpmenu);
		}
		fputs("</div></body></html>\n", fpmenu);
	}
	fputs("<!DOCTYPE html><html><head>\n\t<title>Newsfeed (", fpindex);
	fprintf(fpindex, "%lu", totalnew);
	fputs(")</title>\n\t<link rel=\"stylesheet\" type=\"text/css\" href=\"../style.css\" />\n"
	      "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\" />\n"
	      "</head>\n", fpindex);
	if (showsidebar) {
		fputs("<frameset framespacing=\"0\" cols=\"200,*\" frameborder=\"1\">\n"
		      "	<frame name=\"menu\" src=\"menu.html\" target=\"menu\">\n", fpindex);
	} else {
		fputs("<frameset framespacing=\"0\" cols=\"*\" frameborder=\"1\">\n", fpindex);
	}
	fputs("\t<frameset id=\"frameset\" framespacing=\"0\" cols=\"50%,50%\" frameborder=\"1\">\n"
	      "\t\t<frame name=\"items\" src=\"items.html\" target=\"items\">\n"
	      "\t\t<frame name=\"content\" target=\"content\">\n"
	      "\t</frameset>\n"
	      "</frameset>\n"
	      "</html>\n", fpindex);

	fclose(fpitems);
	fclose(fpmenu);
	fclose(fpindex);

	return 0;
}