/*
**  Copyright (C) 2017 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
**
**  This library is free software; you can redistribute it and/or
**  modify it under the terms of the GNU Lesser General Public License
**  as published by the Free Software Foundation; either version 2.1
**  of the License, or (at your option) any later version.
**
**  This library is distributed in the hope that it will be useful,
**  but WITHOUT ANY WARRANTY; without even the implied warranty of
**  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
**  Lesser General Public License for more details.
**
**  You should have received a copy of the GNU Lesser General Public
**  License along with this library; if not, write to the Free
**  Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
**  02110-1301, USA.
*/

#define _XOPEN_SOURCE
#include <time.h>

#define GNU_SOURCE
#include <stdio.h>
#include <stdint.h>

#include "utils.hh"

#include <string.h>
#include <iostream>
#include <algorithm>

#include <glib.h>
#include <glib/gprintf.h>

using namespace Mux;

namespace {

static gunichar
unichar_tolower (gunichar uc)
{
  if (!g_unichar_isalpha(uc))
    return uc;

  if (g_unichar_get_script (uc) != G_UNICODE_SCRIPT_LATIN)
    return g_unichar_tolower (uc);

  switch (uc)
    {
    case 0x00e6:
    case 0x00c6: return 'e';   /* æ */
    case 0x00f8: return 'o';   /* ø */
    case 0x0110:
    case 0x0111: return 'd';   /* đ */
      /* todo: many more */
    default: return g_unichar_tolower (uc);
    }
}

/**
 * gx_utf8_flatten:
 * @str: a UTF-8 string
 * @len: the length of @str, or -1 if it is %NULL-terminated
 *
 * Flatten some UTF-8 string; that is, downcase it and remove any diacritics.
 *
 * Returns: (transfer full): a flattened string, free with g_free().
 */
static char*
gx_utf8_flatten (const gchar *str, gssize len)
{
  GString *gstr;
  char    *norm, *cur;

  g_return_val_if_fail (str, NULL);

  norm = g_utf8_normalize (str, len, G_NORMALIZE_ALL);
  if (!norm)
    return NULL;

  gstr = g_string_sized_new (strlen (norm));

  for (cur = norm; cur && *cur; cur = g_utf8_next_char (cur))
    {
      gunichar uc;

      uc = g_utf8_get_char (cur);
      if (g_unichar_combining_class (uc) != 0)
	continue;

      g_string_append_unichar (gstr, unichar_tolower(uc));
    }

  g_free (norm);

  return g_string_free (gstr, FALSE);
}

} // namespace

std::string // gx_utf8_flatten
Mux::utf8_flatten (const char *str)
{
	if (!str)
		return {};

	// the pure-ascii case
	if (g_str_is_ascii(str)) {
		auto l = g_ascii_strdown (str, -1);
		std::string s{l};
		g_free (l);
		return s;
	}

	// seems we need the big guns
	char *flat = gx_utf8_flatten (str, -1);
	if (!flat)
		return {};

	std::string s{flat};
	g_free (flat);

	return s;
}

std::string
Mux::utf8_clean (const std::string& dirty)
{
	GString *gstr = g_string_sized_new (dirty.length());

	for (auto cur = dirty.c_str(); cur && *cur; cur = g_utf8_next_char (cur)) {

		const gunichar uc = g_utf8_get_char (cur);
		if (g_unichar_iscntrl (uc))
			g_string_append_c (gstr, ' ');
		else
			g_string_append_unichar (gstr, uc);
	}

	std::string clean(gstr->str, gstr->len);
	g_string_free (gstr, TRUE);

	clean.erase (0, clean.find_first_not_of(" "));
	clean.erase (clean.find_last_not_of(" ") + 1); // remove trailing space

	return clean;
}

std::vector<std::string>
Mux::split (const std::string& str, const std::string& sepa)
{
	char **parts = g_strsplit(str.c_str(), sepa.c_str(), -1);
	std::vector<std::string> vec;
	for (auto part = parts; part && *part; ++part)
		vec.push_back (*part);

	g_strfreev(parts);

	return vec;
}

std::string
Mux::quote (const std::string& str)
{
	char *s = g_strescape (str.c_str(), NULL);
	if (!s)
		return {};

	std::string res (s);
	g_free (s);

	return "\"" + res + "\"";
}

 std::string
 Mux::format (const char *frm, ...)
 {
	 va_list args;

	 va_start (args, frm);

	 char *s = {};
	 const auto res = g_vasprintf (&s, frm, args);
	 va_end (args);
	 if (res == -1) {
		 std::cerr << "string format failed" << std::endl;
		 return {};
	 }

	 std::string str = s;
	 free (s);

	 return str;
 }

constexpr const auto InternalDateFormat = "%010" G_GINT64_FORMAT;
constexpr const char InternalDateMin[] = "0000000000";
constexpr const char InternalDateMax[] = "9999999999";
static_assert(sizeof(InternalDateMin) == 10 + 1, "invalid");
static_assert(sizeof(InternalDateMax) == 10 + 1, "invalid");

static std::string
date_boundary (bool is_first)
{
	return is_first ? InternalDateMin : InternalDateMax;
}

std::string
Mux::date_to_time_t_string (int64_t t)
{
	char buf[sizeof(InternalDateMax)];
	snprintf (buf, sizeof(buf), InternalDateFormat, t);

	return buf;
}

static std::string
delta_ymwdhMs (const std::string& expr)
{
	char *endptr;
	auto num = strtol  (expr.c_str(), &endptr, 10);
	if (num <= 0 || num > 9999 || !endptr || !*endptr)
		return date_boundary (true);

	int years, months, weeks, days, hours, minutes, seconds;
	years = months = weeks = days = hours = minutes = seconds = 0;

	switch (endptr[0]) {
	case 's': seconds = num; break;
	case 'M': minutes = num; break;
	case 'h': hours	  = num; break;
	case 'd': days	  = num; break;
	case 'w': weeks	  = num; break;
	case 'm': months  = num; break;
	case 'y': years	  = num; break;
	default:
		return date_boundary (true);
	}

	GDateTime *then, *now = g_date_time_new_now_local ();
	if (weeks != 0)
		then = g_date_time_add_weeks (now, -weeks);
	else
		then = g_date_time_add_full (now, -years, -months,-days,
					     -hours, -minutes, -seconds);

	time_t t = MAX (0, (gint64)g_date_time_to_unix (then));

	g_date_time_unref (then);
	g_date_time_unref (now);

	return date_to_time_t_string (t);
}

static std::string
special_date (const std::string& d, bool is_first)
{
	if (d == "now")
		return date_to_time_t_string (time(NULL));

	else if (d == "today") {

		GDateTime *dt, *midnight;
		dt	 = g_date_time_new_now_local ();

		if (!is_first) {
			GDateTime *tmp = dt;
			dt = g_date_time_add_days (dt, 1);
			g_date_time_unref (tmp);
		}

		midnight = g_date_time_add_full (dt, 0, 0, 0,
						 -g_date_time_get_hour(dt),
						 -g_date_time_get_minute (dt),
						 -g_date_time_get_second (dt));
		time_t t = MAX(0, (gint64)g_date_time_to_unix (midnight));
		g_date_time_unref (dt);
		g_date_time_unref (midnight);
		return date_to_time_t_string ((time_t)t);

	} else
		return date_boundary (is_first);
}

// if a date has a month day greater than the number of days in that month,
// change it to a valid date point to the last second in that month
static void
fixup_month (struct tm *tbuf)
{
	decltype(tbuf->tm_mday)	max_days;
	const auto	month = tbuf->tm_mon + 1;
	const auto	year  = tbuf->tm_year + 1900;

	switch (month) {
	case 2:
		if (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0))
			max_days = 29;
		else
			max_days = 28;
		break;
	case 4:
	case 6:
	case 9:
	case 11:
		max_days = 30;
		break;
	default:
		max_days = 31;
		break;
	}

	if (tbuf->tm_mday > max_days) {
		tbuf->tm_mday = max_days;
		tbuf->tm_hour  = 23;
		tbuf->tm_min   = 59;
		tbuf->tm_sec   = 59;
	}
}

std::string
Mux::date_to_time_t_string (const std::string& dstr, bool is_first)
{
	gint64		 t;
	struct tm	 tbuf;
	GDateTime	*dtime;

	/* one-sided dates */
	if (dstr.empty())
		return date_boundary (is_first);
	else if (dstr == "today" || dstr == "now")
		return special_date (dstr, is_first);

	else if (dstr.find_first_of("ymdwhMs") != std::string::npos)
		return delta_ymwdhMs (dstr);

	constexpr char UserDateMin[] = "19700101000000";
	constexpr char UserDateMax[] = "29991231235959";

	std::string date (is_first ? UserDateMin : UserDateMax);
	std::copy_if (dstr.begin(), dstr.end(), date.begin(),[](auto c){return isdigit(c);});

	memset (&tbuf, 0, sizeof tbuf);
	if (!strptime (date.c_str(), "%Y%m%d%H%M%S", &tbuf) &&
	    !strptime (date.c_str(), "%Y%m%d%H%M", &tbuf) &&
	    !strptime (date.c_str(), "%Y%m%d", &tbuf) &&
	    !strptime (date.c_str(), "%Y%m", &tbuf) &&
	    !strptime (date.c_str(), "%Y", &tbuf))
		return date_boundary (is_first);

	fixup_month(&tbuf);

	dtime = g_date_time_new_local (tbuf.tm_year + 1900,
				       tbuf.tm_mon + 1,
				       tbuf.tm_mday,
				       tbuf.tm_hour,
				       tbuf.tm_min,
				       tbuf.tm_sec);
	if (!dtime) {
		g_warning ("invalid %s date '%s'",
			   is_first ? "lower" : "upper", date.c_str());
		return date_boundary (is_first);
	}

	t = g_date_time_to_unix (dtime);
	g_date_time_unref (dtime);

	if (t < 0 || t > 9999999999)
		return date_boundary (is_first);
	else
		return date_to_time_t_string (t);
}

constexpr const auto SizeFormat = "%010" G_GINT64_FORMAT;

constexpr const char SizeMin[] = "0000000000";
constexpr const char SizeMax[] = "9999999999";
static_assert(sizeof(SizeMin) == 10 + 1, "invalid");
static_assert(sizeof(SizeMax) == 10 + 1, "invalid");

static std::string
size_boundary (bool is_first)
{
	return is_first ? SizeMin : SizeMax;
}

std::string
Mux::size_to_string (int64_t size)
{
	char buf[sizeof(SizeMax)];
	snprintf (buf, sizeof(buf), SizeFormat, size);

	return buf;
}

std::string
Mux::size_to_string (const std::string& val, bool is_first)
{
	std::string	 str;
	GRegex		*rx;
	GMatchInfo	*minfo;

	/* one-sided ranges */
	if (val.empty())
		return size_boundary (is_first);

	rx = g_regex_new ("(\\d+)(b|k|kb|m|mb|g|gb)?",
			  G_REGEX_CASELESS, (GRegexMatchFlags)0, NULL);
	minfo = NULL;
	if (g_regex_match (rx, val.c_str(), (GRegexMatchFlags)0, &minfo)) {
		gint64 size;
		char *s;

		s = g_match_info_fetch (minfo, 1);
		size = atoll (s);
		g_free (s);

		s = g_match_info_fetch (minfo, 2);
		switch (s ? g_ascii_tolower(s[0]) : 0) {
		case 'k': size *= 1024; break;
		case 'm': size *= (1024 * 1024); break;
		case 'g': size *= (1024 * 1024 * 1024); break;
		default: break;
		}

		g_free (s);
		str = size_to_string (size);
	} else
		str = size_boundary (is_first);

	g_regex_unref (rx);
	g_match_info_unref (minfo);

	return str;
}
