/*
 *
 * This program 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 of the License, or (at your option) version 3.
 *
 * This program 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 the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Copyright (C) 1999-2009 Novell, Inc. (www.novell.com)
 *
 */

#include <glib.h>
#include <glib/gi18n.h>
#include <gtk/gtk.h>

#include "e-datetime-format.h"
#include "e-util.h"

#define KEYS_FILENAME "datetime-formats.ini"
#define KEYS_GROUPNAME "formats"

#ifdef G_OS_WIN32
#ifdef localtime_r
#undef localtime_r
#endif
/* The localtime() in Microsoft's C library *is* thread-safe */
#define localtime_r(timep, result)  (localtime (timep) ? memcpy ((result), localtime (timep), sizeof (*(result))) : 0)
#endif

static GHashTable *key2fmt = NULL;

static GKeyFile *setup_keyfile = NULL; /* used on the combo */
static gint setup_keyfile_instances = 0;

static void
save_keyfile (GKeyFile *keyfile)
{
	gchar *contents;
	gchar *filename;
	gsize length;
	GError *error = NULL;

	g_return_if_fail (keyfile != NULL);

	filename = g_build_filename (e_get_user_data_dir (), KEYS_FILENAME, NULL);
	contents = g_key_file_to_data (keyfile, &length, NULL);

	g_file_set_contents (filename, contents, length, &error);

	if (error != NULL) {
		g_warning ("%s", error->message);
		g_error_free (error);
	}

	g_free (contents);
	g_free (filename);
}

static void
ensure_loaded (void)
{
	GKeyFile *keyfile;
	gchar *str, **keys;
	gint i;

	if (key2fmt)
		return;

	key2fmt = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_free);
	keyfile = g_key_file_new ();

	str = g_build_filename (e_get_user_data_dir (), KEYS_FILENAME, NULL);
	g_key_file_load_from_file (keyfile, str, G_KEY_FILE_NONE, NULL);
	g_free (str);

	keys = g_key_file_get_keys (keyfile, KEYS_GROUPNAME, NULL, NULL);

	if (keys) {
		for (i = 0;  keys[i]; i++) {
			str = g_key_file_get_string (keyfile, KEYS_GROUPNAME, keys[i], NULL);
			if (str)
				g_hash_table_insert (key2fmt, g_strdup (keys[i]), str);
		}

		g_strfreev (keys);
	}

	g_key_file_free (keyfile);
}

static const gchar *
get_default_format (DTFormatKind kind, const gchar *key)
{
	const gchar *res = NULL;

	ensure_loaded ();

	switch (kind) {
	case DTFormatKindDate:
		res = g_hash_table_lookup (key2fmt, "Default-Date");
		if (!res)
			res = "%x";
		break;
	case DTFormatKindTime:
		res = g_hash_table_lookup (key2fmt, "Default-Time");
		if (!res)
			res = "%X";
		break;
	case DTFormatKindDateTime:
		res = g_hash_table_lookup (key2fmt, "Default-DateTime");
		if (!res && key && g_str_has_prefix (key, "mail-table"))
			res = "%ad %H:%M";
		if (!res)
			res = "%x %X"; /* %c is also possible, but it doesn't play well with time zone identifiers */
		break;
	case DTFormatKindShortDate:
		res = g_hash_table_lookup (key2fmt, "Default-ShortDate");
		if (!res)
			res = "%A, %B %d";
		break;
	}

	if (!res)
		res = "%x %X";

	return res;
}

static const gchar *
get_format_internal (const gchar *key, DTFormatKind kind)
{
	const gchar *res;

	ensure_loaded ();

	g_return_val_if_fail (key != NULL, NULL);
	g_return_val_if_fail (key2fmt != NULL, NULL);

	res = g_hash_table_lookup (key2fmt, key);
	if (!res)
		res = get_default_format (kind, key);

	return res;
}

static void
set_format_internal (const gchar *key, const gchar *fmt, GKeyFile *keyfile)
{
	ensure_loaded ();

	g_return_if_fail (key != NULL);
	g_return_if_fail (key2fmt != NULL);
	g_return_if_fail (keyfile != NULL);

	if (!fmt || !*fmt) {
		g_hash_table_remove (key2fmt, key);
		g_key_file_remove_key (keyfile, KEYS_GROUPNAME, key, NULL);
	} else {
		g_hash_table_insert (key2fmt, g_strdup (key), g_strdup (fmt));
		g_key_file_set_string (keyfile, KEYS_GROUPNAME, key, fmt);
	}
}

static gchar *
format_relative_date (time_t tvalue, time_t ttoday, const struct tm *value, const struct tm *today)
{
	gchar *res = g_strdup (get_default_format (DTFormatKindDate, NULL));
	GDate now, val;
	gint diff;

	g_return_val_if_fail (value != NULL, res);
	g_return_val_if_fail (today != NULL, res);

	g_date_set_time_t (&now, ttoday);
	g_date_set_time_t (&val, tvalue);

	diff = g_date_get_julian (&now) - g_date_get_julian (&val);
	/* if it's more than a week, use the default date format */
	if (ABS (diff) > 7)
		return res;

	g_free (res);

	if (value->tm_year == today->tm_year &&
	    value->tm_mon == today->tm_mon &&
	    value->tm_mday == today->tm_mday) {
		res = g_strdup (_("Today"));
	} else {
		gboolean future = FALSE;

		if (diff < 0)
			future = TRUE;

		diff = ABS (diff);

		if (diff <= 1) {
			if (future)
				res = g_strdup (_("Tomorrow"));
			else
				res = g_strdup (_("Yesterday"));
		} else {
			if (future) {
				/* Translators: %a is a strftime modifier, the abbreviated week day name, for example "Next Tue".
				   ngettext is used to be able to define different translations for different days of week, where
				   necessary. Index is between 1 and 7 inclusive, meaning 1 .. Monday, 2 .. Tuesday, ..., 7 .. Sunday */
				res = g_strdup (ngettext ("Next %a", "Next %a", g_date_get_weekday (&val)));
			} else {
				res = g_strdup ("%a");
			}
		}
	}

	return res;
}

static gchar *
format_internal (const gchar *key, DTFormatKind kind, time_t tvalue, struct tm *tm_value)
{
	const gchar *fmt;
	gchar buff[129];
	GString *use_fmt = NULL;
	gint i, last = 0;
	struct tm today, value;
	time_t ttoday;

	tzset ();
	if (!tm_value) {
		localtime_r (&tvalue, &value);
		tm_value = &value;
	} else {
		/* recalculate tvalue to local (system) timezone */
		tvalue = mktime (tm_value);
		localtime_r (&tvalue, &value);
	}

	fmt = get_format_internal (key, kind);
	for (i = 0; fmt[i]; i++) {
		if (fmt[i] == '%') {
			if (fmt[i + 1] == '%') {
				i++;
			} else if (fmt[i + 1] == 'a' && fmt[i + 2] == 'd' && (fmt[i + 3] == 0 || !g_ascii_isalpha (fmt[i + 3]))) {
				gchar *ad;

				/* "%ad" for abbreviated date */
				if (!use_fmt) {
					use_fmt = g_string_new ("");

					ttoday = time (NULL);
					localtime_r (&ttoday, &today);
				}

				g_string_append_len (use_fmt, fmt + last, i - last);
				last = i + 3;
				i += 2;

				ad = format_relative_date (tvalue, ttoday, &value, &today);
				if (ad)
					g_string_append (use_fmt, ad);
				else if (g_ascii_isspace (fmt[i + 3]))
					i++;

				g_free (ad);
			}
		}
	}

	if (use_fmt && last < i) {
		g_string_append_len (use_fmt, fmt + last, i - last);
	}

	e_utf8_strftime_fix_am_pm (buff, sizeof (buff) - 1, use_fmt ? use_fmt->str : fmt, tm_value);

	if (use_fmt)
		g_string_free (use_fmt, TRUE);

	return g_strstrip (g_strdup (buff));
}

static void
fill_combo_formats (GtkWidget *combo, const gchar *key, DTFormatKind kind)
{
	const gchar *date_items[] = {
		N_ ("Use locale default"),
		"%m/%d/%y",	/* American style */
		"%m/%d/%Y",	/* American style, full year */
		"%d.%m.%y",	/* non-American style */
		"%d.%m.%Y",	/* non-American style, full year */
		"%ad",		/* abbreviated date, like "Today" */
		NULL
	};

	const gchar *time_items[] = {
		N_ ("Use locale default"),
		"%I:%M:%S %p",	/* 12hours style */
		"%I:%M %p",	/* 12hours style, without seconds */
		"%H:%M:%S",	/* 24hours style */
		"%H:%M",	/* 24hours style, without seconds */
		NULL
	};

	const gchar *datetime_items[] = {
		N_ ("Use locale default"),
		"%m/%d/%y %I:%M:%S %p",	/* American style */
		"%m/%d/%Y %I:%M:%S %p",	/* American style, full year */
		"%m/%d/%y %I:%M %p",	/* American style, without seconds */
		"%m/%d/%Y %I:%M %p",	/* American style, without seconds, full year */
		"%ad %I:%M:%S %p",	/* %ad is an abbreviated date, like "Today" */
		"%ad %I:%M %p",		/* %ad is an abbreviated date, like "Today", without seconds */
		"%d.%m.%y %H:%M:%S",	/* non-American style */
		"%d.%m.%Y %H:%M:%S",	/* non-American style, full year */
		"%d.%m.%y %H:%M",	/* non-American style, without seconds */
		"%d.%m.%Y %H:%M",	/* non-American style, without seconds, full year */
		"%ad %H:%M:%S",
		"%ad %H:%M",		/* without seconds */
		NULL
	};

	const gchar *shortdate_items[] = {
		"%A, %B %d",
		"%A, %d %B",
		"%a, %b %d",
		"%a, %d %b",
		NULL
	};

	const gchar **items = NULL;
	gint i, idx = 0;
	const gchar *fmt;

	g_return_if_fail (GTK_IS_COMBO_BOX (combo));

	switch (kind) {
	case DTFormatKindDate:
		items = date_items;
		break;
	case DTFormatKindTime:
		items = time_items;
		break;
	case DTFormatKindDateTime:
		items = datetime_items;
		break;
	case DTFormatKindShortDate:
		items = shortdate_items;
		break;
	}

	g_return_if_fail (items != NULL);

	fmt = get_format_internal (key, kind);

	for (i = 0; items[i]; i++) {
		if (i == 0) {
			gtk_combo_box_text_append_text (
				GTK_COMBO_BOX_TEXT (combo), _(items[i]));
		} else {
			gtk_combo_box_text_append_text (
				GTK_COMBO_BOX_TEXT (combo), items[i]);
			if (!idx && fmt && g_str_equal (fmt, items[i]))
				idx = i;
		}
	}

	if (idx == 0 && fmt && !g_str_equal (fmt, get_default_format (kind, key))) {
		gtk_combo_box_text_append_text (
			GTK_COMBO_BOX_TEXT (combo), fmt);
		idx = i;
	}

	gtk_combo_box_set_active ((GtkComboBox *) combo, idx);
}

static void
update_preview_widget (GtkWidget *combo)
{
	GtkWidget *preview;
	const gchar *key;
	gchar *value;
	time_t now;

	g_return_if_fail (GTK_IS_COMBO_BOX (combo));

	preview = g_object_get_data (G_OBJECT (combo), "preview-label");
	g_return_if_fail (preview != NULL);
	g_return_if_fail (GTK_IS_LABEL (preview));

	key = g_object_get_data (G_OBJECT (combo), "format-key");
	g_return_if_fail (key != NULL);

	time (&now);

	value = format_internal (key, GPOINTER_TO_INT (g_object_get_data (G_OBJECT (combo), "format-kind")), now, NULL);
	gtk_label_set_text (GTK_LABEL (preview), value ? value : "");
	g_free (value);
}

static void
format_combo_changed_cb (GtkWidget *combo, gpointer user_data)
{
	const gchar *key;
	DTFormatKind kind;
	GKeyFile *keyfile;

	g_return_if_fail (GTK_IS_COMBO_BOX (combo));

	key = g_object_get_data (G_OBJECT (combo), "format-key");
	g_return_if_fail (key != NULL);

	kind = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (combo), "format-kind"));
	keyfile = g_object_get_data (G_OBJECT (combo), "setup-key-file");

	if (kind != DTFormatKindShortDate && gtk_combo_box_get_active (GTK_COMBO_BOX (combo)) == 0) {
		/* use locale default */
		set_format_internal (key, NULL, keyfile);
	} else {
		gchar *text;

		text = gtk_combo_box_text_get_active_text (
			GTK_COMBO_BOX_TEXT (combo));
		set_format_internal (key, text, keyfile);
		g_free (text);
	}

	update_preview_widget (combo);

	/* save on every change only because 'unref_setup_keyfile' is never called :(
	   how about in kill-bonobo? */
	save_keyfile (keyfile);
}

static gchar *
gen_key (const gchar *component, const gchar *part, DTFormatKind kind)
{
	const gchar *kind_str = NULL;

	g_return_val_if_fail (component != NULL, NULL);
	g_return_val_if_fail (*component != 0, NULL);

	switch (kind) {
	case DTFormatKindDate:
		kind_str = "Date";
		break;
	case DTFormatKindTime:
		kind_str = "Time";
		break;
	case DTFormatKindDateTime:
		kind_str = "DateTime";
		break;
	case DTFormatKindShortDate:
		kind_str = "ShortDate";
		break;
	}

	return g_strconcat (component, (part && *part) ? "-" : "", part && *part ? part : "", "-", kind_str, NULL);
}

static void
unref_setup_keyfile (gpointer ptr)
{
	g_return_if_fail (ptr == setup_keyfile);
	g_return_if_fail (setup_keyfile != NULL);
	g_return_if_fail (setup_keyfile_instances > 0);

	/* this is never called :( */
	setup_keyfile_instances--;
	if (setup_keyfile_instances == 0) {
		save_keyfile (setup_keyfile);
		g_key_file_free (setup_keyfile);
		setup_keyfile = NULL;
	}
}

/**
 * e_datetime_format_add_setup_widget:
 * @table: Where to attach widgets. Requires 3 columns.
 * @row: On which row to attach.
 * @component: Component identifier for the format. Cannot be empty nor NULL.
 * @part: Part in the component, can be NULL or empty string.
 * @kind: Kind of the format for the component/part.
 * @caption: Caption for the widget, can be NULL, then the "Format:" is used.
 *
 * Adds a setup widget for a component and part. The table should have 3 columns.
 * All the work related to loading and saving the value is done automatically,
 * on user's changes.
 **/
void
e_datetime_format_add_setup_widget (GtkWidget *table, gint row, const gchar *component, const gchar *part, DTFormatKind kind, const gchar *caption)
{
	GtkListStore *store;
	GtkWidget *label, *combo, *preview, *align;
	gchar *key;

	g_return_if_fail (table != NULL);
	g_return_if_fail (row >= 0);
	g_return_if_fail (component != NULL);
	g_return_if_fail (*component != 0);

	key = gen_key (component, part, kind);

	label = gtk_label_new_with_mnemonic (caption ? caption : _("Format:"));

	store = gtk_list_store_new (1, G_TYPE_STRING);
	combo = g_object_new (
		GTK_TYPE_COMBO_BOX_TEXT,
		"model", store,
		"has-entry", TRUE,
		"entry-text-column", 0,
		NULL);
	g_object_unref (store);

	fill_combo_formats (combo, key, kind);
	gtk_label_set_mnemonic_widget ((GtkLabel *)label, combo);

	align = gtk_alignment_new (0.0, 0.5, 0.0, 0.0);
	gtk_container_add (GTK_CONTAINER (align), combo);

	gtk_table_attach ((GtkTable *) table, label, 0, 1, row, row + 1, 0, 0, 2, 0);
	gtk_table_attach ((GtkTable *) table, align, 1, 2, row, row + 1, 0, 0, 2, 0);

	preview = gtk_label_new ("");
	gtk_misc_set_alignment (GTK_MISC (preview), 0.0, 0.5);
	gtk_label_set_ellipsize (GTK_LABEL (preview), PANGO_ELLIPSIZE_END);
	gtk_table_attach ((GtkTable *) table, preview, 2, 3, row, row + 1, GTK_EXPAND | GTK_FILL, 0, 2, 0);

	if (!setup_keyfile) {
		gchar *filename;

		filename = g_build_filename (e_get_user_data_dir (), KEYS_FILENAME, NULL);
		setup_keyfile = g_key_file_new ();
		g_key_file_load_from_file (setup_keyfile, filename, G_KEY_FILE_NONE, NULL);
		g_free (filename);

		setup_keyfile_instances = 1;
	} else {
		setup_keyfile_instances++;
	}

	g_object_set_data (G_OBJECT (combo), "preview-label", preview);
	g_object_set_data (G_OBJECT (combo), "format-kind", GINT_TO_POINTER (kind));
	g_object_set_data_full (G_OBJECT (combo), "format-key", key, g_free);
	g_object_set_data_full (G_OBJECT (combo), "setup-key-file", setup_keyfile, unref_setup_keyfile);
	g_signal_connect (combo, "changed", G_CALLBACK (format_combo_changed_cb), NULL);

	update_preview_widget (combo);

	gtk_widget_show_all (table);
}

gchar *
e_datetime_format_format (const gchar *component, const gchar *part, DTFormatKind kind, time_t value)
{
	gchar *key, *res;

	g_return_val_if_fail (component != NULL, NULL);
	g_return_val_if_fail (*component != 0, NULL);

	key = gen_key (component, part, kind);
	g_return_val_if_fail (key != NULL, NULL);

	res = format_internal (key, kind, value, NULL);

	g_free (key);

	return res;
}

gchar *
e_datetime_format_format_tm (const gchar *component, const gchar *part, DTFormatKind kind, struct tm *tm_time)
{
	gchar *key, *res;

	g_return_val_if_fail (component != NULL, NULL);
	g_return_val_if_fail (*component != 0, NULL);
	g_return_val_if_fail (tm_time != NULL, NULL);

	key = gen_key (component, part, kind);
	g_return_val_if_fail (key != NULL, NULL);

	res = format_internal (key, kind, 0, tm_time);

	g_free (key);

	return res;
}