/*
** Copyright (C) 2010-2020 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
**
** This program is free software; you can redistribute it and/or modify it
** under the terms of the GNU General Public License as published by the
** Free Software Foundation; either version 3, or (at your option) any
** later version.
**
** 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 General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software Foundation,
** Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
**
*/

#include "config.h"

#include <stdlib.h>
#include <string.h>

#include "mu-msg.hh"
#include "mu-msg-part.hh"

#include "mu-cmd.hh"
#include "utils/mu-util.h"
#include "utils/mu-str.h"

using namespace Mu;

static gboolean
save_part(MuMsg* msg, const char* targetdir, guint partidx, const MuConfig* opts)
{
	GError*      err;
	gchar*       filepath;
	gboolean     rv;
	MuMsgOptions msgopts;

	err = NULL;
	rv  = FALSE;

	msgopts = mu_config_get_msg_options(opts);

	filepath = mu_msg_part_get_path(msg, msgopts, targetdir, partidx, &err);
	if (!filepath)
		goto exit;

	if (!mu_msg_part_save(msg, msgopts, filepath, partidx, &err))
		goto exit;

	if (opts->play)
		rv = mu_util_play(filepath, TRUE, FALSE, &err);
	else
		rv = TRUE;
exit:
	if (err) {
		g_printerr("error with MIME-part: %s\n", err->message);
		g_clear_error(&err);
	}

	g_free(filepath);
	return rv;
}

static gboolean
save_numbered_parts(MuMsg* msg, const MuConfig* opts)
{
	gboolean rv;
	char **  parts, **cur;

	parts = g_strsplit(opts->parts, ",", 0);

	for (rv = TRUE, cur = parts; cur && *cur; ++cur) {
		unsigned idx;
		int      i;
		char*    endptr;

		idx = (unsigned)(i = strtol(*cur, &endptr, 10));
		if (i < 0 || *cur == endptr) {
			g_printerr("invalid MIME-part index '%s'\n", *cur);
			rv = FALSE;
			break;
		}

		if (!save_part(msg, opts->targetdir, idx, opts)) {
			g_printerr("failed to save MIME-part %d\n", idx);
			rv = FALSE;
			break;
		}
	}

	g_strfreev(parts);
	return rv;
}

static GRegex*
anchored_regex(const char* pattern)
{
	GRegex* rx;
	GError* err;
	gchar*  anchored;

	anchored = g_strdup_printf("%s%s%s",
	                           pattern[0] == '^' ? "" : "^",
	                           pattern,
	                           pattern[strlen(pattern) - 1] == '$' ? "" : "$");

	err = NULL;
	rx  = g_regex_new(anchored,
                         (GRegexCompileFlags)(G_REGEX_CASELESS | G_REGEX_OPTIMIZE),
                         (GRegexMatchFlags)0,
                         &err);
	g_free(anchored);

	if (!rx) {
		g_printerr("error in regular expression '%s': %s\n",
		           pattern,
		           err->message ? err->message : "error");
		g_error_free(err);
		return NULL;
	}

	return rx;
}

static gboolean
save_part_with_filename(MuMsg* msg, const char* pattern, const MuConfig* opts)
{
	GSList *     lst, *cur;
	GRegex*      rx;
	gboolean     rv;
	MuMsgOptions msgopts;

	msgopts = mu_config_get_msg_options(opts);

	/* 'anchor' the pattern with '^...$' if not already */
	rx = anchored_regex(pattern);
	if (!rx)
		return FALSE;

	lst = mu_msg_find_files(msg, msgopts, rx);
	g_regex_unref(rx);
	if (!lst) {
		g_printerr("no matching attachments found");
		return FALSE;
	}

	for (cur = lst, rv = TRUE; cur; cur = g_slist_next(cur))
		rv = rv && save_part(msg, opts->targetdir, GPOINTER_TO_UINT(cur->data), opts);
	g_slist_free(lst);

	return rv;
}

struct _SaveData {
	gboolean        result;
	guint           saved_num;
	const MuConfig* opts;
};
typedef struct _SaveData SaveData;

static gboolean
ignore_part(MuMsg* msg, MuMsgPart* part, SaveData* sd)
{
	/* something went wrong somewhere; stop */
	if (!sd->result)
		return TRUE;

	/* only consider leaf parts */
	if (!(part->part_type & MU_MSG_PART_TYPE_LEAF))
		return TRUE;

	/* filter out non-attachments? */
	if (!sd->opts->save_all && !(mu_msg_part_maybe_attachment(part)))
		return TRUE;

	return FALSE;
}

static void
save_part_if(MuMsg* msg, MuMsgPart* part, SaveData* sd)
{
	gchar*       filepath;
	gboolean     rv;
	GError*      err;
	MuMsgOptions msgopts;

	if (ignore_part(msg, part, sd))
		return;

	rv       = FALSE;
	filepath = NULL;
	err      = NULL;

	msgopts  = mu_config_get_msg_options(sd->opts);
	filepath = mu_msg_part_get_path(msg, msgopts, sd->opts->targetdir, part->index, &err);
	if (!filepath)
		goto exit;

	if (!mu_msg_part_save(msg, msgopts, filepath, part->index, &err))
		goto exit;

	if (sd->opts->play)
		rv = mu_util_play(filepath, TRUE, FALSE, &err);
	else
		rv = TRUE;

	++sd->saved_num;
exit:
	if (err)
		g_printerr("error saving MIME part: %s", err->message);

	g_free(filepath);
	g_clear_error(&err);

	sd->result = rv;
}

static gboolean
save_certain_parts(MuMsg* msg, const MuConfig* opts)
{
	SaveData     sd;
	MuMsgOptions msgopts;

	sd.result    = TRUE;
	sd.saved_num = 0;
	sd.opts      = opts;

	msgopts = mu_config_get_msg_options(opts);
	mu_msg_part_foreach(msg, msgopts, (MuMsgPartForeachFunc)save_part_if, &sd);

	if (sd.saved_num == 0) {
		g_printerr("no %s extracted from this message",
		           opts->save_attachments ? "attachments" : "parts");
		sd.result = FALSE;
	}

	return sd.result;
}

static gboolean
save_parts(const char* path, const char* filename, const MuConfig* opts)
{
	MuMsg*   msg;
	gboolean rv;
	GError*  err;

	err = NULL;
	msg = mu_msg_new_from_file(path, NULL, &err);
	if (!msg) {
		if (err) {
			g_printerr("error: %s", err->message);
			g_error_free(err);
		}
		return FALSE;
	}

	/* note, mu_cmd_extract already checks whether what's in opts
	 * is somewhat, so no need for extensive checking here */

	/* should we save some explicit parts? */
	if (opts->parts)
		rv = save_numbered_parts(msg, opts);
	else if (filename)
		rv = save_part_with_filename(msg, filename, opts);
	else
		rv = save_certain_parts(msg, opts);

	mu_msg_unref(msg);

	return rv;
}

#define color_maybe(C)                                                                             \
	do {                                                                                       \
		if (color)                                                                         \
			fputs((C), stdout);                                                        \
	} while (0)

static const char*
disp_str(MuMsgPartType ptype)
{
	if (ptype & MU_MSG_PART_TYPE_ATTACHMENT)
		return "attach";
	if (ptype & MU_MSG_PART_TYPE_INLINE)
		return "inline";
	return "<none>";
}

static void
each_part_show(MuMsg* msg, MuMsgPart* part, gboolean color)
{
	/* index */
	g_print("  %u ", part->index);

	/* filename */
	color_maybe(MU_COLOR_GREEN);
	{
		gchar* fname;
		fname = mu_msg_part_get_filename(part, FALSE);
		mu_util_fputs_encoded(fname ? fname : "<none>", stdout);
		g_free(fname);
	}
	/* content-type */
	color_maybe(MU_COLOR_BLUE);
	mu_util_print_encoded(" %s/%s ",
	                      part->type ? part->type : "<none>",
	                      part->subtype ? part->subtype : "<none>");

	/* /\* disposition *\/ */
	color_maybe(MU_COLOR_MAGENTA);
	mu_util_print_encoded("[%s]", disp_str(part->part_type));

	/* size */
	if (part->size > 0) {
		color_maybe(MU_COLOR_CYAN);
		g_print(" (%s)", mu_str_size_s(part->size));
	}

	color_maybe(MU_COLOR_DEFAULT);
	fputs("\n", stdout);
}

static gboolean
show_parts(const char* path, const MuConfig* opts, GError** err)
{
	MuMsg*       msg;
	MuMsgOptions msgopts;

	msg = mu_msg_new_from_file(path, NULL, err);
	if (!msg)
		return FALSE;

	msgopts = mu_config_get_msg_options(opts);

	/* TODO: update this for crypto */
	g_print("MIME-parts in this message:\n");
	mu_msg_part_foreach(msg,
	                    msgopts,
	                    (MuMsgPartForeachFunc)each_part_show,
	                    GUINT_TO_POINTER(!opts->nocolor));

	mu_msg_unref(msg);

	return TRUE;
}

static gboolean
check_params(const MuConfig* opts, GError** err)
{
	size_t param_num;

	param_num = mu_config_param_num(opts);

	if (param_num < 2) {
		mu_util_g_set_error(err, MU_ERROR_IN_PARAMETERS, "parameters missing");
		return FALSE;
	}

	if (opts->save_attachments || opts->save_all)
		if (opts->parts || param_num == 3) {
			mu_util_g_set_error(err,
			                    MU_ERROR_IN_PARAMETERS,
			                    "--save-attachments and --save-all don't "
			                    "accept a filename pattern or --parts");
			return FALSE;
		}

	if (opts->save_attachments && opts->save_all) {
		mu_util_g_set_error(err,
		                    MU_ERROR_IN_PARAMETERS,
		                    "only one of --save-attachments and"
		                    " --save-all is allowed");
		return FALSE;
	}

	return TRUE;
}

MuError
Mu::mu_cmd_extract(const MuConfig* opts, GError** err)
{
	int rv;

	g_return_val_if_fail(opts, MU_ERROR_INTERNAL);
	g_return_val_if_fail(opts->cmd == MU_CONFIG_CMD_EXTRACT, MU_ERROR_INTERNAL);

	if (!check_params(opts, err))
		return MU_ERROR_IN_PARAMETERS;

	if (!opts->params[2] && !opts->parts && !opts->save_attachments && !opts->save_all)
		/* show, don't save */
		rv = show_parts(opts->params[1], opts, err);
	else {
		rv = mu_util_check_dir(opts->targetdir, FALSE, TRUE);
		if (!rv)
			mu_util_g_set_error(err,
			                    MU_ERROR_FILE_CANNOT_WRITE,
			                    "target '%s' is not a writable directory",
			                    opts->targetdir);
		else
			rv = save_parts(opts->params[1], opts->params[2], opts); /* save */
	}

	return rv ? MU_OK : MU_ERROR;
}