/*
 * dselect - Debian package maintenance user interface
 * methparse.cc - access method list parsing
 *
 * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
 * Copyright © 2008-2011, 2013-2015 Guillem Jover <guillem@debian.org>
 *
 * This 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 2 of the License, or
 * (at your option) any later version.
 *
 * This 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, see <https://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <compat.h>

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

#include <errno.h>
#include <limits.h>
#include <string.h>
#include <dirent.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>

#include <dpkg/i18n.h>
#include <dpkg/c-ctype.h>
#include <dpkg/dpkg.h>
#include <dpkg/dpkg-db.h>
#include <dpkg/file.h>

#include "dselect.h"
#include "bindings.h"
#include "method.h"

int noptions = 0;
struct dselect_option *options = nullptr;
struct dselect_option *coption = nullptr;
struct method *methods = nullptr;

static void DPKG_ATTR_NORET
badmethod(varbuf &pathname, const char *why)
{
	ohshit(_("syntax error in method options file '%s' -- %s"),
	       pathname.str(), why);
}

static void DPKG_ATTR_NORET
eofmethod(varbuf &pathname, FILE *f, const char *why)
{
	if (ferror(f))
		ohshite(_("error reading options file '%s'"),
		        pathname.str());
	badmethod(pathname, why);
}

// TODO: Refactor to reduce nesting levels.
void
readmethods(const char *pathbase, dselect_option **optionspp, int *nread)
{
	static const char *const methodprograms[] = {
		METHODSETUPSCRIPT,
		METHODUPDATESCRIPT,
		METHODINSTALLSCRIPT,
		nullptr
	};
	const char *const *ccpp;
	int methodlen;
	DIR *dir;
	FILE *names;
	struct dirent *dent;
	struct varbuf vb;
	method *meth;
	dselect_option *opt;

	varbuf path;
	path += pathbase;
	path += "/";

	dir = opendir(path.str());
	if (!dir) {
		if (errno == ENOENT)
			return;
		ohshite(_("unable to read '%s' directory for reading methods"),
		        path.str());
	}

	debug(dbg_general, "readmethods('%s',...) directory open", pathbase);

	while ((dent = readdir(dir)) != nullptr) {
		int c = dent->d_name[0];

		debug(dbg_general, "readmethods('%s',...) considering '%s' ...",
		      pathbase, dent->d_name);
		if (c != '_' && !c_isalpha(c))
			continue;

		char *p = dent->d_name + 1;
		while ((c = *p) != 0 && c_isalnum(c) && c != '_')
			p++;
		if (c)
			continue;

		methodlen = strlen(dent->d_name);
		if (methodlen > IMETHODMAXLEN)
			ohshit(_("method '%s' has name that is too long "
			         "(%d > %d characters)"),
			       dent->d_name, methodlen, IMETHODMAXLEN);

		// FIXME: Add localized method support.

		path.reset();
		path += pathbase;
		path += "/";
		path += dent->d_name;
		path += "/";

		varbuf pathmeth;

		for (ccpp = methodprograms; *ccpp; ccpp++) {
			pathmeth = path;
			pathmeth += *ccpp;
			if (access(pathmeth.str(), R_OK | X_OK))
				ohshite(_("unable to access method script '%s'"),
				        pathmeth.str());
		}
		debug(dbg_general,
		      " readmethods('%s',...) scripts ok", pathbase);

		varbuf pathopts;
		pathopts = path;
		pathopts += METHODOPTIONSFILE;
		names = fopen(pathopts.str(), "r");
		if (!names)
			ohshite(_("unable to read method options file '%s'"),
			        pathopts.str());

		meth = new method;
		meth->name = varbuf(dent->d_name);
		meth->path = path;
		meth->next = methods;
		meth->prev = nullptr;
		if (methods)
			methods->prev = meth;
		methods = meth;
		debug(dbg_general,
		      " readmethods('%s',...) new method name='%s' path='%s'",
		      pathbase, meth->name.str(), meth->path.str());

		while ((c = fgetc(names)) != EOF) {
			if (c_isspace(c))
				continue;

			opt = new dselect_option;
			opt->meth = meth;
			vb.reset();
			do {
				if (!c_isdigit(c))
					badmethod(pathopts, _("non-digit where digit wanted"));
				vb += c;
				c = fgetc(names);
				if (c == EOF)
					eofmethod(pathopts, names, _("end of file in index string"));
			} while (!c_isspace(c));
			if (vb.len() > OPTIONINDEXMAXLEN)
				badmethod(pathopts, _("index string too long"));
			opt->index = vb;
			do {
				if (c == '\n')
					badmethod(pathopts, _("newline before option name start"));
				c = fgetc(names);
				if (c == EOF)
					eofmethod(pathopts, names, _("end of file before option name start"));
			} while (c_isspace(c));
			vb.reset();
			if (!c_isalpha(c) && c != '_')
				badmethod(pathopts, _("nonalpha where option name start wanted"));
			do {
				if (!c_isalnum(c) && c != '_')
					badmethod(pathopts, _("non-alphanum in option name"));
				vb += c;
				c = fgetc(names);
				if (c == EOF)
					eofmethod(pathopts, names, _("end of file in option name"));
			} while (!c_isspace(c));
			opt->name = vb;
			do {
				if (c == '\n')
					badmethod(pathopts, _("newline before summary"));
				c = fgetc(names);
				if (c == EOF)
					eofmethod(pathopts, names, _("end of file before summary"));
			} while (c_isspace(c));
			vb.reset();
			do {
				vb += c;
				c = fgetc(names);
				if (c == EOF)
					eofmethod(pathopts, names, _("end of file in summary - missing newline"));
			} while (c != '\n');
			opt->summary = vb;

			varbuf pathoptsdesc;
			pathoptsdesc += pathopts;
			pathoptsdesc += OPTIONSDESCPFX;
			pathoptsdesc += opt->name;

			dpkg_error err = DPKG_ERROR_INIT;

			if (file_slurp(pathoptsdesc.str(), &opt->description, &err) < 0) {
				if (err.syserrno != ENOENT)
					dpkg_error_print(&err, _("cannot load option description file '%s'"),
					                       pathoptsdesc.str());
			}

			debug(dbg_general,
			      " readmethods('%s',...) new option index='%s' name='%s'"
			      " summary='%.20s' len(description=%s)=%zu method name='%s'"
			      " path='%s'",
			      pathbase,
			      opt->index.str(),
			      opt->name.str(),
			      opt->summary.str(),
			      opt->description.len() ? "'...'" : "<none>",
			      opt->description.len() ? opt->description.len() : -1,
			      opt->meth->name.str(),
			      opt->meth->path.str());

			dselect_option **optinsert = optionspp;
			while (*optinsert &&
			       strcmp(opt->index.str(), (*optinsert)->index.str()) > 0)
				optinsert = &(*optinsert)->next;
			opt->next = *optinsert;
			*optinsert = opt;
			(*nread)++;
		}
		if (ferror(names))
			ohshite(_("error during read of method options file '%s'"),
			        pathopts.str());
		fclose(names);
	}
	closedir(dir);
	debug(dbg_general, "readmethods('%s',...) done", pathbase);
}

static char *methoptfile = nullptr;

void
getcurrentopt()
{
	char methoptbuf[IMETHODMAXLEN + 1 + IOPTIONMAXLEN + 2];
	FILE *cmo;
	int l;
	char *p;

	if (methoptfile == nullptr)
		methoptfile = dpkg_db_get_path(CMETHOPTFILE);

	coption = nullptr;
	cmo = fopen(methoptfile, "r");
	if (!cmo) {
		if (errno == ENOENT)
			return;
		ohshite(_("unable to open current option file '%s'"),
		        methoptfile);
	}
	debug(dbg_general, "getcurrentopt() cmethopt open");

	if (!fgets(methoptbuf, sizeof(methoptbuf), cmo)) {
		fclose(cmo);
		return;
	}
	if (fgetc(cmo) != EOF) {
		fclose(cmo);
		return;
	}
	if (!feof(cmo)) {
		fclose(cmo);
		return;
	}
	debug(dbg_general, "getcurrentopt() cmethopt eof");
	fclose(cmo);

	debug(dbg_general, "getcurrentopt() cmethopt read");
	l = strlen(methoptbuf);
	if (!l || methoptbuf[l - 1] != '\n')
		return;
	methoptbuf[--l] = 0;
	debug(dbg_general, "getcurrentopt() cmethopt len and newline");

	p = strchr(methoptbuf, ' ');
	if (!p)
		return;
	debug(dbg_general, "getcurrentopt() cmethopt space");

	*p++ = 0;
	debug(dbg_general, "getcurrentopt() cmethopt meth name '%s'",
	      methoptbuf);
	method *meth = methods;
	while (meth && strcmp(methoptbuf, meth->name.str()))
		meth = meth->next;
	if (!meth)
		return;

	debug(dbg_general, "getcurrentopt() cmethopt meth found; opt '%s'", p);
	dselect_option *opt = options;
	while (opt && (opt->meth != meth || strcmp(p, opt->name.str())))
		opt = opt->next;
	if (!opt)
		return;

	debug(dbg_general, "getcurrentopt() cmethopt opt found");
	coption = opt;
}

void
writecurrentopt()
{
	struct atomic_file *file;

	if (methoptfile == nullptr)
		internerr("method options filename is nullptr");

	file = atomic_file_new(methoptfile, ATOMIC_FILE_NORMAL);
	atomic_file_open(file);
	if (fprintf(file->fp, "%s %s\n", coption->meth->name.str(), coption->name.str()) == EOF)
		ohshite(_("unable to write new option to '%s'"),
		        file->name_new);
	atomic_file_close(file);
	atomic_file_commit(file);
	atomic_file_free(file);
}