/*-
 * Copyright (c) 2013 Juan Romero Pardines.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <errno.h>

#include "xbps_api_impl.h"

/*
 * Verify reverse dependencies for packages in transaction.
 * This will catch cases where a package update would break its reverse dependencies:
 *
 * 	- foo-1.0 is being updated to 2.0.
 * 	- baz-1.1 depends on foo<2.0.
 * 	- foo is updated to 2.0, hence baz-1.1 is currently broken.
 *
 * Abort transaction if such case is found.
 */
static bool
check_virtual_pkgs(struct xbps_handle *xhp,
		   xbps_dictionary_t trans_pkgd,
		   xbps_dictionary_t rev_pkgd)
{
	xbps_array_t provides, rundeps, mdeps;
	const char *pkgver, *revpkgver, *pkgpattern;
	char *pkgname, *vpkgname, *vpkgver, *str;
	unsigned int i, x;
	bool matched = false;

	provides = xbps_dictionary_get(trans_pkgd, "provides");
	for (i = 0; i < xbps_array_count(provides); i++) {
		char *tmp = NULL;

		xbps_array_get_cstring(provides, i, &vpkgver);
		if (strchr(vpkgver, '_') == NULL) {
			tmp = xbps_xasprintf("%s_1", vpkgver);
			vpkgver = strdup(tmp);
		}
		vpkgname = xbps_pkg_name(vpkgver);
		assert(vpkgname);
		rundeps = xbps_dictionary_get(rev_pkgd, "run_depends");
		for (x = 0; x < xbps_array_count(rundeps); x++) {
			xbps_array_get_cstring_nocopy(rundeps, x, &pkgpattern);
			if (((pkgname = xbps_pkgpattern_name(pkgpattern)) == NULL) &&
			    ((pkgname = xbps_pkg_name(pkgpattern)) == NULL))
				continue;

			if (strcmp(vpkgname, pkgname)) {
				free(pkgname);
				continue;
			}
			free(pkgname);
			if (xbps_pkgpattern_match(vpkgver, pkgpattern))
				continue;

			mdeps = xbps_dictionary_get(xhp->transd, "missing_deps");
			xbps_dictionary_get_cstring_nocopy(trans_pkgd, "pkgver", &pkgver);
			xbps_dictionary_get_cstring_nocopy(rev_pkgd, "pkgver", &revpkgver);
			str = xbps_xasprintf("CONFLICT: `%s' update "
			    "breaks `%s', needs `%s' virtual pkg (got `%s`)",
			    pkgver, revpkgver, pkgpattern, vpkgver);
			xbps_array_add_cstring(mdeps, str);
			free(str);
			matched = true;
		}
		free(vpkgver);
	}
	return matched;
}

void HIDDEN
xbps_transaction_revdeps(struct xbps_handle *xhp)
{
	xbps_array_t mdeps, unsorted, pkgrdeps, rundeps;
	xbps_dictionary_t revpkgd;
	xbps_object_t obj;
	const char *pkgver, *revpkgver, *curpkgver, *tract;
	char *pkgname, *str;
	unsigned int i, x;

	unsorted = xbps_dictionary_get(xhp->transd, "unsorted_deps");

	for (i = 0; i < xbps_array_count(unsorted); i++) {
		obj = xbps_array_get(unsorted, i);
		/*
		 * Only check packages in transaction being updated.
		 */
		xbps_dictionary_get_cstring_nocopy(obj, "transaction", &tract);
		if (strcmp(tract, "update"))
			continue;
		/*
		 * if pkg in transaction is not installed,
		 * pass to next one.
		 */
		xbps_dictionary_get_cstring_nocopy(obj, "pkgver", &pkgver);
		pkgname = xbps_pkg_name(pkgver);
		assert(pkgname);
		if (xbps_pkg_is_installed(xhp, pkgname) == 0) {
			free(pkgname);
			continue;
		}
		/*
		 * If pkg is installed but does not have revdeps,
		 * pass to next one.
		 */
		pkgrdeps = xbps_pkgdb_get_pkg_revdeps(xhp, pkgname);
		if (!xbps_array_count(pkgrdeps)) {
			free(pkgname);
			continue;
		}
		free(pkgname);
		/*
		 * Time to validate revdeps for current pkg.
		 */
		for (x = 0; x < xbps_array_count(pkgrdeps); x++) {
			xbps_array_get_cstring_nocopy(pkgrdeps, x, &curpkgver);
			revpkgd = xbps_pkgdb_get_pkg(xhp, curpkgver);
			/*
			 * First try to match any supported virtual package.
			 */
			if (check_virtual_pkgs(xhp, obj, revpkgd))
				continue;
			/*
			 * Try to match real dependencies.
			 */
			rundeps = xbps_dictionary_get(revpkgd, "run_depends");
			if (xbps_match_pkgdep_in_array(rundeps, pkgver))
				continue;
			/*
			 * Installed package conflicts with package
			 * in transaction being updated, check
			 * if a new version of this conflicting package
			 * is in the transaction.
			 */
			pkgname = xbps_pkg_name(curpkgver);
			if (xbps_find_pkg_in_array(unsorted, pkgname)) {
				free(pkgname);
				continue;
			}
			free(pkgname);
			mdeps = xbps_dictionary_get(xhp->transd, "missing_deps");
			xbps_dictionary_get_cstring_nocopy(revpkgd,
			    "pkgver", &revpkgver);
			str = xbps_xasprintf("CONFLICT: `%s' "
			    "update breaks `%s', needs `%s'",
			    pkgver, revpkgver, curpkgver);
			xbps_array_add_cstring(mdeps, str);
			free(str);
		}

	}
}