/*
 *  sync.c
 *
 *  Copyright (c) 2002-2007 by Judd Vinet <jvinet@zeroflux.org>
 *  Copyright (c) 2005 by Aurelien Foret <orelien@chez.com>
 *  Copyright (c) 2005 by Christian Hamar <krics@linuxforum.hu>
 *  Copyright (c) 2005, 2006 by Miklos Vajna <vmiklos@frugalware.org>
 *
 *  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 2 of the License, 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, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include <sys/types.h> /* off_t */
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <dirent.h>

/* libalpm */
#include "sync.h"
#include "alpm_list.h"
#include "log.h"
#include "package.h"
#include "db.h"
#include "cache.h"
#include "deps.h"
#include "conflict.h"
#include "trans.h"
#include "util.h"
#include "handle.h"
#include "alpm.h"
#include "dload.h"
#include "delta.h"

pmsyncpkg_t *_alpm_sync_new(pmpkgreason_t newreason, pmpkg_t *spkg, alpm_list_t *removes)
{
	pmsyncpkg_t *sync;

	ALPM_LOG_FUNC;

	CALLOC(sync, 1, sizeof(pmsyncpkg_t), RET_ERR(PM_ERR_MEMORY, NULL));

	sync->newreason = newreason;
	sync->pkg = spkg;
	sync->removes = removes;

	return(sync);
}

void _alpm_sync_free(pmsyncpkg_t *sync)
{
	ALPM_LOG_FUNC;

	if(sync == NULL) {
		return;
	}

	alpm_list_free(sync->removes);
	sync->removes = NULL;
	FREE(sync);
}

/* Find recommended replacements for packages during a sync.
 */
static int find_replacements(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync)
{
	alpm_list_t *i, *j, *k; /* wow */

	ALPM_LOG_FUNC;

	/* check for "recommended" package replacements */
	_alpm_log(PM_LOG_DEBUG, "checking for package replacements\n");
	for(i = dbs_sync; i; i = i->next) {
		pmdb_t *db = i->data;

		/* for each db, check each package's REPLACES list */
		for(j = _alpm_db_get_pkgcache(db); j; j = j->next) {
			pmpkg_t *spkg = j->data;

			for(k = alpm_pkg_get_replaces(spkg); k; k = k->next) {
				const char *replacement = k->data;

				pmpkg_t *lpkg = _alpm_db_get_pkgfromcache(db_local, replacement);
				if(!lpkg) {
					continue;
				}

				_alpm_log(PM_LOG_DEBUG, "checking replacement '%s' for package '%s'\n",
						replacement, spkg->name);
				/* ignore if EITHER the local or replacement package are to be ignored */
				if(_alpm_pkg_should_ignore(spkg) || _alpm_pkg_should_ignore(lpkg)) {
					_alpm_log(PM_LOG_WARNING, _("%s-%s: ignoring package upgrade (to be replaced by %s-%s)\n"),
										alpm_pkg_get_name(lpkg), alpm_pkg_get_version(lpkg),
										alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
				} else {
					int doreplace = 0;
					QUESTION(trans, PM_TRANS_CONV_REPLACE_PKG, lpkg, spkg, db->treename, &doreplace);
					if(!doreplace) {
						continue;
					}

					/* if confirmed, add this to the 'final' list, designating 'lpkg' as
					 * the package to replace.
					 */
					pmsyncpkg_t *sync;

					/* check if spkg->name is already in the packages list. */
					/* TODO: same package name doesn't mean same package */
					sync = _alpm_sync_find(trans->packages, alpm_pkg_get_name(spkg));
					if(sync) {
						/* found it -- just append to the removes list */
						sync->removes = alpm_list_add(sync->removes, lpkg);
						/* check the to-be-replaced package's reason field */
						if(lpkg->reason == PM_PKG_REASON_EXPLICIT) {
							sync->newreason = PM_PKG_REASON_EXPLICIT;
						}
					} else {
						/* none found -- enter pkg into the final sync list */
						/* copy over reason */
						sync = _alpm_sync_new(alpm_pkg_get_reason(lpkg), spkg, NULL);
						if(sync == NULL) {
							pm_errno = PM_ERR_MEMORY;
							return(-1);
						}
						sync->removes = alpm_list_add(NULL, lpkg);
						_alpm_log(PM_LOG_DEBUG, "adding package %s-%s to the transaction targets\n",
									alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
						trans->packages = alpm_list_add(trans->packages, sync);
					}
					_alpm_log(PM_LOG_DEBUG, "%s-%s elected for removal (to be replaced by %s-%s)\n",
							alpm_pkg_get_name(lpkg), alpm_pkg_get_version(lpkg),
							alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
				}
			}
		}
	}
	return(0);
}

/** Check for new version of pkg in sync repos
 * (only the first occurrence is considered in sync)
 */
pmpkg_t SYMEXPORT *alpm_sync_newversion(pmpkg_t *pkg, alpm_list_t *dbs_sync)
{
	alpm_list_t *i;
	pmpkg_t *spkg = NULL;
	int cmp;

	for(i = dbs_sync; !spkg && i; i = i->next) {
		spkg = _alpm_db_get_pkgfromcache(i->data, alpm_pkg_get_name(pkg));
	}

	if(spkg == NULL) {
		_alpm_log(PM_LOG_DEBUG, "'%s' not found in sync db => no upgrade\n",
				alpm_pkg_get_name(pkg));
		return(NULL);
	}

	/* compare versions and see if spkg is an upgrade */
	cmp = _alpm_pkg_compare_versions(spkg, pkg);
	if(cmp > 0) {
		_alpm_log(PM_LOG_DEBUG, "new version of '%s' found (%s => %s)\n",
					alpm_pkg_get_name(pkg), alpm_pkg_get_version(pkg),
					alpm_pkg_get_version(spkg));
		return(spkg);
	}
	if (cmp < 0) {
			pmdb_t *db = spkg->origin_data.db;
			_alpm_log(PM_LOG_WARNING, _("%s: local (%s) is newer than %s (%s)\n"),
					alpm_pkg_get_name(pkg), alpm_pkg_get_version(pkg),
					alpm_db_get_name(db), alpm_pkg_get_version(spkg));
	}
	return(NULL);
}

int _alpm_sync_sysupgrade(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync)
{
	alpm_list_t *i, *j, *replaced = NULL;

	ALPM_LOG_FUNC;

	/* check for "recommended" package replacements */
	if(find_replacements(trans, db_local, dbs_sync)) {
		return(-1);
	}

	/* compute the to-be-replaced packages for efficiency */
	for(i = trans->packages; i; i = i->next) {
		pmsyncpkg_t *sync = i->data;
		for(j = sync->removes; j; j = j->next) {
			replaced = alpm_list_add(replaced, j->data);
		}
	}

	/* for all not-replaced local package we check for upgrade */
	_alpm_log(PM_LOG_DEBUG, "checking for package upgrades\n");
	for(i = _alpm_db_get_pkgcache(db_local); i; i = i->next) {
		pmpkg_t *local = i->data;

		if(_alpm_pkg_find(replaced, alpm_pkg_get_name(local))) {
			_alpm_log(PM_LOG_DEBUG, "'%s' is already elected for removal -- skipping\n",
					alpm_pkg_get_name(local));
			continue;
		}

		pmpkg_t *spkg = alpm_sync_newversion(local, dbs_sync);
		if(spkg) {
			/* we found a new version */
			/* skip packages in IgnorePkg or in IgnoreGroup */
			if(_alpm_pkg_should_ignore(spkg)) {
				_alpm_log(PM_LOG_WARNING, _("%s: ignoring package upgrade (%s => %s)\n"),
						alpm_pkg_get_name(local), alpm_pkg_get_version(local),
						alpm_pkg_get_version(spkg));
				continue;
			}

			/* add the upgrade package to our pmsyncpkg_t list */
			if(_alpm_sync_find(trans->packages, alpm_pkg_get_name(spkg))) {
				/* avoid duplicated targets */
				continue;
			}
			/* we can set any reason here, it will be overridden by add_commit */
			pmsyncpkg_t *sync = _alpm_sync_new(PM_PKG_REASON_EXPLICIT, spkg, NULL);
			if(sync == NULL) {
				alpm_list_free(replaced);
				return(-1);
			}
			_alpm_log(PM_LOG_DEBUG, "adding package %s-%s to the transaction targets\n",
							alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
			trans->packages = alpm_list_add(trans->packages, sync);
		}
	}

	alpm_list_free(replaced);
	return(0);
}

int _alpm_sync_addtarget(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync, char *name)
{
	char *targline;
	char *targ;
	alpm_list_t *j;
	pmpkg_t *local, *spkg;
	pmdepend_t *dep; /* provisions and dependencies are also allowed */

	ALPM_LOG_FUNC;

	ASSERT(db_local != NULL, RET_ERR(PM_ERR_DB_NULL, -1));
	ASSERT(trans != NULL, RET_ERR(PM_ERR_TRANS_NULL, -1));
	ASSERT(name != NULL, RET_ERR(PM_ERR_WRONG_ARGS, -1));

	STRDUP(targline, name, RET_ERR(PM_ERR_MEMORY, -1));
	targ = strchr(targline, '/');
	if(targ) {
		/* we are looking for a package in a specific database */
		alpm_list_t *dbs = NULL;
		*targ = '\0';
		targ++;
		_alpm_log(PM_LOG_DEBUG, "searching for target '%s' in repo '%s'\n", targ, targline);
		for(j = dbs_sync; j; j = j->next) {
			pmdb_t *db = j->data;
			if(strcmp(db->treename, targline) == 0) {
				dbs = alpm_list_add(NULL, db);
				break;
			}
		}
		if(dbs == NULL) {
			_alpm_log(PM_LOG_ERROR, _("repository '%s' not found\n"), targline);
			FREE(targline);
			RET_ERR(PM_ERR_PKG_REPO_NOT_FOUND, -1);
		}
		dep = _alpm_splitdep(targ);
		spkg = _alpm_resolvedep(dep, dbs, NULL, 1);
		_alpm_dep_free(dep);
		alpm_list_free(dbs);
	} else {
		dep = _alpm_splitdep(targline);
		spkg = _alpm_resolvedep(dep, dbs_sync, NULL, 1);
		_alpm_dep_free(dep);
	}
	FREE(targline);

	if(spkg == NULL) {
		RET_ERR(PM_ERR_PKG_NOT_FOUND, -1);
	}

	if(_alpm_sync_find(trans->packages, alpm_pkg_get_name(spkg))) {
		RET_ERR(PM_ERR_TRANS_DUP_TARGET, -1);
	}

	local = _alpm_db_get_pkgfromcache(db_local, alpm_pkg_get_name(spkg));
	if(local) {
		int cmp = _alpm_pkg_compare_versions(spkg, local);
		if(cmp == 0) {
			if(trans->flags & PM_TRANS_FLAG_NEEDED) {
				/* with the NEEDED flag, packages up to date are not reinstalled */
				_alpm_log(PM_LOG_WARNING, _("%s-%s is up to date -- skipping\n"),
						alpm_pkg_get_name(local), alpm_pkg_get_version(local));
				return(0);
			} else {
				_alpm_log(PM_LOG_WARNING, _("%s-%s is up to date -- reinstalling\n"),
						alpm_pkg_get_name(local), alpm_pkg_get_version(local));

			}
		} else if(cmp < 0) {
			/* local version is newer */
			_alpm_log(PM_LOG_WARNING, _("downgrading package %s (%s => %s)\n"),
					alpm_pkg_get_name(local), alpm_pkg_get_version(local),
					alpm_pkg_get_version(spkg));
		}
	}

	/* add the package to the transaction */
	pmsyncpkg_t *sync = _alpm_sync_new(PM_PKG_REASON_EXPLICIT, spkg, NULL);
	if(sync == NULL) {
		return(-1);
	}
	_alpm_log(PM_LOG_DEBUG, "adding package %s-%s to the transaction targets\n",
						alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
	trans->packages = alpm_list_add(trans->packages, sync);

	return(0);
}

/* Helper functions for alpm_list_remove
*/
static int syncpkg_cmp(const void *s1, const void *s2)
{
	const pmsyncpkg_t *sp1 = s1;
	const pmsyncpkg_t *sp2 = s2;
	pmpkg_t *p1 = alpm_sync_get_pkg(sp1);
	pmpkg_t *p2 = alpm_sync_get_pkg(sp2);
	return(strcmp(alpm_pkg_get_name(p1), alpm_pkg_get_name(p2)));
}

/** Compute the size of the files that will be downloaded to install a
 * package.
 * @param newpkg the new package to upgrade to
 */
static int compute_download_size(pmpkg_t *newpkg)
{
	const char *fname;
	char *fpath;
	off_t size = 0;

	fname = alpm_pkg_get_filename(newpkg);
	ASSERT(fname != NULL, RET_ERR(PM_ERR_PKG_INVALID_NAME, -1));
	fpath = _alpm_filecache_find(fname);

	if(fpath) {
		FREE(fpath);
		size = 0;
	} else if(handle->usedelta) {
		off_t dltsize;
		off_t pkgsize = alpm_pkg_get_size(newpkg);

		dltsize = _alpm_shortest_delta_path(
			alpm_pkg_get_deltas(newpkg),
			alpm_pkg_get_filename(newpkg),
			alpm_pkg_get_md5sum(newpkg),
			&newpkg->delta_path);

		if(newpkg->delta_path && (dltsize < pkgsize * MAX_DELTA_RATIO)) {
			_alpm_log(PM_LOG_DEBUG, "using delta size\n");
			size = dltsize;
		} else {
			_alpm_log(PM_LOG_DEBUG, "using package size\n");
			size = alpm_pkg_get_size(newpkg);
			alpm_list_free(newpkg->delta_path);
			newpkg->delta_path = NULL;
		}
	} else {
		size = alpm_pkg_get_size(newpkg);
	}

	_alpm_log(PM_LOG_DEBUG, "setting download size %lld for pkg %s\n",
			(long long)size, alpm_pkg_get_name(newpkg));

	newpkg->download_size = size;
	return(0);
}

int _alpm_sync_prepare(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync, alpm_list_t **data)
{
	alpm_list_t *deps = NULL;
	alpm_list_t *list = NULL, *remove = NULL; /* allow checkdeps usage with trans->packages */
	alpm_list_t *unresolvable = NULL;
	alpm_list_t *i, *j;
	int ret = 0;

	ALPM_LOG_FUNC;

	ASSERT(db_local != NULL, RET_ERR(PM_ERR_DB_NULL, -1));
	ASSERT(trans != NULL, RET_ERR(PM_ERR_TRANS_NULL, -1));

	if(data) {
		*data = NULL;
	}

	if(trans->flags & PM_TRANS_FLAG_NODEPS) {
		for(i = trans->packages; i; i = i->next) {
			pmsyncpkg_t *sync = i->data;
			list = alpm_list_add(list, sync->pkg);
		}
	} else {
		/* Build up list by repeatedly resolving each transaction package */
		/* Resolve targets dependencies */
		EVENT(trans, PM_TRANS_EVT_RESOLVEDEPS_START, NULL, NULL);
		_alpm_log(PM_LOG_DEBUG, "resolving target's dependencies\n");

		/* build remove list for resolvedeps */
		for(i = trans->packages; i; i = i->next) {
			pmsyncpkg_t *sync = i->data;
			for(j = sync->removes; j; j = j->next) {
				remove = alpm_list_add(remove, j->data);
			}
		}

		/* Resolve packages in the transaction one at a time, in addtion
		   building up a list of packages which could not be resolved. */
		for(i = trans->packages; i; i = i->next) {
			pmpkg_t *pkg = ((pmsyncpkg_t *) i->data)->pkg;
			if(_alpm_resolvedeps(db_local, dbs_sync, pkg, &list, remove, data) == -1) {
				unresolvable = alpm_list_add(unresolvable, pkg);
			}
			/* Else, [list] now additionally contains [pkg] and all of its
			   dependencies not already on the list */
		}

		/* If there were unresolvable top-level packages, prompt the user to
		   see if they'd like to ignore them rather than failing the sync */
		if(unresolvable != NULL) {
			int remove_unresolvable = 0;
			QUESTION(handle->trans, PM_TRANS_CONV_REMOVE_PKGS, unresolvable,
					NULL, NULL, &remove_unresolvable);
			if (remove_unresolvable) {
				/* User wants to remove the unresolvable packages from the
				   transaction, so simply drop the unresolvable list.  The
				   packages will be removed from the actual transaction when
				   the transaction packages are replaced with a
				   dependency-reordered list below */
				alpm_list_free(unresolvable);
				unresolvable = NULL;
			}
			else {
				/* pm_errno is set by resolvedeps */
				ret = -1;
				goto cleanup;
			}
		}

		/* Add all packages which were "pulled" (i.e. weren't already in the
		   transaction) to the transaction in pmsyncpkg_t structures */
		for(i = list; i; i = i->next) {
			pmpkg_t *spkg = i->data;
			for(j = trans->packages; j; j = j->next) {
				if(_alpm_pkg_cmp(spkg, ((pmsyncpkg_t *) j->data)->pkg) == 0) {
					spkg = NULL;
					break;
				}
			}
			if (spkg == NULL) {
				continue;
			}

			pmsyncpkg_t *sync = _alpm_sync_new(PM_PKG_REASON_DEPEND, spkg, NULL);
			if(sync == NULL) {
				ret = -1;
				goto cleanup;
			}
			trans->packages = alpm_list_add(trans->packages, sync);
			_alpm_log(PM_LOG_DEBUG, "adding package %s-%s to the transaction targets\n",
								alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
		}

		/* re-order w.r.t. dependencies */
		alpm_list_t *sortlist = _alpm_sortbydeps(list, 0);
		alpm_list_t *newpkgs = NULL;
		for(i = sortlist; i; i = i->next) {
			for(j = trans->packages; j; j = j->next) {
				pmsyncpkg_t *s = j->data;
				if(s->pkg == i->data) {
					newpkgs = alpm_list_add(newpkgs, s);
					break;
				}
			}
		}
		alpm_list_free(sortlist);
		alpm_list_free(trans->packages);
		trans->packages = newpkgs;

		EVENT(trans, PM_TRANS_EVT_RESOLVEDEPS_DONE, NULL, NULL);
	}

	if(!(trans->flags & PM_TRANS_FLAG_NOCONFLICTS)) {
		/* check for inter-conflicts and whatnot */
		EVENT(trans, PM_TRANS_EVT_INTERCONFLICTS_START, NULL, NULL);

		_alpm_log(PM_LOG_DEBUG, "looking for conflicts\n");

		/* 1. check for conflicts in the target list */
		_alpm_log(PM_LOG_DEBUG, "check targets vs targets\n");
		deps = _alpm_innerconflicts(list);

		for(i = deps; i; i = i->next) {
			pmconflict_t *conflict = i->data;
			pmsyncpkg_t *rsync, *sync, *sync1, *sync2;

			/* have we already removed one of the conflicting targets? */
			sync1 = _alpm_sync_find(trans->packages, conflict->package1);
			sync2 = _alpm_sync_find(trans->packages, conflict->package2);
			if(!sync1 || !sync2) {
				continue;
			}

			_alpm_log(PM_LOG_DEBUG, "conflicting packages in the sync list: '%s' <-> '%s'\n",
					conflict->package1, conflict->package2);

			/* if sync1 provides sync2, we remove sync2 from the targets, and vice versa */
			pmdepend_t *dep1 = _alpm_splitdep(conflict->package1);
			pmdepend_t *dep2 = _alpm_splitdep(conflict->package2);
			if(alpm_depcmp(sync1->pkg, dep2)) {
				rsync = sync2;
				sync = sync1;
			} else if(alpm_depcmp(sync2->pkg, dep1)) {
				rsync = sync1;
				sync = sync2;
			} else {
				_alpm_log(PM_LOG_ERROR, _("unresolvable package conflicts detected\n"));
				pm_errno = PM_ERR_CONFLICTING_DEPS;
				ret = -1;
				if(data) {
					pmconflict_t *newconflict = _alpm_conflict_dup(conflict);
					if(newconflict) {
						*data = alpm_list_add(*data, newconflict);
					}
				}
				alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_conflict_free);
				alpm_list_free(deps);
				_alpm_dep_free(dep1);
				_alpm_dep_free(dep2);
				goto cleanup;
			}
			_alpm_dep_free(dep1);
			_alpm_dep_free(dep2);

			/* Prints warning */
			_alpm_log(PM_LOG_WARNING,
					_("removing '%s' from target list because it conflicts with '%s'\n"),
					rsync->pkg->name, sync->pkg->name);
			void *vpkg;
			trans->packages = alpm_list_remove(trans->packages, rsync,
					syncpkg_cmp, &vpkg);
			pmsyncpkg_t *syncpkg = vpkg;
			list = alpm_list_remove(list, syncpkg->pkg, _alpm_pkg_cmp, NULL);
			_alpm_sync_free(syncpkg);
			continue;
		}

		alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_conflict_free);
		alpm_list_free(deps);
		deps = NULL;

		/* 2. we check for target vs db conflicts (and resolve)*/
		_alpm_log(PM_LOG_DEBUG, "check targets vs db and db vs targets\n");
		deps = _alpm_outerconflicts(db_local, list);

		for(i = deps; i; i = i->next) {
			pmconflict_t *conflict = i->data;

			/* if conflict->package2 (the local package) is not elected for removal,
			   we ask the user */
			int found = 0;
			for(j = trans->packages; j && !found; j = j->next) {
				pmsyncpkg_t *sync = j->data;
				if(_alpm_pkg_find(sync->removes, conflict->package2)) {
					found = 1;
				}
			}
			if(found) {
				continue;
			}

			_alpm_log(PM_LOG_DEBUG, "package '%s' conflicts with '%s'\n",
					conflict->package1, conflict->package2);

			pmsyncpkg_t *sync = _alpm_sync_find(trans->packages, conflict->package1);
			pmpkg_t *local = _alpm_db_get_pkgfromcache(db_local, conflict->package2);
			int doremove = 0;
			QUESTION(trans, PM_TRANS_CONV_CONFLICT_PKG, conflict->package1,
								conflict->package2, NULL, &doremove);
			if(doremove) {
				/* append to the removes list */
				_alpm_log(PM_LOG_DEBUG, "electing '%s' for removal\n", conflict->package2);
				sync->removes = alpm_list_add(sync->removes, local);
			} else { /* abort */
				_alpm_log(PM_LOG_ERROR, _("unresolvable package conflicts detected\n"));
				pm_errno = PM_ERR_CONFLICTING_DEPS;
				ret = -1;
				if(data) {
					pmconflict_t *newconflict = _alpm_conflict_dup(conflict);
					if(newconflict) {
						*data = alpm_list_add(*data, newconflict);
					}
				}
				alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_conflict_free);
				alpm_list_free(deps);
				goto cleanup;
			}
		}
		EVENT(trans, PM_TRANS_EVT_INTERCONFLICTS_DONE, NULL, NULL);
		alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_conflict_free);
		alpm_list_free(deps);
	}

	if(!(trans->flags & PM_TRANS_FLAG_NODEPS)) {
		/* rebuild remove list */
		alpm_list_free(remove);
		remove = NULL;
		for(i = trans->packages; i; i = i->next) {
			pmsyncpkg_t *sync = i->data;
			for(j = sync->removes; j; j = j->next) {
				remove = alpm_list_add(remove, j->data);
			}
		}

		_alpm_log(PM_LOG_DEBUG, "checking dependencies\n");
		deps = alpm_checkdeps(_alpm_db_get_pkgcache(db_local), 1, remove, list);
		if(deps) {
			pm_errno = PM_ERR_UNSATISFIED_DEPS;
			ret = -1;
			if(data) {
				*data = deps;
			} else {
				alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_depmiss_free);
				alpm_list_free(deps);
			}
			goto cleanup;
		}
	}
	for(i = list; i; i = i->next) {
		/* update download size field */
		pmpkg_t *spkg = i->data;
		if(compute_download_size(spkg) != 0) {
			ret = -1;
			goto cleanup;
		}
	}

cleanup:
	alpm_list_free(list);
	alpm_list_free(remove);
	alpm_list_free(unresolvable);

	return(ret);
}

/** Returns the size of the files that will be downloaded to install a
 * package.
 * @param newpkg the new package to upgrade to
 * @return the size of the download
 */
off_t SYMEXPORT alpm_pkg_download_size(pmpkg_t *newpkg)
{
	return(newpkg->download_size);
}

/** Applies delta files to create an upgraded package file.
 *
 * All intermediate files are deleted, leaving only the starting and
 * ending package files.
 *
 * @param trans the transaction
 *
 * @return 0 if all delta files were able to be applied, 1 otherwise.
 */
static int apply_deltas(pmtrans_t *trans)
{
	alpm_list_t *i;
	int ret = 0;
	const char *cachedir = _alpm_filecache_setup();

	for(i = trans->packages; i; i = i->next) {
		pmsyncpkg_t *sync = i->data;
		pmpkg_t *spkg = sync->pkg;
		alpm_list_t *delta_path = spkg->delta_path;
		alpm_list_t *dlts = NULL;

		if(!delta_path) {
			continue;
		}

		for(dlts = delta_path; dlts; dlts = dlts->next) {
			pmdelta_t *d = dlts->data;
			char *delta, *from, *to;
			char command[PATH_MAX];
			int len = 0;

			delta = _alpm_filecache_find(d->delta);
			/* the initial package might be in a different cachedir */
			if(dlts == delta_path) {
				from = _alpm_filecache_find(d->from);
			} else {
				/* len = cachedir len + from len + '/' + null */
				len = strlen(cachedir) + strlen(d->from) + 2;
				CALLOC(from, len, sizeof(char), RET_ERR(PM_ERR_MEMORY, 1));
				snprintf(from, len, "%s/%s", cachedir, d->from);
			}
			len = strlen(cachedir) + strlen(d->to) + 2;
			CALLOC(to, len, sizeof(char), RET_ERR(PM_ERR_MEMORY, 1));
			snprintf(to, len, "%s/%s", cachedir, d->to);

			/* an example of the patch command: (using /cache for cachedir)
			 * xdelta patch /path/to/pacman_3.0.0-1_to_3.0.1-1-i686.delta \
			 *              /path/to/pacman-3.0.0-1-i686.pkg.tar.gz       \
			 *              /cache/pacman-3.0.1-1-i686.pkg.tar.gz
			 */

			/* build the patch command */
			snprintf(command, PATH_MAX, "xdelta patch %s %s %s", delta, from, to);

			_alpm_log(PM_LOG_DEBUG, _("command: %s\n"), command);

			EVENT(trans, PM_TRANS_EVT_DELTA_PATCH_START, d->to, d->delta);

			int retval = system(command);
			if(retval == 0) {
				EVENT(trans, PM_TRANS_EVT_DELTA_PATCH_DONE, NULL, NULL);

				/* delete the delta file */
				unlink(delta);

				/* Delete the 'from' package but only if it is an intermediate
				 * package. The starting 'from' package should be kept, just
				 * as if deltas were not used. */
				if(dlts != delta_path) {
					unlink(from);
				}
			}
			FREE(from);
			FREE(to);
			FREE(delta);

			if(retval != 0) {
				/* one delta failed for this package, cancel the remaining ones */
				EVENT(trans, PM_TRANS_EVT_DELTA_PATCH_FAILED, NULL, NULL);
				ret = 1;
				break;
			}
		}
	}

	return(ret);
}

/** Compares the md5sum of a file to the expected value.
 *
 * If the md5sum does not match, the user is asked whether the file
 * should be deleted.
 *
 * @param trans the transaction
 * @param filename the filename of the file to test
 * @param md5sum the expected md5sum of the file
 *
 * @return 0 if the md5sum matched, 1 if not, -1 in case of errors
 */
static int test_md5sum(pmtrans_t *trans, const char *filename,
		const char *md5sum)
{
	char *filepath;
	int ret;

	filepath = _alpm_filecache_find(filename);

	ret = _alpm_test_md5sum(filepath, md5sum);

	if(ret == 1) {
		int doremove = 0;
		QUESTION(trans, PM_TRANS_CONV_CORRUPTED_PKG, (char *)filename,
				NULL, NULL, &doremove);
		if(doremove) {
			unlink(filepath);
		}
	}

	FREE(filepath);

	return(ret);
}

int _alpm_sync_commit(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t **data)
{
	alpm_list_t *i, *j, *files = NULL;
	alpm_list_t *deltas = NULL;
	pmtrans_t *tr = NULL;
	int replaces = 0;
	int errors = 0;
	const char *cachedir = NULL;
	int ret = -1;

	ALPM_LOG_FUNC;

	ASSERT(trans != NULL, RET_ERR(PM_ERR_TRANS_NULL, -1));

	cachedir = _alpm_filecache_setup();
	trans->state = STATE_DOWNLOADING;

	/* Total progress - figure out the total download size if required to
	 * pass to the callback. This function is called once, and it is up to the
	 * frontend to compute incremental progress. */
	if(handle->totaldlcb) {
		off_t total_size = (off_t)0;
		/* sum up the download size for each package and store total */
		for(i = trans->packages; i; i = i->next) {
			pmsyncpkg_t *sync = i->data;
			pmpkg_t *spkg = sync->pkg;
			total_size += spkg->download_size;
		}
		handle->totaldlcb(total_size);
	}

	/* group sync records by repository and download */
	for(i = handle->dbs_sync; i; i = i->next) {
		pmdb_t *current = i->data;

		for(j = trans->packages; j; j = j->next) {
			pmsyncpkg_t *sync = j->data;
			pmpkg_t *spkg = sync->pkg;
			pmdb_t *dbs = spkg->origin_data.db;

			if(current == dbs) {
				const char *fname = NULL;

				fname = alpm_pkg_get_filename(spkg);
				ASSERT(fname != NULL, RET_ERR(PM_ERR_PKG_INVALID_NAME, -1));
				if(spkg->download_size != 0) {
					alpm_list_t *delta_path = spkg->delta_path;
					if(delta_path) {
						alpm_list_t *dlts = NULL;

						for(dlts = delta_path; dlts; dlts = dlts->next) {
							pmdelta_t *d = dlts->data;

							if(d->download_size != 0) {
								/* add the delta filename to the download list if
								 * it's not in the cache */
								files = alpm_list_add(files, strdup(d->delta));
							}

							/* keep a list of the delta files for md5sums */
							deltas = alpm_list_add(deltas, d);
						}

					} else {
						/* not using deltas, so add the file to the download list */
						files = alpm_list_add(files, strdup(fname));
					}
				}
			}
		}

		if(files) {
			EVENT(trans, PM_TRANS_EVT_RETRIEVE_START, current->treename, NULL);
			if(_alpm_download_files(files, current->servers, cachedir)) {
				_alpm_log(PM_LOG_WARNING, _("failed to retrieve some files from %s\n"),
						current->treename);
				pm_errno = PM_ERR_RETRIEVE;
				goto error;
			}
			FREELIST(files);
		}
	}

	/* clear out value to let callback know we are done */
	if(handle->totaldlcb) {
		handle->totaldlcb(0);
	}

	if(handle->usedelta) {
		int ret = 0;

		/* only output if there are deltas to work with */
		if(deltas) {
			errors = 0;
			/* Check integrity of deltas */
			EVENT(trans, PM_TRANS_EVT_DELTA_INTEGRITY_START, NULL, NULL);

			for(i = deltas; i; i = i->next) {
				pmdelta_t *d = alpm_list_getdata(i);
				const char *filename = alpm_delta_get_filename(d);
				const char *md5sum = alpm_delta_get_md5sum(d);

				if(test_md5sum(trans, filename, md5sum) != 0) {
					errors++;
					*data = alpm_list_add(*data, strdup(filename));
				}
			}
			if(errors) {
				pm_errno = PM_ERR_DLT_INVALID;
				goto error;
			}
			EVENT(trans, PM_TRANS_EVT_DELTA_INTEGRITY_DONE, NULL, NULL);

			/* Use the deltas to generate the packages */
			EVENT(trans, PM_TRANS_EVT_DELTA_PATCHES_START, NULL, NULL);
			ret = apply_deltas(trans);
			EVENT(trans, PM_TRANS_EVT_DELTA_PATCHES_DONE, NULL, NULL);

		}
		if(ret) {
			pm_errno = PM_ERR_DLT_PATCHFAILED;
			goto error;
		}
	}

	/* Check integrity of packages */
	EVENT(trans, PM_TRANS_EVT_INTEGRITY_START, NULL, NULL);

	errors = 0;
	for(i = trans->packages; i; i = i->next) {
		pmsyncpkg_t *sync = i->data;
		pmpkg_t *spkg = sync->pkg;
		const char *filename = alpm_pkg_get_filename(spkg);
		const char *md5sum = alpm_pkg_get_md5sum(spkg);

		if(test_md5sum(trans, filename, md5sum) != 0) {
			errors++;
			*data = alpm_list_add(*data, strdup(filename));
		}
	}
	if(errors) {
		pm_errno = PM_ERR_PKG_INVALID;
		goto error;
	}
	EVENT(trans, PM_TRANS_EVT_INTEGRITY_DONE, NULL, NULL);
	if(trans->flags & PM_TRANS_FLAG_DOWNLOADONLY) {
		return(0);
	}

	/* remove conflicting and to-be-replaced packages */
	trans->state = STATE_COMMITING;
	tr = _alpm_trans_new();
	if(tr == NULL) {
		_alpm_log(PM_LOG_ERROR, _("could not create removal transaction\n"));
		goto error;
	}

	if(_alpm_trans_init(tr, PM_TRANS_TYPE_REMOVE, PM_TRANS_FLAG_NODEPS, NULL, NULL, NULL) == -1) {
		_alpm_log(PM_LOG_ERROR, _("could not initialize the removal transaction\n"));
		goto error;
	}

	for(i = trans->packages; i; i = i->next) {
		pmsyncpkg_t *sync = i->data;
		alpm_list_t *j;
		for(j = sync->removes; j; j = j->next) {
			pmpkg_t *pkg = j->data;
			if(!_alpm_pkg_find(tr->packages, pkg->name)) {
				if(_alpm_trans_addtarget(tr, pkg->name) == -1) {
					goto error;
				}
				replaces++;
			}
		}
	}
	if(replaces) {
		_alpm_log(PM_LOG_DEBUG, "removing conflicting and to-be-replaced packages\n");
		if(_alpm_trans_prepare(tr, data) == -1) {
			_alpm_log(PM_LOG_ERROR, _("could not prepare removal transaction\n"));
			goto error;
		}
		/* we want the frontend to be aware of commit details */
		tr->cb_event = trans->cb_event;
		if(_alpm_trans_commit(tr, NULL) == -1) {
			_alpm_log(PM_LOG_ERROR, _("could not commit removal transaction\n"));
			goto error;
		}
	}
	_alpm_trans_free(tr);
	tr = NULL;

	/* install targets */
	_alpm_log(PM_LOG_DEBUG, "installing packages\n");
	tr = _alpm_trans_new();
	if(tr == NULL) {
		_alpm_log(PM_LOG_ERROR, _("could not create transaction\n"));
		goto error;
	}
	if(_alpm_trans_init(tr, PM_TRANS_TYPE_UPGRADE, trans->flags | PM_TRANS_FLAG_NODEPS, trans->cb_event, trans->cb_conv, trans->cb_progress) == -1) {
		_alpm_log(PM_LOG_ERROR, _("could not initialize transaction\n"));
		goto error;
	}
	for(i = trans->packages; i; i = i->next) {
		pmsyncpkg_t *sync = i->data;
		pmpkg_t *spkg = sync->pkg;
		const char *fname;
		char *fpath;

		fname = alpm_pkg_get_filename(spkg);
		if(fname == NULL) {
			goto error;
		}
		/* Loop through the cache dirs until we find a matching file */
		fpath = _alpm_filecache_find(fname);

		if(_alpm_trans_addtarget(tr, fpath) == -1) {
			FREE(fpath);
			goto error;
		}
		FREE(fpath);

		/* using alpm_list_last() is ok because addtarget() adds the new target at the
		 * end of the tr->packages list */
		spkg = alpm_list_last(tr->packages)->data;
		spkg->reason = sync->newreason;
	}
	if(_alpm_trans_prepare(tr, data) == -1) {
		_alpm_log(PM_LOG_ERROR, _("could not prepare transaction\n"));
		/* pm_errno is set by trans_prepare */
		goto error;
	}
	if(_alpm_trans_commit(tr, NULL) == -1) {
		_alpm_log(PM_LOG_ERROR, _("could not commit transaction\n"));
		goto error;
	}
	ret = 0;

error:
	FREELIST(files);
	alpm_list_free(deltas);
	deltas = NULL;
	_alpm_trans_free(tr);
	tr = NULL;
	return(ret);
}

pmsyncpkg_t *_alpm_sync_find(alpm_list_t *syncpkgs, const char* pkgname)
{
	alpm_list_t *i;
	for(i = syncpkgs; i; i = i->next) {
		pmsyncpkg_t *syncpkg = i->data;
		if(!syncpkg) {
			continue;
		}

		pmpkg_t *pkg = alpm_sync_get_pkg(syncpkg);
		if(strcmp(alpm_pkg_get_name(pkg), pkgname) == 0) {
			return(syncpkg);
		}
	}

	return(NULL); /* not found */
}

pmpkg_t SYMEXPORT *alpm_sync_get_pkg(const pmsyncpkg_t *sync)
{
	/* Sanity checks */
	ASSERT(sync != NULL, return(NULL));

	return sync->pkg;
}

alpm_list_t SYMEXPORT *alpm_sync_get_removes(const pmsyncpkg_t *sync)
{
	/* Sanity checks */
	ASSERT(sync != NULL, return(NULL));

	return sync->removes;
}

/* vim: set ts=2 sw=2 noet: */