/*
 * pkg.c
 * higher-level dependency graph compilation, management and manipulation
 *
 * Copyright (c) 2011 William Pitcock <nenolod@dereferenced.org>.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * 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 "pkg.h"

pkg_t *
pkg_find(const char *name)
{
	char locbuf[BUFSIZ];

	snprintf(locbuf, sizeof locbuf, "/usr/lib/pkgconfig/%s.pc", name);

	return parse_file(locbuf);
}

/*
 * pkg_compare_version(a, b)
 *
 * compare versions using RPM version comparison rules as described in the LSB.
 */
int
pkg_compare_version(const char *a, const char *b)
{
	char oldch1, oldch2;
	char *str1, *str2;
	char *one, *two;
	int ret;
	bool isnum;

	/* optimization: if version matches then it's the same version. */
	if (!strcasecmp(a, b))
		return 0;

	str1 = LOCAL_COPY(a);
	str2 = LOCAL_COPY(b);

	one = str1;
	two = str2;

	while (*one && *two)
	{
		while (*one && !isalnum(*one))
			one++;
		while (*two && !isalnum(*two))
			two++;

		if (!(*one && *two))
			break;

		str1 = one;
		str2 = two;

		if (isdigit(*str1))
		{
			while (*str1 && isdigit(*str1))
				str1++;

			while (*str2 && isdigit(*str2))
				str2++;

			isnum = true;
		}
		else
		{
			while (*str1 && isalpha(*str1))
				str1++;

			while (*str2 && isalpha(*str2))
				str2++;

			isnum = false;
		}

		oldch1 = *str1;
		oldch2 = *str2;

		*str1 = '\0';
		*str2 = '\0';

		if (one == str1)
			return -1;

		if (two == str2)
			return (isnum ? 1 : -1);

		if (isnum)
		{
			int onelen, twolen;

			while (*one == '0')
				one++;

			while (*two == '0')
				two++;

			onelen = strlen(one);
			twolen = strlen(two);

			if (onelen > twolen)
				return 1;
			else if (twolen > onelen)
				return -1;
		}

		ret = strcmp(one, two);
		if (ret)
			return ret;

		*str1 = oldch1;
		*str2 = oldch2;

		one = str1;
		two = str2;
	}

	if ((!*one) && (!*two))
		return 0;

	if (!*one)
		return -1;

	return 1;
}

/*
 * pkg_verify_dependency(pkgdep)
 *
 * verify a pkg_dependency_t node in the depgraph.  if the dependency is solvable,
 * return the appropriate pkg_t object, else NULL.
 */
pkg_t *
pkg_verify_dependency(pkg_dependency_t *pkgdep)
{
	pkg_t *pkg;

	pkg = pkg_find(pkgdep->package);
	if (pkg == NULL)
		return NULL;

	switch(pkgdep->compare)
	{
	case PKG_LESS_THAN:
		if (pkg_compare_version(pkgdep->version, pkg->version) < 0)
			return pkg;
		break;
	case PKG_GREATER_THAN:
		if (pkg_compare_version(pkgdep->version, pkg->version) > 0)
			return pkg;
		break;
	case PKG_LESS_THAN_EQUAL:
		if (pkg_compare_version(pkgdep->version, pkg->version) <= 0)
			return pkg;
		break;
	case PKG_GREATER_THAN_EQUAL:
		if (pkg_compare_version(pkgdep->version, pkg->version) >= 0)
			return pkg;
		break;
	case PKG_EQUAL:
		if (pkg_compare_version(pkgdep->version, pkg->version) == 0)
			return pkg;
		break;
	case PKG_NOT_EQUAL:
		if (pkg_compare_version(pkgdep->version, pkg->version) != 0)
			return pkg;
		break;
	case PKG_ANY:
	default:
		return pkg;
	}

	return NULL;
}

/*
 * pkg_verify_graph(root, depth)
 *
 * verify the graph dependency nodes are satisfiable by walking the tree using
 * pkg_traverse().
 */
void
pkg_verify_graph(pkg_t *root, int depth)
{
	pkg_traverse(root, NULL, NULL, depth);
}

void
pkg_traverse(pkg_t *root,
	void (*pkg_traverse_func)(pkg_t *package, void *data),
	void *data,
	int maxdepth)
{
	pkg_dependency_t *node;

	if (maxdepth == 0)
		return;

	foreach_list_entry(root->requires, node)
	{
		pkg_t *pkgdep;

		if (*node->package == '\0')
			continue;

		pkgdep = pkg_verify_dependency(node);
		if (pkgdep == NULL)	
		{
			fprintf(stderr, "Package %s was not found in the pkg-config search path.\n", node->package);
			fprintf(stderr, "Perhaps you should add the directory containing `%s.pc'\n", node->package);
			fprintf(stderr, "to the PKG_CONFIG_PATH environment variable\n");
			fprintf(stderr, "No package '%s' found\n", node->package);
			exit(EXIT_FAILURE);
		}

		pkg_traverse(pkgdep, pkg_traverse_func, data, maxdepth - 1);
	}

	if (pkg_traverse_func != NULL)
		pkg_traverse_func(root, data);
}