/*-
 * Copyright (c) 2015 Nuxi, https://nuxi.nl/
 *
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 <atf-c.h>
#define _SEARCH_PRIVATE
#include <search.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>

static int n_nodes = 0;
static int n_seen = 0;

/* Validates the integrity of an AVL tree. */
static inline unsigned int
tnode_assert(const posix_tnode *n)
{
        unsigned int height_left, height_right;
        int balance;

        if (n == NULL)
                return 0;
        height_left = tnode_assert(n->llink);
        height_right = tnode_assert(n->rlink);
        balance = (int)height_left - (int)height_right;
        ATF_CHECK(balance >= -1);
        ATF_CHECK(balance <= 1);
        ATF_CHECK_EQ(balance, n->balance);
        return (height_left > height_right ? height_left : height_right) + 1;
}

static int
compar(const void *a, const void *b)
{

        return *(int *)a - *(int *)b;
}

static void
treewalk(const posix_tnode *node, VISIT v, int level)
{

        if (v == postorder || v == leaf)
                n_seen++;
}

ATF_TC_WITHOUT_HEAD(tsearch_test);
ATF_TC_BODY(tsearch_test, tc)
{
        /*
         * Run the test below in a deterministic fashion to prevent this
         * test from potentially flapping. We assume that this provides
         * enough coverage.
         */
#if 0
        unsigned short random_state[3];
        arc4random_buf(random_state, sizeof(random_state));
#else
        unsigned short random_state[3] = { 26554, 13330, 3246 };
#endif

#define NKEYS 1000
        /* Create 1000 possible keys. */
        int keys[NKEYS];
        for (int i = 0; i < NKEYS; ++i)
                keys[i] = i;

        /* Apply random operations on a binary tree and check the results. */
        posix_tnode *root = NULL;
        bool present[NKEYS] = {};
        for (int i = 0; i < NKEYS * 10; ++i) {
                int key = nrand48(random_state) % NKEYS;
                int sample = i;

                /*
                 * Ensure each case is tested at least 10 times, plus a
                 * random sampling.
                 */
                if ((sample % NKEYS) > 3)
                        sample = nrand48(random_state) % 3;

                switch (sample) {
                case 0:  /* tdelete(). */
                        if (present[key]) {
                                ATF_CHECK(tdelete(&key, &root, compar) != NULL);
                                present[key] = false;
                                ATF_CHECK(n_nodes > 0);
                                n_nodes--;
                        } else {
                                ATF_CHECK_EQ(NULL,
                                    tdelete(&key, &root, compar));
                        }
                        break;
                case 1:  /* tfind(). */
                        if (present[key]) {
                                ATF_CHECK_EQ(&keys[key],
                                    *(int **)tfind(&key, &root, compar));
                        } else {
                                ATF_CHECK_EQ(NULL, tfind(&key, &root, compar));
                        }
                        break;
                case 2:  /* tsearch(). */
                        if (present[key]) {
                                ATF_CHECK_EQ(&keys[key],
                                    *(int **)tsearch(&key, &root, compar));
                        } else {
                                ATF_CHECK_EQ(&keys[key], *(int **)tsearch(
                                    &keys[key], &root, compar));
                                present[key] = true;
                                n_nodes++;
                        }
                        break;
                }
                tnode_assert(root);
        }

        /* Walk the tree. */
        twalk(root, treewalk);
        ATF_CHECK_EQ(n_nodes, n_seen);

        /* Remove all entries from the tree. */
        for (int key = 0; key < NKEYS; ++key)
                if (present[key])
                        ATF_CHECK(tdelete(&key, &root, compar) != NULL);
        ATF_CHECK_EQ(NULL, root);
}

static int nodes;

struct my_data {
        int key;
};

static struct my_data *
new_my_data(int key)
{
        struct my_data *res;

        res = malloc(sizeof(struct my_data));
        res->key = key;
        nodes++;
        return (res);
}

void
free_my_data(void *mdp)
{
        free(mdp);
        nodes--;
}

static int
compare_my_data(const void *mdp1, const void *mdp2)
{
        const struct my_data *md1, *md2;

        md1 = mdp1;
        md2 = mdp2;

        return (md1->key - md2->key);
}

static posix_tnode *root = NULL;

static void
insert(int x)
{
        struct my_data *md;

        md = new_my_data(x);
        tsearch(md, &root, compare_my_data);
}

ATF_TC_WITHOUT_HEAD(tdestroy_test);
ATF_TC_BODY(tdestroy_test, tc)
{
        root = NULL;
        insert(1);
        insert(100);
        insert(1000);
        insert(5);
        insert(6);
        insert(12);
        insert(2000);
        insert(3);

        ATF_CHECK_EQ(8, nodes);
        tdestroy(root, free_my_data);
        ATF_CHECK_EQ(0, nodes);
}

ATF_TP_ADD_TCS(tp)
{

        ATF_TP_ADD_TC(tp, tsearch_test);
        ATF_TP_ADD_TC(tp, tdestroy_test);

        return (atf_no_error());
}