/*
 * Copyright (c) 2025 Ian Marco Moffett and the Osmora Team.
 * 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.
 * 3. Neither the name of Hyra nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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 <sys/queue.h>
#include <sys/errno.h>
#include <ldo/object.h>
#include <ldo/cdefs.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <math.h>

/*
 * Checks if an object is in the static array
 * queue and returns it if so, otherwise NULL
 * will be returned.
 *
 * @qp: Queue to check.
 * @op: Object to look for.
 */
static struct sarry_obj *
sarry_obj(struct sarry_objq *qp, struct sarry_obj *op)
{
    struct sarry_obj *tmp;

    TAILQ_FOREACH(tmp, &qp->q, link) {
        if (tmp == op) {
            return tmp;
        }
    }

    return NULL;
}

/*
 * Initialize an object queue.
 *
 * @qp: Object queue pointer.
 * @cap: Capacity
 *
 * XXX: `cap' must be a power-of-two and must not exceed
 *      OBJQ_MAXCAP.
 */
int
sarry_init_objq(struct sarry_objq *qp, size_t cap)
{
    uint8_t e;

    /*
     * Power-of-two sizes are good for block
     * based processing
     */
    if ((OBJQ_MAXCAP & 1) != 0) {
        fprintf(stderr, "OBJQ_MAXCAP is not a power of two\n");
        return -EINVAL;
    }

    /* Ensure `cap' doesn't exceed the limit */
    if (cap > OBJQ_MAXCAP) {
        e = log2(OBJQ_MAXCAP);
        fprintf(stderr, "cap exceeds OBJQ_MAXCAP, rejecting...\n");
        fprintf(stderr, "cap must be <= 2^%d (%d) entries\n", e, cap);
        return -EINVAL;
    }

    TAILQ_INIT(&qp->q);
    qp->count = 0;
    qp->cap = cap;
}

/*
 * Insert an object into an object queue.
 *
 * @qp: Object queue pointer.
 * @op: Object pointer.
 */
int
sarry_objq_in(struct sarry_objq *qp, struct sarry_obj *op)
{
    size_t new_count;

    new_count = (qp->count + 1);
    if (new_count > OBJQ_MAXCAP) {
        fprintf(stderr, "sarry_insert: object queue full\n");
        return -ENOSPC;
    }

    TAILQ_INSERT_TAIL(&qp->q, op, link);
    ++qp->count;
    return 0;
}

/*
 * Flush an object queue.
 *
 * @qp: The pointer to the object queue.
 * @op: Object to remove (if NULL, the entire queue is flushed)
 */
int
sarry_objq_flush(struct sarry_objq *qp, struct sarry_obj *op)
{
    struct sarry_obj *obj;
    struct sarry_obj *tmp;

    /*
     * If the object we are trying to remove is not
     * found in the queue, something went poorly. This
     * happening might even imply ldo is in an undefined
     * state from this point out, however, just warn the
     * user and see what happens as this should not throw
     * anything _completly_ off...
     */
    tmp = sarry_obj(qp, op);
    if (__unlikely(op != NULL && tmp == NULL)) {
        fprintf(stdout, "[warn] sarry_objq_flush: 'op' not in 'qp'\n");
        return -EIO;
    }

    /*
     * Do we have a specific object we want to remove?
     * If so, then that's all the work that needs to
     * be done.
     */
    if (op != NULL) {
        TAILQ_REMOVE(&qp->q, op, link);
        return 0;
    }

    while (!TAILQ_EMPTY(&qp->q)) {
        /* Pop object off the queue */
        obj = TAILQ_FIRST(&qp->q);
        TAILQ_REMOVE(&qp->q, obj, link);
        free(obj);
    }

    return 0;
}