/**
 * Copyright (c) 2019 Leonardo Vencovsky
 *
 * This file is part of the C Macro Collections Library.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

/* Implementation Detail Functions */
static void CMC_(PFX, _impl_float_up)(struct SNAME *_heap_, size_t index);
static void CMC_(PFX, _impl_float_down)(struct SNAME *_heap_, size_t index);

struct SNAME *CMC_(PFX, _new)(size_t capacity, enum cmc_heap_order HO, struct CMC_DEF_FVAL(SNAME) * f_val)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    return CMC_(PFX, _new_custom)(capacity, HO, f_val, NULL, NULL);
}

struct SNAME *CMC_(PFX, _new_custom)(size_t capacity, enum cmc_heap_order HO, struct CMC_DEF_FVAL(SNAME) * f_val,
                                     CMC_ALLOC_TYPE alloc, CMC_CALLBACK_TYPE callbacks)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    CMC_CALLBACKS_MAYBE_UNUSED(callbacks);

    if (capacity < 1)
        return NULL;

    if (HO != CMC_MIN_HEAP && HO != CMC_MAX_HEAP)
        return NULL;

    if (!f_val)
        return NULL;

    if (!alloc)
        alloc = &cmc_alloc_node_default;

    struct SNAME *_heap_ = alloc->malloc(sizeof(struct SNAME));

    if (!_heap_)
        return NULL;

    _heap_->buffer = alloc->calloc(capacity, sizeof(V));

    if (!_heap_->buffer)
    {
        alloc->free(_heap_);
        return NULL;
    }

    _heap_->capacity = capacity;
    _heap_->count = 0;
    _heap_->HO = HO;
    _heap_->flag = CMC_FLAG_OK;
    _heap_->f_val = f_val;
    _heap_->alloc = alloc;
    CMC_CALLBACKS_ASSIGN(_heap_, callbacks);

    return _heap_;
}

void CMC_(PFX, _clear)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    if (_heap_->f_val->free)
    {
        for (size_t i = 0; i < _heap_->count; i++)
        {
            _heap_->f_val->free(_heap_->buffer[i]);
        }
    }

    memset(_heap_->buffer, 0, sizeof(V) * _heap_->capacity);

    _heap_->count = 0;
    _heap_->flag = CMC_FLAG_OK;
}

void CMC_(PFX, _free)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    if (_heap_->f_val->free)
    {
        for (size_t i = 0; i < _heap_->count; i++)
        {
            _heap_->f_val->free(_heap_->buffer[i]);
        }
    }

    _heap_->alloc->free(_heap_->buffer);
    _heap_->alloc->free(_heap_);
}

void CMC_(PFX, _customize)(struct SNAME *_heap_, CMC_ALLOC_TYPE alloc, CMC_CALLBACK_TYPE callbacks)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    CMC_CALLBACKS_MAYBE_UNUSED(callbacks);

    if (!alloc)
        _heap_->alloc = &cmc_alloc_node_default;
    else
        _heap_->alloc = alloc;

    CMC_CALLBACKS_ASSIGN(_heap_, callbacks);

    _heap_->flag = CMC_FLAG_OK;
}

bool CMC_(PFX, _insert)(struct SNAME *_heap_, V value)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    if (CMC_(PFX, _full)(_heap_))
    {
        if (!CMC_(PFX, _resize)(_heap_, _heap_->count * 2))
            return false;
    }

    _heap_->buffer[_heap_->count++] = value;

    if (_heap_->count > 1)
    {
        CMC_(PFX, _impl_float_up)(_heap_, _heap_->count - 1);
    }

    _heap_->flag = CMC_FLAG_OK;

    CMC_CALLBACKS_CALL(_heap_);

    return true;
}

bool CMC_(PFX, _remove)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    if (CMC_(PFX, _empty)(_heap_))
    {
        _heap_->flag = CMC_FLAG_EMPTY;
        return false;
    }

    _heap_->buffer[0] = _heap_->buffer[_heap_->count - 1];
    _heap_->buffer[_heap_->count - 1] = (V){ 0 };

    _heap_->count--;

    CMC_(PFX, _impl_float_down)(_heap_, 0);

    _heap_->flag = CMC_FLAG_OK;

    CMC_CALLBACKS_CALL(_heap_);

    return true;
}

V CMC_(PFX, _peek)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    if (CMC_(PFX, _empty)(_heap_))
    {
        _heap_->flag = CMC_FLAG_EMPTY;
        return (V){ 0 };
    }

    _heap_->flag = CMC_FLAG_OK;

    CMC_CALLBACKS_CALL(_heap_);

    return _heap_->buffer[0];
}

bool CMC_(PFX, _contains)(struct SNAME *_heap_, V value)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    _heap_->flag = CMC_FLAG_OK;

    bool result = false;

    for (size_t i = 0; i < _heap_->count; i++)
    {
        if (_heap_->f_val->cmp(_heap_->buffer[i], value) == 0)
        {
            result = true;
            break;
        }
    }

    CMC_CALLBACKS_CALL(_heap_);

    return result;
}

bool CMC_(PFX, _empty)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    return _heap_->count == 0;
}

bool CMC_(PFX, _full)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    return _heap_->count >= _heap_->capacity;
}

size_t CMC_(PFX, _count)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    return _heap_->count;
}

size_t CMC_(PFX, _capacity)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    return _heap_->capacity;
}

int CMC_(PFX, _flag)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    return _heap_->flag;
}

bool CMC_(PFX, _resize)(struct SNAME *_heap_, size_t capacity)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    _heap_->flag = CMC_FLAG_OK;

    if (_heap_->capacity == capacity)
        goto success;

    if (capacity < _heap_->count)
    {
        _heap_->flag = CMC_FLAG_INVALID;
        return false;
    }

    V *new_buffer = _heap_->alloc->realloc(_heap_->buffer, sizeof(V) * capacity);

    if (!new_buffer)
    {
        _heap_->flag = CMC_FLAG_ALLOC;
        return false;
    }

    /* TODO zero out new slots */

    _heap_->buffer = new_buffer;
    _heap_->capacity = capacity;

success:

    CMC_CALLBACKS_CALL(_heap_);

    return true;
}

struct SNAME *CMC_(PFX, _copy_of)(struct SNAME *_heap_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    struct SNAME *result = CMC_(PFX, _new_custom)(_heap_->capacity, _heap_->HO, _heap_->f_val, _heap_->alloc, NULL);

    if (!result)
    {
        _heap_->flag = CMC_FLAG_ERROR;
        return NULL;
    }

    CMC_CALLBACKS_ASSIGN(result, _heap_->callbacks);

    if (_heap_->f_val->cpy)
    {
        for (size_t i = 0; i < _heap_->count; i++)
            result->buffer[i] = _heap_->f_val->cpy(_heap_->buffer[i]);
    }
    else
        memcpy(result->buffer, _heap_->buffer, sizeof(V) * _heap_->count);

    result->count = _heap_->count;

    _heap_->flag = CMC_FLAG_OK;

    return result;
}

bool CMC_(PFX, _equals)(struct SNAME *_heap1_, struct SNAME *_heap2_)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    _heap1_->flag = CMC_FLAG_OK;
    _heap2_->flag = CMC_FLAG_OK;

    if (_heap1_->count != _heap2_->count)
        return false;

    for (size_t i = 0; i < _heap1_->count; i++)
    {
        if (_heap1_->f_val->cmp(_heap1_->buffer[i], _heap2_->buffer[i]) != 0)
            return false;
    }

    return true;
}

static void CMC_(PFX, _impl_float_up)(struct SNAME *_heap_, size_t index)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    /* Current index */
    size_t C = index;
    V child = _heap_->buffer[C];
    V parent = _heap_->buffer[(index - 1) / 2];

    int mod = _heap_->HO;

    while (C > 0 && _heap_->f_val->cmp(child, parent) * mod > 0)
    {
        /* Swap between C (current element) and its parent */
        V tmp = _heap_->buffer[C];
        _heap_->buffer[C] = _heap_->buffer[(C - 1) / 2];
        _heap_->buffer[(C - 1) / 2] = tmp;

        /* Go to parent */
        C = (C - 1) / 2;

        /* Prevent the two lines below from accessing a negative index */
        if (C == 0)
            break;

        child = _heap_->buffer[C];
        parent = _heap_->buffer[(C - 1) / 2];
    }
}

static void CMC_(PFX, _impl_float_down)(struct SNAME *_heap_, size_t index)
{
#ifdef CMC_DEV
    CMC_DEV_FCALL;
#endif

    int mod = _heap_->HO;

    while (index < _heap_->count)
    {
        size_t L = 2 * index + 1;
        size_t R = 2 * index + 2;
        size_t C = index;

        /* Determine if we swap with the left or right element */
        if (L < _heap_->count && _heap_->f_val->cmp(_heap_->buffer[L], _heap_->buffer[C]) * mod > 0)
        {
            C = L;
        }

        if (R < _heap_->count && _heap_->f_val->cmp(_heap_->buffer[R], _heap_->buffer[C]) * mod > 0)
        {
            C = R;
        }

        /* Swap only if either left or right was picked, otherwise done */
        if (C != index)
        {
            V tmp = _heap_->buffer[index];
            _heap_->buffer[index] = _heap_->buffer[C];
            _heap_->buffer[C] = tmp;

            index = C;
        }
        else
            break;
    }
}