/**
 * 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_max)(struct SNAME *_heap_);
static void CMC_(PFX, _impl_float_up_min)(struct SNAME *_heap_);
static void CMC_(PFX, _impl_float_down_max)(struct SNAME *_heap_);
static void CMC_(PFX, _impl_float_down_min)(struct SNAME *_heap_);

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

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

struct SNAME *CMC_(PFX, _new_custom)(size_t capacity, 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 == 0 || capacity == UINTMAX_MAX)
        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;

    capacity = (capacity + capacity % 2) / 2;

    _heap_->buffer = alloc->calloc(capacity, sizeof(V[2]));

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

    _heap_->capacity = capacity;
    _heap_->size = 0;
    _heap_->count = 0;
    _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 / 2][i % 2]);
        }
    }

    memset(_heap_->buffer, 0, sizeof(V[2]) * _heap_->capacity);

    _heap_->size = 0;
    _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 / 2][i % 2]);
        }
    }

    _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_->capacity * 4))
            return false;
    }

    if (_heap_->count % 2 == 0)
    {
        /* Occupying a new node */
        _heap_->buffer[_heap_->size][0] = value;
        _heap_->buffer[_heap_->size][1] = (V){ 0 };

        _heap_->size++;
    }
    else
    {
        V(*node)[2] = &(_heap_->buffer[_heap_->size - 1]);

        /* Decide if the new element goes into the MinHeap or MaxHeap */
        if (_heap_->f_val->cmp((*node)[0], value) > 0)
        {
            /* Swap current value and add new element to the MinHeap */
            (*node)[1] = (*node)[0];
            (*node)[0] = value;
        }
        else
        {
            /* No need to swap and add the new element to the MaxHeap */
            (*node)[1] = value;
        }
    }

    _heap_->count++;
    _heap_->flag = CMC_FLAG_OK;

    if (_heap_->count > 2)
    {
        /* Determine wheather to do a MaxHeap insert or a MinHeap */
        /* insert. For any integer this index calculation results in */
        /* an even number representing the parent of the last value */
        V(*parent)[2] = &(_heap_->buffer[(_heap_->size - 2) / 2]);

        if (_heap_->f_val->cmp((*parent)[0], value) > 0)
            CMC_(PFX, _impl_float_up_min)(_heap_);
        else if (_heap_->f_val->cmp((*parent)[1], value) < 0)
            CMC_(PFX, _impl_float_up_max)(_heap_);
        /* else no float up required */
    }

    CMC_CALLBACKS_CALL(_heap_);

    return true;
}

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

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

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

        _heap_->count--;
        _heap_->size--;

        goto success;
    }

    /* Swap the result with the last element in the MaxHeap and float */
    /* it down */
    V(*last_node)[2] = &(_heap_->buffer[_heap_->size - 1]);

    if (_heap_->count % 2 == 1)
    {
        /* Grab from MinHeap and discard last node */
        _heap_->buffer[0][1] = (*last_node)[0];

        (*last_node)[0] = (V){ 0 };

        _heap_->size--;
    }
    else
    {
        _heap_->buffer[0][1] = (*last_node)[1];

        (*last_node)[1] = (V){ 0 };
    }

    _heap_->count--;

    /* FLoat Down on the MaxHeap */
    CMC_(PFX, _impl_float_down_max)(_heap_);

success:

    _heap_->flag = CMC_FLAG_OK;

    CMC_CALLBACKS_CALL(_heap_);

    return true;
}

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

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

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

        _heap_->count--;
        _heap_->size--;

        goto success;
    }

    /* Swap the result with the last element in the MinHeap and float */
    /* it down */
    V(*last_node)[2] = &(_heap_->buffer[_heap_->size - 1]);

    _heap_->buffer[0][0] = (*last_node)[0];

    if (_heap_->count % 2 == 1)
    {
        /* Discard last node */
        (*last_node)[0] = (V){ 0 };

        _heap_->size--;
    }
    else
    {
        /* Place the MaxHeap value in the MinHeap value spot */
        (*last_node)[0] = (*last_node)[1];
        (*last_node)[1] = (V){ 0 };
    }

    _heap_->count--;

    /* FLoat Down on the MinHeap */
    CMC_(PFX, _impl_float_down_min)(_heap_);

success:

    _heap_->flag = CMC_FLAG_OK;

    CMC_CALLBACKS_CALL(_heap_);

    return true;
}

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

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

    if (_heap_->count == 1)
    {
        _heap_->buffer[0][0] = value;
    }
    else if (_heap_->f_val->cmp(value, _heap_->buffer[0][0]) < 0)
    {
        /* Corner case: we are updating the Max value but it is less */
        /* than the Min value */
        _heap_->buffer[0][1] = _heap_->buffer[0][0];
        _heap_->buffer[0][0] = value;

        CMC_(PFX, _impl_float_down_max)(_heap_);
    }
    else
    {
        /* Update Max element and float it down */
        _heap_->buffer[0][1] = value;

        CMC_(PFX, _impl_float_down_max)(_heap_);
    }

    _heap_->flag = CMC_FLAG_OK;

    CMC_CALLBACKS_CALL(_heap_);

    return true;
}

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

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

    if (_heap_->count == 1)
    {
        _heap_->buffer[0][0] = value;
    }
    else if (_heap_->f_val->cmp(value, _heap_->buffer[0][1]) > 0)
    {
        /* Corner case: we are updating the Min value but it is greater */
        /* than the Max value. */
        _heap_->buffer[0][0] = _heap_->buffer[0][1];
        _heap_->buffer[0][1] = value;

        CMC_(PFX, _impl_float_down_min)(_heap_);
    }
    else
    {
        /* Update Min element and float it down */
        _heap_->buffer[0][0] = value;

        CMC_(PFX, _impl_float_down_min)(_heap_);
    }

    _heap_->flag = CMC_FLAG_OK;

    CMC_CALLBACKS_CALL(_heap_);

    return true;
}

V CMC_(PFX, _max)(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_);

    /* If there is only one element, then the maximum element is the */
    /* same as the one in the MinHeap */
    if (_heap_->count == 1)
        return _heap_->buffer[0][0];

    return _heap_->buffer[0][1];
}

V CMC_(PFX, _min)(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][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 / 2][i % 2], 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

    /* The heap is full if all nodes are completely filled */
    return _heap_->size >= _heap_->capacity && _heap_->count % 2 == 0;
}

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

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

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

    /* Prevent overflow */
    if (capacity == UINTMAX_MAX)
    {
        _heap_->flag = CMC_FLAG_ERROR;
        return false;
    }

    capacity += capacity % 2;

    V(*new_buffer)[2] = _heap_->alloc->realloc(_heap_->buffer, sizeof(V[2]) * capacity);

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

    if (capacity > _heap_->capacity)
    {
        memset(new_buffer + _heap_->capacity, 0, sizeof(V[2]) * (capacity - _heap_->capacity));
    }

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

success:

    _heap_->flag = CMC_FLAG_OK;

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

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

    memcpy(result, _heap_, sizeof(struct SNAME));

    result->buffer = _heap_->alloc->malloc(sizeof(V[2]) * _heap_->capacity);

    if (!result->buffer)
    {
        _heap_->alloc->free(result);
        _heap_->flag = CMC_FLAG_ALLOC;
        return NULL;
    }

    if (_heap_->f_val->cpy)
    {
        for (size_t i = 0; i < _heap_->count; i++)
            result->buffer[i / 2][i % 2] = _heap_->f_val->cpy(_heap_->buffer[i / 2][i % 2]);
    }
    else
        memcpy(result->buffer, _heap_->buffer, sizeof(V[2]) * _heap_->capacity);

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

    _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++)
    {
        V value1 = _heap1_->buffer[i / 2][i % 2];
        V value2 = _heap2_->buffer[i / 2][i % 2];

        if (_heap1_->f_val->cmp(value1, value2) != 0)
            return false;
    }

    return true;
}

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

    size_t index = _heap_->size - 1;

    V(*curr_node)[2] = &(_heap_->buffer[index]);

    /* FLoat Up on the MaxHeap */
    while (index > 0)
    {
        /* Parent index */
        size_t P_index = (index - 1) / 2;

        V(*parent)[2] = &(_heap_->buffer[P_index]);

        if (index == _heap_->size - 1 && _heap_->count % 2 != 0)
        {
            /* In this case, the current node has no MaxHeap value so */
            /* we instead compare with the MinHeap value */
            if (_heap_->f_val->cmp((*curr_node)[0], (*parent)[1]) < 0)
                break;

            /* Since the comparison above passed now we need to swap   */
            /* the current node with the parent but it will have to be */
            /* done with the node's MinHeap value since the MaxHeap */
            /* value doesn't exist */
            V tmp = (*curr_node)[0];
            (*curr_node)[0] = (*parent)[1];
            (*parent)[1] = tmp;
        }
        else
        {
            /* Usual case, just compare both MaxHeap values */
            if (_heap_->f_val->cmp((*curr_node)[1], (*parent)[1]) < 0)
                break;

            /* Swap with parent and repeat */
            V tmp = (*curr_node)[1];
            (*curr_node)[1] = (*parent)[1];
            (*parent)[1] = tmp;
        }

        /* Update indexe and node */
        index = P_index;
        curr_node = parent;
    }
}

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

    size_t index = _heap_->size - 1;

    V(*curr_node)[2] = &(_heap_->buffer[index]);

    /* FLoat Up on the MinHeap */
    while (index > 0)
    {
        /* Parent index */
        size_t P_index = (index - 1) / 2;

        V(*parent)[2] = &(_heap_->buffer[P_index]);

        if (_heap_->f_val->cmp((*curr_node)[0], (*parent)[0]) >= 0)
            break;

        /* Swap with parent and repeat */
        V tmp = (*curr_node)[0];
        (*curr_node)[0] = (*parent)[0];
        (*parent)[0] = tmp;

        /* Update indexe and node */
        index = P_index;
        curr_node = parent;
    }
}

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

    /* Floats Down from the MaxHeap */
    size_t index = 0;

    V(*curr_node)[2] = &(_heap_->buffer[index]);

    while (true)
    {
        /* If there are no children it is done */
        if (2 * index + 1 >= _heap_->size)
            break;

        /* Child index to be compared with current value */
        size_t child;
        size_t L_index = index * 2 + 1;
        size_t R_index = index * 2 + 2;

        /* If there are two children, pick the smallest one */
        if (R_index < _heap_->size)
        {
            V(*L)[2] = &(_heap_->buffer[L_index]);
            V(*R)[2] = &(_heap_->buffer[R_index]);

            /* If the right child is the last node and there is no */
            /* MaxHeap value */
            /* then do the comparison with the MinHeap value */
            if (R_index == _heap_->size - 1 && _heap_->count % 2 != 0)
                child = _heap_->f_val->cmp((*L)[1], (*R)[0]) > 0 ? L_index : R_index;
            else
                child = _heap_->f_val->cmp((*L)[1], (*R)[1]) > 0 ? L_index : R_index;
        }
        /* Pick the only one available */
        else
            child = L_index;

        V(*child_node)[2] = &(_heap_->buffer[child]);

        /* Again, check if the child node is the last one and has no */
        /* MaxHeap value */
        if (child == _heap_->size - 1 && _heap_->count % 2 != 0)
        {
            /* Odd case, compare with MinHeap value */
            /* If current value is not less than the child node's */
            /* value it is done */
            if (_heap_->f_val->cmp((*curr_node)[1], (*child_node)[0]) >= 0)
                break;

            /* Otherwise swap and continue */
            V tmp = (*child_node)[0];
            (*child_node)[0] = (*curr_node)[1];
            (*curr_node)[1] = tmp;
        }
        else
        {
            /* If current value is not less than the child node's   */
            /* value it is done */
            if (_heap_->f_val->cmp((*curr_node)[1], (*child_node)[1]) >= 0)
                break;

            /* Otherwise swap and continue */
            V tmp = (*child_node)[1];
            (*child_node)[1] = (*curr_node)[1];
            (*curr_node)[1] = tmp;

            /* Check if the MinHeap and MaxHeap values need to be */
            /* swapped                  */
            if (_heap_->f_val->cmp((*child_node)[0], (*child_node)[1]) > 0)
            {
                /* Swap because the MinHeap value is greater than the */
                /* MaxHeap value */
                tmp = (*child_node)[0];
                (*child_node)[0] = (*child_node)[1];
                (*child_node)[1] = tmp;
            }
        }

        /* Update index and node */
        index = child;
        curr_node = child_node;
    }
}

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

    /* Floats Down from the MinHeap */
    size_t index = 0;

    V(*curr_node)[2] = &(_heap_->buffer[index]);

    while (true)
    {
        /* If there are no children it is done */
        if (2 * index + 1 >= _heap_->size)
            break;

        /* Child index to be compared with current value */
        size_t child;
        size_t L_index = index * 2 + 1;
        size_t R_index = index * 2 + 2;

        /* If there are two children, pick the smallest one */
        if (R_index < _heap_->size)
        {
            V(*L)[2] = &(_heap_->buffer[L_index]);
            V(*R)[2] = &(_heap_->buffer[R_index]);

            child = _heap_->f_val->cmp((*L)[0], (*R)[0]) < 0 ? L_index : R_index;
        }
        /* Pick the only one available */
        else
            child = L_index;

        V(*child_node)[2] = &(_heap_->buffer[child]);

        /* If current value is smaller than the child node's value, it */
        /* is done */
        if (_heap_->f_val->cmp((*curr_node)[0], (*child_node)[0]) < 0)
            break;

        /* Otherwise swap and continue */
        V tmp = (*child_node)[0];
        (*child_node)[0] = (*curr_node)[0];
        (*curr_node)[0] = tmp;

        /* If the child node is the last node check if the MinHeap and */
        /* MaxHeap values need to be swapped */
        if (child != _heap_->size - 1 || _heap_->count % 2 == 0)
        {
            if (_heap_->f_val->cmp((*child_node)[0], (*child_node)[1]) > 0)
            {
                /* Swap because the MinHeap value is greater than the */
                /* MaxHeap value */
                tmp = (*child_node)[0];
                (*child_node)[0] = (*child_node)[1];
                (*child_node)[1] = tmp;
            }
        }

        /* Update index and node */
        index = child;
        curr_node = child_node;
    }
}