/*
 * This code is part of the strategy game operational-space.
 * operational-space comes with ABSOLUTELY NO WARRANTY and is licensed under GPL-2.0.
 *    Copyright (C) 2024  VegOwOtenks, Sleppo04
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
#include "dynamicbuffer.h"

int DynamicBuffer_Create(dynamic_buffer_t *destination, size_t initial_capacity)
{
	return DynamicBuffer_CreateWithAllocator(destination, initial_capacity, NULL);
}

int DynamicBuffer_CreateWithAllocator(dynamic_buffer_t *destination, size_t initial_capacity, allocator_t* allocator)
{
    if (destination == NULL) {
        return EDESTADDRREQ;
    }
    // Some malloc() implementations return NULL and other return valid pointers on zero-byte-allocation, I'm not handling this shit
    if (initial_capacity == 0) {
        return EINVAL;
    }

    dynamic_buffer_t local;

    local.allocator = allocator;
    local.capacity  = initial_capacity;
    local.used      = 0;

    if (allocator != NULL) {
        local.array = allocator->allocate(allocator, initial_capacity);
    } else {
    	local.array = malloc(initial_capacity);
    }
    if (local.array == NULL) {
        return ENOMEM;
    }

    destination[0] = local;

    return EXIT_SUCCESS;
}

int DynamicBuffer_EnsureUnusedCapacity(dynamic_buffer_t* buffer, size_t needed_unused)
{
    if (buffer == NULL) {
        return EINVAL;
    }

    size_t unused_space = buffer->capacity - buffer->used;

    if (needed_unused < unused_space) {
        return EXIT_SUCCESS;
    }

    size_t needed_capacity = buffer->capacity + needed_unused;
    int resize_code = DynamicBuffer_Resize(buffer, needed_capacity);

    if (resize_code) {
        // ENOMEM
        return resize_code;
    }

    return EXIT_SUCCESS;
}

int DynamicBuffer_EnsureCapacity(dynamic_buffer_t* buffer, size_t minimal_capacity)
{
    if (buffer == NULL) {
        return EINVAL;
    }

    if (minimal_capacity < buffer->capacity) {
        return EXIT_SUCCESS;
    }

    int resize_code = DynamicBuffer_Resize(buffer, minimal_capacity);
    if (resize_code) {
        // ENOMEM
        return resize_code;
    }

    return EXIT_SUCCESS;
}

int DynamicBuffer_Resize(dynamic_buffer_t* buffer, size_t new_capacity)
{
    if (buffer == NULL) {
        return EINVAL;
    }
    if (new_capacity == 0) {
        return EINVAL;
    }

    char* new_array;
    if (buffer->allocator != NULL) {
    	new_array = buffer->allocator->reallocate(buffer->allocator, buffer->array, buffer->capacity, new_capacity);
    } else {
    	new_array = realloc(buffer->array, new_capacity);
    }
    if (new_array == NULL) {
        return ENOMEM;
    }

    buffer->array = new_array;
    buffer->capacity = new_capacity;

    return EXIT_SUCCESS;
}

int DynamicBuffer_Prune(dynamic_buffer_t* buffer)
{
	if (buffer == NULL) {
		return ENOMEM;
	}

	return DynamicBuffer_Resize(buffer, buffer->used);
}

int DynamicBuffer_Reset(dynamic_buffer_t* buffer)
{
    if (buffer == NULL) {
        return EINVAL;
    }

    buffer->used = 0;

    return EXIT_SUCCESS;
}

int DynamicBuffer_RewindBytes(dynamic_buffer_t* buffer, size_t bytes)
{
	if (buffer == NULL) {
		return EINVAL;
	}
	if (buffer->used < bytes) {
		return EBOUNDS;
	}

	buffer->used -= bytes;

	return EXIT_SUCCESS;
}

int DynamicBuffer_Store(dynamic_buffer_t* buffer, const void* data, size_t data_size)
{
    if (buffer == NULL) {
        return EINVAL;
    }
    if (data == NULL) {
        return EINVAL;
    }
    if (data_size == 0) {
        return EXIT_SUCCESS;
    }

    int ensure_code = DynamicBuffer_EnsureUnusedCapacity(buffer, data_size);
    if (ensure_code) {
        // ENOMEM
        return ensure_code;
    }

    void* destination = ((char*) buffer->array) + buffer->used;
    memcpy(destination, data, data_size);
    buffer->used += data_size;

    return EXIT_SUCCESS;
}

size_t DynamicBuffer_GetBlockCount(dynamic_buffer_t* buffer, size_t block_size)
{
	return buffer->used / block_size;
}

void* DynamicBuffer_ReadAt(dynamic_buffer_t* buffer, size_t offset)
{
	if (offset >= buffer->used) {
		return NULL;
	}

	return (void*) (((char*) buffer->array) + offset);
}

void* DynamicBuffer_ReadBlockAt(dynamic_buffer_t* buffer, size_t block_size, size_t index)
{
	return DynamicBuffer_ReadAt(buffer, block_size * index);
}

int DynamicBuffer_Destroy(dynamic_buffer_t* buffer)
{
    if (buffer == NULL) {
        return EINVAL;
    }
    if (buffer->allocator == NULL) {
    	free(buffer->array);
    } else {
    	buffer->allocator->free(buffer->allocator, buffer->array, buffer->capacity);
    }
    buffer->array = NULL;
    buffer->capacity = 0;
    buffer->used = 0;

    return EXIT_SUCCESS;
}