#include "core/RingBuffer.h"

#include <assert.h>
#include <stdio.h>
#include <string.h>

#include "core/Utility.h"

void coreDestroyRingBuffer(CoreRingBuffer* r) {
    coreClearRingBuffer(r);
    r->dataSize = 0;
    r->capacity = 0;
    coreFree(r->data);
    r->data = nullptr;
}

static void* getPointer(CoreRingBuffer* r, size_t index) {
    return (char*)r->data + r->dataSize * index;
}

CoreRingBuffer* coreRingBufferAddPointer(CoreRingBuffer* r, const void* data) {
    if(r->length >= r->capacity) {
        return nullptr;
    } else if(r->data == nullptr) {
        r->data = coreAllocate(r->capacity * r->dataSize);
    }
    memcpy(getPointer(r, r->writeIndex), data, r->dataSize);
    r->writeIndex = (r->writeIndex + 1) % r->capacity;
    r->length++;
    return r;
}

void* coreRingBufferGetVoidPointer(CoreRingBuffer* r, size_t index) {
    return getPointer(r, (index + r->readIndex) % r->capacity);
}

const void* coreRingBufferGetVoidPointerC(const CoreRingBuffer* r,
                                          size_t index) {
    return (char*)r->data +
           r->dataSize * ((index + r->readIndex) % r->capacity);
}

void coreClearRingBuffer(CoreRingBuffer* r) {
    r->writeIndex = 0;
    r->readIndex = 0;
    r->length = 0;
}

void coreRingBufferRemove(CoreRingBuffer* r) {
    assert(r->length > 0);
    r->length--;
    r->readIndex = (r->readIndex + 1) % r->capacity;
}

size_t coreToStringRingBuffer(CoreRingBuffer* r, char* buffer, size_t n,
                              CoreToString c) {
    size_t w = 0;
    coreStringAddI(&w, &buffer, &n, snprintf(buffer, n, "["));
    size_t end = r->length;
    if(end > 0) {
        end--;
        for(size_t i = 0; i < end; i++) {
            coreStringAdd(&w, &buffer, &n,
                          c(coreRingBufferGetVoidPointer(r, i), buffer, n));
            coreStringAddI(&w, &buffer, &n, snprintf(buffer, n, ", "));
        }
        coreStringAdd(&w, &buffer, &n,
                      c(coreRingBufferGetVoidPointer(r, end), buffer, n));
    }
    coreStringAddI(&w, &buffer, &n, snprintf(buffer, n, "]"));
    return w;
}

void coreSwapRingBuffer(CoreRingBuffer* a, CoreRingBuffer* b) {
    CoreRingBuffer tmp = *a;
    *a = *b;
    *b = tmp;
}