#include "alloc.h"
#include "klibc.h"
#include "ringbuffer.h"

struct ringbuffer_instance_t {
    int32_t wr_pos;
    int32_t rd_pos;
    uint8_t *data;
    uint32_t capacity;
    bool_t full;
};

ringbuffer_t ringbufferCreate(uint32_t capacity)
{
    ringbuffer_t inst = zalloc(1* sizeof(struct ringbuffer_instance_t));
    inst->data        = zalloc(capacity * sizeof(uint8_t));
    inst->capacity    = capacity;
    inst->wr_pos      = 0;
    inst->rd_pos      = 0;
    inst->full        = capacity == 0;

    return inst;
}

uint32_t ringbufferCapacity(ringbuffer_t instance)
{
    return instance->capacity;
}

uint32_t ringbufferUsed(ringbuffer_t instance)
{
    if (instance->full)
        return instance->capacity;

    return (instance->wr_pos - instance->rd_pos) % instance->capacity;
}

bool_t ringbufferEmpty(ringbuffer_t instance)
{
    return (!instance->full && (instance->wr_pos == instance->rd_pos));
}

bool_t ringbufferFull(ringbuffer_t instance)
{
    return instance->full;
}

bool_t ringbufferEnqueue(ringbuffer_t instance, uint8_t item)
{
    if (ringbufferFull(instance))
        return FALSE;

    instance->data[instance->wr_pos] = item;
    instance->wr_pos                 = (instance->wr_pos + 1) % instance->capacity;
    if (instance->rd_pos == instance->wr_pos)
        instance->full = TRUE;

    return TRUE;
}

bool_t ringbufferDequeue(ringbuffer_t instance, uint8_t *item)
{
    if (ringbufferEmpty(instance))
        return FALSE;

    instance->full   = FALSE;
    *item            = instance->data[instance->rd_pos];
    instance->rd_pos = (instance->rd_pos + 1) % instance->capacity;

    return TRUE;
}

void ringbufferDestroy(ringbuffer_t instance)
{
    if (instance) {
        if (instance->data) {
            free(instance->data);
        }
        free(instance);
    }
}

void ringbufferDebug(ringbuffer_t instance)
{
    printf("%d/%d %d %d %s\n", ringbufferUsed(instance), ringbufferCapacity(instance),
           instance->wr_pos, instance->rd_pos, instance->full ? "(full)" : "");
}