#include "history.h"

void hisbuf_init(HistoryBuffer *sb) {
    sb->front = 0;
    sb->rear = 0;
    sb->size = 0;
}

int hisbuf_is_full(HistoryBuffer *sb) {
    return sb->size == HISTORY_SIZE;
}

int hisbuf_push(HistoryBuffer *sb, HistoryEntry entry) {
    if (sb->size < HISTORY_SIZE) {
        sb->data[sb->rear] = entry;
        sb->rear = (sb->rear + 1) % HISTORY_SIZE;
        sb->size++;
        return 1; // Success
    }
    return 0; // Buffer full
}

int hisbuf_pop(HistoryBuffer *sb) {
    if (sb->size > 0) {
        sb->front = (sb->front + 1) % HISTORY_SIZE;
        sb->size--;
        return 1; // Success
    }
    return 0; // Buffer empty
}

int hisbuf_pop_data(HistoryBuffer *sb, HistoryEntry *out) {
    if (sb->size > 0) {
        *out = sb->data[sb->front];
        sb->front = (sb->front + 1) % HISTORY_SIZE;
        sb->size--;
        return 1; // Success
    }
    return 0; // Buffer empty
}

void hisbuf_get(HistoryBuffer *sb, HistoryEntry *out, int lookahead) {
    if (lookahead >= 0 && lookahead < sb->size) {
        // 가장 최근에 넣은 것(rear - 1)을 기준으로 lookahead
        int index = (sb->rear - 1 - lookahead + HISTORY_SIZE) % HISTORY_SIZE;
        *out = sb->data[index];
    }
}