package com.vincent.rsf.common.utils;

import lombok.extern.slf4j.Slf4j;

import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.List;

/**
 * news stories for zoneyung
 * Created by vincent on 2022/12/22
 */
@Slf4j
@SuppressWarnings({"all"})
public class CoolsQueue<T> {

    private final transient Class<T> cls;
    private final T[] arr;
    private final int capacity;
    private int head;
    private int tail;

    { this.head = 0; this.tail = 0; }

    public CoolsQueue(Class<T> cls, int capacity) {
        this.cls = cls;
        this.arr = (T[]) Array.newInstance(cls, capacity);
        this.capacity = capacity;
    }

    public synchronized boolean offer(T t) {
        if (this.tail == this.capacity) {
            this.peek();
        }
        this.reform();
        this.arr[this.tail] = t;
        this.tail ++;
        return true;
    }

    public synchronized boolean put(T t) {
        if (this.tail == this.capacity) {
            return false;
        } else {
            this.reform();
        }
        this.arr[this.tail] = t;
        this.tail ++;
        return true;
    }

    public synchronized T peek() {
        if (this.head == this.tail) {
            return null;
        }
        T t = this.arr[this.head];
        this.head ++;
        this.reform();
        return t;
    }

    private void reform() {
        for (int i = this.head; i < this.tail; i++) {
            this.arr[i-this.head] = this.arr[i];
        }
        this.tail -= this.head;
        this.head = 0;
    }

    public synchronized int size() {
        return this.tail - this.head;
    }

    public synchronized List<T> data() {
        T[] ts = (T[]) Array.newInstance(this.cls, size());
        if (this.tail - this.head >= 0) {
            System.arraycopy(this.arr, this.head, ts, 0, this.tail - this.head);
        }
        return Arrays.asList(ts);
    }

}