<?php

declare(strict_types=1);

namespace Doctrine\RST\Parser;

use function array_pop;
use function count;
use function implode;

final class Buffer
{
    /** @var string[] */
    private $lines = [];

    /** @param string[] $lines */
    public function __construct(array $lines = [])
    {
        $this->lines = $lines;
    }

    public function isEmpty(): bool
    {
        return $this->lines === [];
    }

    public function count(): int
    {
        return count($this->lines);
    }

    public function has(int $key): bool
    {
        return isset($this->lines[$key]);
    }

    public function get(int $key): string
    {
        return $this->lines[$key] ?? '';
    }

    public function push(string $line): void
    {
        $this->lines[] = $line;
    }

    public function set(int $key, string $line): void
    {
        $this->lines[$key] = $line;
    }

    /** @return string[] */
    public function getLines(): array
    {
        return $this->lines;
    }

    public function getLinesString(): string
    {
        return implode("\n", $this->lines);
    }

    public function pop(): ?string
    {
        return array_pop($this->lines);
    }

    public function getLastLine(): ?string
    {
        $lastLineKey = count($this->lines) - 1;

        if (! isset($this->lines[$lastLineKey])) {
            return null;
        }

        return $this->lines[$lastLineKey];
    }
}