<?php

namespace App\Services;

class DataSetReader {
    public array $lines = [];
    private array $currentLines = [];

    private int $lastReadLineIndex = -1;

    public function __construct(
        public string $filename,
    ) {
        // For now, we only support CSV files, so we can delegate to CsvReader
        $csvReader = new CsvReader($filename);
        $this->readEntireFile($csvReader);
        $this->reset();
    }

    private function readEntireFile(CsvReader $reader): void
    {
        while ($line = $reader->readNextLine()) {
            $this->lines[] = $line;
        }
    }

    public function getRandomLine(): array | null
    {
        if (empty($this->currentLines)) {
            return null; // No more lines to read
        }
        $randomNumber = array_rand($this->currentLines);
        $randomLine = $this->currentLines[$randomNumber];
        // Remove the line from the current lines to avoid repetition
        unset($this->currentLines[$randomNumber]);
        $this->lastReadLineIndex = array_search($randomLine, $this->lines, true);
        return $randomLine;
    }

    public function reset(): void
    {
        $this->currentLines = $this->lines;
    }

    public function getLastReadLineIndex(): int
    {
        return $this->lastReadLineIndex;
    }
}