<?php

namespace App\Services\DatasetReader;

use App\Services\CsvReader;

class LinearOrderDataSetReader implements IDataSetReader
{
    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()) {
            $newLine = [];
            foreach ($line as $value) { // Transform to float
                $newLine[] = (float) $value;
            }

            $this->lines[] = $newLine;
        }
    }

    public function getNextLine(): ?array
    {
        if (! isset($this->currentLines[0])) {
            return null; // No more lines to read
        }

        $this->lastReadLineIndex = array_search($this->currentLines[0], $this->lines, true);

        return array_shift($this->currentLines);
    }

    public function getInputSize(): int
    {
        return count($this->lines[0]) - 1; // Don't count the label
    }

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

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

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