<?php

namespace NoccyLabs\Dataset;

use Iterator;
use NoccyLabs\Dataset\Readers\CsvReader;
use NoccyLabs\Dataset\Readers\JsonReader;

/**
 * 
 * 
 * 
 */
class Dataset
{
    protected string $packageName;

    protected string $datasetName;

    protected string $identifier;
    
    protected array $options;

    protected string $version;

    /**
     * 
     * 
     * @param string $identifier The identifier for the dataset (vendor/package#dataset)
     * @param array $options Configured options for the dataset
     * @param string|null $version The package version
     */
    public function __construct(string $identifier, array $options, ?string $version=null)
    {
        $this->identifier = $identifier;
        $this->options = $options;
        $this->version = $version??"0.0.0.0";

        [$this->packageName, $this->datasetName] = explode("#", $identifier, 2);
    }

    /**
     * 
     * @return string
     */
    public function getIdentifier(): string
    {
        return $this->identifier;
    }

    /**
     * 
     * @return string
     */
    public function getPackageName(): string
    {
        return $this->packageName;
    }

    /**
     * 
     * @return string
     */
    public function getDatasetName(): string
    {
        return $this->datasetName;
    }

    /**
     * 
     * @return string
     */
    public function getVersion(): string
    {
        return $this->version;
    }

    /**
     * 
     * @return string|null
     */
    public function getComment(): ?string
    {
        return array_key_exists('comment', $this->options) ? $this->options['comment'] : null;
    }

    /**
     * 
     * @return string|null
     */
    public function getLicense(): ?string
    {
        return array_key_exists('license', $this->options) ? $this->options['license'] : null;
    }

    /**
     * 
     * @return Iterator
     */
    public function open(): Iterator
    {
        $filename = $this->options['filename'];
        $reader = $this->determineReaderForFile($filename);
        $inst = new $reader($filename, $this->options);
        return $inst;
    }

    /**
     * 
     * @param string $filename
     * @return string
     */
    private function determineReaderForFile(string $filename): string
    {
        if ($reader = $this->options['reader']??null) {
            return $reader;
        }
        $ext = pathinfo($filename, PATHINFO_EXTENSION);
        return match ($ext) {
            'json' => JsonReader::class,
            'csv' => CsvReader::class,
            default => throw new \RuntimeException("Unable to determine reader for dataset file")
        };
    }
    
}