<?php

namespace WP_CLI\Iterators;

use Countable;
use Iterator;
use ReturnTypeWillChange;
use SplFileObject;
use WP_CLI;

/**
 * Allows incrementally reading and parsing lines from a CSV file.
 */
class CSV implements Countable, Iterator {

    const ROW_SIZE = 4096;

    private $filename;
    private $file_pointer;

    private $delimiter;
    private $columns;

    private $current_index;
    private $current_element;

    public function __construct( $filename, $delimiter = ',' ) {
        $this->filename     = $filename;
        $this->file_pointer = fopen( $filename, 'rb' );
        if ( ! $this->file_pointer ) {
            WP_CLI::error( sprintf( 'Could not open file: %s', $filename ) );
        }

        $this->delimiter = $delimiter;
    }

    #[ReturnTypeWillChange]
    public function rewind() {
        rewind( $this->file_pointer );

        $this->columns = fgetcsv( $this->file_pointer, self::ROW_SIZE, $this->delimiter, '"', '\\' );

        $this->current_index = -1;
        $this->next();
    }

    #[ReturnTypeWillChange]
    public function current() {
        return $this->current_element;
    }

    #[ReturnTypeWillChange]
    public function key() {
        return $this->current_index;
    }

    #[ReturnTypeWillChange]
    public function next() {
        $this->current_element = false;

        while ( true ) {
            $row = fgetcsv( $this->file_pointer, self::ROW_SIZE, $this->delimiter, '"', '\\' );

            if ( false === $row ) {
                break;
            }

            $element = [];
            foreach ( $this->columns as $i => $key ) {
                if ( isset( $row[ $i ] ) ) {
                    $element[ $key ] = $row[ $i ];
                }
            }

            if ( ! empty( $element ) ) {
                $this->current_element = $element;
                ++$this->current_index;

                break;
            }
        }
    }

    #[ReturnTypeWillChange]
    public function count() {
        $file = new SplFileObject( $this->filename, 'r' );
        $file->seek( PHP_INT_MAX );
        return $file->key() + 1;
    }

    #[ReturnTypeWillChange]
    public function valid() {
        return is_array( $this->current_element );
    }
}