<?php

class AWPCP_CSV_Reader {

    private $file = null;

    private $path = null;
    private $settings = array();

    private $header = null;

    private $number_of_rows = null;
    private $current_line = 0;
    private $number_of_lines_processed = 0;

    public function __construct( $path, $settings = array() ) {
        $this->path = $path;
        $this->settings = wp_parse_args( $settings, array(
            'csv-separator' => ',',
        ) );
    }

    public function get_state() {
        return array(
            'path' => $this->path,
            'settings' => $this->settings,
            'header' => $this->header,
            'number_of_rows' => $this->get_number_of_rows(),
            'current_line' => $this->current_line,
            'number_of_lines_processed' => $this->number_of_lines_processed,
        );
    }

    public function get_number_of_rows() {
        if ( is_null( $this->number_of_rows ) ) {
            $this->number_of_rows = $this->get_number_of_lines();
        }

        return $this->number_of_rows;
    }

    private function get_number_of_lines() {
        $auto_detect_line_endings = ini_get( 'auto_detect_line_endings' );
        ini_set( 'auto_detect_line_endings', true );

        $file = $this->get_file_object();
        $file->seek( PHP_INT_MAX );
        $last_line_number = absint( $file->key() );
        $file = null;

        ini_set( 'auto_detect_line_endings', $auto_detect_line_endings );

        return $last_line_number;
    }

    public function get_current_line() {
        return $this->current_line;
    }

    public function get_header() {
        if ( is_null( $this->header ) ) {
            $this->header = $this->get_row_data( 0 );
        }

        return $this->header;
    }

    private function get_row_data( $line_number ) {
        $auto_detect_line_endings = ini_get( 'auto_detect_line_endings' );
        ini_set( 'auto_detect_line_endings', true );

        $file = $this->get_file_object();

        if ( $this->current_line + 1 == $line_number ) {
            $file->next();
            $this->current_line = $line_number;
        } else if ( $line_number != $this->current_line ) {
            $file->seek( $line_number );
            $this->current_line = $line_number;
        }

        if ( ! $file->eof() ) {
            $row_data = $file->current();
            $row_data = array_map( 'awpcp_remove_utf8_non_characters', $row_data );
            $row_data = array_map( 'awpcp_maybe_convert_to_utf8', $row_data );

            // remove unexpected quotes
            foreach ( $row_data as  $index => $column_value ) {
                $row_data[ $index ] = trim( $column_value, '"' );
            }
        } else {
            $row_data = array();
        }

        $file = null;

        ini_set( 'auto_detect_line_endings', $auto_detect_line_endings );

        return $row_data;
    }

    private function get_file_object() {
        if ( is_null( $this->file ) ) {
            $this->file = new SplFileObject( $this->path );
            $this->file->setFlags( SplFileObject::READ_CSV );

            $this->current_line = 0;
        }

        return $this->file;
    }

    public function get_row( $row_number = null ) {
        $header = $this->get_header();
        $row_data = $this->get_row_data( $row_number );
        $filtered_row_data = array_filter( $row_data );

        if ( empty( $filtered_row_data ) ) {
            throw new UnexpectedValueException( __( 'The row was empty.', 'another-wordpress-classifieds-plugin' ) );
        } else if ( count( $header ) != count( $row_data ) ) {
            $message = __( "The number of values in the row (<number-of-values-in-row>) does not match the number of columns in the file's header (<number-of-columns>).", 'another-wordpress-classifieds-plugin' );
            $message = str_replace( '<number-of-values-in-row>', count( $row_data ), $message );
            $message = str_replace( '<number-of-columns>', count( $header ), $message );

            throw new UnexpectedValueException( $message );
        }

        $this->number_of_lines_processed = $this->number_of_lines_processed + 1;

        return array_combine( $header, $row_data );
    }

    public function release() {
        $this->file = null;
    }
}