<?php

namespace com\foo;

use \Exception;

/**
 * A class for handling tabular data
 *
 * @package com.foo
 * @author Tomas Sandven
 **/
class Tabular_Data
{
    // Constants
    const SUPPORTED_FILE_TYPES = 'csv,xls,xlsx';

    // Fields
    private $data = false;
    private $initiated = false;

    /**
     * Constructor for Tabular_Data class. Use factory functions.
     *
     * @author Tomas Sandven
     **/
    public function __construct() {}

    /**
     * Creates a new Tabular_Data object and attempts to load data from the
     * input file. Throws exceptions upon errors. Error codes:
     * - 1001: Input file does not exist
     * - 1002: No read access of input file
     * - 1003: Input file type is not supported
     * - 1004: Error reading file content, could be corrupt file or a code bug
     *
     * Supported file types:
     * - *.csv
     * - *.xls
     * - *.xlsx
     *
     * @param $filepath: The path of the tabular data file
     * @param $columns: An array of the column names to include. This can be
     *                  omitted to load all columns.
     *
     * @return Tabular_Data
     * @author Tomas Sandven
     **/
    public function loadFromFile($filepath)
    {
        // Prepare locals necessary for validation
        $filename = @end(explode('/', $filepath));
        $extension = @end(explode('.', $filename));
        $exts = explode(',', self::SUPPORTED_FILE_TYPES);

        // Don't let this class be initiated twice
        if($this->initiated) throw new Exception(
            'Already initiated! Only use factory functions!', 1);

        // Check if the file exists
        if(!is_file($filepath)) throw new Exception(
            'Input file does not exist', 1001);

        // File must be readable
        if(!is_readable($filepath)) throw new Exception(
            'Lacking permission to read the input file', 1002);

        // File type must be supported
        if(!in_array($extension, $exts))
            throw new Exception('File type not supported', 1003);

        // TODO
    }

    /**
     * Loads tabular data using the PHPExcel library.
     *
     * @param $filepath: The path of the tabular data file
     * @param $columns: An array of the column names to include. This can be
     *                  omitted to load all columns.
     *
     * @return array
     * @author Tomas Sandven
    **/
    public function _loadExcelData($filepath, $columns = false)
    {

    }

    // #############################
    // ##### FACTORY FUNCTIONS #####
    // #############################

    /**
     * Shortcut for running creating a Tabular_Data instance from a file
     *
     * @author Tomas Sandven
     **/
    public static function fromFile($filepath, $columns = false)
    {
        $td = new Tabular_Data;
        $td->loadFromFile($filepath, $columns);

        return $td;
    }
}

// Debug
if(!defined('BITO'))
{
    $td = Tabular_Data::fromFile('/home/codemonkey/foo/bison.xlsx');
}