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<?php

namespace VSP\Core\Traits;

defined( 'ABSPATH' ) || exit;

/**
 * Trait VSP_String_Trait
 *
 * @author Varun Sridharan <varunsridharan23@gmail.com>
 */
trait String_Helper {
    /**
     * MB_ENCODING
     *
     * @var string
     */
    protected static $mb_enc = 'UTF-8';

    /**
     * Returns true if the haystack string starts with needle
     *
     * Note: case-sensitive
     *
     * @param string $haystack
     * @param string $needle
     *
     * @return bool
     */
    public static function str_starts_with( $haystack, $needle ) {
        if ( static::multibyte_loaded() ) {
            if ( '' === $needle ) {
                return true;
            }
            return 0 === mb_strpos( $haystack, $needle, 0, self::$mb_enc );
        } else {
            $needle = self::str_to_ascii( $needle );
            if ( '' === $needle ) {
                return true;
            }
            return 0 === strpos( self::str_to_ascii( $haystack ), self::str_to_ascii( $needle ) );
        }
    }

    /**
     * Returns a string with all non-ASCII characters removed. This is useful
     * for any string functions that expect only ASCII chars and can't
     * safely handle UTF-8. Note this only allows ASCII chars in the range
     * 33-126 (newlines/carriage returns are stripped)
     *
     * @param string $string string to make ASCII
     *
     * @return string
     */
    public static function str_to_ascii( $string ) {
        // strip ASCII chars 32 and under
        $string = filter_var( $string, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_LOW );
        // strip ASCII chars 127 and higher
        return filter_var( $string, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_HIGH );
    }

    /**
     * Return true if the haystack string ends with needle
     * Note: case-sensitive
     *
     * @param string $haystack
     * @param string $needle
     *
     * @return bool
     */
    public static function str_ends_with( $haystack, $needle ) {
        if ( '' === $needle ) {
            return true;
        }
        if ( self::multibyte_loaded() ) {
            return mb_substr( $haystack, -mb_strlen( $needle, self::$mb_enc ), null, self::$mb_enc ) === $needle;
        } else {
            $haystack = self::str_to_ascii( $haystack );
            $needle   = self::str_to_ascii( $needle );
            return substr( $haystack, -strlen( $needle ) ) === $needle;
        }
    }

    /**
     * Returns true if the needle exists in haystack
     * Note: case-sensitive
     *
     * @param string $haystack
     * @param string $needle
     *
     * @return bool
     */
    public static function str_exists( $haystack, $needle ) {
        if ( self::multibyte_loaded() ) {
            if ( '' === $needle ) {
                return false;
            }
            return false !== mb_strpos( $haystack, $needle, 0, self::$mb_enc );
        } else {
            $needle = self::str_to_ascii( $needle );
            if ( '' === $needle ) {
                return false;
            }
            return false !== strpos( self::str_to_ascii( $haystack ), self::str_to_ascii( $needle ) );
        }
    }

    /**
     * Truncates a given $string after a given $length if string is longer than
     * $length. The last characters will be replaced with the $omission string
     * for a total length not exceeding $length
     *
     * @param string $string text to truncate
     * @param int    $length total desired length of string, including omission
     * @param string $omission omission text, defaults to '...'
     *
     * @return string
     */
    public static function str_truncate( $string, $length, $omission = '...' ) {
        if ( self::multibyte_loaded() ) {
            // bail if string doesn't need to be truncated
            if ( mb_strlen( $string, self::$mb_enc ) <= $length ) {
                return $string;
            }
            $length -= mb_strlen( $omission, self::$mb_enc );
            return mb_substr( $string, 0, $length, self::$mb_enc ) . $omission;
        } else {
            $string = self::str_to_ascii( $string );
            // bail if string doesn't need to be truncated
            if ( strlen( $string ) <= $length ) {
                return $string;
            }
            $length -= strlen( $omission );
            return substr( $string, 0, $length ) . $omission;
        }
    }

    /**
     * Converts Numeric Value into Human Readable View
     *
     * @param     $bytes
     * @param int $precision
     *
     * @return string
     * @example 1024B => 1KB | 1024KB => 1MB | 1024MB => 1GB
     */
    public static function to_human_bytes( $bytes, $precision = 2 ) {
        $kilobyte = 1024;
        $megabyte = $kilobyte * 1024;
        $gigabyte = $megabyte * 1024;
        $terabyte = $gigabyte * 1024;

        if ( ( $bytes >= 0 ) && ( $bytes < $kilobyte ) ) {
            return $bytes . ' B';
        } elseif ( ( $bytes >= $kilobyte ) && ( $bytes < $megabyte ) ) {
            return round( $bytes / $kilobyte, $precision ) . ' KB';
        } elseif ( ( $bytes >= $megabyte ) && ( $bytes < $gigabyte ) ) {
            return round( $bytes / $megabyte, $precision ) . ' MB';
        } elseif ( ( $bytes >= $gigabyte ) && ( $bytes < $terabyte ) ) {
            return round( $bytes / $gigabyte, $precision ) . ' GB';
        } elseif ( $bytes >= $terabyte ) {
            return round( $bytes / $terabyte, $precision ) . ' TB';
        } else {
            return $bytes . ' B';
        }
    }
}