Passed
Pull Request — 2.0 (#36)
by Donald
02:59 queued 01:27
created

Key::resolveIndex()   A

Complexity

Conditions 5
Paths 4

Size

Total Lines 19
Code Lines 8

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 0
CRAP Score 30

Importance

Changes 0
Metric Value
eloc 8
dl 0
loc 19
rs 9.6111
c 0
b 0
f 0
ccs 0
cts 0
cp 0
cc 5
nc 4
nop 2
crap 30
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<?php namespace Chekote\NounStore;
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use InvalidArgumentException;
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class Key
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{
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    use Singleton;
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    const ORDINAL_ST = 'st';
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    const ORDINAL_ND = 'nd';
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    const ORDINAL_RD = 'rd';
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    const ORDINAL_TH = 'th';
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    protected static $ordinals = [
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        0 => self::ORDINAL_TH,
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        1 => self::ORDINAL_ST,
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        2 => self::ORDINAL_ND,
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        3 => self::ORDINAL_RD,
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        4 => self::ORDINAL_TH,
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        5 => self::ORDINAL_TH,
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        6 => self::ORDINAL_TH,
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        7 => self::ORDINAL_TH,
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        8 => self::ORDINAL_TH,
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        9 => self::ORDINAL_TH,
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    ];
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    const POSSESSION = "'s ";
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    /**
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     * Builds a key from it's separate key and index values.
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     *
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     * @example buildKey("Item", null): "Item"
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     * @example buildKey("Item", 0): "1st Item"
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     * @example buildKey("Item", 1): "2nd Item"
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     * @example buildKey("Item", 2): "3rd Item"
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     *
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     * @param  string                   $key   The key to check.
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     * @param  int|null                 $index The index (zero indexed) value for the key. If not specified, the method
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     *                                         will not add an index notation to the key.
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     * @throws InvalidArgumentException if $index is less than -1. Note: It should really be zero or higher, but this
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     *                                        method does not assert that. The error is bubbling up from getOrdinal()
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     * @return string                   the key with the index, or just the key if index is null.
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     */
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    public function build($key, $index)
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    {
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        if ($index === null) {
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            return $key;
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        }
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        $nth = $index + 1;
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        return $nth . $this->getOrdinal($nth) . ' ' . $key;
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    }
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    /**
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     * Provides the ordinal notation for the specified nth number.
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     *
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     * @param  int                      $nth the number to determine the ordinal for
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     * @throws InvalidArgumentException if $nth is not a positive number.
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     * @return string                   the ordinal
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     */
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    public function getOrdinal($nth)
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    {
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        if ($nth < 0) {
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            throw new InvalidArgumentException('$nth must be a positive number');
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        }
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        return $nth > 9 && $nth < 20 ? self::ORDINAL_TH : self::$ordinals[substr($nth, -1)];
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    }
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    /**
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     * Parses a key into the separate key and index value.
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     *
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     * @example parseKey("Item"): ["Item", null]
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     * @example parseKey("1st Item"): ["Item", 0]
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     * @example parseKey("2nd Item"): ["Item", 1]
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     * @example parseKey("3rd Item"): ["Item", 2]
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     *
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     * @param  string                   $key the key to parse.
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     * @throws InvalidArgumentException if the key syntax is invalid.
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     * @return array                    a tuple, the 1st being the key with the nth removed, and the 2nd being the
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     *                                      index that the nth translates to, or null if no nth was specified.
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     */
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    public function parse($key)
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    {
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        if (!preg_match("/^(([1-9][0-9]*)(?:st|nd|rd|th) )?([^']+)$/", $key, $matches)) {
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            throw new InvalidArgumentException('Key syntax is invalid');
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        }
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        // @todo use null coalescing operator when upgrading to PHP 7
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        $index = isset($matches[2]) && $matches[2] !== '' ? $matches[2] - 1 : null;
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        $key = $matches[3];
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        return [$key, $index];
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    }
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    /**
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     * Resolves an index and parsed nth value to an index.
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     *
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     * Ensures that if both an index and parsed nth value are provided, that they are equivalent. If only one is
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     * provided, then the appropriate index will be returned. e.g. if an index is provided, it is returned as-is, as
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     * it is already an index. If an nth is provided, it will be returned decremented by 1.
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     *
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     * @param  int|null                 $index the index to process
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     * @param  int|null                 $nth   the nth to process
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     * @throws InvalidArgumentException if both an $index and $key are provided, but the $key contains an nth value
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     *                                        that does not match the index.
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     * @throws InvalidArgumentException if nth is not null and is less than 1
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     * @return int                      the resolved index.
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     */
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    protected function resolveIndex($index, $nth)
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    {
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        // If we don't have an nth, there's nothing to process. We'll just return the $index, even if it's null.
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        if ($nth === null) {
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            return $index;
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        }
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        $decrementedNth = $nth - 1;
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        // If both index and nth are provided, but they aren't equivalent, we need to error out.
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        if ($index !== null && $index !== $decrementedNth) {
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            throw new InvalidArgumentException("index $index was provided with nth $nth, but they are not equivalent");
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        }
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        if ($decrementedNth < 0) {
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            throw new InvalidArgumentException('nth must be equal to or larger than 1');
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        }
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        return $decrementedNth;
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    }
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    /**
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     * Determines if the specified key is a possessive noun.
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     *
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     * @param  string $key
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     * @return bool   true if the key is possessive, false if not
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     */
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    protected function isPossessive($key)
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    {
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        return strpos($key, self::POSSESSION) !== false;
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    }
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}
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