<?php

namespace TablePress\PhpOffice\PhpSpreadsheet\Worksheet\PivotTable;

/**
 * Describes how a single source (cache) field is grouped in a pivot table.
 *
 * Two kinds of grouping are supported:
 *
 * - Numeric range grouping: values are bucketed into fixed-width intervals
 *   between a start and end number (e.g. 0-100, 100-200, ...).
 * - Date grouping: date/time values are grouped by one or more calendar parts
 *   (years, quarters, months, ...).
 *
 * The grouping is emitted into the pivot cache definition; when the workbook is
 * opened, the spreadsheet application applies it while refreshing the pivot.
 *
 * @see PivotTableBuilder
 */
class PivotFieldGroup
{
	const TYPE_NUMERIC = 'numeric';
	const TYPE_DATE = 'date';

	// Date grouping units, matching the rangePr@groupBy attribute values.
	const GROUP_BY_SECONDS = 'seconds';
	const GROUP_BY_MINUTES = 'minutes';
	const GROUP_BY_HOURS = 'hours';
	const GROUP_BY_DAYS = 'days';
	const GROUP_BY_MONTHS = 'months';
	const GROUP_BY_QUARTERS = 'quarters';
	const GROUP_BY_YEARS = 'years';

	private string $type;

	/**
	 * Numeric grouping: the width of each bucket.
	 */
	private float $interval = 1.0;

	private ?float $startNum = null;

	private ?float $endNum = null;

	/**
	 * Date grouping: the calendar units to group by, in coarse-to-fine order.
	 *
	 * @var string[]
	 */
	private array $groupBy = [];

	private ?string $startDate = null;

	private ?string $endDate = null;

	private function __construct(string $type)
	{
		$this->type = $type;
	}

	/**
	 * Create a numeric range grouping (buckets of $interval width).
	 */
	public static function numeric(float $interval, ?float $startNum = null, ?float $endNum = null): self
	{
		$group = new self(self::TYPE_NUMERIC);
		$group->interval = $interval;
		$group->startNum = $startNum;
		$group->endNum = $endNum;

		return $group;
	}

	/**
	 * Create a date grouping by one or more calendar units.
	 *
	 * @param string|string[] $groupBy one or more GROUP_BY_* constants
	 */
	public static function date($groupBy, ?string $startDate = null, ?string $endDate = null): self
	{
		$group = new self(self::TYPE_DATE);
		$group->groupBy = is_array($groupBy) ? array_values($groupBy) : [$groupBy];
		$group->startDate = $startDate;
		$group->endDate = $endDate;

		return $group;
	}

	public function getType(): string
	{
		return $this->type;
	}

	public function isNumeric(): bool
	{
		return $this->type === self::TYPE_NUMERIC;
	}

	public function isDate(): bool
	{
		return $this->type === self::TYPE_DATE;
	}

	public function getInterval(): float
	{
		return $this->interval;
	}

	public function getStartNum(): ?float
	{
		return $this->startNum;
	}

	public function getEndNum(): ?float
	{
		return $this->endNum;
	}

	/**
	 * @return string[]
	 */
	public function getGroupBy(): array
	{
		return $this->groupBy;
	}

	public function getStartDate(): ?string
	{
		return $this->startDate;
	}

	public function getEndDate(): ?string
	{
		return $this->endDate;
	}
}