<?php
/**
 * Bulk actions (price changes in Free; Pro adds more) processed in chunks.
 *
 * @package CodeCraft\Gridsmith
 */

defined( 'ABSPATH' ) || exit;

/**
 * Chunked bulk runner.
 */
class BDBE_Bulk {

	/**
	 * Records processed per request.
	 */
	const CHUNK = 40;

	/**
	 * Price modes.
	 *
	 * @return array
	 */
	public static function price_modes() {
		return array(
			'increase_percent'      => __( 'Increase by %', 'gridsmith' ),
			'decrease_percent'      => __( 'Decrease by %', 'gridsmith' ),
			'increase_amount'       => __( 'Increase by fixed amount', 'gridsmith' ),
			'decrease_amount'       => __( 'Decrease by fixed amount', 'gridsmith' ),
			'set'                   => __( 'Set to', 'gridsmith' ),
			'regular_minus_percent' => __( 'Regular price minus % (sale price only)', 'gridsmith' ),
			'clear'                 => __( 'Remove (sale price only)', 'gridsmith' ),
		);
	}

	/**
	 * Registered bulk actions.
	 *
	 * @return array name => array( label, params, compute )
	 */
	public static function actions() {
		$actions = array(
			'price' => array(
				'label'   => __( 'Bulk price change', 'gridsmith' ),
				'params'  => array( __CLASS__, 'price_params' ),
				'compute' => array( __CLASS__, 'price_compute' ),
				'prices'  => true,
			),
		);
		return (array) apply_filters( 'bdbe_bulk_actions', $actions );
	}

	/**
	 * Sanitise price parameters.
	 *
	 * @param array $raw Raw params.
	 * @return array|WP_Error
	 */
	public static function price_params( array $raw ) {
		$target = isset( $raw['target'] ) ? sanitize_key( $raw['target'] ) : '';
		$mode   = isset( $raw['mode'] ) ? sanitize_key( $raw['mode'] ) : '';
		$value  = isset( $raw['value'] ) ? wc_format_decimal( sanitize_text_field( (string) $raw['value'] ) ) : '';

		if ( ! in_array( $target, array( 'regular_price', 'sale_price' ), true ) ) {
			return new WP_Error( 'bdbe_target', __( 'Choose which price to change.', 'gridsmith' ), array( 'status' => 400 ) );
		}
		if ( ! array_key_exists( $mode, self::price_modes() ) ) {
			return new WP_Error( 'bdbe_mode', __( 'Choose how to change the price.', 'gridsmith' ), array( 'status' => 400 ) );
		}
		if ( in_array( $mode, array( 'regular_minus_percent', 'clear' ), true ) && 'sale_price' !== $target ) {
			return new WP_Error( 'bdbe_mode', __( 'This option only works on the sale price.', 'gridsmith' ), array( 'status' => 400 ) );
		}
		if ( 'clear' !== $mode && ( '' === $value || ! is_numeric( $value ) || (float) $value < 0 ) ) {
			return new WP_Error( 'bdbe_value', __( 'Enter a number of 0 or more.', 'gridsmith' ), array( 'status' => 400 ) );
		}
		if ( in_array( $mode, array( 'decrease_percent', 'regular_minus_percent' ), true ) && (float) $value > 100 ) {
			return new WP_Error( 'bdbe_value', __( 'A percentage decrease cannot be more than 100.', 'gridsmith' ), array( 'status' => 400 ) );
		}

		$labels = array(
			'regular_price' => __( 'Regular price', 'gridsmith' ),
			'sale_price'    => __( 'Sale price', 'gridsmith' ),
		);
		$signs  = array(
			'increase_percent'      => '+' . $value . '%',
			'decrease_percent'      => '−' . $value . '%',
			'increase_amount'       => '+' . $value,
			'decrease_amount'       => '−' . $value,
			'set'                   => '= ' . $value,
			/* translators: %s: percentage. */
			'regular_minus_percent' => sprintf( __( '= regular − %s%%', 'gridsmith' ), $value ),
			'clear'                 => __( 'removed', 'gridsmith' ),
		);

		return array(
			'target' => $target,
			'mode'   => $mode,
			'value'  => (float) $value,
			'label'  => $labels[ $target ] . ' ' . $signs[ $mode ],
		);
	}

	/**
	 * New price for one product.
	 *
	 * @param WC_Product $product Product.
	 * @param array      $params  Sanitised params.
	 * @return array|null field => value, or null to skip.
	 */
	public static function price_compute( $product, array $params ) {
		if ( ! BDBE_Entity_Products::has_own_price( $product ) ) {
			return null;
		}
		$target  = $params['target'];
		$value   = (float) $params['value'];
		$regular = $product->get_regular_price( 'edit' );
		$base    = 'regular_price' === $target ? $regular : $product->get_sale_price( 'edit' );

		switch ( $params['mode'] ) {
			case 'set':
				$new = $value;
				break;
			case 'clear':
				return array( $target => '' );
			case 'regular_minus_percent':
				if ( '' === $regular ) {
					return null;
				}
				$new = (float) $regular * ( 1 - $value / 100 );
				break;
			default:
				if ( '' === $base ) {
					return null;
				}
				$base = (float) $base;
				if ( 'increase_percent' === $params['mode'] ) {
					$new = $base * ( 1 + $value / 100 );
				} elseif ( 'decrease_percent' === $params['mode'] ) {
					$new = $base * ( 1 - $value / 100 );
				} elseif ( 'increase_amount' === $params['mode'] ) {
					$new = $base + $value;
				} else {
					$new = $base - $value;
				}
		}

		$decimals = wc_get_price_decimals();
		$new      = max( 0, round( $new, $decimals ) );
		return array( $target => wc_format_decimal( $new, $decimals ) );
	}

	/**
	 * Run one chunk of a bulk action.
	 *
	 * @param string $action  Action name.
	 * @param array  $params  Raw params.
	 * @param array  $scope   { ids: int[] } or { filters: array }.
	 * @param int    $offset  Offset in the matching list.
	 * @param string $token   Batch token ('' starts a new batch).
	 * @param string $context bulk|schedule.
	 * @return array|WP_Error
	 */
	public static function run( $action, array $params, array $scope, $offset, $token, $context = 'bulk' ) {
		$actions = self::actions();
		if ( ! isset( $actions[ $action ] ) ) {
			return new WP_Error( 'bdbe_action', __( 'Unknown bulk action.', 'gridsmith' ), array( 'status' => 400 ) );
		}
		$def    = $actions[ $action ];
		$params = call_user_func( $def['params'], $params );
		if ( is_wp_error( $params ) ) {
			return $params;
		}

		$entity = BDBE_Plugin::entity( 'product' );
		if ( ! empty( $scope['ids'] ) ) {
			$ids = array_values( array_unique( array_filter( array_map( 'absint', (array) $scope['ids'] ) ) ) );
		} else {
			$ids = $entity->matching_ids( isset( $scope['filters'] ) ? (array) $scope['filters'] : array() );
		}

		$offset  = max( 0, (int) $offset );
		$token   = '' !== $token ? $token : wp_generate_uuid4();
		$total   = count( $ids );
		$chunk   = array_slice( $ids, $offset, self::CHUNK );
		$changes = array();
		$names   = array();
		$skipped = 0;

		foreach ( $chunk as $id ) {
			$product = $entity->load( $id );
			if ( ! $product ) {
				++$skipped;
				continue;
			}
			$targets = array( $product );
			if ( $product->is_type( 'variable' ) ) {
				/**
				 * Variations to process in place of a variable product (Pro).
				 *
				 * @param WC_Product[] $variations Variations (empty in Free).
				 * @param WC_Product   $product    Variable product.
				 * @param array        $scope      Scope incl. include_variations.
				 */
				$targets = (array) apply_filters( 'bdbe_bulk_expand', array(), $product, $scope );
				if ( ! $targets && ! empty( $def['prices'] ) ) {
					++$skipped;
					continue;
				}
				if ( ! $targets ) {
					$targets = array( $product );
				}
			}
			foreach ( $targets as $target ) {
				$fields = call_user_func( $def['compute'], $target, $params );
				if ( null === $fields || is_wp_error( $fields ) || ! $fields ) {
					if ( null === $fields && ! empty( $def['prices'] ) ) {
						++$skipped;
					}
					continue;
				}
				$changes[ $target->get_id() ] = $fields;
				$names[ $target->get_id() ]   = $target->get_name();
			}
		}

		$result = BDBE_Changes::apply(
			$entity,
			$changes,
			array(
				'label'   => $params['label'],
				'token'   => $token,
				'context' => $context,
			)
		);

		$errors = array();
		foreach ( $result['errors'] as $id => $messages ) {
			$name     = isset( $names[ $id ] ) ? $names[ $id ] : '#' . $id;
			$errors[] = $name . ': ' . implode( ' ', $messages );
		}
		$next = $offset + count( $chunk );

		return array(
			'token'       => $token,
			'total'       => $total,
			'processed'   => count( $chunk ),
			'changed'     => count( $result['saved'] ),
			'skipped'     => $skipped,
			'errors'      => $errors,
			'next_offset' => $next < $total ? $next : null,
			'label'       => $params['label'],
		);
	}
}