<?php
/**
 * CSV export of loans and import of borrowers. Cells that a spreadsheet would read as a formula
 * are prefixed with an apostrophe (CSV injection).
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class WPIMLend_CSV {

	public static function cell( $value ) {
		$value = (string) $value;
		if ( '' !== $value && in_array( $value[0], [ '=', '+', '-', '@', "\t", "\r" ], TRUE ) ) {
			$value = "'" . $value;
		}

		return $value;
	}

	/**
	 * Streams the loans of a dashboard view (open | due_today | overdue | returned | history).
	 */
	public static function export_loans( $view ) {
		$views = [ 'open', 'due_today', 'overdue', 'returned', 'history' ];
		$view  = in_array( $view, $views, TRUE ) ? $view : 'open';

		nocache_headers();
		header( 'Content-Type: text/csv; charset=utf-8' );
		header( 'Content-Disposition: attachment; filename="lending-' . $view . '-' . wp_date( 'Y-m-d' ) . '.csv"' );

		$out = fopen( 'php://output', 'w' );
		fputcsv( $out, [ 'loan_id', 'borrower', 'email', 'group', 'item_number', 'item_name', 'unit', 'quantity', 'still_out', 'checked_out', 'due_date', 'status' ] );

		$today  = WPIMLend_Availability::today();
		$offset = 0;
		do {
			$loans = WPIMLend_Repo::list_loans( $view, $today, [], 500, $offset );
			$lines = WPIMLend_Repo::lines_for_loans( wp_list_pluck( $loans, 'loan_id' ) );
			$ids   = [];
			foreach ( $lines as $ls ) {
				foreach ( $ls as $l ) {
					$ids[] = $l->inventory_id;
				}
			}
			$core = WPIMLend_Repo::get_core_items( $ids );

			foreach ( $loans as $loan ) {
				foreach ( isset( $lines[ $loan->loan_id ] ) ? $lines[ $loan->loan_id ] : [] as $l ) {
					$c    = isset( $core[ $l->inventory_id ] ) ? $core[ $l->inventory_id ] : NULL;
					$unit = $l->unit_id ? WPIMLend_Repo::get_unit( $l->unit_id ) : NULL;
					fputcsv( $out, array_map( [ __CLASS__, 'cell' ], [
						$loan->loan_id,
						$loan->borrower_name,
						$loan->borrower_email,
						$loan->borrower_group,
						$c ? $c->inventory_number : '',
						$c ? $c->inventory_name : '(deleted)',
						$unit ? $unit->code : '',
						$l->quantity,
						(int) $l->quantity - (int) $l->returned_quantity,
						get_date_from_gmt( $loan->out_at, 'Y-m-d H:i' ),
						$loan->due_date,
						$loan->status,
					] ) );
				}
			}
			$offset += 500;
		} while ( count( $loans ) === 500 );

		fclose( $out ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fclose -- closes the php://output stream opened above
	}

	/**
	 * @param array|null $file An entry from $_FILES.
	 *
	 * @return array [ 'ok' => bool, 'message' => string ]
	 */
	public static function import_borrowers( $file ) {
		if ( empty( $file['tmp_name'] ) || ! is_uploaded_file( $file['tmp_name'] ) ) {
			return [ 'ok' => FALSE, 'message' => __( 'Choose a CSV file.', 'borrowdesk' ) ];
		}
		$check = wp_check_filetype( $file['name'], [ 'csv' => 'text/csv', 'txt' => 'text/plain' ] );
		if ( ! $check['ext'] ) {
			return [ 'ok' => FALSE, 'message' => __( 'That is not a CSV file.', 'borrowdesk' ) ];
		}

		$handle = fopen( $file['tmp_name'], 'r' ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fopen -- fgetcsv() over the uploaded temp file; WP_Filesystem has no CSV line reader
		if ( ! $handle ) {
			return [ 'ok' => FALSE, 'message' => __( 'The file could not be read.', 'borrowdesk' ) ];
		}

		$added   = 0;
		$skipped = 0;
		$row_no  = 0;
		while ( ( $row = fgetcsv( $handle ) ) !== FALSE ) {
			$row_no ++;
			$row = array_map( 'trim', $row );
			if ( 1 === $row_no && isset( $row[0] ) && 'name' === strtolower( preg_replace( '/^\xEF\xBB\xBF/', '', $row[0] ) ) ) {
				continue; // header
			}
			$name = sanitize_text_field( $row[0] ?? '' );
			if ( '' === $name ) {
				$skipped ++;
				continue;
			}
			$email = sanitize_email( $row[1] ?? '' );
			if ( $email && WPIMLend_Repo::find_borrower_by_email( $email ) ) {
				$skipped ++;
				continue;
			}
			$id = WPIMLend_Repo::save_borrower( [
				'name'           => $name,
				'email'          => $email,
				'phone'          => sanitize_text_field( $row[2] ?? '' ),
				'borrower_group' => sanitize_text_field( $row[3] ?? '' ),
				'notes'          => sanitize_textarea_field( $row[4] ?? '' ),
				'user_id'        => 0,
			] );
			$id ? $added ++ : $skipped ++;
		}
		fclose( $handle ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fclose -- closes the uploaded temp file opened above

		return [
			'ok'      => TRUE,
			/* translators: 1: added, 2: skipped */
			'message' => sprintf( __( 'Imported %1$d borrowers, skipped %2$d.', 'borrowdesk' ), $added, $skipped ),
		];
	}
}