<?php
/**
 * Reports REST controller.
 *
 * @package HostKhata
 */

namespace HostKhata\Rest;

defined( 'ABSPATH' ) || exit;

use HostKhata\Core\Capabilities;
use HostKhata\Database\Repositories\ReportRepository;
use HostKhata\Settings\Settings;
use HostKhata\Support\Date;
use WP_Error;
use WP_REST_Request;
use WP_REST_Response;
use WP_REST_Server;

/**
 * `/hostkhata/v1/reports`: the dashboard numbers and the money reports.
 * Needs `hostkhata_view_reports`.
 *
 * @since 0.1.0
 */
final class ReportsController extends BaseController {

	const MAX_DAYS = 1830;

	/**
	 * Route base.
	 *
	 * @var string
	 */
	protected $rest_base = 'reports';

	/**
	 * Report queries.
	 *
	 * @var ReportRepository
	 */
	private $reports;

	/**
	 * Settings.
	 *
	 * @var Settings
	 */
	private $settings;

	/**
	 * Constructor.
	 *
	 * @param ReportRepository $reports  Report queries.
	 * @param Settings         $settings Settings.
	 */
	public function __construct( ReportRepository $reports, Settings $settings ) {
		$this->reports  = $reports;
		$this->settings = $settings;
	}

	/**
	 * Registers the routes.
	 *
	 * @since 0.1.0
	 *
	 * @return void
	 */
	public function register_routes() {
		$permission = Permissions::require_capability( Capabilities::VIEW_REPORTS );
		$range      = array(
			'from' => array(
				'type'    => 'string',
				'default' => '',
			),
			'to'   => array(
				'type'    => 'string',
				'default' => '',
			),
		);

		register_rest_route(
			$this->namespace,
			'/' . $this->rest_base . '/dashboard',
			array(
				'methods'             => WP_REST_Server::READABLE,
				'callback'            => array( $this, 'dashboard' ),
				'permission_callback' => $permission,
			)
		);

		register_rest_route(
			$this->namespace,
			'/' . $this->rest_base . '/summary',
			array(
				'methods'             => WP_REST_Server::READABLE,
				'callback'            => array( $this, 'summary' ),
				'permission_callback' => $permission,
				'args'                => $range,
			)
		);
	}

	/**
	 * Numbers for the dashboard: counts, this month and last 12 months.
	 *
	 * @since 0.1.0
	 *
	 * @return WP_REST_Response
	 */
	public function dashboard(): WP_REST_Response {
		$today = Date::today_gmt();
		$month = substr( $today, 0, 8 ) . '01';
		$from  = Date::add_months( $month, -11 );

		$counts = $this->reports->dashboard_counts( $today, $month, Date::add_days( $today, 30 ) );
		$totals = $this->reports->totals( $month, $today );

		$counts['overdue_amount_formatted'] = $this->settings->format_money( $counts['overdue_amount'] );
		$counts['outstanding_formatted']    = $this->settings->format_money( $counts['outstanding'] );

		return rest_ensure_response(
			array(
				'counts'  => $counts,
				'month'   => array_merge(
					$totals,
					array(
						'net'                => $totals['received'] - $totals['refunded'],
						'received_formatted' => $this->settings->format_money( $totals['received'] - $totals['refunded'] ),
						'invoiced_formatted' => $this->settings->format_money( $totals['invoiced'] ),
					)
				),
				'revenue' => $this->with_money( $this->fill_months( $this->reports->revenue_by_month( $from, $today ), $from, 12 ) ),
				'aging'   => $this->with_money( $this->reports->aging( $today ), 'amount' ),
			)
		);
	}

	/**
	 * The reports for a date range.
	 *
	 * @since 0.1.0
	 *
	 * @param WP_REST_Request $request Request: `from`, `to` (`YYYY-MM-DD`).
	 * @return WP_REST_Response|WP_Error
	 */
	public function summary( $request ) {
		$range = $this->range( (string) $request['from'], (string) $request['to'] );

		if ( is_wp_error( $range ) ) {
			return $range;
		}

		list( $from, $to ) = $range;

		$totals = $this->reports->totals( $from, $to );

		return rest_ensure_response(
			array(
				'from'          => $from,
				'to'            => $to,
				'totals'        => array_merge(
					$totals,
					array(
						'net'                => $totals['received'] - $totals['refunded'],
						'received_formatted' => $this->settings->format_money( $totals['received'] ),
						'refunded_formatted' => $this->settings->format_money( $totals['refunded'] ),
						'invoiced_formatted' => $this->settings->format_money( $totals['invoiced'] ),
						'tax_formatted'      => $this->settings->format_money( $totals['tax'] ),
						'net_formatted'      => $this->settings->format_money( $totals['received'] - $totals['refunded'] ),
					)
				),
				'by_month'      => $this->with_money( $this->reports->revenue_by_month( $from, $to ) ),
				'by_method'     => $this->with_money( $this->reports->revenue_by_method( $from, $to ) ),
				'tax'           => array_map(
					function ( array $row ) {
						$row['net_formatted'] = $this->settings->format_money( $row['net'] );
						$row['tax_formatted'] = $this->settings->format_money( $row['tax'] );

						return $row;
					},
					$this->reports->tax_by_rate( $from, $to )
				),
				'aging'         => $this->with_money( $this->reports->aging( Date::today_gmt() ), 'amount' ),
				'top_customers' => $this->with_money( $this->reports->top_customers( $from, $to, 10 ) ),
			)
		);
	}

	/**
	 * Validates a date range; defaults to the last 12 months.
	 *
	 * @param string $from From.
	 * @param string $to   To.
	 * @return array{0: string, 1: string}|WP_Error
	 */
	private function range( string $from, string $to ) {
		$today = Date::today_gmt();
		$to    = '' === $to ? $today : $to;
		$from  = '' === $from ? Date::add_months( substr( $today, 0, 8 ) . '01', -11 ) : $from;

		if ( ! Date::is_valid_date( $from ) || ! Date::is_valid_date( $to ) ) {
			return $this->error( 'hostkhata_invalid_range', __( 'Choose valid dates.', 'hostkhata' ), 400 );
		}

		if ( $from > $to ) {
			return $this->error( 'hostkhata_invalid_range', __( 'The start date must not be after the end date.', 'hostkhata' ), 400 );
		}

		if ( Date::days_between( $from, $to ) > self::MAX_DAYS ) {
			return $this->error( 'hostkhata_invalid_range', __( 'Choose a period of five years or less.', 'hostkhata' ), 400 );
		}

		return array( $from, $to );
	}

	/**
	 * Adds a formatted amount next to each `total` (or the named key).
	 *
	 * @param array<int, array<string, mixed>> $rows Rows.
	 * @param string                           $key  Amount key.
	 * @return array<int, array<string, mixed>>
	 */
	private function with_money( array $rows, string $key = 'total' ): array {
		foreach ( $rows as &$row ) {
			$row[ $key . '_formatted' ] = $this->settings->format_money( (int) $row[ $key ] );
		}

		return $rows;
	}

	/**
	 * Gives every month in the range a row, so a chart has no gaps.
	 *
	 * @param array<int, array<string, mixed>> $rows   Rows from the query.
	 * @param string                           $start  First day of the first month.
	 * @param int                              $months Number of months.
	 * @return array<int, array<string, mixed>>
	 */
	private function fill_months( array $rows, string $start, int $months ): array {
		$by_month = array();

		foreach ( $rows as $row ) {
			$by_month[ $row['month'] ] = $row;
		}

		$result = array();

		for ( $i = 0; $i < $months; $i++ ) {
			$key      = substr( Date::add_months( $start, $i ), 0, 7 );
			$result[] = $by_month[ $key ] ?? array(
				'month'    => $key,
				'total'    => 0,
				'payments' => 0,
			);
		}

		return $result;
	}
}