<?php

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

/**
 * Handles scheduled supplier exports and related admin actions.
 */
class Siti_Stock_Supplier_Exports {

	const CRON_HOOK = 'siti_stock_plugin_supplier_export';
	const SUPPLIER_META_KEY = '_wpbc_supplier';

	/**
	 * @var Siti_Stock_Settings
	 */
	private $settings;

	/**
	 * @var Siti_Stock_Admin_Notices
	 */
	private $notices;

	/**
	 * Cached supplier configs.
	 *
	 * @var array<string,array<string,mixed>>|null
	 */
	private $supplier_cache = null;

	/**
	 * @param Siti_Stock_Settings      $settings Settings repository.
	 * @param Siti_Stock_Admin_Notices $notices Notice handler.
	 */
	public function __construct( Siti_Stock_Settings $settings, Siti_Stock_Admin_Notices $notices ) {
		$this->settings = $settings;
		$this->notices  = $notices;
	}

	/**
	 * Register hooks for cron and admin actions.
	 */
	public function register_hooks() {
		add_action( self::CRON_HOOK, array( $this, 'run_scheduled_export' ), 10, 1 );
		add_action( 'admin_post_siti_stock_send_supplier_export', array( $this, 'handle_manual_export' ) );
		add_action( 'admin_post_siti_stock_save_supplier_schedule', array( $this, 'handle_schedule_save' ) );
		add_action( 'update_option_' . $this->settings->get_option_key(), array( $this, 'handle_settings_update' ), 10, 2 );
	}

	/**
	 * Trigger export when cron fires.
	 *
	 * @param string $supplier_key Supplier identifier.
	 */
	public function run_scheduled_export( $supplier_key ) {
		$this->send_export( $supplier_key );
	}

	/**
	 * Ensure all configured suppliers are scheduled.
	 */
	public function maybe_schedule_all() {
		$configs = $this->get_supplier_configs();

		foreach ( $configs as $key => $config ) {
			if ( empty( $config['enabled'] ) || empty( $config['time'] ) ) {
				$this->clear_schedule_for_supplier( $key );
				continue;
			}

			if ( ! wp_next_scheduled( self::CRON_HOOK, array( $key ) ) ) {
				$this->schedule_supplier( $key, $config );
			}
		}
	}

	/**
	 * Clear and reschedule cron hooks based on current settings.
	 */
	public function reschedule_all() {
		wp_clear_scheduled_hook( self::CRON_HOOK );

		$configs = $this->get_supplier_configs();
		foreach ( $configs as $key => $config ) {
			$this->schedule_supplier( $key, $config );
		}
	}

	/**
	 * Remove scheduled events and cache.
	 */
	public function reset_cache() {
		$this->supplier_cache = null;
	}

	/**
	 * Clear all cron events for this feature.
	 */
	public static function clear_all_schedules() {
		wp_clear_scheduled_hook( self::CRON_HOOK );
	}

	/**
	 * Handle manual export submission.
	 */
	public function handle_manual_export() {
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_die( esc_html__( 'Onvoldoende rechten.', 'siti-stock-plugin' ) );
		}

		check_admin_referer( 'siti_stock_send_supplier_export' );

		$supplier_key = isset( $_POST['supplier_key'] ) ? sanitize_text_field( wp_unslash( $_POST['supplier_key'] ) ) : '';
		$result       = $this->send_export( $supplier_key );

		if ( is_wp_error( $result ) ) {
			$this->notices->add_notice( $result->get_error_message(), 'error' );
		} else {
			$this->notices->add_notice(
				sprintf(
					/* translators: %s supplier label */
					__( 'Export voor %s verzonden.', 'siti-stock-plugin' ),
					isset( $result['label'] ) ? $result['label'] : $supplier_key
				),
				'success'
			);
		}

		wp_safe_redirect( wp_get_referer() ? wp_get_referer() : admin_url( 'admin.php?page=siti-stock-plugin-stock-updates' ) );
		exit;
	}

	/**
	 * Handle saving of schedule settings.
	 */
	public function handle_schedule_save() {
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_die( esc_html__( 'Onvoldoende rechten.', 'siti-stock-plugin' ) );
		}

		check_admin_referer( 'siti_stock_save_supplier_schedule' );

		$raw_input = isset( $_POST['supplier_exports'] ) ? (array) wp_unslash( $_POST['supplier_exports'] ) : array();
		$this->persist_supplier_settings( $raw_input );
		$this->notices->add_notice( __( 'Voorkeuren opgeslagen.', 'siti-stock-plugin' ) );

		wp_safe_redirect( wp_get_referer() ? wp_get_referer() : admin_url( 'admin.php?page=siti-stock-plugin-stock-updates' ) );
		exit;
	}

	/**
	 * React to option updates by refreshing cron.
	 *
	 * @param array<string,mixed> $old_value Old settings.
	 * @param array<string,mixed> $value     New settings.
	 */
	public function handle_settings_update( $old_value, $value ) {
		unset( $old_value ); // Unused.
		unset( $value );

		$this->reset_cache();
		$this->reschedule_all();
	}

	/**
	 * Retrieve supplier configs for display/scheduling.
	 *
	 * @return array<string,array<string,mixed>>
	 */
	public function get_supplier_configs() {
		if ( null !== $this->supplier_cache ) {
			return $this->supplier_cache;
		}

		$settings  = $this->settings->get_all();
		$configured = isset( $settings['supplier_exports'] ) && is_array( $settings['supplier_exports'] )
			? $settings['supplier_exports']
			: array();

		$configured = $this->ensure_defaults( $configured );
		$configured = $this->ensure_distinct_meta_suppliers( $configured );

		uasort(
			$configured,
			function ( $a, $b ) {
				return strcmp(
					strtolower( isset( $a['supplier'] ) ? $a['supplier'] : '' ),
					strtolower( isset( $b['supplier'] ) ? $b['supplier'] : '' )
				);
			}
		);

		$this->supplier_cache = $configured;

		return $configured;
	}

	/**
	 * Retrieve config for specific supplier key.
	 *
	 * @param string $supplier_key Supplier key.
	 * @return array<string,mixed>|null
	 */
	public function get_supplier_config( $supplier_key ) {
		$configs = $this->get_supplier_configs();

		return isset( $configs[ $supplier_key ] ) ? $configs[ $supplier_key ] : null;
	}

	/**
	 * Send the mail export for supplier key.
	 *
	 * @param string $supplier_key Supplier key.
	 * @return array<string,mixed>|WP_Error
	 */
	public function send_export( $supplier_key ) {
		$supplier_key = sanitize_title( $supplier_key );
		$config       = $this->get_supplier_config( $supplier_key );

		if ( empty( $config ) || empty( $config['supplier'] ) ) {
			return new WP_Error( 'siti_stock_unknown_supplier', __( 'Onbekende leverancier.', 'siti-stock-plugin' ) );
		}

		if ( ! function_exists( 'wc_get_orders' ) ) {
			return new WP_Error( 'siti_stock_missing_wc', __( 'WooCommerce is vereist voor de exports.', 'siti-stock-plugin' ) );
		}

		$data = $this->collect_rows_for_supplier( $config['supplier'] );

		$admin_email = get_option( 'admin_email' );
		if ( ! $admin_email || ! is_email( $admin_email ) ) {
			return new WP_Error( 'siti_stock_missing_email', __( 'Admin e-mailadres kon niet worden opgehaald.', 'siti-stock-plugin' ) );
		}

		$csv     = $this->render_csv( $data['rows'] );
		$subject = sprintf(
			/* translators: %s supplier name */
			__( 'Bestellingen %s (24 uur)', 'siti-stock-plugin' ),
			$config['supplier']
		);

		$body_lines   = array();
		$body_lines[] = sprintf(
			/* translators: %s supplier name */
			__( 'Overzicht voor leverancier %s.', 'siti-stock-plugin' ),
			$config['supplier']
		);
		$body_lines[] = sprintf(
			/* translators: %d total items */
			__( 'Totaal aantal regels: %d.', 'siti-stock-plugin' ),
			count( $data['rows'] )
		);
		if ( empty( $data['rows'] ) ) {
			$body_lines[] = __( 'Er zijn geen bestellingen gevonden in de afgelopen 24 uur.', 'siti-stock-plugin' );
		}
		$body_lines[] = '';
		$body_lines[] = $csv;

		$headers = array( 'Content-Type: text/plain; charset=UTF-8' );
		$sent    = wp_mail( $admin_email, $subject, implode( "\n", $body_lines ), $headers );

		if ( ! $sent ) {
			return new WP_Error( 'siti_stock_mail_failed', __( 'E-mail verzenden is mislukt.', 'siti-stock-plugin' ) );
		}

		return array(
			'label' => $config['supplier'],
			'rows'  => count( $data['rows'] ),
		);
	}

	/**
	 * Persist sanitized supplier settings.
	 *
	 * @param array<string,mixed> $input Input from form.
	 */
	private function persist_supplier_settings( array $input ) {
		$current   = $this->get_supplier_configs();
		$sanitized = array();

		foreach ( $current as $key => $config ) {
			$row      = isset( $input[ $key ] ) ? (array) $input[ $key ] : array();
			$time_raw = isset( $row['time'] ) ? sanitize_text_field( $row['time'] ) : ( isset( $config['time'] ) ? $config['time'] : '' );
			$time     = $this->normalize_time( $time_raw );

			$sanitized[ $key ] = array(
				'supplier' => isset( $config['supplier'] ) ? $config['supplier'] : '',
				'time'     => $time,
				'enabled'  => ! empty( $row['enabled'] ),
			);
		}

		$settings                       = $this->settings->get_all();
		$settings['supplier_exports']    = $sanitized;
		$this->settings->reset_cache();
		update_option( $this->settings->get_option_key(), $settings );
		$this->reset_cache();
	}

	/**
	 * Collect CSV rows for supplier meta value.
	 *
	 * @param string $supplier Supplier label.
	 * @return array<string,mixed>
	 */
	private function collect_rows_for_supplier( $supplier ) {
		$key = $this->normalize_supplier_key( $supplier );

		$site_timezone = function_exists( 'wp_timezone' ) ? wp_timezone() : new DateTimeZone( wp_timezone_string() );
		$after_date    = new DateTimeImmutable( 'now', $site_timezone );
		$after_date    = $after_date->sub( new DateInterval( 'P1D' ) );
		$after_utc     = $after_date->setTimezone( new DateTimeZone( 'UTC' ) );

		$date_query = array(
			array(
				'column'    => 'date_created_gmt',
				'after'     => $after_utc->format( 'Y-m-d H:i:s' ),
				'inclusive' => true,
			),
		);

		$query = new WC_Order_Query(
			array(
				'status'       => array( 'pending', 'processing', 'on-hold', 'completed' ),
				'limit'        => -1,
				'type'         => 'shop_order',
				'return'       => 'objects',
				'date_query'   => $date_query,
			)
		);

		$orders  = $query->get_orders();
		$results = array();

		foreach ( $orders as $order ) {
			foreach ( $order->get_items( 'line_item' ) as $item ) {
				$product = $item->get_product();

				if ( ! $product ) {
					continue;
				}

				$item_supplier = $this->get_product_supplier( $product );

				if ( '' === $item_supplier || $this->normalize_supplier_key( $item_supplier ) !== $key ) {
					continue;
				}

				$sku = $this->get_product_sku( $product );

				if ( '' === $sku ) {
					$sku = sprintf( 'product-%d', $product->get_id() );
				}

				$index = strtolower( $sku );

				if ( ! isset( $results[ $index ] ) ) {
					$results[ $index ] = array(
						'sku'      => $sku,
						'quantity' => 0,
					);
				}

				$results[ $index ]['quantity'] += (int) $item->get_quantity();
			}
		}

		return array(
			'rows' => array_values( $results ),
		);
	}

	/**
	 * Retrieve supplier meta for product (falls back to parent).
	 *
	 * @param WC_Product $product Product.
	 * @return string
	 */
	private function get_product_supplier( $product ) {
		$product_id = $product->get_id();
		$value      = get_post_meta( $product_id, self::SUPPLIER_META_KEY, true );

		if ( '' !== $value ) {
			return trim( (string) $value );
		}

		$parent_id = $product->get_parent_id();

		if ( $parent_id ) {
			$parent_value = get_post_meta( $parent_id, self::SUPPLIER_META_KEY, true );

			if ( '' !== $parent_value ) {
				return trim( (string) $parent_value );
			}
		}

		return '';
	}

	/**
	 * Retrieve SKU, falling back to parent product SKU.
	 *
	 * @param WC_Product $product Product.
	 * @return string
	 */
	private function get_product_sku( $product ) {
		$sku = $product->get_sku();

		if ( '' !== $sku ) {
			return $sku;
		}

		$parent_id = $product->get_parent_id();

		if ( $parent_id ) {
			$parent = wc_get_product( $parent_id );

			if ( $parent && '' !== $parent->get_sku() ) {
				return $parent->get_sku();
			}
		}

		return '';
	}

	/**
	 * Convert an array of SKU rows to CSV text separated with semicolons.
	 *
	 * @param array<int,array<string,int|string>> $rows Rows.
	 * @return string
	 */
	private function render_csv( array $rows ) {
		$lines   = array( 'sku;aantal' );

		foreach ( $rows as $row ) {
			$sku      = isset( $row['sku'] ) ? $row['sku'] : '';
			$quantity = isset( $row['quantity'] ) ? (int) $row['quantity'] : 0;
			$lines[]  = sprintf( '%s;%d', $sku, $quantity );
		}

		return implode( "\n", $lines );
	}

	/**
	 * Schedule supplier if enabled.
	 *
	 * @param string                       $supplier_key Key.
	 * @param array<string,mixed>|null     $config Config.
	 */
	private function schedule_supplier( $supplier_key, $config ) {
		if ( empty( $config ) || empty( $config['enabled'] ) || empty( $config['time'] ) ) {
			return;
		}

		$timestamp = $this->calculate_next_timestamp( $config['time'] );
		wp_schedule_event( $timestamp, 'daily', self::CRON_HOOK, array( $supplier_key ) );
	}

	/**
	 * Remove scheduled event for supplier.
	 *
	 * @param string $supplier_key Key.
	 */
	private function clear_schedule_for_supplier( $supplier_key ) {
		$timestamp = wp_next_scheduled( self::CRON_HOOK, array( $supplier_key ) );

		while ( $timestamp ) {
			wp_unschedule_event( $timestamp, self::CRON_HOOK, array( $supplier_key ) );
			$timestamp = wp_next_scheduled( self::CRON_HOOK, array( $supplier_key ) );
		}
	}

	/**
	 * Ensure default suppliers exist in config.
	 *
	 * @param array<string,mixed> $configured Configured values.
	 * @return array<string,array<string,mixed>>
	 */
	private function ensure_defaults( array $configured ) {
		foreach ( $this->get_default_suppliers() as $key => $data ) {
			if ( isset( $configured[ $key ] ) ) {
				if ( empty( $configured[ $key ]['supplier'] ) ) {
					$configured[ $key ]['supplier'] = $data['label'];
				}
				$configured[ $key ]['time'] = $this->normalize_time(
					isset( $configured[ $key ]['time'] ) ? $configured[ $key ]['time'] : $data['time']
				);
				if ( ! isset( $configured[ $key ]['enabled'] ) ) {
					$configured[ $key ]['enabled'] = $data['enabled'];
				}
				continue;
			}

			$configured[ $key ] = array(
				'supplier' => $data['label'],
				'time'     => $data['time'],
				'enabled'  => $data['enabled'],
			);
		}

		return $configured;
	}

	/**
	 * Add entries for suppliers found in product meta.
	 *
	 * @param array<string,mixed> $configured Configured values.
	 * @return array<string,mixed>
	 */
	private function ensure_distinct_meta_suppliers( array $configured ) {
		foreach ( $this->get_distinct_suppliers() as $supplier ) {
			$key = $this->normalize_supplier_key( $supplier );

			if ( isset( $configured[ $key ] ) ) {
				$configured[ $key ]['supplier'] = $supplier;
				continue;
			}

			$configured[ $key ] = array(
				'supplier' => $supplier,
				'time'     => $this->get_default_time_for_key( $key ),
				'enabled'  => $this->is_default_enabled( $key ),
			);
		}

		return $configured;
	}

	/**
	 * Retrieve suppliers from product meta.
	 *
	 * @return array<int,string>
	 */
	private function get_distinct_suppliers() {
		global $wpdb;

		$meta_table = $wpdb->postmeta;
		$post_table = $wpdb->posts;
		$sql        = "
			SELECT DISTINCT pm.meta_value
			FROM {$meta_table} pm
			INNER JOIN {$post_table} p ON p.ID = pm.post_id
			WHERE pm.meta_key = %s
				AND pm.meta_value <> ''
				AND p.post_type IN ('product','product_variation')
				AND p.post_status NOT IN ('trash','auto-draft')
		";

		$results = $wpdb->get_col( $wpdb->prepare( $sql, self::SUPPLIER_META_KEY ) ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared

		if ( empty( $results ) ) {
			return array();
		}

		return array_map(
			function ( $value ) {
				return trim( (string) $value );
			},
			$results
		);
	}

	/**
	 * Normalize supplier key to slug.
	 *
	 * @param string $value Value.
	 * @return string
	 */
	private function normalize_supplier_key( $value ) {
		return sanitize_title( (string) $value );
	}

	/**
	 * Normalize HH:MM strings, fallback to midnight.
	 *
	 * @param string $time Time string.
	 * @return string
	 */
	private function normalize_time( $time ) {
		$time = trim( (string) $time );
		if ( ! preg_match( '/^\d{1,2}:\d{2}$/', $time ) ) {
			return '00:00';
		}

		list( $hour, $minute ) = array_map( 'intval', explode( ':', $time, 2 ) );

		$hour   = max( 0, min( 23, $hour ) );
		$minute = max( 0, min( 59, $minute ) );

		return sprintf( '%02d:%02d', $hour, $minute );
	}

	/**
	 * Calculate the next timestamp for a given HH:MM.
	 *
	 * @param string $time Time in HH:MM.
	 * @return int
	 */
	private function calculate_next_timestamp( $time ) {
		$time = $this->normalize_time( $time );
		list( $hour, $minute ) = array_map( 'intval', explode( ':', $time ) );

		$timezone = wp_timezone();
		$now      = new DateTimeImmutable( 'now', $timezone );
		$target   = $now->setTime( $hour, $minute );

		if ( $target <= $now ) {
			$target = $target->modify( '+1 day' );
		}

		return $target->getTimestamp();
	}

	/**
	 * Default suppliers (label + default time/settings).
	 *
	 * @return array<string,array<string,mixed>>
	 */
	private function get_default_suppliers() {
		return array(
			'orion'       => array(
				'label'   => 'Orion',
				'time'    => '09:00',
				'enabled' => true,
			),
			'shots'       => array(
				'label'   => 'Shots',
				'time'    => '10:00',
				'enabled' => true,
			),
			'stots'       => array(
				'label'   => 'Stots',
				'time'    => '10:00',
				'enabled' => true,
			),
			'leg-avenue'  => array(
				'label'   => 'Leg Avenue',
				'time'    => '14:00',
				'enabled' => true,
			),
			'oproducts'   => array(
				'label'   => 'Oproducts',
				'time'    => '13:00',
				'enabled' => true,
			),
		);
	}

	/**
	 * Retrieve default time for supplier key.
	 *
	 * @param string $key Supplier key.
	 * @return string
	 */
	private function get_default_time_for_key( $key ) {
		$defaults = $this->get_default_suppliers();

		return isset( $defaults[ $key ] ) ? $defaults[ $key ]['time'] : '09:00';
	}

	/**
	 * Determine default enabled state for supplier key.
	 *
	 * @param string $key Supplier key.
	 * @return bool
	 */
	private function is_default_enabled( $key ) {
		$defaults = $this->get_default_suppliers();

		return isset( $defaults[ $key ] ) ? (bool) $defaults[ $key ]['enabled'] : false;
	}
}