<?php
/**
 * Installation, upgrades and removal of plugin data.
 *
 * @package StockAlibi
 */

declare( strict_types=1 );

namespace StockAlibi\Database;

use StockAlibi\Jobs\Lock;
use StockAlibi\Jobs\Reconciler;
use StockAlibi\Jobs\Scheduler;
use StockAlibi\Recorder\Fields;
use StockAlibi\Settings;

defined( 'ABSPATH' ) || exit;

/**
 * Creates, upgrades and removes the plugin's tables and options.
 */
final class Installer {

	/**
	 * Option that stores the installed schema version.
	 */
	public const VERSION_OPTION = 'stal_db_version';

	/**
	 * Action Scheduler group of the plugin's background jobs.
	 */
	public const SCHEDULER_GROUP = 'stock-alibi';

	/**
	 * Activation hook.
	 *
	 * On a network activation every site gets its tables lazily, through
	 * `maybe_upgrade()` on its first request.
	 */
	public static function activate(): void {
		global $wpdb;

		self::install();

		/*
		 * Changes made while the plugin was inactive were not recorded. Without
		 * this reset, reconciliation would report them as external: every field
		 * starts again from its current value.
		 */
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Plugin's own table.
		$wpdb->query( $wpdb->prepare( 'DELETE FROM %i', Schema::state_table() ) );
		update_option( Reconciler::ACTIVATED_OPTION, gmdate( 'Y-m-d H:i:s' ), false );
		delete_option( Reconciler::PROGRESS_OPTION );
		delete_option( Scheduler::OPTION );
	}

	/**
	 * Deactivation hook: removes the scheduled jobs. Data is kept.
	 */
	public static function deactivate(): void {
		self::unschedule();
		delete_option( Scheduler::OPTION );
	}

	/**
	 * Removes every scheduled job of the plugin.
	 */
	private static function unschedule(): void {
		if ( function_exists( 'as_unschedule_all_actions' ) ) {
			as_unschedule_all_actions( '', array(), self::SCHEDULER_GROUP );
		}
	}

	/**
	 * Runs the installer when the stored schema version differs from the
	 * code's. Cheap enough for every request: one autoloaded option read.
	 */
	public static function maybe_upgrade(): void {
		if ( Schema::VERSION !== get_option( self::VERSION_OPTION ) ) {
			self::install();
		}
	}

	/**
	 * Creates or updates the tables and stores the schema version.
	 */
	public static function install(): void {
		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		self::prepare_upgrade();
		dbDelta( Schema::definitions() );

		add_option( Settings::OPTION, Settings::defaults() );
		update_option( self::VERSION_OPTION, Schema::VERSION, true );

		/**
		 * Fires after the plugin's tables were created or updated.
		 *
		 * @since 0.1.0
		 *
		 * @param string $version Schema version that was installed.
		 */
		do_action( 'stock_alibi_installed', Schema::VERSION );
	}

	/**
	 * What dbDelta() cannot do on its own: drops the indexes of earlier schema
	 * versions (it only adds), and shortens references longer than the
	 * `source_ref` column of version 3 (strict SQL modes refuse to truncate).
	 */
	private static function prepare_upgrade(): void {
		global $wpdb;

		$events = Schema::events_table();
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Schema check, must not be cached.
		if ( $events === $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $wpdb->esc_like( $events ) ) ) ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Upgrade of the plugin's own table.
			$wpdb->query( $wpdb->prepare( 'UPDATE %i SET source_ref = LEFT( source_ref, %d ) WHERE CHAR_LENGTH( source_ref ) > %d', $events, Fields::MAX_REF_LENGTH, Fields::MAX_REF_LENGTH ) );
		}

		foreach ( Schema::OBSOLETE_INDEXES as $table => $indexes ) {
			$table = $wpdb->prefix . $table;
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Schema check, must not be cached.
			if ( $table !== $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $wpdb->esc_like( $table ) ) ) ) {
				continue;
			}
			foreach ( $indexes as $index ) {
				// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Schema check, must not be cached.
				if ( $wpdb->get_var( $wpdb->prepare( 'SHOW INDEX FROM %i WHERE Key_name = %s', $table, $index ) ) ) {
					// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.DirectDatabaseQuery.SchemaChange -- Upgrade of the plugin's own table.
					$wpdb->query( $wpdb->prepare( 'ALTER TABLE %i DROP INDEX %i', $table, $index ) );
				}
			}
		}
	}

	/**
	 * Whether every plugin table exists on the current site.
	 */
	public static function tables_exist(): bool {
		global $wpdb;

		foreach ( Schema::tables() as $table ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Schema check, must not be cached.
			if ( $table !== $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $wpdb->esc_like( $table ) ) ) ) {
				return false;
			}
		}

		return true;
	}

	/**
	 * Every option the plugin stores.
	 *
	 * @return string[]
	 */
	public static function options(): array {
		return array(
			Settings::OPTION,
			self::VERSION_OPTION,
			Reconciler::PROGRESS_OPTION,
			Reconciler::ACTIVATED_OPTION,
			Scheduler::OPTION,
			Lock::PREFIX . 'reconcile',
			Lock::PREFIX . 'cleanup',
		);
	}

	/**
	 * Removes all plugin data from the current site: tables, options and
	 * scheduled jobs. Called from uninstall.php only when the user chose to
	 * delete data.
	 */
	public static function remove_site_data(): void {
		global $wpdb;

		foreach ( Schema::tables() as $table ) {
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.DirectDatabaseQuery.SchemaChange -- Uninstall drops the plugin's own tables.
			$wpdb->query( $wpdb->prepare( 'DROP TABLE IF EXISTS %i', $table ) );
		}

		foreach ( self::options() as $option ) {
			delete_option( $option );
		}

		self::unschedule();
	}
}