<?php
/**
 * Plugin activation handler.
 *
 * @package VacuumImageOptimizer\Core
 */

namespace VacuumImageOptimizer\Core;

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

/**
 * Handles plugin activation.
 */
class Installer {

	/**
	 * Plugin option key for DB version.
	 *
	 * @var string
	 */
	private const OPTION_DB_VERSION = 'vacimg_db_version';

	/**
	 * Option key used to mark the Phase 5 queue schema as installed.
	 *
	 * @var string
	 */
	private const OPTION_QUEUE_READY = 'vacimg_queue_table_ready';

	/**
	 * Activate the plugin.
	 *
	 * @return void
	 */
	public static function activate(): void {
		self::check_requirements();
		self::migrate_short_prefix_options();
		self::create_tables();
		self::set_default_options();
		self::schedule_cron();
	}

	/**
	 * Run safe database upgrades when the admin area loads.
	 *
	 * @return void
	 */
	public static function maybe_upgrade(): void {
		$stored_version = (string) get_option( self::OPTION_DB_VERSION, '' );
		$queue_ready    = (bool) get_option( self::OPTION_QUEUE_READY, false );

		if ( VACIMG_VERSION === $stored_version && $queue_ready ) {
			return;
		}

		self::migrate_short_prefix_options();
		self::create_tables();
		self::set_default_options();
	}

	/**
	 * Check minimum requirements.
	 *
	 * @return void
	 * @throws \Exception If requirements not met.
	 */
	private static function check_requirements(): void {
		if ( version_compare( PHP_VERSION, '8.1', '<' ) ) {
			wp_die(
				esc_html__( 'Vacuum Image Optimizer requires PHP 8.1 or higher.', 'vacuum-image-optimizer' ),
				esc_html__( 'Plugin Activation Error', 'vacuum-image-optimizer' ),
				[ 'back_link' => true ]
			);
		}
	}

	/**
	 * Create custom database tables.
	 *
	 * @return void
	 */
	private static function create_tables(): void {
		global $wpdb;

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';

		$charset_collate = $wpdb->get_charset_collate();
		$prefix          = $wpdb->prefix;

		$sql_queue = "CREATE TABLE {$prefix}vacimg_queue (
			id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
			attachment_id bigint(20) unsigned NOT NULL DEFAULT 0,
			status varchar(20) NOT NULL DEFAULT 'pending',
			created_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
			started_at datetime DEFAULT NULL,
			completed_at datetime DEFAULT NULL,
			attempts int(10) unsigned NOT NULL DEFAULT 0,
			error_message text DEFAULT NULL,
			PRIMARY KEY (id),
			KEY attachment_id (attachment_id),
			KEY status_created (status, created_at)
		) {$charset_collate};";

		$sql_stats = "CREATE TABLE {$prefix}vacimg_stats (
			id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
			attachment_id bigint(20) unsigned NOT NULL DEFAULT 0,
			size_name varchar(50) NOT NULL DEFAULT 'full',
			original_size bigint(20) unsigned NOT NULL DEFAULT 0,
			optimized_size bigint(20) unsigned NOT NULL DEFAULT 0,
			webp_size bigint(20) unsigned DEFAULT NULL,
			avif_size bigint(20) unsigned DEFAULT NULL,
			compression_ratio decimal(5,2) NOT NULL DEFAULT 0.00,
			profile varchar(20) NOT NULL DEFAULT 'balanced',
			engine varchar(20) NOT NULL DEFAULT 'gd',
			created_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
			PRIMARY KEY (id),
			UNIQUE KEY attachment_size (attachment_id, size_name),
			KEY attachment_id (attachment_id)
		) {$charset_collate};";

		$sql_backups = "CREATE TABLE {$prefix}vacimg_backups (
			id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
			attachment_id bigint(20) unsigned NOT NULL DEFAULT 0,
			size_name varchar(50) NOT NULL DEFAULT 'full',
			backup_path text NOT NULL,
			original_path text NOT NULL,
			file_hash varchar(64) NOT NULL DEFAULT '',
			created_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
			expires_at datetime DEFAULT NULL,
			PRIMARY KEY (id),
			UNIQUE KEY attachment_size (attachment_id, size_name),
			KEY expires_at (expires_at),
			KEY attachment_id (attachment_id)
		) {$charset_collate};";

		dbDelta( $sql_queue );
		dbDelta( $sql_stats );
		dbDelta( $sql_backups );
	}

	/**
	 * Copy simple legacy options into their current keys when present.
	 *
	 * @return void
	 */
	private static function migrate_short_prefix_options(): void {
		$legacy_prefix = 'v' . 'io_';
		$pairs         = [
			$legacy_prefix . 'settings'               => 'vacimg_settings',
			$legacy_prefix . 'queue_state'            => 'vacimg_queue_state',
			$legacy_prefix . 'db_version'             => self::OPTION_DB_VERSION,
			$legacy_prefix . 'phase5_queue_ready'     => self::OPTION_QUEUE_READY,
			$legacy_prefix . 'queue_table_ready'      => self::OPTION_QUEUE_READY,
			$legacy_prefix . 'last_auto_processed_at' => 'vacimg_last_auto_processed_at',
			$legacy_prefix . 'last_backup_cleanup'    => 'vacimg_last_backup_cleanup',
		];

		foreach ( $pairs as $old_key => $new_key ) {
			if ( false !== get_option( $new_key, false ) ) {
				continue;
			}

			$value = get_option( $old_key, false );
			if ( false !== $value ) {
				add_option( $new_key, $value );
			}
		}
	}

	/**
	 * Set default plugin options.
	 *
	 * @return void
	 */
	private static function set_default_options(): void {
		$defaults = [
			'quality'               => 82,
			'profile'               => 'balanced',
			'enable_webp'           => true,
			'auto_optimize_uploads' => false,
			'auto_optimize_mode'    => 'queue',
			'enable_avif'           => false,
			'avif_quality'          => 60,
			'enable_frontend_delivery' => false,
			'preferred_format'      => 'auto',
			'enable_backups'        => true,
			'backup_retention_days' => 0,
			'enable_lazy_loading'   => true,
			'safe_mode'             => true,
			'max_width'             => 0,
			'max_height'            => 0,
			'exclude_mime_types'    => [],
			'min_file_size'         => 0,
			'max_file_size'         => 0,
			'exclude_filename_patterns' => '',
			'exclude_path_patterns' => '',
			'exclude_gif'           => true,
			'exclude_svg'           => true,
			'interface_language'    => 'wordpress',
		];

		if ( false === get_option( 'vacimg_settings' ) ) {
			add_option( 'vacimg_settings', $defaults );
		} else {
			$settings = get_option( 'vacimg_settings', [] );
			if ( is_array( $settings ) ) {
				update_option( 'vacimg_settings', array_merge( $defaults, $settings ) );
			}
		}

		if ( false === get_option( 'vacimg_queue_state' ) ) {
			add_option( 'vacimg_queue_state', 'idle' );
		}

		if ( false === get_option( 'vacimg_setup_wizard_status' ) ) {
			add_option( 'vacimg_setup_wizard_status', 'pending' );
		}

		update_option( self::OPTION_DB_VERSION, VACIMG_VERSION );
		update_option( self::OPTION_QUEUE_READY, true );
	}

	/**
	 * Schedule cron events.
	 *
	 * @return void
	 */
	private static function schedule_cron(): void {
		if ( ! wp_next_scheduled( 'vacimg_cleanup_backups' ) ) {
			wp_schedule_event( time(), 'daily', 'vacimg_cleanup_backups' );
		}
	}
}
