<?php
// PHP 7.4 compatible. No Composer. No build step. WordPress coding standards.
// All data keyed by instance ID — never by section slug (PRD §4.1).

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

class SLBUILD_DataStore {

	const PAGE_META_KEY     = '_slbuild_page_data';
	const DRAFT_META_KEY    = '_slbuild_page_data_draft';
	const SETTINGS_META_KEY = '_slbuild_page_settings';
	const GLOBAL_OPTION_PREFIX = 'slbuild_global_';

	/**
	 * Get the full page data blob for a post.
	 * Returns array with 'layout' and 'instances' keys.
	 *
	 * @param int $post_id
	 * @return array
	 */
	public function get_page_data( $post_id ) {
		$raw = get_post_meta( $post_id, self::PAGE_META_KEY, true );
		if ( ! is_array( $raw ) ) {
			return array(
				'layout'    => array(),
				'instances' => array(),
			);
		}
		return $raw;
	}

	/**
	 * Get the draft data for a post. Falls back to live data if no draft exists yet.
	 *
	 * @param int $post_id
	 * @return array
	 */
	public function get_draft_data( $post_id ): array {
		$raw = get_post_meta( $post_id, self::DRAFT_META_KEY, true );
		if ( ! is_array( $raw ) ) {
			return $this->get_page_data( $post_id );
		}
		return $raw;
	}

	/**
	 * Save the current editor state to the draft meta (does not affect the live page).
	 *
	 * @param int   $post_id
	 * @param array $layout
	 * @param array $instances
	 * @return bool
	 */
	public function save_draft( $post_id, $layout, $instances ): bool {
		$data = array( 'layout' => $layout, 'instances' => $instances );
		update_post_meta( $post_id, self::DRAFT_META_KEY, $data );
		return true;
	}

	/**
	 * Promote the current draft to live by copying draft meta to page meta.
	 * Stamps modified_at so drift detection can compare against dev snapshots.
	 *
	 * @param int $post_id
	 * @return bool False if there is no draft to publish.
	 */
	public function publish( $post_id ): bool {
		$draft = get_post_meta( $post_id, self::DRAFT_META_KEY, true );
		if ( ! is_array( $draft ) ) {
			return false;
		}
		$draft['meta']['modified_at'] = time();
		update_post_meta( $post_id, self::PAGE_META_KEY, $draft );
		return true;
	}

	/**
	 * Draft-aware layout read.
	 *
	 * @param int $post_id
	 * @return array
	 */
	public function get_draft_layout( $post_id ): array {
		$data = $this->get_draft_data( $post_id );
		return isset( $data['layout'] ) ? $data['layout'] : array();
	}

	/**
	 * Draft-aware instance values read.
	 *
	 * @param int    $post_id
	 * @param string $instance_id
	 * @return array
	 */
	public function get_draft_instance_values( $post_id, $instance_id ): array {
		$data = $this->get_draft_data( $post_id );
		if ( ! isset( $data['instances'][ $instance_id ]['settings'] ) ) {
			return array();
		}
		return $data['instances'][ $instance_id ]['settings'];
	}

	/**
	 * Draft-aware instance blocks read.
	 *
	 * @param int    $post_id
	 * @param string $instance_id
	 * @return array
	 */
	public function get_draft_instance_blocks( $post_id, $instance_id ): array {
		$data = $this->get_draft_data( $post_id );
		if ( ! isset( $data['instances'][ $instance_id ]['blocks'] ) ) {
			return array();
		}
		return $data['instances'][ $instance_id ]['blocks'];
	}

	/**
	 * Save the full page data blob for a post.
	 *
	 * @param int   $post_id
	 * @param array $data Must have 'layout' and 'instances' keys.
	 * @return bool
	 */
	public function set_page_data( $post_id, $data ) {
		// update_post_meta returns false when the value is unchanged — that is not an error.
		update_post_meta( $post_id, self::PAGE_META_KEY, $data );
		return true;
	}

	/**
	 * Get the ordered layout array for a post.
	 * Each item: [ 'instance' => 'hero_x1', 'type' => 'hero' ]
	 *
	 * @param int $post_id
	 * @return array
	 */
	public function get_layout( $post_id ) {
		$data = $this->get_page_data( $post_id );
		return isset( $data['layout'] ) ? $data['layout'] : array();
	}

	/**
	 * Get field values for a specific section instance.
	 *
	 * @param int    $post_id
	 * @param string $instance_id
	 * @return array Field values, keyed by field id. Empty array if not found.
	 */
	public function get_instance_values( $post_id, $instance_id ) {
		$data = $this->get_page_data( $post_id );
		if ( ! isset( $data['instances'][ $instance_id ]['settings'] ) ) {
			return array();
		}
		return $data['instances'][ $instance_id ]['settings'];
	}

	/**
	 * Get block instances for a specific section instance.
	 *
	 * @param int    $post_id
	 * @param string $instance_id
	 * @return array Ordered block instances array.
	 */
	public function get_instance_blocks( $post_id, $instance_id ) {
		$data = $this->get_page_data( $post_id );
		if ( ! isset( $data['instances'][ $instance_id ]['blocks'] ) ) {
			return array();
		}
		return $data['instances'][ $instance_id ]['blocks'];
	}

	/**
	 * Save the full layout + all instance data for a post atomically.
	 *
	 * @param int   $post_id
	 * @param array $layout    Ordered array of [ 'instance' => id, 'type' => slug ]
	 * @param array $instances Keyed by instance_id: [ 'settings' => [], 'blocks' => [] ]
	 * @return bool
	 */
	public function save_page( $post_id, $layout, $instances ) {
		$data = array(
			'layout'    => $layout,
			'instances' => $instances,
		);
		return $this->set_page_data( $post_id, $data );
	}

	/**
	 * Read a global region (header, footer, etc.) from wp_options.
	 *
	 * @param string $region Region name e.g. 'header', 'footer'.
	 * @return array Same structure as page data (layout + instances).
	 */
	public function get_global( $region ) {
		$raw = get_option( self::GLOBAL_OPTION_PREFIX . $region, null );
		if ( ! is_array( $raw ) ) {
			return array(
				'layout'    => array(),
				'instances' => array(),
			);
		}
		return $raw;
	}

	/**
	 * Save a global region to wp_options.
	 *
	 * @param string $region
	 * @param array  $layout
	 * @param array  $instances
	 * @return bool
	 */
	public function save_global( $region, $layout, $instances ) {
		$data = array(
			'layout'    => $layout,
			'instances' => $instances,
		);
		return update_option( self::GLOBAL_OPTION_PREFIX . $region, $data, false );
	}

	/**
	 * Return slugs of all saved global regions (e.g. ['header','footer','announcement']).
	 *
	 * @return string[]
	 */
	public function get_all_global_region_keys(): array {
		global $wpdb;
		$prefix    = self::GLOBAL_OPTION_PREFIX;
		$cache_key = 'slbuild_global_region_keys';
		$rows      = wp_cache_get( $cache_key, 'slb-section-layout-builder' );
		if ( false === $rows ) {
			$like = $wpdb->esc_like( $prefix ) . '%';
			$rows = $wpdb->get_col( $wpdb->prepare( // phpcs:ignore WordPress.DB.DirectDatabaseQuery
				"SELECT option_name FROM {$wpdb->options} WHERE option_name LIKE %s",
				$like
			) );
			wp_cache_set( $cache_key, $rows, 'slb-section-layout-builder', 300 );
		}
		$slugs = array();
		foreach ( $rows as $row ) {
			$slug = substr( $row, strlen( $prefix ) );
			if ( $slug !== '' ) {
				$slugs[] = $slug;
			}
		}
		return $slugs;
	}

	/**
	 * Get per-page display settings (header/footer visibility).
	 * Defaults: both 'default' (theme-controlled).
	 *
	 * @param int $post_id
	 * @return array { header: 'default'|'hidden', footer: 'default'|'hidden' }
	 */
	public function get_page_settings( int $post_id ): array {
		$raw      = get_post_meta( $post_id, self::SETTINGS_META_KEY, true );
		$defaults = array( 'header' => 'default', 'footer' => 'default' );
		if ( ! is_array( $raw ) ) {
			return $defaults;
		}
		return array_merge( $defaults, $raw );
	}

	/**
	 * Save per-page display settings.
	 *
	 * @param int   $post_id
	 * @param array $settings
	 * @return bool
	 */
	public function save_page_settings( int $post_id, array $settings ): bool {
		$allowed = array( 'default', 'hidden' );
		$clean   = array(
			'header' => in_array( $settings['header'] ?? '', $allowed, true ) ? $settings['header'] : 'default',
			'footer' => in_array( $settings['footer'] ?? '', $allowed, true ) ? $settings['footer'] : 'default',
		);
		update_post_meta( $post_id, self::SETTINGS_META_KEY, $clean );
		return true;
	}
}