<?php

namespace Yipresser\AdminOptimizer\Modules;

use Yipresser\AdminOptimizer\Support\Logger;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Custom_Code_Cache
 *
 * Rebuilds and clears the frontend output cache stored in wp_options.
 * Called by the admin save handler on publish/update.
 */
class Custom_Code_Cache {

	use Logger;

	/**
	 * Rebuild the cache after a post is saved.
	 *
	 * Accepts the pre-save locations/display/position so stale cache
	 * entries for removed locations can also be cleared.
	 *
	 * @param int    $post_id
	 * @param array  $old_locations Locations cached before this save.
	 * @param string $old_display   Display method cached before this save (CSS only).
	 * @param string $old_position  Position cached before this save (JS/HTML only).
	 * @param string $old_priority  Load priority cached before this save (Pro only; ignored here).
	 * @return void
	 */
	public function rebuild( int $post_id, array $old_locations = [], string $old_display = 'inline', string $old_position = '', string $old_priority = 'default' ): void {
		$type      = get_post_meta( $post_id, '_ao_cc_type', true );
		$locations = get_post_meta( $post_id, '_ao_cc_locations', true );

		// Shortcode snippets are registered at runtime via add_shortcode(); no cache entry.
		if ( ! in_array( $type, Custom_Code::TYPES, true ) || 'shortcode' === $type ) {
			return;
		}

		$locations = is_array( $locations ) ? $locations : [];

		if ( 'css' === $type ) {
			$display_raw = get_post_meta( $post_id, '_ao_cc_display', true );
			$display     = $display_raw !== '' ? $display_raw : 'inline';
			$this->rebuild_css( $locations, $display );

			// When display mode changes, rebuild kept locations for the old display
			// so their stale inline/external options are cleared.
			$kept = array_intersect( $old_locations, $locations );
			if ( ! empty( $kept ) && ! empty( $old_display ) && $old_display !== $display ) {
				$this->rebuild_css( array_values( $kept ), $old_display );
			}

			$removed = array_diff( $old_locations, $locations );
			if ( ! empty( $removed ) && ! empty( $old_display ) ) {
				$this->rebuild_css( array_values( $removed ), $old_display );
			}
		} else {
			$position = get_post_meta( $post_id, '_ao_cc_position', true );
			if ( ! empty( $position ) ) {
				$this->rebuild_scripts( $locations, $position, $type );
			}

			$removed = array_diff( $old_locations, $locations );
			if ( ! empty( $removed ) && ! empty( $old_position ) ) {
				$this->rebuild_scripts( $removed, $old_position, $type );
			}
		}
	}

	/**
	 * Rebuild every cache entry from scratch.
	 *
	 * Collects all unique location+display and location+position combinations
	 * from both the stored location index (which may contain stale entries) and
	 * all currently published posts, then rebuilds each one.  Any location whose
	 * aggregated CSS/JS is now empty will have its option deleted automatically
	 * by the underlying rebuild_css / rebuild_scripts methods.
	 *
	 * @return void
	 */
	public function rebuild_all(): void {
		// --- CSS ---
		$css_combos = [];

		// Start from the stored index so stale entries from deleted posts get cleared.
		$stored_css = get_option( 'ao_cc_css_locations', [] );
		foreach ( Custom_Code::VALID_DISPLAYS as $d ) {
			foreach ( array_keys( $stored_css[ $d ] ?? [] ) as $loc ) {
				$css_combos[ $d ][ $loc ] = 1;
			}
		}

		// Collect combos from published posts (index may be missing new entries).
		$css_posts = get_posts(
			[
				'post_type'      => Custom_Code::POST_TYPE,
				'post_status'    => 'publish',
				'posts_per_page' => -1,
				'fields'         => 'ids',
				'meta_query'     => [ [ 'key' => '_ao_cc_type', 'value' => 'css' ] ], // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- Admin-triggered full cache rebuild over the low-volume Custom Code post type, not a hot request-time query.
			]
		);
		update_postmeta_cache( $css_posts );
		foreach ( $css_posts as $id ) {
			$locs    = get_post_meta( $id, '_ao_cc_locations', true );
			$display_raw = get_post_meta( $id, '_ao_cc_display', true );
			$display     = $display_raw !== '' ? $display_raw : 'inline';
			if ( is_array( $locs ) ) {
				foreach ( $locs as $loc ) {
					$css_combos[ $display ][ $loc ] = 1;
				}
			}
		}

		// Sitewide is never tracked in the index — always rebuild it.
		$css_combos['inline']['sitewide']    = 1;
		$css_combos['external']['sitewide']  = 1;

		foreach ( $css_combos as $display => $locs_map ) {
			$this->rebuild_css( array_keys( $locs_map ), $display );
		}

		// --- Scripts ---
		$script_combos = [];

		$stored_scripts = get_option( 'ao_cc_script_locations', [] );
		$stored_html    = get_option( 'ao_cc_html_locations', [] );
		foreach ( Custom_Code::VALID_POSITIONS as $pos ) {
			foreach ( array_keys( $stored_scripts[ $pos ] ?? [] ) as $loc ) {
				$script_combos[ $pos ][ $loc ] = 1;
			}
			foreach ( array_keys( $stored_html[ $pos ] ?? [] ) as $loc ) {
				$script_combos[ $pos ][ $loc ] = 1;
			}
		}

		$script_posts = get_posts(
			[
				'post_type'      => Custom_Code::POST_TYPE,
				'post_status'    => 'publish',
				'posts_per_page' => -1,
				'fields'         => 'ids',
				// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- Admin-triggered full cache rebuild over the low-volume Custom Code post type, not a hot request-time query.
				'meta_query'     => [
					'relation' => 'AND',
					[
						'key'     => '_ao_cc_type',
						'value'   => [ 'js', 'html' ],
						'compare' => 'IN',
					],
				],
			]
		);
		update_postmeta_cache( $script_posts );
		foreach ( $script_posts as $id ) {
			$locs     = get_post_meta( $id, '_ao_cc_locations', true );
			$position = get_post_meta( $id, '_ao_cc_position', true );
			if ( is_array( $locs ) && in_array( $position, Custom_Code::VALID_POSITIONS, true ) ) {
				foreach ( $locs as $loc ) {
					$script_combos[ $position ][ $loc ] = 1;
				}
			}
		}

		// Sitewide is never tracked in the index — always rebuild it.
		foreach ( Custom_Code::VALID_POSITIONS as $pos ) {
			$script_combos[ $pos ]['sitewide'] = 1;
		}

		foreach ( $script_combos as $position => $locs_map ) {
			$this->rebuild_scripts( array_keys( $locs_map ), $position, 'js' );
			$this->rebuild_scripts( array_keys( $locs_map ), $position, 'html' );
		}


		do_action( 'ao_cc_cache_rebuilt' ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- ao_cc_ is this module's established hook prefix, used consistently throughout Custom Code.
	}

	/**
	 * Rebuild the CSS cache for the given locations and display method.
	 *
	 * @param array  $locations
	 * @param string $display
	 * @return void
	 */
	private function rebuild_css( array $locations, string $display ): void {
		if ( ! in_array( $display, Custom_Code::VALID_DISPLAYS, true ) || empty( $locations ) ) {
			return;
		}

		$filesystem          = new Custom_Code_Filesystem();
		$ao_cc_css_locations = get_option( 'ao_cc_css_locations', [] );

		$all_css_posts = get_posts(
			[
				'post_type'      => Custom_Code::POST_TYPE,
				'post_status'    => 'publish',
				'posts_per_page' => -1,
				'fields'         => 'ids',
				// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- Admin-triggered full cache rebuild over the low-volume Custom Code post type, not a hot request-time query.
				'meta_query'     => [
					[
						'key'   => '_ao_cc_type',
						'value' => 'css',
					],
				],
			]
		);
		update_postmeta_cache( $all_css_posts );

		foreach ( $locations as $location ) {
			if ( ! array_key_exists( $location, Custom_Code::ALL_LOCATIONS ) ) {
				continue;
			}

			$css_code = '';
			foreach ( $all_css_posts as $css_id ) {
				$post_locations = get_post_meta( $css_id, '_ao_cc_locations', true );
				$post_display_raw = get_post_meta( $css_id, '_ao_cc_display', true );
				$post_display     = $post_display_raw !== '' ? $post_display_raw : 'inline';

				if ( ! is_array( $post_locations ) || ! in_array( $location, $post_locations, true ) || $post_display !== $display ) {
					continue;
				}

				$css_code = $this->append_code( $css_code, get_post_field( 'post_content', $css_id ) );
			}

			if ( ! empty( $css_code ) ) {
				$autoload = 'sitewide' === $location ? 'yes' : 'no';
				if ( 'inline' === $display ) {
					update_option( "ao_cc_css_{$location}_inline", $css_code, $autoload );
					delete_option( "ao_cc_css_{$location}_external" );
					$filesystem->delete_file( 'css', $location );
					do_action( "ao_cc_css_updated_inline_{$location}", $css_code ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- ao_cc_ is this module's established hook prefix, used consistently throughout Custom Code.
				} elseif ( $filesystem->can_write( 'css', $location ) ) {
						$file_uri = $filesystem->create_external_file( $css_code, 'css', $location );
					if ( $file_uri ) {
						update_option( "ao_cc_css_{$location}_external", $file_uri, $autoload );
						delete_option( "ao_cc_css_{$location}_inline" );
					}
				} else {
					$this->warning(
						'Cannot write external CSS file.',
						[ 'location' => $location ],
						'external_css_write_failed'
					);
				}

				if ( 'sitewide' !== $location ) {
					$ao_cc_css_locations[ $display ][ $location ] = 1;
				}
			} else {
				if ( 'inline' === $display ) {
					delete_option( "ao_cc_css_{$location}_inline" );
				} else {
					delete_option( "ao_cc_css_{$location}_external" );
					$filesystem->delete_file( 'css', $location );
				}
				if ( 'sitewide' !== $location ) {
					unset( $ao_cc_css_locations[ $display ][ $location ] );
				}
			}

		}

		update_option( 'ao_cc_css_locations', $ao_cc_css_locations );
	}

	/**
	 * Rebuild the script/HTML cache for the given locations and position.
	 *
	 * @param array  $locations
	 * @param string $position
	 * @param string $type      'js' or 'html'.
	 * @return void
	 */
	private function rebuild_scripts( array $locations, string $position, string $type = 'js' ): void {
		if ( ! in_array( $position, Custom_Code::VALID_POSITIONS, true ) || empty( $locations ) ) {
			return;
		}

		$option_prefix          = 'html' === $type ? 'ao_cc_html' : 'ao_cc_script';
		$locations_key          = 'html' === $type ? 'ao_cc_html_locations' : 'ao_cc_script_locations';
		$ao_cc_script_locations = get_option( $locations_key, [] );

		$all_script_posts = get_posts(
			[
				'post_type'      => Custom_Code::POST_TYPE,
				'post_status'    => 'publish',
				'posts_per_page' => -1,
				'fields'         => 'ids',
				// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- Admin-triggered full cache rebuild over the low-volume Custom Code post type, not a hot request-time query.
				'meta_query'     => [
					'relation' => 'AND',
					[
						'key'   => '_ao_cc_type',
						'value' => $type,
					],
					[
						'key'   => '_ao_cc_position',
						'value' => $position,
					],
				],
			]
		);
		update_postmeta_cache( $all_script_posts );

		foreach ( $locations as $location ) {
			if ( ! array_key_exists( $location, Custom_Code::ALL_LOCATIONS ) ) {
				continue;
			}

			$script_code = '';
			foreach ( $all_script_posts as $script_id ) {
				$post_locations = get_post_meta( $script_id, '_ao_cc_locations', true );
				if ( ! is_array( $post_locations ) || ! in_array( $location, $post_locations, true ) ) {
					continue;
				}
				$script_code = $this->append_code( $script_code, get_post_field( 'post_content', $script_id ) );
			}

			$autoload = 'sitewide' === $location ? 'yes' : 'no';
			if ( ! empty( $script_code ) ) {
				update_option( "{$option_prefix}_{$position}_{$location}", $script_code, $autoload );
				if ( 'sitewide' !== $location ) {
					$ao_cc_script_locations[ $position ][ $location ] = 1;
				}
			} else {
				delete_option( "{$option_prefix}_{$position}_{$location}" );
				if ( 'sitewide' !== $location ) {
					unset( $ao_cc_script_locations[ $position ][ $location ] );
				}
			}

		}

		update_option( $locations_key, $ao_cc_script_locations );
	}

	/**
	 * Append one snippet to an aggregate cache string with normalized line endings.
	 *
	 * @param string $aggregate Existing cached code.
	 * @param string $content   Snippet content to append.
	 * @return string
	 */
	protected function append_code( string $aggregate, string $content ): string {
		$content = str_replace( [ "\r\n", "\r" ], "\n", $content );

		if ( '' === $aggregate ) {
			return $content;
		}

		return rtrim( $aggregate ) . "\n" . ltrim( $content );
	}

	/**
	 * Rebuild the post-meta cache for post-ID-targeted snippets.
	 *
	 * A no-op on Free — specific-post targeting is a Pro-only capability.
	 * Custom_Code_Cache_Pro overrides this with the real implementation.
	 *
	 * @param array $old_ids Post IDs targeted before this save.
	 * @param array $new_ids Post IDs targeted after this save.
	 * @return void
	 */
	public function rebuild_post_meta( array $old_ids, array $new_ids ): void {
	}

}