<?php

namespace Elementor\Modules\Mcp\Abilities;

use Elementor\Modules\AtomicWidgets\CssConverter\Converter_Registry_Factory;
use Elementor\Modules\AtomicWidgets\CssConverter\Css_Converter;
use Elementor\Modules\AtomicWidgets\CssConverter\Expander_Registry_Factory;
use Elementor\Modules\AtomicWidgets\CssConverter\Metrics\Null_Failure_Reporter;
use Elementor\Modules\AtomicWidgets\CssConverter\Variable_Prop_Value_Transformer;
use Elementor\Modules\AtomicWidgets\Module as AtomicWidgetsModule;
use Elementor\Modules\AtomicWidgets\Utils\Utils;
use Elementor\Modules\GlobalClasses\Database\Migrations\Add_Capabilities;
use Elementor\Modules\GlobalClasses\Global_Classes_Labels;
use Elementor\Modules\GlobalClasses\Global_Classes_Repository;
use Elementor\Modules\GlobalClasses\Global_Classes_REST_API;
use Elementor\Modules\Mcp\Abilities\Utils\Bulk_Operations_Result;
use Elementor\Modules\Mcp\Abilities\Utils\Style_Variants_Merger;
use Elementor\Modules\Mcp\Abilities\Utils\Tool_Performance_Metrics;
use Elementor\Modules\Mcp\Events\Mcp_Event_Dispatcher;
use Elementor\Modules\Variables\Module as Variables_Module;
use Elementor\Modules\Variables\Services\Batch_Operations\Batch_Processor;
use Elementor\Modules\Variables\Services\Variables_Service;
use Elementor\Modules\Variables\Storage\Variables_Repository;
use Elementor\Plugin;

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

class Manage_Classes_Ability extends Abstract_Ability {

	const CLASS_TYPE = 'class';
	const DESKTOP_BREAKPOINT = 'desktop';
	const MAX_BATCH_SIZE = 50;

	private ?Global_Classes_Repository $repository;
	private ?Css_Converter $css_converter;

	public function __construct( ?Global_Classes_Repository $repository = null, ?Css_Converter $css_converter = null ) {
		$this->repository = $repository;
		$this->css_converter = $css_converter;
	}

	protected function get_ability_id(): string {
		return 'elementor/manage-classes';
	}

	protected function get_definition(): Ability_Definition {
		return new Ability_Definition(
			__( 'Manage Global Classes', 'elementor' ),
			__( 'Manage V4 global CSS classes on the active kit. Bulk create, update, or delete using raw CSS declarations (up to 50 operations). Duplicate labels are auto-renamed with a DUP_ prefix.', 'elementor' ),
			'elementor',
			[
				'type' => 'object',
				'required' => [ 'status', 'results', 'order' ],
				'properties' => [
					'status' => [ 'type' => 'string' ],
					'results' => [ 'type' => 'array' ],
					'order' => [
						'type' => 'array',
						'items' => [ 'type' => 'string' ],
					],
				],
			],
			[
				'annotations' => [
					'readonly' => false,
					'idempotent' => false,
					'destructive' => false,
				],
			],
			fn() => current_user_can( Add_Capabilities::UPDATE_CLASS ),
			[
				'type' => 'object',
				'required' => [ 'operations' ],
				'properties' => [
					'operations' => [
						'type' => 'array',
						'description' => 'Bulk operations (1–50). Each item requires action. create needs label and css. update/delete need id or label (both unique identifiers; label is also updated if provided on update). Use mode to control merge behaviour on update (patch = upsert, replace = overwrite breakpoint).',
						'items' => [
							'type' => 'object',
							'required' => [ 'action' ],
							'properties' => [
								'action' => [
									'type' => 'string',
									'enum' => [ 'create', 'update', 'delete' ],
								],
								'id' => [ 'type' => 'string' ],
								'label' => [ 'type' => 'string' ],
								'css' => [
									'type' => 'string',
									'description' => 'Plain CSS string. Supports &:hover/&:focus/&:active nesting and @media(--breakpoint) blocks. In patch mode: "prop: null" removes that prop; "all: null" wipes the variant.',
								],
								'mode' => [
									'type' => 'string',
									'enum' => [ 'patch', 'replace' ],
									'default' => 'patch',
									'description' => 'patch (default): upsert variants, preserving untouched ones; null/all:null deletions apply. replace: discard all variants for the affected breakpoints, then store new ones; null values have no effect.',
								],
							],
						],
					],
				],
			]
		);
	}

	public function execute( $input = [] ) {
		$started_at = hrtime( true );
		$input      = is_array( $input ) ? $input : [];
		$operations = $input['operations'] ?? null;

		if ( ! is_array( $operations ) ) {
			$error = $this->bad_request( __( 'operations array is required.', 'elementor' ) );
			$this->emit_mcp_manage_classes_executed( $started_at, [], $error );
			return $error;
		}

		if ( empty( $operations ) ) {
			$error = $this->bad_request( __( 'operations must not be empty.', 'elementor' ) );
			$this->emit_mcp_manage_classes_executed( $started_at, [], $error );
			return $error;
		}

		if ( count( $operations ) > self::MAX_BATCH_SIZE ) {
			$error = new \WP_Error(
				'batch_size_exceeded',
				sprintf(
					/* translators: %d: maximum operations per request */
					__( 'Maximum %d operations per request.', 'elementor' ),
					self::MAX_BATCH_SIZE
				),
				[
					'status' => \WP_Http::BAD_REQUEST,
					'max_allowed' => self::MAX_BATCH_SIZE,
				]
			);
			$this->emit_mcp_manage_classes_executed( $started_at, $operations, $error );
			return $error;
		}

		$response = $this->handle_bulk( $operations );
		$this->emit_mcp_manage_classes_executed( $started_at, $operations, null, $response );
		return $response;
	}

	private function handle_bulk( array $operations ): array {
		$results = new Bulk_Operations_Result();
		$repo = $this->get_repository();
		$all_labels = $repo->all_labels();
		$current_order = $repo->get_order();

		$intents = $this->translate_operations( $operations, $all_labels, $current_order, $results );

		$touched_items = $this->build_touched_items( $intents, $all_labels, $results );

		$this->handle_duplicated_labels( $intents, $touched_items, $all_labels, $results );

		$this->enforce_max_items( $intents, $touched_items, $all_labels, $results );

		$added_ids = array_values( array_intersect( $intents['added_ids'], array_keys( $touched_items ) ) );
		$modified_ids = array_values( array_intersect( $intents['modified_ids'], array_keys( $touched_items ) ) );
		$deleted_ids = $intents['deleted_ids'];

		$new_order = $this->compute_new_order( $current_order, $added_ids, $deleted_ids );

		// NOTE: null_props is an internal patch-merge signal; strip it from all variants before persisting.
		foreach ( $touched_items as &$item ) {
			foreach ( $item['variants'] as &$variant ) {
				unset( $variant['null_props'] );
			}
		}
		unset( $item, $variant );

		if ( ! empty( $added_ids ) || ! empty( $modified_ids ) || ! empty( $deleted_ids ) ) {
			$repo->apply_changes(
				$touched_items,
				[
					'added' => $added_ids,
					'deleted' => $deleted_ids,
					'modified' => $modified_ids,
					'order' => $new_order !== $current_order,
				],
				$new_order
			);

			$this->clear_cache();
			$this->emit_class_created_events( $results );
		}

		return $results->to_array() + [ 'order' => $new_order ];
	}

	private function translate_operations( array $operations, array $all_labels, array $current_order, Bulk_Operations_Result $results ): array {
		$intents = [
			'creates' => [],
			'updates' => [],
			'deletes' => [],
			'added_ids' => [],
			'modified_ids' => [],
			'deleted_ids' => [],
		];

		$reserved_ids = array_keys( $all_labels );
		$deleted_set = [];

		foreach ( $operations as $index => $operation ) {
			if ( ! is_array( $operation ) ) {
				$results->add_error( $index, '', 'invalid_input', __( 'Invalid operation.', 'elementor' ) );
				continue;
			}

			$action = $operation['action'] ?? '';

			switch ( $action ) {
				case 'create':
					$this->translate_create( $index, $operation, $intents, $reserved_ids, $results );
					break;

				case 'update':
					$this->translate_update( $index, $operation, $intents, $all_labels, $current_order, $deleted_set, $results );
					break;

				case 'delete':
					$this->translate_delete( $index, $operation, $intents, $all_labels, $current_order, $deleted_set, $results );
					break;

				default:
					$results->add_error(
						$index,
						$action,
						'invalid_input',
						sprintf(
							/* translators: %s: action name */
							__( 'Unknown action: %s.', 'elementor' ),
							$action
						)
					);
			}
		}

		return $intents;
	}

	private function translate_create( int $index, array $operation, array &$intents, array &$reserved_ids, Bulk_Operations_Result $results ): void {
		$label      = $operation['label'] ?? '';
		$css_string = $operation['css'] ?? null;

		if ( '' === $label ) {
			$results->add_error( $index, 'create', 'invalid_input', __( 'Create requires label.', 'elementor' ) );
			return;
		}

		if ( ! is_string( $css_string ) || '' === trim( $css_string ) ) {
			$results->add_error( $index, 'create', 'invalid_input', __( 'Create requires label and css.', 'elementor' ) );
			return;
		}

		$parsed = Style_Variants_Merger::parse_css_string( $css_string, $this->get_active_breakpoint_keys(), $index, 'create', $results, fn() => $this->get_css_converter() );
		if ( null === $parsed ) {
			return;
		}

		$class_id       = Utils::generate_id( 'g-', $reserved_ids );
		$reserved_ids[] = $class_id;

		$intents['creates'][ $index ] = [
			'id'                => $class_id,
			'label'             => $label,
			'breakpoint_blocks' => $parsed['breakpoint_blocks'],
		];
		$intents['added_ids'][] = $class_id;
	}

	private function translate_update( int $index, array $operation, array &$intents, array $all_labels, array $current_order, array $deleted_set, Bulk_Operations_Result $results ): void {
		$id    = $operation['id'] ?? '';
		$label = $operation['label'] ?? '';

		if ( '' === $id && '' === $label ) {
			$results->add_error( $index, 'update', 'invalid_input', __( 'Update requires id or label.', 'elementor' ) );
			return;
		}

		if ( '' === $id ) {
			$id = $this->resolve_class_id_by_label( $label, $all_labels );
			if ( null === $id ) {
				$results->add_error( $index, 'update', 'class_not_found', __( 'Global class not found', 'elementor' ) );
				return;
			}
		}

		if ( '' === $label ) {
			$label = $all_labels[ $id ] ?? '';
		}

		$mode = $operation['mode'] ?? 'patch';
		if ( ! in_array( $mode, [ 'patch', 'replace' ], true ) ) {
			$results->add_error( $index, 'update', 'invalid_input', sprintf( 'Unknown mode: %s. Valid modes: patch, replace.', $mode ) );
			return;
		}

		if ( ! in_array( $id, $current_order, true ) || isset( $deleted_set[ $id ] ) ) {
			$results->add_error( $index, 'update', 'class_not_found', __( 'Global class not found', 'elementor' ) );
			return;
		}

		$existing = $this->get_repository()->get( $id );
		if ( ! $existing ) {
			$results->add_error( $index, 'update', 'class_not_found', __( 'Global class not found', 'elementor' ) );
			return;
		}

		$css_string = $operation['css'] ?? null;

		if ( is_string( $css_string ) && '' !== trim( $css_string ) ) {
			$parsed = Style_Variants_Merger::parse_css_string( $css_string, $this->get_active_breakpoint_keys(), $index, 'update', $results, fn() => $this->get_css_converter() );
			if ( null === $parsed ) {
				return;
			}

			$intents['updates'][ $index ] = [
				'id'                  => $id,
				'label'               => $label,
				'breakpoint_blocks'   => $parsed['breakpoint_blocks'],
				'removal_breakpoints' => $parsed['removal_breakpoints'],
				'mode'                => $operation['mode'] ?? 'patch',
				'existing_variants'   => $existing['variants'] ?? [],
			];
		} else {
			$intents['updates'][ $index ] = [
				'id'                => $id,
				'label'             => $label,
				'mode'              => $operation['mode'] ?? 'patch',
				'existing_variants' => $existing['variants'] ?? [],
			];
		}

		if ( ! in_array( $id, $intents['modified_ids'], true ) ) {
			$intents['modified_ids'][] = $id;
		}
	}

	protected function get_active_breakpoint_keys(): array {
		return Plugin::$instance->breakpoints->get_active_devices_list();
	}

	private function translate_delete( int $index, array $operation, array &$intents, array $all_labels, array $current_order, array &$deleted_set, Bulk_Operations_Result $results ): void {
		$id    = $operation['id'] ?? '';
		$label = $operation['label'] ?? '';

		if ( '' === $id && '' === $label ) {
			$results->add_error( $index, 'delete', 'invalid_input', __( 'Delete requires id or label.', 'elementor' ) );
			return;
		}

		if ( '' === $id ) {
			$id = $this->resolve_class_id_by_label( $label, $all_labels );
			if ( null === $id ) {
				$results->add_error( $index, 'delete', 'class_not_found', __( 'Global class not found', 'elementor' ) );
				return;
			}
		}

		if ( ! in_array( $id, $current_order, true ) || isset( $deleted_set[ $id ] ) ) {
			$results->add_error( $index, 'delete', 'class_not_found', __( 'Global class not found', 'elementor' ) );
			return;
		}

		$existing = $this->get_repository()->get( $id );
		if ( ! $existing ) {
			$results->add_error( $index, 'delete', 'class_not_found', __( 'Global class not found', 'elementor' ) );
			return;
		}

		$label = $all_labels[ $id ] ?? ( $existing['label'] ?? '' );
		$deleted_set[ $id ] = true;

		$intents['deletes'][ $index ] = [
			'id' => $id,
			'label' => $label,
		];
		$intents['deleted_ids'][] = $id;

		$results->add_success( $index, 'delete', [
			'id' => $id,
			'label' => $label,
		] );
	}

	private function build_touched_items( array $intents, array $all_labels, Bulk_Operations_Result $results ): array {
		$touched_items = [];

		foreach ( $intents['creates'] as $index => $intent ) {
			$variants                      = Style_Variants_Merger::build_variants( $intent['breakpoint_blocks'], $this->get_css_converter() );
			$touched_items[ $intent['id'] ] = [
				'id'       => $intent['id'],
				'label'    => $intent['label'],
				'type'     => self::CLASS_TYPE,
				'variants' => $variants,
			];
		}

		foreach ( $intents['updates'] as $index => $intent ) {
			if ( isset( $intent['breakpoint_blocks'] ) ) {
				$new_variants           = Style_Variants_Merger::build_variants( $intent['breakpoint_blocks'], $this->get_css_converter() );
				$removal_breakpoints    = $intent['removal_breakpoints'];
				$existing_after_removal = array_values(
					array_filter(
						$intent['existing_variants'],
						fn( $v ) => ! in_array( $v['meta']['breakpoint'] ?? null, $removal_breakpoints, true )
					)
				);
				$merged_variants = Style_Variants_Merger::apply_mode(
					$existing_after_removal,
					$new_variants,
					$intent['mode'],
					array_column( $intent['breakpoint_blocks'], 'breakpoint' )
				);
				$touched_items[ $intent['id'] ] = [
					'id'       => $intent['id'],
					'label'    => $intent['label'],
					'type'     => self::CLASS_TYPE,
					'variants' => $merged_variants,
				];
				continue;
			}

			// Label-only update — preserve existing variants, only apply new label.
			$touched_items[ $intent['id'] ] = [
				'id'       => $intent['id'],
				'label'    => $intent['label'],
				'type'     => self::CLASS_TYPE,
				'variants' => $intent['existing_variants'],
			];
		}

		return $touched_items;
	}

	private function handle_duplicated_labels( array $intents, array &$touched_items, array $all_labels, Bulk_Operations_Result $results ): void {
		$deleted_ids = $intents['deleted_ids'];
		$existing_labels = [];

		foreach ( $all_labels as $id => $label ) {
			if ( ! in_array( $id, $deleted_ids, true ) ) {
				$existing_labels[] = $label;
			}
		}

		$pending_labels = [];

		foreach ( $intents['creates'] as $index => $intent ) {
			if ( ! isset( $touched_items[ $intent['id'] ] ) ) {
				continue;
			}

			$label = $intent['label'];
			$is_duplicate = in_array( $label, $existing_labels, true ) || in_array( $label, $pending_labels, true );

			if ( $is_duplicate ) {
				$all_existing = array_merge( $existing_labels, $pending_labels );
				$new_label = Global_Classes_Labels::generate_unique_label( $label, $all_existing );

				$touched_items[ $intent['id'] ]['label'] = $new_label;
				$pending_labels[] = $new_label;

				$results->add_success( $index, 'create', [
					'id' => $intent['id'],
					'label' => $new_label,
					'modified_label' => [
						'original' => $label,
						'modified' => $new_label,
					],
				] );
			} else {
				$pending_labels[] = $label;
				$results->add_success( $index, 'create', [
					'id' => $intent['id'],
					'label' => $label,
				] );
			}
		}

		foreach ( $intents['updates'] as $index => $intent ) {
			if ( ! isset( $touched_items[ $intent['id'] ] ) ) {
				continue;
			}

			$label = $intent['label'];
			$current_label = $all_labels[ $intent['id'] ] ?? '';

			$is_duplicate = false;
			if ( $label !== $current_label ) {
				$is_duplicate = in_array( $label, $existing_labels, true ) || in_array( $label, $pending_labels, true );
			}

			if ( $is_duplicate ) {
				$all_existing = array_merge( $existing_labels, $pending_labels );
				$new_label = Global_Classes_Labels::generate_unique_label( $label, $all_existing );

				$touched_items[ $intent['id'] ]['label'] = $new_label;
				$pending_labels[] = $new_label;

				$results->add_success( $index, 'update', [
					'id' => $intent['id'],
					'label' => $new_label,
					'modified_label' => [
						'original' => $label,
						'modified' => $new_label,
					],
				] );
			} else {
				if ( $label !== $current_label ) {
					$pending_labels[] = $label;
				}
				$results->add_success( $index, 'update', [
					'id' => $intent['id'],
					'label' => $label,
				] );
			}
		}
	}

	private function enforce_max_items( array $intents, array &$touched_items, array $all_labels, Bulk_Operations_Result $results ): void {
		$deleted_count = count( $intents['deleted_ids'] );
		$existing_count = count( $all_labels ) - $deleted_count;
		$added_count = count( array_intersect( $intents['added_ids'], array_keys( $touched_items ) ) );

		$total_count = $existing_count + $added_count;

		if ( $total_count <= Global_Classes_REST_API::MAX_ITEMS ) {
			return;
		}

		$overflow = $total_count - Global_Classes_REST_API::MAX_ITEMS;
		$error_message = sprintf(
			/* translators: %d: Maximum allowed items. */
			__( 'Global classes limit exceeded. Maximum allowed: %d', 'elementor' ),
			Global_Classes_REST_API::MAX_ITEMS
		);

		$creates_to_reject = array_slice( $intents['creates'], -$overflow, $overflow, true );

		foreach ( $creates_to_reject as $index => $intent ) {
			if ( isset( $touched_items[ $intent['id'] ] ) ) {
				unset( $touched_items[ $intent['id'] ] );

				$results->add_error( $index, 'create', 'global_classes_limit_exceeded', $error_message );
			}
		}
	}

	private function compute_new_order( array $current_order, array $added_ids, array $deleted_ids ): array {
		$new_order = array_filter( $current_order, fn( $id ) => ! in_array( $id, $deleted_ids, true ) );
		$new_order = array_values( $new_order );

		return array_merge( $new_order, $added_ids );
	}

	private function resolve_class_id_by_label( string $label, array $all_labels ): ?string {
		$id = array_search( $label, $all_labels, true );
		return false !== $id ? $id : null;
	}

	private function bad_request( string $message ): \WP_Error {
		return new \WP_Error( 'invalid_input', $message, [ 'status' => \WP_Http::BAD_REQUEST ] );
	}

	private function clear_cache(): void {
		if ( ! class_exists( Plugin::class ) || ! isset( Plugin::$instance ) ) {
			return;
		}

		Plugin::$instance->files_manager->clear_cache();
	}

	private function get_repository(): Global_Classes_Repository {
		if ( $this->repository ) {
			return $this->repository;
		}

		$kit = Plugin::$instance->kits_manager->get_active_kit();

		return Global_Classes_Repository::make( $kit );
	}

	private function get_css_converter(): Css_Converter {
		if ( $this->css_converter ) {
			return $this->css_converter;
		}

		$variables_service = $this->create_variables_service();

		$variable_transformer = $variables_service
			? new Variable_Prop_Value_Transformer( $variables_service )
			: null;

		return new Css_Converter(
			Converter_Registry_Factory::create( $variables_service ),
			new Null_Failure_Reporter(),
			Expander_Registry_Factory::create( $variables_service ),
			$variable_transformer
		);
	}

	private function create_variables_service(): ?Variables_Service {
		if ( ! $this->is_variables_active() ) {
			return null;
		}

		$kit = Plugin::$instance->kits_manager->get_active_kit();

		if ( ! $kit ) {
			return null;
		}

		return new Variables_Service(
			new Variables_Repository( $kit ),
			new Batch_Processor()
		);
	}

	private function is_variables_active(): bool {
		$experiments = Plugin::$instance->experiments;

		return $experiments->is_feature_active( Variables_Module::EXPERIMENT_NAME )
			&& $experiments->is_feature_active( AtomicWidgetsModule::EXPERIMENT_NAME );
	}

	private function emit_class_created_events( Bulk_Operations_Result $results ): void {
		foreach ( $results->to_array()['results'] as $row ) {
			if ( 'ok' !== ( $row['status'] ?? '' ) || 'create' !== ( $row['action'] ?? '' ) ) {
				continue;
			}

			Mcp_Event_Dispatcher::emit( 'class_created', [
				'id'   => $row['id'] ?? '',
				'name' => $row['label'] ?? '',
			] );
		}
	}

	private function emit_mcp_manage_classes_executed(
		int $started_at,
		array $operations,
		?\WP_Error $top_level_error = null,
		array $response = []
	): void {
		$duration_ms = Tool_Performance_Metrics::duration_ms_since( $started_at );

		[ 'status' => $status, 'error_code' => $error_code ] = Tool_Performance_Metrics::resolve_status( $response, $top_level_error );

		$failed_results = array_filter( $response['results'] ?? [], fn( $r ) => 'error' === ( $r['status'] ?? '' ) );
		$failed_count   = count( $failed_results );
		$failed_codes   = array_values( array_unique( array_column( $failed_results, 'code' ) ) );

		$ops_count = count( $operations );
		$by_action = [];
		$mode_used = null;
		$all_css   = '';

		foreach ( $operations as $op ) {
			$action = $op['action'] ?? '';
			if ( is_string( $action ) && '' !== $action ) {
				$by_action[ $action ] = ( $by_action[ $action ] ?? 0 ) + 1;
			}

			if ( 'update' === $action ) {
				$mode_used = $mode_used ?? ( $op['mode'] ?? 'patch' );
			}

			if ( isset( $op['css'] ) && is_string( $op['css'] ) ) {
				$all_css .= ' ' . $op['css'];
			}
		}

		$dominant_action = '';
		if ( ! empty( $by_action ) ) {
			arsort( $by_action );
			$dominant_action = (string) array_key_first( $by_action );
		}

		$vars_count = 0;
		$var_labels = [];
		if ( '' !== trim( $all_css ) ) {
			preg_match_all( '/var\(--([a-zA-Z0-9_-]+)\)/', $all_css, $matches );
			$var_labels = array_values( array_unique( $matches[1] ?? [] ) );
			$vars_count = count( $matches[0] ?? [] );
		}

		$payload = [
			'tool_name'                  => $this->get_ability_id(),
			'status'                     => $status,
			'duration_ms'                => $duration_ms,
			'action'                     => $dominant_action,
			'operations_count'           => $ops_count,
			'operations_by_type'         => $by_action,
			'failed_operations_count'    => $failed_count,
			'failed_operation_codes'     => $failed_codes,
			'variables_referenced_count' => $vars_count,
			'variable_labels'            => $var_labels,
			'warning_count'              => 0,
			'warning_types'              => [],
		];

		if ( null !== $mode_used ) {
			$payload['mode_used'] = $mode_used;
		}

		if ( null !== $error_code ) {
			$payload['error_code'] = $error_code;
		}

		Mcp_Event_Dispatcher::emit( 'mcp_manage_classes_executed', $payload );
	}
}