<?php
namespace AdvancedAddons;

/** A shared, editor-specific library of animation configurations. */
class Animation_Presets_Controller {
	const OPTION = 'advanced_addons_animation_presets';
	const NAMESPACE_NAME = 'advanced-animation/v1';

	public function __construct() {
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
	}

	public function register_routes() {
		register_rest_route( self::NAMESPACE_NAME, '/presets', array(
			array( 'methods' => 'GET', 'callback' => array( $this, 'list_presets' ), 'permission_callback' => array( $this, 'can_manage' ) ),
			array( 'methods' => 'POST', 'callback' => array( $this, 'create_preset' ), 'permission_callback' => array( $this, 'can_manage' ) ),
		) );
		register_rest_route( self::NAMESPACE_NAME, '/presets/(?P<id>[a-zA-Z0-9-]+)', array(
			array( 'methods' => 'GET', 'callback' => array( $this, 'get_preset' ), 'permission_callback' => array( $this, 'can_manage' ) ),
			array( 'methods' => 'PUT', 'callback' => array( $this, 'update_preset' ), 'permission_callback' => array( $this, 'can_manage' ) ),
			array( 'methods' => 'DELETE', 'callback' => array( $this, 'delete_preset' ), 'permission_callback' => array( $this, 'can_manage' ) ),
		) );
	}

	public function can_manage() {
		return current_user_can( 'edit_posts' );
	}

	private function all() {
		$value = get_option( self::OPTION, array() );
		return is_array( $value ) ? array_values( $value ) : array();
	}

	private function save( $presets ) {
		// The option is intentionally absent until the first successful save.
		if ( false === get_option( self::OPTION, false ) ) {
			add_option( self::OPTION, array_values( $presets ), '', false );
		} else {
			update_option( self::OPTION, array_values( $presets ), false );
		}
	}

	private function editor( $request ) {
		$editor = $request->get_param( 'editor' );
		return in_array( $editor, array( 'gutenberg', 'elementor' ), true ) ? $editor : null;
	}

	private function invalid( $message, $status = 400 ) {
		return new \WP_Error( 'animation_preset_error', $message, array( 'status' => $status ) );
	}

	private function find_index( $presets, $id ) {
		foreach ( $presets as $index => $preset ) {
			if ( isset( $preset['id'] ) && $preset['id'] === $id ) return $index;
		}
		return -1;
	}

	private function duplicate_name( $presets, $editor, $name, $except_id = '' ) {
		foreach ( $presets as $preset ) {
			if ( $preset['editor'] === $editor && $preset['id'] !== $except_id && 0 === strcasecmp( $preset['name'], $name ) ) return true;
		}
		return false;
	}

	private function input( $request ) {
		$editor = $this->editor( $request );
		$name = $request->get_param( 'name' );
		$config = $request->get_param( 'config' );
		if ( ! $editor ) return $this->invalid( __( 'Choose a valid editor.', 'advanced-animation' ) );
		if ( ! is_string( $name ) || '' === trim( $name ) ) return $this->invalid( __( 'Enter a preset name.', 'advanced-animation' ) );
		$name = sanitize_text_field( trim( $name ) );
		if ( '' === $name ) return $this->invalid( __( 'Enter a preset name.', 'advanced-animation' ) );
		if ( strlen( $name ) > 100 ) return $this->invalid( __( 'Preset names must be 100 characters or fewer.', 'advanced-animation' ) );
		if ( ! is_array( $config ) || empty( $config ) || array_keys( $config ) === range( 0, count( $config ) - 1 ) || strlen( wp_json_encode( $config ) ) > 100000 ) {
			return $this->invalid( __( 'Enter a valid animation configuration.', 'advanced-animation' ) );
		}
		return array( 'editor' => $editor, 'name' => $name, 'config' => $config );
	}

	public function list_presets( $request ) {
		$editor = $this->editor( $request );
		if ( ! $editor ) return $this->invalid( __( 'Choose a valid editor.', 'advanced-animation' ) );
		return rest_ensure_response( array( 'presets' => array_values( array_filter( $this->all(), function ( $preset ) use ( $editor ) {
			return isset( $preset['editor'] ) && $preset['editor'] === $editor;
		} ) ) ) );
	}

	public function get_preset( $request ) {
		$presets = $this->all();
		$index = $this->find_index( $presets, $request->get_param( 'id' ) );
		if ( $index < 0 ) return $this->invalid( __( 'Preset not found.', 'advanced-animation' ), 404 );
		return rest_ensure_response( array( 'preset' => $presets[ $index ] ) );
	}

	public function create_preset( $request ) {
		$input = $this->input( $request );
		if ( is_wp_error( $input ) ) return $input;
		$presets = $this->all();
		if ( $this->duplicate_name( $presets, $input['editor'], $input['name'] ) ) return $this->invalid( __( 'A preset with this name already exists.', 'advanced-animation' ), 409 );
		$preset = array_merge( array( 'id' => wp_generate_uuid4() ), $input );
		$presets[] = $preset;
		$this->save( $presets );
		return rest_ensure_response( array( 'preset' => $preset ) );
	}

	public function update_preset( $request ) {
		$presets = $this->all();
		$index = $this->find_index( $presets, $request->get_param( 'id' ) );
		if ( $index < 0 ) return $this->invalid( __( 'Preset not found.', 'advanced-animation' ), 404 );
		$input = $this->input( $request );
		if ( is_wp_error( $input ) ) return $input;
		if ( $input['editor'] !== $presets[ $index ]['editor'] ) return $this->invalid( __( 'Preset editor cannot change.', 'advanced-animation' ) );
		if ( $this->duplicate_name( $presets, $input['editor'], $input['name'], $presets[ $index ]['id'] ) ) return $this->invalid( __( 'A preset with this name already exists.', 'advanced-animation' ), 409 );
		$presets[ $index ] = array_merge( array( 'id' => $presets[ $index ]['id'] ), $input );
		$this->save( $presets );
		return rest_ensure_response( array( 'preset' => $presets[ $index ] ) );
	}

	public function delete_preset( $request ) {
		$presets = $this->all();
		$index = $this->find_index( $presets, $request->get_param( 'id' ) );
		if ( $index < 0 ) return $this->invalid( __( 'Preset not found.', 'advanced-animation' ), 404 );
		array_splice( $presets, $index, 1 );
		$this->save( $presets );
		return rest_ensure_response( array( 'deleted' => true ) );
	}
}