<?php
/**
 * Form AJAX Handler
 *
 * Handles form submissions via AJAX for the form block.
 *
 * @since      1.0.0
 * @package    Acumenpopup
 * @subpackage Acumenpopup/includes/Form
 */

namespace Acumenpopup\Form;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Class Handler
 *
 * Manages form submission handling via AJAX (Singleton).
 *
 * @since   1.0.0
 * @package Acumenpopup
 */
class Handler {

	/**
	 * The single instance of the class.
	 *
	 * @since  1.0.0
	 * @access private
	 * @var    Handler|null
	 */
	private static $instance = null;

	/**
	 * Private constructor to prevent direct instantiation.
	 *
	 * @since  1.0.0
	 * @access private
	 */
	private function __construct() {
		$this->init_hooks();
	}

	/**
	 * Get the single instance of the Handler class.
	 *
	 * @since  1.0.0
	 * @access public
	 *
	 * @return Handler The single instance.
	 */
	public static function get_instance() {
		if ( is_null( self::$instance ) ) {
			self::$instance = new self();
		}

		return self::$instance;
	}

	/**
	 * Initialize WordPress hooks.
	 *
	 * @since  1.0.0
	 * @access private
	 *
	 * @return void
	 */
	private function init_hooks() {
		add_action( 'wp_ajax_acumenpopup_form_submit', array( $this, 'handle_form_submission' ) );
		add_action( 'wp_ajax_nopriv_acumenpopup_form_submit', array( $this, 'handle_form_submission' ) );
	}

	/**
	 * Handle form submission via AJAX.
	 *
	 * Validates the request, retrieves form configuration,
	 * and sends the email.
	 *
	 * @since  1.0.0
	 * @access public
	 *
	 * @return void Sends JSON response and exits.
	 */
	public function handle_form_submission() {
		// Verify nonce.
		$nonce = isset( $_POST['nonce'] ) ? sanitize_text_field( wp_unslash( $_POST['nonce'] ) ) : '';

		if ( ! wp_verify_nonce( $nonce, 'acumenpopup_form_submit' ) ) {
			wp_send_json_error(
				array( 'message' => esc_html__( 'Invalid security token.', 'acumen-popup' ) ),
				403
			);
		}

		// Collect and sanitize posted data.
		$data       = isset( $_POST['data'] ) ? $this->sanitize_form_data( wp_unslash( $_POST['data'] ) ) : array(); // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
		$form_id    = isset( $_POST['formId'] ) ? sanitize_text_field( wp_unslash( $_POST['formId'] ) ) : '';
		$popup_id   = isset( $_POST['popupId'] ) ? sanitize_text_field( wp_unslash( $_POST['popupId'] ) ) : '';
		$form_title = isset( $data['nx_form_title']['value'] )
			? sanitize_text_field( $data['nx_form_title']['value'] )
			: esc_html__( 'Form Submission', 'acumen-popup' );

		// Validate required fields.
		if ( empty( $popup_id ) || empty( $form_id ) ) {
			wp_send_json_error(
				array( 'message' => esc_html__( 'Configuration error: Missing Popup ID or Form ID.', 'acumen-popup' ) ),
				400
			);
		}

		// Get form configuration from the block.
		$config = $this->get_form_config( $popup_id, $form_id );

		if ( ! $config ) {
			wp_send_json_error(
				array( 'message' => esc_html__( 'Configuration error: Form not found.', 'acumen-popup' ) ),
				404
			);
		}

		// Extract email configuration (server-side only).
		$to      = ! empty( $config['emailTo'] ) ? sanitize_email( $config['emailTo'] ) : get_option( 'admin_email' );
		$subject = ! empty( $config['emailSubject'] )
			? sanitize_text_field( $config['emailSubject'] )
			: esc_html__( 'New Form Submission', 'acumen-popup' );
		$cc      = ! empty( $config['emailCC'] ) ? sanitize_text_field( $config['emailCC'] ) : '';
		$bcc     = ! empty( $config['emailBCC'] ) ? sanitize_text_field( $config['emailBCC'] ) : '';

		// Build email body.
		$body = $this->build_email_body( $form_title, $form_id, $popup_id, $data );

		// Build email headers.
		$headers = $this->build_email_headers( $cc, $bcc );

		// Send email.
		$sent = wp_mail( $to, $subject, $body, $headers );

		if ( $sent ) {
			// Track conversion for analytics
			$args = array(
				'post_type'      => 'acumen_popup_cmpgn',
				'meta_key'       => 'acumenpopup_popup_id', // phpcs:ignore
				'meta_value'     => $popup_id, // phpcs:ignore
				'fields'         => 'ids',
				'numberposts'    => 1,
				'post_status'    => 'any',
			);
			$posts = get_posts( $args );
			$post_id = ! empty( $posts ) ? $posts[0] : ( is_numeric( $popup_id ) ? absint( $popup_id ) : 0 );
			if ( $post_id ) {
				$current_conversions = (int) get_post_meta( $post_id, 'acumenpopup_conversions', true );
				update_post_meta( $post_id, 'acumenpopup_conversions', $current_conversions + 1 );
			}

			wp_send_json_success(
				array( 'message' => esc_html__( 'Form submitted successfully.', 'acumen-popup' ) )
			);
		} else {
			wp_send_json_error(
				array( 'message' => esc_html__( 'Failed to send email.', 'acumen-popup' ) ),
				500
			);
		}
	}

	/**
	 * Sanitize form data array.
	 *
	 * @since  1.0.0
	 * @access private
	 *
	 * @param array $data Raw form data.
	 *
	 * @return array Sanitized form data.
	 */
	private function sanitize_form_data( $data ) {
		if ( ! is_array( $data ) ) {
			return array();
		}

		$sanitized = array();

		foreach ( $data as $key => $item ) {
			$sanitized_key = sanitize_key( $key );

			if ( is_array( $item ) ) {
				$sanitized[ $sanitized_key ] = array(
					'label' => isset( $item['label'] ) ? sanitize_text_field( $item['label'] ) : '',
					'value' => isset( $item['value'] ) ? wp_kses_post( $item['value'] ) : '',
				);
			} else {
				$sanitized[ $sanitized_key ] = sanitize_text_field( $item );
			}
		}

		return $sanitized;
	}

	/**
	 * Build the email body from form data.
	 *
	 * @since  1.0.0
	 * @access private
	 *
	 * @param string $form_title The form title.
	 * @param string $form_id    The form ID.
	 * @param string $popup_id   The popup ID.
	 * @param array  $data       The sanitized form data.
	 *
	 * @return string The formatted email body.
	 */
	private function build_email_body( $form_title, $form_id, $popup_id, $data ) {
		$lines = array(
			sprintf( 'Form: %s', esc_html( $form_title ) ),
			sprintf( 'Form ID: %s', esc_html( $form_id ) ),
			sprintf( 'Popup ID: %s', esc_html( $popup_id ) ),
			'',
		);

		// Internal config keys to skip.
		$skip_keys = array(
			'nx_form_title',
			'nx_email_to',
			'nx_email_subject',
			'nx_email_cc',
			'nx_email_bcc',
		);

		foreach ( $data as $key => $item ) {
			if ( in_array( $key, $skip_keys, true ) ) {
				continue;
			}

			if ( is_array( $item ) ) {
				$label = isset( $item['label'] ) ? $item['label'] : $key;
				$value = isset( $item['value'] ) ? $item['value'] : '';
			} else {
				$label = $key;
				$value = $item;
			}

			$lines[] = sprintf( '%s: %s', esc_html( $label ), esc_html( $value ) );
		}

		return implode( "\n", $lines );
	}

	/**
	 * Build email headers with CC and BCC.
	 *
	 * @since  1.0.0
	 * @access private
	 *
	 * @param string $cc  Carbon copy email address.
	 * @param string $bcc Blind carbon copy email address.
	 *
	 * @return array Array of email headers.
	 */
	private function build_email_headers( $cc, $bcc ) {
		$headers = array( 'Content-Type: text/plain; charset=UTF-8' );

		if ( ! empty( $cc ) ) {
			$headers[] = 'Cc: ' . sanitize_email( $cc );
		}

		if ( ! empty( $bcc ) ) {
			$headers[] = 'Bcc: ' . sanitize_email( $bcc );
		}

		return $headers;
	}

	/**
	 * Retrieve form configuration from the popup block.
	 *
	 * @since  1.0.0
	 * @access private
	 *
	 * @param string $popup_id_str The unique popup ID string.
	 * @param string $form_id      The unique form ID.
	 *
	 * @return array|false Form configuration array or false if not found.
	 */
	private function get_form_config( $popup_id_str, $form_id ) {
		// First try: Find the Campaign Post by meta.
		$posts = get_posts(
			array(
				'post_type'      => 'acumen_popup_cmpgn',
				'meta_key'       => 'acumenpopup_popup_id', // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key
				'meta_value'     => sanitize_text_field( $popup_id_str ), // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_value
				'posts_per_page' => 1,
				'fields'         => 'ids',
			)
		);

		// Second try: If no posts found by meta, search all campaigns by block content.
		if ( empty( $posts ) ) {
			$all_campaigns = get_posts(
				array(
					'post_type'      => 'acumen_popup_cmpgn',
					'post_status'    => 'any',
					'posts_per_page' => -1,
				)
			);

			foreach ( $all_campaigns as $campaign ) {
				$blocks      = parse_blocks( $campaign->post_content );
				$popup_block = $this->find_popup_block_by_id( $blocks, $popup_id_str );

				if ( $popup_block ) {
					// Found matching popup, now search for form.
					$form_block = $this->find_form_block_recursive( $blocks, $form_id );
					if ( $form_block && isset( $form_block['attrs'] ) ) {
						return $form_block['attrs'];
					}
				}
			}

			return false;
		}

		$post_id = $posts[0];
		$post    = get_post( $post_id );

		if ( ! $post ) {
			return false;
		}

		$blocks     = parse_blocks( $post->post_content );
		$form_block = $this->find_form_block_recursive( $blocks, $form_id );

		if ( $form_block && isset( $form_block['attrs'] ) ) {
			return $form_block['attrs'];
		}

		return false;
	}

	/**
	 * Find popup block by acumenpopupId attribute.
	 *
	 * @since  1.0.0
	 * @access private
	 *
	 * @param array  $blocks   Array of parsed blocks.
	 * @param string $popup_id The popup ID to find.
	 *
	 * @return array|null The popup block or null if not found.
	 */
	private function find_popup_block_by_id( $blocks, $popup_id ) {
		foreach ( $blocks as $block ) {
			if (
				isset( $block['blockName'] ) &&
				'acumenpopup/popup-builder' === $block['blockName'] &&
				isset( $block['attrs']['acumenpopupId'] ) &&
				$block['attrs']['acumenpopupId'] === $popup_id
			) {
				return $block;
			}

			// Search inner blocks.
			if ( ! empty( $block['innerBlocks'] ) ) {
				$found = $this->find_popup_block_by_id( $block['innerBlocks'], $popup_id );
				if ( $found ) {
					return $found;
				}
			}
		}

		return null;
	}

	/**
	 * Recursively search for a form block by ID.
	 *
	 * @since  1.0.0
	 * @access private
	 *
	 * @param array  $blocks  Array of parsed blocks.
	 * @param string $form_id The form ID to find.
	 *
	 * @return array|null The form block or null if not found.
	 */
	private function find_form_block_recursive( $blocks, $form_id ) {
		foreach ( $blocks as $block ) {
			// Check if this is the form block we're looking for.
			if (
				isset( $block['blockName'] ) &&
				'acumenpopup/form' === $block['blockName'] &&
				isset( $block['attrs']['formId'] ) &&
				$block['attrs']['formId'] === $form_id
			) {
				return $block;
			}

			// Search inner blocks.
			if ( ! empty( $block['innerBlocks'] ) ) {
				$found = $this->find_form_block_recursive( $block['innerBlocks'], $form_id );
				if ( $found ) {
					return $found;
				}
			}
		}

		return null;
	}

	/**
	 * Prevent cloning of the instance.
	 *
	 * @since  1.0.0
	 * @access public
	 *
	 * @return void
	 */
	public function __clone() {
		_doing_it_wrong(
			__FUNCTION__,
			esc_html__( 'Cloning is forbidden.', 'acumen-popup' ),
			'1.0.0'
		);
	}

	/**
	 * Prevent unserializing of the instance.
	 *
	 * @since  1.0.0
	 * @access public
	 *
	 * @return void
	 */
	public function __wakeup() {
		_doing_it_wrong(
			__FUNCTION__,
			esc_html__( 'Unserializing is forbidden.', 'acumen-popup' ),
			'1.0.0'
		);
	}
}