<?php

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

function x_pixel_broker_connect_url() {
	if ( defined( 'X_PIXEL_BROKER_URL' ) ) {
		return untrailingslashit( X_PIXEL_BROKER_URL );
	}
	$host = wp_parse_url( home_url(), PHP_URL_HOST );
	if ( $host === 'localhost' || $host === '127.0.0.1' ) {
		return 'https://localhost.x.com:3000/manager/api/integrations/wordpress/connect';
	}
	return 'https://ads.x.com/manager/api/integrations/wordpress/connect';
}

function x_pixel_allowed_redirect_hosts( $hosts ) {
	$hosts   = is_array( $hosts ) ? $hosts : array();
	$hosts[] = 'ads.x.com';
	$hosts[] = 'api.x.com';
	$hosts[] = 'x.com';
	$hosts[] = 'api.twitter.com';
	$hosts[] = 'twitter.com';
	$broker  = wp_parse_url( x_pixel_broker_connect_url(), PHP_URL_HOST );
	if ( is_string( $broker ) && $broker !== '' ) {
		$hosts[] = strtolower( $broker );
	}
	return array_values( array_unique( $hosts ) );
}

function x_pixel_redirect_to_x( $url, $status = 302 ) {
	add_filter( 'allowed_redirect_hosts', 'x_pixel_allowed_redirect_hosts' );
	nocache_headers();
	wp_safe_redirect( $url, $status );
	exit;
}

function x_pixel_settings_url( $args = array() ) {
	return add_query_arg(
		$args,
		admin_url( 'options-general.php?page=x-pixel' )
	);
}

function x_pixel_oauth_state_key( $state ) {
	return 'x_pixel_oauth_' . hash( 'sha256', $state );
}

function x_pixel_oauth_blob_key( $state ) {
	return 'x_pixel_oauth_blob_' . hash( 'sha256', $state );
}

function x_pixel_oauth_state_record( $state ) {
	if ( $state === '' ) {
		return null;
	}
	$record = get_transient( x_pixel_oauth_state_key( $state ) );
	if ( ! is_array( $record ) || empty( $record['state'] ) || ! is_string( $record['state'] ) || empty( $record['user_id'] ) ) {
		return null;
	}
	if ( ! hash_equals( $record['state'], $state ) ) {
		return null;
	}
	return array(
		'state'   => $record['state'],
		'user_id' => (int) $record['user_id'],
	);
}

function x_pixel_oauth_forget_state( $state ) {
	if ( $state === '' ) {
		return;
	}
	delete_transient( x_pixel_oauth_state_key( $state ) );
	delete_transient( x_pixel_oauth_blob_key( $state ) );
}

function x_pixel_oauth_start() {
	if ( ! current_user_can( 'manage_options' ) ) {
		wp_die( esc_html__( 'You do not have permission to connect X Ads.', 'x-pixel' ) );
	}
	check_admin_referer( 'x_pixel_oauth_start' );

	$state = wp_generate_password( 32, false, false );
	set_transient(
		x_pixel_oauth_state_key( $state ),
		array(
			'state'   => $state,
			'user_id' => get_current_user_id(),
		),
		20 * MINUTE_IN_SECONDS
	);

	$return_url = add_query_arg(
		array(
			'action'   => 'x_pixel_oauth_return',
			'wp_state' => $state,
		),
		admin_url( 'admin-post.php' )
	);

	x_pixel_redirect_to_x( add_query_arg( 'return_url', rawurlencode( $return_url ), x_pixel_broker_connect_url() ) );
}
add_action( 'admin_post_x_pixel_oauth_start', 'x_pixel_oauth_start' );

function x_pixel_oauth_request( $key ) {
	if ( isset( $_POST[ $key ] ) && ! is_array( $_POST[ $key ] ) ) {
		return sanitize_text_field( wp_unslash( $_POST[ $key ] ) );
	}
	if ( isset( $_GET[ $key ] ) && ! is_array( $_GET[ $key ] ) ) {
		return sanitize_text_field( wp_unslash( $_GET[ $key ] ) );
	}
	return null;
}

function x_pixel_oauth_state_param() {
	$state = (string) x_pixel_oauth_request( 'wp_state' );
	return preg_match( '/^[A-Za-z0-9]{32}$/', $state ) === 1 ? $state : '';
}

function x_pixel_oauth_opaque_param( $key ) {
	$value = (string) x_pixel_oauth_request( $key );
	return preg_match( '/^[A-Za-z0-9_-]+$/', $value ) === 1 ? $value : '';
}

function x_pixel_oauth_state_is_live( $state ) {
	$record = x_pixel_oauth_state_record( $state );
	if ( $record === null ) {
		return false;
	}
	return $record['user_id'] === get_current_user_id() && current_user_can( 'manage_options' );
}

function x_pixel_oauth_stash() {
	$state = x_pixel_oauth_state_param();
	$token = x_pixel_oauth_opaque_param( 'oauth_token' );
	$blob  = x_pixel_oauth_opaque_param( 'blob' );
	if ( ! x_pixel_oauth_state_is_live( $state ) || $token === '' || $blob === '' ) {
		wp_safe_redirect( x_pixel_settings_url( array( 'x_pixel_oauth' => 'bad_state' ) ) );
		exit;
	}
	set_transient( x_pixel_oauth_blob_key( $state ), $blob, 20 * MINUTE_IN_SECONDS );
	x_pixel_redirect_to_x( add_query_arg( 'oauth_token', rawurlencode( $token ), 'https://api.x.com/oauth/authorize' ) );
}
add_action( 'admin_post_x_pixel_oauth_stash', 'x_pixel_oauth_stash' );

function x_pixel_oauth_resume() {
	$state    = x_pixel_oauth_state_param();
	$token    = x_pixel_oauth_opaque_param( 'oauth_token' );
	$verifier = x_pixel_oauth_opaque_param( 'oauth_verifier' );
	$sealed   = x_pixel_oauth_opaque_param( 'r' );
	$blob     = x_pixel_oauth_state_is_live( $state ) ? get_transient( x_pixel_oauth_blob_key( $state ) ) : false;
	if ( ! is_string( $blob ) || $blob === '' || $token === '' || $verifier === '' || $sealed === '' ) {
		wp_safe_redirect( x_pixel_settings_url( array( 'x_pixel_oauth' => 'bad_state' ) ) );
		exit;
	}
	delete_transient( x_pixel_oauth_blob_key( $state ) );

	$fields = array(
		'r'              => $sealed,
		'blob'           => $blob,
		'oauth_token'    => $token,
		'oauth_verifier' => $verifier,
	);
	$action = str_replace( '/connect', '/callback', x_pixel_broker_connect_url() );

	x_pixel_redirect_to_x( $action . '?' . http_build_query( $fields, '', '&', PHP_QUERY_RFC3986 ), 303 );
}
add_action( 'admin_post_x_pixel_oauth_resume', 'x_pixel_oauth_resume' );

function x_pixel_oauth_return() {
	nocache_headers();

	$state  = x_pixel_oauth_state_param();
	$record = x_pixel_oauth_state_record( $state );
	x_pixel_oauth_forget_state( $state );

	$owner = $record === null ? 0 : $record['user_id'];
	if ( $owner <= 0 || ! user_can( $owner, 'manage_options' ) || ( is_user_logged_in() && get_current_user_id() !== $owner ) ) {
		wp_safe_redirect( x_pixel_settings_url( array( 'x_pixel_oauth' => 'bad_state' ) ) );
		exit;
	}

	$error = x_pixel_oauth_request( 'error' );
	if ( $error !== null ) {
		$code = sanitize_key( $error );
		if ( $code === '' ) {
			$code = 'exchange_failed';
		}
		wp_safe_redirect( x_pixel_settings_url( array( 'x_pixel_oauth' => $code ) ) );
		exit;
	}

	$pixel = x_pixel_clean_id( (string) x_pixel_oauth_request( 'pixel_id' ) );
	if ( $pixel === '' ) {
		wp_safe_redirect( x_pixel_settings_url( array( 'x_pixel_oauth' => 'pixel' ) ) );
		exit;
	}

	$map = array(
		'event_purchase'     => X_PIXEL_OPTION_EVENT_PURCHASE,
		'event_add_to_cart'  => X_PIXEL_OPTION_EVENT_ATC,
		'event_checkout'     => X_PIXEL_OPTION_EVENT_CHECKOUT,
		'event_content_view' => X_PIXEL_OPTION_EVENT_VIEW,
	);

	$previous = get_option( X_PIXEL_OPTION_ID, '' );
	if ( $previous !== '' && $previous !== $pixel ) {
		delete_option( X_PIXEL_OPTION_CAPI );
		foreach ( $map as $option ) {
			delete_option( $option );
		}
	}
	update_option( X_PIXEL_OPTION_ID, $pixel );

	$token = x_pixel_clean_token( (string) x_pixel_oauth_request( 'capi_token' ) );
	if ( $token !== '' ) {
		update_option( X_PIXEL_OPTION_CAPI, $token );
	}

	foreach ( $map as $query => $option ) {
		$value = x_pixel_clean_id( (string) x_pixel_oauth_request( $query ) );
		if ( $value !== '' ) {
			update_option( $option, $value );
		}
	}

	$complete = get_option( X_PIXEL_OPTION_CAPI, '' ) !== '';
	foreach ( $map as $option ) {
		if ( get_option( $option, '' ) === '' ) {
			$complete = false;
		}
	}

	wp_safe_redirect( x_pixel_settings_url( array( 'x_pixel_oauth' => $complete ? 'ok' : 'partial' ) ) );
	exit;
}
add_action( 'admin_post_x_pixel_oauth_return', 'x_pixel_oauth_return' );
add_action( 'admin_post_nopriv_x_pixel_oauth_return', 'x_pixel_oauth_return' );

function x_pixel_oauth_notices() {
	$screen = get_current_screen();
	if ( ! $screen || $screen->id !== 'settings_page_x-pixel' || ! current_user_can( 'manage_options' ) ) {
		return;
	}
	if ( ! isset( $_GET['x_pixel_oauth'] ) ) {
		return;
	}
	$code = sanitize_key( wp_unslash( $_GET['x_pixel_oauth'] ) );
	if ( $code === 'ok' ) {
		echo '<div class="notice notice-success is-dismissible"><p>';
		echo esc_html__( 'Connected to X Ads. Pixel, Conversion API token, and store event IDs were saved.', 'x-pixel' );
		echo '</p></div>';
		return;
	}
	if ( $code === 'partial' ) {
		echo '<div class="notice notice-warning is-dismissible"><p>';
		echo esc_html__( 'Connected to X Ads and saved the pixel, but the Conversion API token or some store event IDs were not returned. Click Reconnect X Ads to try again, or paste the missing values from Events Manager.', 'x-pixel' );
		echo '</p></div>';
		return;
	}
	if ( $code === 'disconnected' ) {
		echo '<div class="notice notice-success is-dismissible"><p>';
		echo esc_html__( 'X Pixel settings were cleared.', 'x-pixel' );
		echo '</p></div>';
		return;
	}
	$messages = array(
		'denied'               => __( 'X Ads authorization was cancelled.', 'x-pixel' ),
		'ads_api'              => __( 'This X developer app does not have Ads API access. Pixel connect cannot finish until Ads API is enabled on the app.', 'x-pixel' ),
		'no_account'           => __( 'No X Ads account was found on the authorized user.', 'x-pixel' ),
		'bad_state'            => __( 'The connect session expired. Click Connect X Ads and try again.', 'x-pixel' ),
		'invalid_state'        => __( 'The connect session did not match. Click Connect X Ads and try again.', 'x-pixel' ),
		'pixel'                => __( 'X Ads connected but no pixel ID was returned.', 'x-pixel' ),
		'exchange_failed'      => __( 'Could not finish connecting to X Ads. Try again.', 'x-pixel' ),
		'request_token_failed' => __( 'Could not start X Ads authorization. Try again in a few minutes.', 'x-pixel' ),
	);
	$message  = isset( $messages[ $code ] ) ? $messages[ $code ] : $messages['exchange_failed'];
	echo '<div class="notice notice-error is-dismissible"><p>' . esc_html( $message ) . '</p></div>';
}
add_action( 'admin_notices', 'x_pixel_oauth_notices' );

function x_pixel_oauth_connect_url() {
	return wp_nonce_url(
		admin_url( 'admin-post.php?action=x_pixel_oauth_start' ),
		'x_pixel_oauth_start'
	);
}

function x_pixel_disconnect_url() {
	return wp_nonce_url(
		admin_url( 'admin-post.php?action=x_pixel_disconnect' ),
		'x_pixel_disconnect'
	);
}

function x_pixel_disconnect() {
	if ( ! current_user_can( 'manage_options' ) ) {
		wp_die( esc_html__( 'You do not have permission to disconnect X Pixel.', 'x-pixel' ) );
	}
	check_admin_referer( 'x_pixel_disconnect' );
	delete_option( X_PIXEL_OPTION_ID );
	delete_option( X_PIXEL_OPTION_CAPI );
	delete_option( X_PIXEL_OPTION_EVENT_PURCHASE );
	delete_option( X_PIXEL_OPTION_EVENT_ATC );
	delete_option( X_PIXEL_OPTION_EVENT_CHECKOUT );
	delete_option( X_PIXEL_OPTION_EVENT_VIEW );
	wp_safe_redirect( x_pixel_settings_url( array( 'x_pixel_oauth' => 'disconnected' ) ) );
	exit;
}
add_action( 'admin_post_x_pixel_disconnect', 'x_pixel_disconnect' );