<?php

namespace ChargeForms\Includes\Integrations;

use ChargeForms\Includes\Settings;
use ChargeForms\Includes\Api_Log;
use ChargeForms\Includes\Field_Sanitizer;

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

/**
 * Built-in integration: appends a row to a Google Sheet on every
 * submission. A single site-wide service account (Settings::get(
 * 'google_sheets_service_account_json') — see Google_Sheets_Client's own
 * doc comment for why a service account rather than interactive OAuth);
 * which spreadsheet/sheet a given form writes to is per-form (Form::
 * settings.integrations.sheets).
 *
 * Writes a header row automatically the first time a form ever submits to
 * a given sheet (checked via one extra read of row 1 — see process()) so
 * the destination is immediately readable without the site owner having to
 * hand-type column headers first; every column after "Submitted At" is one
 * form field, in the form's own field order.
 */
class Google_Sheets_Integration extends Abstract_Integration {

	private static $pending_context = null;

	const RETRY_HOOK          = 'chargeforms_retry_sheets';
	const MAX_ATTEMPTS        = 3;
	const RETRY_DELAY_SECONDS = 300;

	public static function boot() {
		add_action( self::RETRY_HOOK, [ __CLASS__, 'handle_retry' ], 10, 5 );
	}

	public function key(): string {
		return 'sheets';
	}

	public function label(): string {
		return __( 'Google Sheets', 'chargeforms' );
	}

	public function is_configured( array $settings ): bool {
		return ! empty( $settings['enabled'] ) && ! empty( $settings['spreadsheet_id'] ) && '' !== Settings::get( 'google_sheets_service_account_json', '' );
	}

	public function process( array $values, array $form, int $entry_id, array $settings, $attempt = 1 ) {
		$spreadsheet_id = $settings['spreadsheet_id'];
		$sheet_name     = ! empty( $settings['sheet_name'] ) ? $settings['sheet_name'] : 'Sheet1';

		$token = Google_Sheets_Client::access_token( Settings::get( 'google_sheets_service_account_json', '' ) );
		if ( is_wp_error( $token ) ) {
			Api_Log::log( 'sheets', $form['id'], $spreadsheet_id, null, $token->get_error_message() );
			return;
		}

		$fields = array_values( array_filter(
			Field_Sanitizer::flatten_submittable_fields( $form['fields'] ),
			function ( $field ) {
				return ! in_array( $field['type'], Field_Sanitizer::NON_INPUT_TYPES, true );
			}
		) );

		$this->maybe_write_header( $token, $spreadsheet_id, $sheet_name, $fields );

		$row = [ current_time( 'mysql' ) ];
		foreach ( $fields as $field ) {
			$value = $values[ $field['id'] ] ?? '';
			$row[] = is_array( $value ) ? wp_json_encode( $value ) : (string) $value;
		}

		self::$pending_context = [ 'values' => $values, 'form' => $form, 'entry_id' => $entry_id, 'settings' => $settings, 'attempt' => $attempt ];

		$result = Google_Sheets_Client::append_row( $token, $spreadsheet_id, $sheet_name, $row );

		if ( is_wp_error( $result ) ) {
			$data = $result->get_error_data();
			Api_Log::log( 'sheets', $form['id'], $spreadsheet_id, $data['status'] ?? null, $result->get_error_message() );
			$this->maybe_retry( $attempt );
			self::$pending_context = null;
			return;
		}

		Api_Log::log( 'sheets', $form['id'], $spreadsheet_id, 200, __( 'Row appended.', 'chargeforms' ) );
		self::$pending_context = null;
	}

	/**
	 * One extra read of row 1 per submission is the cost of "never write a
	 * header on top of real data" — an unconditional write-on-every-call
	 * would clobber row 1 the moment the sheet had any content there
	 * already (including a header a human wrote by hand before connecting
	 * the integration). Only writes when row 1 is genuinely empty.
	 */
	private function maybe_write_header( $token, $spreadsheet_id, $sheet_name, array $fields ) {
		$existing = Google_Sheets_Client::get_values( $token, $spreadsheet_id, $sheet_name . '!1:1' );
		if ( is_wp_error( $existing ) || ! empty( $existing ) ) {
			return;
		}
		$headers = [ __( 'Submitted At', 'chargeforms' ) ];
		foreach ( $fields as $field ) {
			$headers[] = $field['label'] ?? $field['id'];
		}
		Google_Sheets_Client::update_values( $token, $spreadsheet_id, $sheet_name . '!1:1', [ $headers ] );
	}

	/** WP-Cron callback — same shape as Mailchimp_Integration::handle_retry(). */
	public static function handle_retry( $values, $form, $entry_id, $settings, $attempt ) {
		( new self() )->process( $values, $form, $entry_id, $settings, $attempt );
	}

	private function maybe_retry( $attempt ) {
		if ( ! self::$pending_context || $attempt >= self::MAX_ATTEMPTS ) {
			return;
		}
		$ctx = self::$pending_context;
		wp_schedule_single_event(
			time() + self::RETRY_DELAY_SECONDS,
			self::RETRY_HOOK,
			[ $ctx['values'], $ctx['form'], $ctx['entry_id'], $ctx['settings'], $ctx['attempt'] + 1 ]
		);
	}
}