<?php
/**
 * Plugin settings stored in the storebridge_settings option.
 *
 * @package Storebridge
 */

declare( strict_types=1 );

namespace Storebridge;

defined( 'ABSPATH' ) || exit;

/**
 * Typed access to the storebridge_settings option (never autoloaded).
 */
final class Settings {

	public const OPTION = 'storebridge_settings';

	/**
	 * Steps of the onboarding wizard (SPEC.md M1), in order.
	 */
	public const ONBOARDING_STEPS = array( 'account', 'market', 'connect', 'defaults', 'mapping', 'finish' );

	/**
	 * Whether the store is registered with Storebridge Cloud.
	 */
	public function is_registered(): bool {
		return null !== $this->credentials();
	}

	/**
	 * Cloud credentials, or null before registration.
	 *
	 * @return array{shop_id: string, key_id: string, secret: string}|null
	 */
	public function credentials(): ?array {
		$cloud = $this->get( 'cloud' );
		if ( ! is_array( $cloud ) || empty( $cloud['shop_id'] ) || empty( $cloud['key_id'] ) || empty( $cloud['secret'] ) ) {
			return null;
		}
		return array(
			'shop_id' => (string) $cloud['shop_id'],
			'key_id'  => (string) $cloud['key_id'],
			'secret'  => (string) $cloud['secret'],
		);
	}

	/**
	 * Market chosen at registration.
	 */
	public function market(): ?string {
		$cloud = $this->get( 'cloud' );
		return is_array( $cloud ) && isset( $cloud['market'] ) ? (string) $cloud['market'] : null;
	}

	/**
	 * ID of the WooCommerce API key created for Storebridge Cloud.
	 */
	public function woo_api_key_id(): ?int {
		$cloud = $this->get( 'cloud' );
		return is_array( $cloud ) && isset( $cloud['woo_api_key_id'] ) ? (int) $cloud['woo_api_key_id'] : null;
	}

	/**
	 * Store the credentials returned by POST /v1/shops/register.
	 *
	 * @param string $shop_id        Cloud shop id.
	 * @param string $key_id         Public key id.
	 * @param string $secret         Signing secret.
	 * @param string $market         Market code.
	 * @param int    $woo_api_key_id WooCommerce API key id.
	 * @param string $status         Initial shop status.
	 */
	public function save_registration( string $shop_id, string $key_id, string $secret, string $market, int $woo_api_key_id, string $status ): void {
		$this->set( 'cloud', compact( 'shop_id', 'key_id', 'secret', 'market', 'woo_api_key_id' ) );
		$this->save_connection(
			array(
				'status' => $status,
				'tiktok' => null,
				'reason' => null,
			)
		);
	}

	/**
	 * Last known connection state (from a status call or a push from the cloud).
	 *
	 * @return array{status: string, tiktok: array<string, mixed>|null, reason: array<string, mixed>|null, updated_at: string}|null
	 */
	public function connection(): ?array {
		$connection = $this->get( 'connection' );
		if ( ! is_array( $connection ) || ! isset( $connection['status'], $connection['updated_at'] ) ) {
			return null;
		}
		return array(
			'status'     => (string) $connection['status'],
			'tiktok'     => isset( $connection['tiktok'] ) && is_array( $connection['tiktok'] ) ? $connection['tiktok'] : null,
			'reason'     => isset( $connection['reason'] ) && is_array( $connection['reason'] ) ? $connection['reason'] : null,
			'updated_at' => (string) $connection['updated_at'],
		);
	}

	/**
	 * Store a connection snapshot.
	 *
	 * Pushes from the cloud carry the cloud's `occurred_at`; a push older than the last push is an
	 * out-of-order delivery and is ignored. Snapshots taken locally (registration, status calls) are
	 * always stored, so a difference between the WordPress and cloud clocks never drops an update.
	 *
	 * @param array{status: string, tiktok: array<string, mixed>|null, reason: array<string, mixed>|null} $connection Snapshot.
	 * @param string|null                                                                                 $pushed_at  `occurred_at` of a cloud push; null for local snapshots.
	 * @return bool False when the push was older than the last one.
	 */
	public function save_connection( array $connection, ?string $pushed_at = null ): bool {
		$stored    = $this->get( 'connection' );
		$last_push = is_array( $stored ) && isset( $stored['pushed_at'] ) ? (string) $stored['pushed_at'] : null;
		if ( null !== $pushed_at && null !== $last_push && strtotime( $last_push ) > strtotime( $pushed_at ) ) {
			return false;
		}
		$this->set(
			'connection',
			array_merge(
				$connection,
				array(
					'updated_at' => gmdate( 'c' ),
					'pushed_at'  => $pushed_at ?? $last_push,
				)
			)
		);
		return true;
	}

	/**
	 * Plan and limits from the last status call; Free until the cloud says otherwise.
	 *
	 * @return array{plan: string, limits: array<string, mixed>, orders_waiting: int}
	 */
	public function plan(): array {
		$plan = $this->get( 'plan' );
		return array(
			'plan'           => is_array( $plan ) && isset( $plan['plan'] ) ? (string) $plan['plan'] : 'free',
			'limits'         => is_array( $plan ) && isset( $plan['limits'] ) && is_array( $plan['limits'] ) ? $plan['limits'] : array(
				'max_products'      => 25,
				'auto_order_import' => false,
				'max_shops'         => 1,
			),
			'orders_waiting' => is_array( $plan ) && isset( $plan['orders_waiting'] ) ? (int) $plan['orders_waiting'] : 0,
		);
	}

	/**
	 * Store the plan from a status call.
	 *
	 * @param array{plan: string, limits: array<string, mixed>, orders_waiting: int} $plan Plan snapshot.
	 */
	public function save_plan( array $plan ): void {
		$this->set( 'plan', $plan );
	}

	/**
	 * Current onboarding wizard step: one of ONBOARDING_STEPS, or 'done'.
	 *
	 * Stores that connected TikTok Shop before the wizard existed are marked done, so existing
	 * merchants are not sent through it.
	 */
	public function onboarding_step(): string {
		$step = $this->get( 'onboarding_step' );
		if ( is_string( $step ) && ( 'done' === $step || in_array( $step, self::ONBOARDING_STEPS, true ) ) ) {
			return $step;
		}
		$connection = $this->connection();
		if ( null !== $connection && in_array( $connection['status'], array( 'connected', 'reauth_required' ), true ) ) {
			$this->save_onboarding_step( 'done' );
			return 'done';
		}
		return self::ONBOARDING_STEPS[0];
	}

	/**
	 * Store the onboarding step.
	 *
	 * @param string $step One of ONBOARDING_STEPS, or 'done'.
	 */
	public function save_onboarding_step( string $step ): void {
		$this->set( 'onboarding_step', $step );
		if ( 'done' === $step ) {
			$this->set( 'onboarding_completed_at', gmdate( 'c' ) );
			$this->set( 'onboarding_skipped', false );
		}
	}

	/**
	 * Whether the merchant finished the wizard once (it can be reopened to edit details).
	 */
	public function onboarding_completed(): bool {
		return null !== $this->get( 'onboarding_completed_at' );
	}

	/**
	 * Whether the merchant chose to skip the wizard for now.
	 */
	public function onboarding_skipped(): bool {
		return true === $this->get( 'onboarding_skipped' );
	}

	/**
	 * Skip or resume the wizard.
	 *
	 * @param bool $skipped Whether the wizard is skipped.
	 */
	public function set_onboarding_skipped( bool $skipped ): void {
		$this->set( 'onboarding_skipped', $skipped );
	}

	/**
	 * Last known account state (contract AccountState) from Storebridge Cloud, or null.
	 *
	 * @return array<string, mixed>|null
	 */
	public function account(): ?array {
		$account = $this->get( 'account' );
		return is_array( $account ) && isset( $account['current_terms_version'] ) ? $account : null;
	}

	/**
	 * Store the account state returned by the cloud.
	 *
	 * @param array<string, mixed> $account Contract AccountState.
	 */
	public function save_account( array $account ): void {
		$this->set( 'account', $account );
	}

	/**
	 * Remove everything (used by uninstall and tests).
	 */
	public function forget(): void {
		delete_option( self::OPTION );
	}

	/**
	 * Read a top-level key.
	 *
	 * @param string $key Key.
	 * @return mixed
	 */
	private function get( string $key ) {
		return $this->load()[ $key ] ?? null;
	}

	/**
	 * Write a top-level key.
	 *
	 * @param string $key   Key.
	 * @param mixed  $value Value.
	 */
	private function set( string $key, $value ): void {
		$data         = $this->load();
		$data[ $key ] = $value;
		update_option( self::OPTION, $data, false );
	}

	/**
	 * Read the option (cached by WordPress' object cache).
	 *
	 * @return array<string, mixed>
	 */
	private function load(): array {
		$value = get_option( self::OPTION, array() );
		return is_array( $value ) ? $value : array();
	}
}