<?php

namespace AIBP;

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

/**
 * Handles plugin option defaults, reads, and sanitization.
 *
 * @package AI_Blog_Poster
 */
class Settings {

	const OPTION_GROUP = 'aibp_settings_group';
	const OPTION_NAME  = 'aibp_settings';

	/**
	 * Returns the default plugin settings.
	 *
	 * @return array<string, mixed>
	 */
	public function get_defaults() {
		return array(
			'api_key'             => '',
			'sync_mode'           => 'wp_cron',
			'sync_frequency'      => 30,
			'default_author_id'   => $this->get_required_author_id(),
			'default_category_id' => 0,
			'default_post_status' => 'publish',
			'cron_token'          => wp_generate_password( 32, false, false ),
			'last_sync'           => 0,
			'last_run'            => 0,
		);
	}

	/**
	 * Ensures all default settings exist in the database.
	 */
	public function set_defaults() {
		$current = get_option( self::OPTION_NAME, array() );

		update_option(
			self::OPTION_NAME,
			wp_parse_args( $current, $this->get_defaults() ),
			false
		);
	}

	/**
	 * Returns the saved settings merged with defaults.
	 *
	 * @return array<string, mixed>
	 */
	public function get_all() {
		$settings = wp_parse_args( get_option( self::OPTION_NAME, array() ), $this->get_defaults() );

		if ( empty( $settings['cron_token'] ) ) {
			$settings['cron_token'] = wp_generate_password( 32, false, false );
			update_option( self::OPTION_NAME, $settings, false );
		}

		if ( empty( $settings['default_author_id'] ) || ! get_user_by( 'id', (int) $settings['default_author_id'] ) ) {
			$settings['default_author_id'] = $this->get_required_author_id();
			update_option( self::OPTION_NAME, $settings, false );
		}

		return $settings;
	}

	/**
	 * Reads a single setting.
	 *
	 * @param string $key     Setting key.
	 * @param mixed  $default Fallback value.
	 * @return mixed
	 */
	public function get( $key, $default = null ) {
		$settings = $this->get_all();

		return isset( $settings[ $key ] ) ? $settings[ $key ] : $default;
	}

	/**
	 * Merges and stores updated settings.
	 *
	 * @param array<string, mixed> $values Partial setting values.
	 */
	public function update( array $values ) {
		$current = $this->get_all();
		$updated = array_merge( $current, $values );

		update_option( self::OPTION_NAME, $updated, false );
	}

	/**
	 * Stores the latest successful sync timestamp.
	 *
	 * @param int $timestamp Unix timestamp.
	 */
	public function update_last_sync( $timestamp ) {
		$this->update(
			array(
				'last_sync' => absint( $timestamp ),
			)
		);
	}

	/**
	 * Stores the wall-clock time of the most recent sync attempt.
	 *
	 * @param int $timestamp Unix timestamp (typically time()).
	 */
	public function update_last_run( $timestamp ) {
		$this->update(
			array(
				'last_run' => absint( $timestamp ),
			)
		);
	}

	/**
	 * Generates and stores a fresh cron token.
	 *
	 * @return string
	 */
	public function regenerate_cron_token() {
		$token = wp_generate_password( 32, false, false );
		$this->update(
			array(
				'cron_token' => $token,
			)
		);

		return $token;
	}

	/**
	 * Masks an API key, keeping the first and last five characters visible.
	 *
	 * @param string $api_key Saved API key.
	 * @return string
	 */
	public function mask_api_key( $api_key ) {
		$api_key = (string) $api_key;
		$length  = strlen( $api_key );

		if ( '' === $api_key ) {
			return '';
		}

		if ( $length <= 10 ) {
			return str_repeat( 'X', $length );
		}

		return substr( $api_key, 0, 5 ) . str_repeat( 'X', $length - 10 ) . substr( $api_key, -5 );
	}

	/**
	 * Registers the option with the WordPress Settings API.
	 */
	public function register() {
		register_setting(
			self::OPTION_GROUP,
			self::OPTION_NAME,
			array( $this, 'sanitize' )
		);
	}

	/**
	 * Sanitizes submitted admin settings before saving.
	 *
	 * @param array<string, mixed> $input Raw submitted values.
	 * @return array<string, mixed>
	 */
	public function sanitize( $input ) {
		$current     = $this->get_all();
		$author_id   = isset( $input['default_author_id'] ) ? absint( $input['default_author_id'] ) : $current['default_author_id'];
		$category_id = isset( $input['default_category_id'] ) ? absint( $input['default_category_id'] ) : $current['default_category_id'];
		$sync_mode   = isset( $input['sync_mode'] ) ? sanitize_key( $input['sync_mode'] ) : $current['sync_mode'];
		$post_status = isset( $input['default_post_status'] ) ? sanitize_key( $input['default_post_status'] ) : $current['default_post_status'];
		$api_key     = isset( $input['api_key'] ) ? sanitize_text_field( $input['api_key'] ) : '';
		$masked_key  = $this->mask_api_key( $current['api_key'] );

		if ( ! in_array( $sync_mode, array( 'wp_cron', 'manual_cron' ), true ) ) {
			$sync_mode = 'wp_cron';
		}

		if ( ! in_array( $post_status, array( 'publish', 'draft', 'pending', 'private' ), true ) ) {
			$post_status = 'publish';
		}

		if ( $author_id <= 0 || ! get_user_by( 'id', $author_id ) ) {
			$author_id = $this->get_required_author_id();
		}

		if ( $category_id > 0 && ! term_exists( $category_id, 'category' ) ) {
			$category_id = 0;
		}

		return array(
			'api_key'             => '' !== $api_key && $api_key !== $masked_key ? $api_key : $current['api_key'],
			'sync_mode'           => $sync_mode,
			'sync_frequency'      => isset( $input['sync_frequency'] ) ? max( 5, absint( $input['sync_frequency'] ) ) : $current['sync_frequency'],
			'default_author_id'   => $author_id,
			'default_category_id' => $category_id,
			'default_post_status' => $post_status,
			'cron_token'          => isset( $current['cron_token'] ) ? sanitize_text_field( $current['cron_token'] ) : wp_generate_password( 32, false, false ),
			'last_sync'           => isset( $current['last_sync'] ) ? absint( $current['last_sync'] ) : 0,
			'last_run'            => isset( $current['last_run'] ) ? absint( $current['last_run'] ) : 0,
		);
	}

	/**
	 * Returns a valid author ID for imported posts.
	 *
	 * @return int
	 */
	private function get_required_author_id() {
		$current_user_id = get_current_user_id();

		if ( $current_user_id > 0 && user_can( $current_user_id, 'edit_posts' ) ) {
			return $current_user_id;
		}

		$users = get_users(
			array(
				'number'     => 1,
				'orderby'    => 'ID',
				'order'      => 'ASC',
				'fields'     => array( 'ID' ),
				'capability' => 'edit_posts',
			)
		);

		if ( ! empty( $users[0]->ID ) ) {
			return (int) $users[0]->ID;
		}

		return 1;
	}
}