<?php
/**
 * @package AKSRT
 */

namespace AKSRT\Credits;

defined('ABSPATH') || exit;

class PointsFree {

	public const META_DETAIL = 'free_points_detail';
	public const META_LOGIN  = 'aksrt_free_points_login_date';
	public const META_SIGNIN = 'aksrt_free_points_signin_date';
	public const META_TASKS  = 'aksrt_free_points_task_dates';

	/**
	 * Task catalog: key => [label, short_desc, default_points]
	 *
	 * @return array<string, array{0:string,1:string,2:int}>
	 */
	public static function catalog(): array {
		return [
			'sign_up'        => [__('注册奖励', 'aksrt'), __('新用户注册成功后发放', 'aksrt'), 10],
			'sign_in'        => [__('每日签到', 'aksrt'), __('完成每日签到', 'aksrt'), 1],
			'login'          => [__('每日登录', 'aksrt'), __('每日首次登录', 'aksrt'), 1],
			'followed'       => [__('被关注', 'aksrt'), __('被其他用户关注', 'aksrt'), 1],
			'post_new'       => [__('发布文章', 'aksrt'), __('发布并通过审核的文章', 'aksrt'), 5],
			'post_like'      => [__('文章被赞', 'aksrt'), __('你的文章被点赞', 'aksrt'), 1],
			'post_favorite'  => [__('文章被收藏', 'aksrt'), __('你的文章被收藏', 'aksrt'), 1],
			'comment_new'    => [__('发表评论', 'aksrt'), __('发表并通过审核的评论', 'aksrt'), 1],
			'comment_like'   => [__('评论被赞', 'aksrt'), __('你的评论被点赞', 'aksrt'), 1],
		];
	}

	/**
	 * Runtime free-task settings from theme options.
	 *
	 * @return array{day_max:int,tasks:array<string,int>}
	 */
	public static function settings(): array {
		$all = class_exists('\AKSRT\Settings\Settings') ? \AKSRT\Settings\Settings::get_all() : [];
		$tasks = [];
		foreach (self::catalog() as $key => $meta) {
			$flat_key = 'points_free_' . $key;
			$tasks[$key] = max(0, (int) ($all[$flat_key] ?? $meta[2]));
		}

		$day_max = array_key_exists('points_earn_daily_limit', $all)
			? max(0, (int) $all['points_earn_daily_limit'])
			: 50;

		return [
			'day_max' => $day_max,
			'tasks'   => $tasks,
		];
	}

	/**
	 * Points configured for a task (0 = disabled).
	 */
	public static function task_points(string $key): int {
		$cfg = self::settings();
		return max(0, (int) ($cfg['tasks'][$key] ?? 0));
	}

	/**
	 * Whether free points system can run (credits enabled).
	 */
	public static function enabled(): bool {
		return class_exists('\AKSRT\Settings\Settings') && \AKSRT\Settings\Settings::credits_enabled();
	}

	/**
	 * Today's free points total.
	 */
	public static function today_total(int $user_id): int {
		if ($user_id <= 0) {
			return 0;
		}
		$detail = self::detail_map($user_id);
		$today  = self::today_key();
		return max(0, (int) ($detail[$today] ?? 0));
	}

	/**
	 * Remaining free points allowed today (PHP_INT_MAX if unlimited).
	 */
	public static function remaining_today(int $user_id): int {
		$day_max = (int) self::settings()['day_max'];
		if ($day_max <= 0) {
			return PHP_INT_MAX;
		}
		return max(0, $day_max - self::today_total($user_id));
	}

	/**
	 * Daily free points detail (newest first).
	 *
	 * @return array<string,int>
	 */
	public static function date_detail(int $user_id): array {
		$detail = self::detail_map($user_id);
		krsort($detail, SORT_STRING);
		return $detail;
	}

	/**
	 * Grant free points for a task. Respects day_max; clamps amount.
	 *
	 * @param array{type?:string,id?:int} $ref
	 * @return int|\WP_Error granted amount (0 if skipped)
	 */
	public static function grant(int $user_id, string $task_key, int $points = 0, array $ref = []) {
		if (!self::enabled() || $user_id <= 0) {
			return 0;
		}
		$task_key = sanitize_key($task_key);
		if ($task_key === '') {
			return 0;
		}
		if ($points <= 0) {
			$points = self::task_points($task_key);
		}
		$points = max(0, (int) $points);
		if ($points <= 0) {
			return 0;
		}

		$remaining = self::remaining_today($user_id);
		if ($remaining <= 0) {
			return 0;
		}
		if ($points > $remaining) {
			$points = $remaining;
		}

		$reason = 'free_' . $task_key;
		$today = self::today_key();
		$operation_key = \AKSRT\Ledger\OperationKey::deterministic('points-free', [$user_id, $task_key, $today]);
		$result = \AKSRT\Ledger\LedgerService::get_instance()->credit(
			$user_id,
			\AKSRT\Ledger\AssetType::POINTS,
			$points,
			$operation_key,
			$reason,
			$ref,
			self::catalog()[$task_key][0] ?? $task_key,
			0,
			['task' => $task_key, 'date' => $today],
			static function () use ($user_id, $points, $task_key) {
				if (self::remaining_today($user_id) < $points) {
					return new \WP_Error('aksrt_points_daily_limit', __('今日积分奖励已达上限', 'aksrt'), ['status' => 409]);
				}
				self::bump_detail($user_id, $points);
				self::mark_task_done_today($user_id, $task_key);
				return true;
			}
		);
		if (is_wp_error($result)) {
			return $result;
		}

		return $points;
	}

	/**
	 * Grant with explicit amount (e.g. signin streak reward), still under day_max.
	 *
	 * @return int|\WP_Error
	 */
	public static function grant_amount(int $user_id, int $points, string $task_key, array $ref = []) {
		return self::grant($user_id, $task_key, $points, $ref);
	}

	/**
	 * Task list DTO for user center UI.
	 *
	 * @return list<array{key:string,title:string,desc:string,points:int,enabled:bool}>
	 */
	public static function task_list_for_user(int $user_id = 0): array {
		$cfg  = self::settings();
		$list = [];
		$today = self::today_key();
		$login_done = false;
		$signin_done = false;
		$task_dates = [];
		if ($user_id > 0) {
			$login_done = (string) get_user_meta($user_id, self::META_LOGIN, true) === $today;
			$signin_done = (string) get_user_meta($user_id, self::META_SIGNIN, true) === $today;
			$raw = get_user_meta($user_id, self::META_TASKS, true);
			$task_dates = is_array($raw) ? $raw : [];
		}

		$passive = ['post_like', 'post_favorite', 'followed', 'comment_like'];
		$active_once = ['post_new', 'comment_new'];

		foreach (self::catalog() as $key => $meta) {
			$pts = (int) ($cfg['tasks'][$key] ?? 0);
			if ($key === 'sign_up') {
				continue;
			}
			if ($pts <= 0) {
				continue;
			}
			$status = 'todo';
			$progress = null;
			$target = null;
			if ($key === 'login' && $login_done) {
				$status = 'done_today';
				$progress = 1;
				$target = 1;
			} elseif ($key === 'sign_in' && $signin_done) {
				$status = 'done_today';
				$progress = 1;
				$target = 1;
			} elseif (in_array($key, $passive, true)) {
				$status = 'passive';
			} elseif (in_array($key, $active_once, true)) {
				$target = 1;
				$done_day = is_array($task_dates[$key] ?? null) ? (string) ($task_dates[$key]['day'] ?? '') : (string) ($task_dates[$key] ?? '');
				if ($done_day === $today) {
					$status = 'done_today';
					$progress = 1;
				} else {
					$progress = 0;
				}
			}
			$list[] = [
				'key'      => $key,
				'title'    => $meta[0],
				'desc'     => $meta[1],
				'points'   => $pts,
				'enabled'  => true,
				'status'   => $status,
				'progress' => $progress,
				'target'   => $target,
			];
		}
		return $list;
	}

	/**
	 * Mark a free-task as completed today (for progress DTO).
	 */
	public static function mark_task_done_today(int $user_id, string $task_key): void {
		if ($user_id <= 0) {
			return;
		}
		$task_key = sanitize_key($task_key);
		$today = self::today_key();
		if ($task_key === 'login') {
			update_user_meta($user_id, self::META_LOGIN, $today);
			return;
		}
		if ($task_key === 'sign_in') {
			update_user_meta($user_id, self::META_SIGNIN, $today);
			return;
		}
		$raw = get_user_meta($user_id, self::META_TASKS, true);
		$map = is_array($raw) ? $raw : [];
		$map[$task_key] = ['day' => $today, 'ts' => time()];
		if (count($map) > 40) {
			$map = array_slice($map, -40, null, true);
		}
		update_user_meta($user_id, self::META_TASKS, $map);
	}

	private static function today_key(): string {
		return (new \DateTimeImmutable('today', wp_timezone()))->format('Y-m-d');
	}

	/**
	 * @return array<string,int>
	 */
	private static function detail_map(int $user_id): array {
		$raw = get_user_meta($user_id, self::META_DETAIL, true);
		if (!is_array($raw)) {
			return [];
		}
		$out = [];
		foreach ($raw as $day => $val) {
			$day = is_string($day) ? $day : (string) $day;
			if (!preg_match('/^\d{4}-\d{2}-\d{2}$/', $day)) {
				continue;
			}
			$out[$day] = max(0, (int) $val);
		}
		return $out;
	}

	private static function bump_detail(int $user_id, int $points): void {
		if ($points <= 0) {
			return;
		}
		$detail = self::detail_map($user_id);
		$today  = self::today_key();
		$detail[$today] = max(0, (int) ($detail[$today] ?? 0)) + $points;
		// Keep ~50 newest days.
		krsort($detail, SORT_STRING);
		$detail = array_slice($detail, 0, 50, true);
		update_user_meta($user_id, self::META_DETAIL, $detail);
	}

}