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

namespace AKSRT\User;

defined('ABSPATH') || exit;

class Restriction {

    private static $instance = null;

    const TYPE_WARN    = 'warn';
    const TYPE_MUTE    = 'mute';
    const TYPE_SUSPEND = 'suspend';
    const TYPE_BAN     = 'ban';

    const SCOPE_GLOBAL     = 'global';
    const SCOPE_COMMENT    = 'comment';

    const TYPES   = [self::TYPE_WARN, self::TYPE_MUTE, self::TYPE_SUSPEND, self::TYPE_BAN];
    const SCOPES  = [self::SCOPE_GLOBAL, self::SCOPE_COMMENT];

    /**
     * 治理展示态（与 user-home.css 的 --banned/--restricted/--muted 色调修饰符同名）：
     * 资料卡提示框、用户中心页头、评论拒绝态、昵称徽章共用同一组键。
     */
    const STATE_BANNED     = 'banned';
    const STATE_RESTRICTED = 'restricted';
    const STATE_MUTED      = 'muted';

    public static function get_instance(): self {
        if (null === self::$instance) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    public function init(): void {
        // 禁封用户前台拦截（对齐参考主题 zib_user_ban_restrict_login：
        // 封号用户可正常登录，但前台任何页面均展示禁封状态页；禁封中
        // 不得拦截登录本身——登录后的落地页即禁封页）。
        add_action('template_redirect', [$this, 'restrict_frontend_access'], 1);
        // Enforce comment mute
        add_filter('pre_comment_on_post', [$this, 'enforce_comment_mute']);
    }

    /**
     * Get the restriction table name.
     */
    private function table(): string {
        global $wpdb;
        return $wpdb->prefix . 'aksrt_user_restriction';
    }

    /**
     * Add a restriction to a user.
     */
    public function restrict(int $user_id, string $type, string $reason, string $scope = self::SCOPE_GLOBAL, string $expires_at = '', int $created_by = 0): array {
        global $wpdb;

        if (!in_array($type, self::TYPES, true)) {
            return ['success' => false, 'message' => 'Invalid restriction type.'];
        }
        if (!in_array($scope, self::SCOPES, true)) {
            return ['success' => false, 'message' => 'Invalid scope.'];
        }
        if ($created_by <= 0) {
            $created_by = get_current_user_id();
        }

        $data = [
            'user_id'    => $user_id,
            'type'       => $type,
            'reason'     => sanitize_textarea_field($reason),
            'scope'      => $scope,
            'expires_at' => $expires_at ? gmdate('Y-m-d H:i:s', strtotime($expires_at)) : null,
            'created_by' => $created_by,
            'created_at' => current_time('mysql', true),
        ];

        $result = $wpdb->insert($this->table(), $data);
        if ($result === false) {
            return ['success' => false, 'message' => 'Database error.'];
        }

        // 封禁立即生效：销毁目标用户全部登录会话
        if ($type === self::TYPE_BAN && $user_id > 0) {
            \WP_Session_Tokens::get_instance($user_id)->destroy_all();
        }

        do_action('aksrt_user_restriction_changed', $user_id, $type, 'applied', (string) $data['reason']);

        return ['success' => true, 'id' => $wpdb->insert_id];
    }

    /**
     * Remove a restriction by ID.
     */
    public function remove_restriction(int $restriction_id): bool {
        global $wpdb;
        $restriction = $this->get_restriction($restriction_id);
        if (!$restriction) return false;

        $result = $wpdb->delete($this->table(), ['id' => $restriction_id]);
        if ($result) {
            do_action('aksrt_user_restriction_changed', (int) $restriction['user_id'], (string) ($restriction['type'] ?? ''), 'removed', '');
        }
        return (bool) $result;
    }

    /**
     * 解除用户生效中的限制（可选按类型过滤），用于申诉通过或举报工单"解除限制"。
     *
     * @param int   $user_id 用户 ID
     * @param array $types   要解除的类型，默认解除 ban/suspend/mute（保留 warn 警告记录）
     * @return int 解除的记录数
     */
    public function lift_user_restriction(int $user_id, array $types = [self::TYPE_BAN, self::TYPE_SUSPEND, self::TYPE_MUTE]): int {
        global $wpdb;

        $types = array_values(array_intersect($types, self::TYPES));
        if ($user_id <= 0 || empty($types)) {
            return 0;
        }

        $placeholders = implode(',', array_fill(0, count($types), '%s'));
        $deleted = $wpdb->query($wpdb->prepare(
            "DELETE FROM {$this->table()} WHERE user_id = %d AND (expires_at IS NULL OR expires_at > %s) AND type IN ({$placeholders})",
            array_merge([$user_id, current_time('mysql', true)], $types)
        ));

        if ($deleted > 0) {
            do_action('aksrt_user_restriction_changed', $user_id, implode(',', $types), 'lifted', '');
        }

        return (int) $deleted;
    }

    /**
     * Get a single restriction by ID.
     */
    public function get_restriction(int $restriction_id): ?array {
        global $wpdb;
        $row = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM {$this->table()} WHERE id = %d",
            $restriction_id
        ), ARRAY_A);
        return $row ?: null;
    }

    /**
     * Get all active restrictions for a user.
     */
    public function get_user_restrictions(int $user_id, bool $active_only = true): array {
        global $wpdb;
        $now = current_time('mysql', true);

        if ($active_only) {
            $rows = $wpdb->get_results($wpdb->prepare(
                "SELECT * FROM {$this->table()} WHERE user_id = %d AND (expires_at IS NULL OR expires_at > %s) ORDER BY created_at DESC",
                $user_id, $now
            ), ARRAY_A);
        } else {
            $rows = $wpdb->get_results($wpdb->prepare(
                "SELECT * FROM {$this->table()} WHERE user_id = %d ORDER BY created_at DESC",
                $user_id
            ), ARRAY_A);
        }

        return $rows ?: [];
    }

    /**
     * Check if a user has an active restriction of a given type and scope.
     */
    public function is_restricted(int $user_id, string $type = '', string $scope = ''): bool {
        $restrictions = $this->get_user_restrictions($user_id, true);
        foreach ($restrictions as $r) {
            if ($type && $r['type'] !== $type) continue;
            if ($scope && $r['scope'] !== $scope && $r['scope'] !== self::SCOPE_GLOBAL) continue;
            return true;
        }
        return false;
    }

    /**
     * Check if a user is banned (global).
     */
    public function is_banned(int $user_id): bool {
        return $this->is_restricted($user_id, self::TYPE_BAN, self::SCOPE_GLOBAL);
    }

    /**
     * 治理展示态（空串 = 无治理状态；ban 优先于 suspend，对齐后台单一状态语义）。
     *
     * 供公开主页身份行徽章、用户中心元信息、评论拒绝态、昵称徽章共用，
     * 徽章字段（文案/颜色/图标）见 state_badges()。
     */
    public function get_display_state(int $user_id): string {
        if ($user_id <= 0) {
            return '';
        }
        if ($this->is_banned($user_id)) {
            return self::STATE_BANNED;
        }
        if ($this->is_suspended($user_id)) {
            return self::STATE_RESTRICTED;
        }
        if ($this->is_restricted($user_id, self::TYPE_MUTE)) {
            return self::STATE_MUTED;
        }
        return '';
    }

    /**
     * 治理展示态徽章字段（颜色 / 文案 / 图标统一管理，全前端提示面共用）：
     *   封号(ban)     → c-red    违规已封号（最严重：无法登录）；
     *   小黑屋(suspend) → c-yellow 小黑屋禁封中（部分限制）；
     *   禁言(mute)    → c-gray   禁言中（评论域限制）。
     * 对齐参考主题 zib_ban_author_header_identity_filter 的红/默认双色语义，
     * 禁言为 AKSRT 扩展状态。
     *
     * @return array<string,array{label:string,tone:string,icon:string}> 展示态 => 徽章字段
     */
    public static function state_badges(): array {
        return [
            self::STATE_BANNED     => ['label' => __('违规已封号', 'aksrt'),   'tone' => 'c-red',    'icon' => 'ban'],
            self::STATE_RESTRICTED => ['label' => __('小黑屋禁封中', 'aksrt'), 'tone' => 'c-yellow', 'icon' => 'ban'],
            self::STATE_MUTED      => ['label' => __('禁言中', 'aksrt'),       'tone' => 'c-gray',   'icon' => 'comment-slash'],
        ];
    }

    /**
     * 生效禁封信息行（查看禁封状态弹窗 / 申诉弹窗 / 登录后禁封页 / 管理端
     * 禁封解封弹窗共用；对齐参考主题 zib_get_ban_info_modal 的字段集）。
     *
     * @return array<string,mixed>|array{} 空数组表示无生效禁封/小黑屋。
     */
    public function get_ban_info(int $user_id): array {
        if ($user_id <= 0) {
            return [];
        }
        $ban = $this->get_active_ban($user_id) ?: $this->get_active_suspend($user_id);
        if (!is_array($ban)) {
            return [];
        }

        $type   = (string) ($ban['type'] ?? '');
        $raw    = (string) ($ban['reason'] ?? '');
        $reason = $raw;
        $desc   = '';
        $marker = "\n" . __('禁封说明：', 'aksrt');
        $pos    = strpos($raw, $marker);
        if (false !== $pos) {
            $reason = substr($raw, 0, $pos);
            $desc   = trim(substr($raw, $pos + strlen($marker)));
        }

        $no_appeal      = get_user_meta($user_id, '_aksrt_no_appeal', true);
        $no_appeal_desc = is_array($no_appeal) ? trim((string) ($no_appeal['desc'] ?? '')) : '';

        return [
            'type'            => $type,
            'status'          => $type === self::TYPE_BAN ? __('禁封中(禁止登录)', 'aksrt') : __('小黑屋禁封中', 'aksrt'),
            'start'           => (string) ($ban['created_at'] ?? ''),
            'end'             => !empty($ban['expires_at']) ? (string) $ban['expires_at'] : __('永久', 'aksrt'),
            'reason'          => trim($reason),
            'desc'            => $desc,
            'no_appeal'       => $no_appeal_desc !== '',
            'no_appeal_desc'  => $no_appeal_desc,
        ];
    }

    /**
     * Check if a user is in 小黑屋 (active global suspend).
     *
     * 对齐参考主题语义：小黑屋用户失去所有发布权限（发帖、评论等）及大部分操作权限。
     */
    public function is_suspended(int $user_id): bool {
        return $this->is_restricted($user_id, self::TYPE_SUSPEND, self::SCOPE_GLOBAL);
    }

    /**
     * Get the active suspend restriction for a user (if any).
     */
    public function get_active_suspend(int $user_id): ?array {
        $restrictions = $this->get_user_restrictions($user_id, true);
        foreach ($restrictions as $r) {
            if ($r['type'] === self::TYPE_SUSPEND && $r['scope'] === self::SCOPE_GLOBAL) {
                return $r;
            }
        }
        return null;
    }

    /**
     * Get the active ban restriction for a user (if any).
     */
    public function get_active_ban(int $user_id): ?array {
        $restrictions = $this->get_user_restrictions($user_id, true);
        foreach ($restrictions as $r) {
            if ($r['type'] === self::TYPE_BAN && $r['scope'] === self::SCOPE_GLOBAL) {
                return $r;
            }
        }
        return null;
    }

    /**
     * 前台禁封拦截页（1:1 复刻参考主题 zib_user_ban_restrict_login /
     * zib_die_page）：封号(ban)用户登录后访问任何前台页面，均展示禁封状态页
     * （红盒提示 + 禁封信息行 + 申诉权限 + 退出登录/申诉按钮）。
     * 小黑屋/禁言为部分限制，可正常浏览站点，不走此拦截。
     */
    public function restrict_frontend_access(): void {
        if (is_admin() || wp_doing_cron() || wp_doing_ajax()) {
            return;
        }
        $user_id = get_current_user_id();
        if ($user_id <= 0 || !$this->is_banned($user_id)) {
            return;
        }
        if (!function_exists('aksrt_render_user_ban_block_page')) {
            require_once AKSRT_DIR . '/inc/helpers/user-ban.php';
        }
        aksrt_render_user_ban_block_page($user_id);
    }

    /**
     * Enforce comment restriction on submission (mute / 小黑屋).
     *
     * 禁言（mute，评论域）与小黑屋（suspend，全域）都会拦截评论——
     * 对齐参考主题：小黑屋用户失去评论等发布权限。
     */
    public function enforce_comment_mute($post_id) {
        $user_id = get_current_user_id();
        if ($user_id <= 0) {
            return $post_id;
        }
        if ($this->is_restricted($user_id, self::TYPE_MUTE, self::SCOPE_COMMENT)) {
            wp_die('您已被限制评论。', '评论限制', ['response' => 403]);
        }
        if ($this->is_suspended($user_id)) {
            $suspend = $this->get_active_suspend($user_id);
            $message = '您已被关入小黑屋，暂时无法评论。';
            if (!empty($suspend['reason'])) {
                $message .= '原因：' . $suspend['reason'];
            }
            wp_die($message, '发布限制', ['response' => 403]);
        }
        return $post_id;
    }

    /**
     * Get restriction stats for admin overview.
     */
    public function get_stats(): array {
        global $wpdb;
        $now = current_time('mysql', true);
        $table = $this->table();

        $total = (int) $wpdb->get_var("SELECT COUNT(*) FROM {$table}");
        $active = (int) $wpdb->get_var($wpdb->prepare(
            "SELECT COUNT(*) FROM {$table} WHERE expires_at IS NULL OR expires_at > %s", $now
        ));
        $banned = (int) $wpdb->get_var($wpdb->prepare(
            "SELECT COUNT(*) FROM {$table} WHERE type = %s AND (expires_at IS NULL OR expires_at > %s)",
            self::TYPE_BAN, $now
        ));

        return ['total' => $total, 'active' => $active, 'banned' => $banned];
    }
}