<?php
declare(strict_types=1);

namespace Soon\Api\Services;

use Soon\Api\Core\Config;
use Soon\Api\Core\Db;
use Soon\Api\Core\Json;

/**
 * 会员与配额服务。
 */
final class MembershipService
{
    public static function plans(): array
    {
        $stmt = Db::pdo()->query(
            'SELECT id, code, name, description, price_cents, quota_mb, max_files, duration_days, '
            . 'features, sort_order, is_recommended, is_active FROM plans WHERE is_active = 1 '
            . 'ORDER BY sort_order ASC, price_cents ASC'
        );
        $items = [];
        foreach ($stmt->fetchAll() as $row) {
            $items[] = self::enrichPlan($row);
        }
        return $items;
    }

    public static function currentPlan(int $userId): array
    {
        $pdo = Db::pdo();
        $usage = self::usageStats($userId);

        $stmt = $pdo->prepare(
            'SELECT p.*, s.id AS subscription_id, s.expires_at AS subscription_expires_at, s.started_at AS subscription_started_at '
            . 'FROM subscriptions s JOIN plans p ON p.id = s.plan_id '
            . 'WHERE s.user_id = :u AND s.status = "active" AND s.expires_at > NOW() '
            . 'ORDER BY s.expires_at DESC LIMIT 1'
        );
        $stmt->execute(['u' => $userId]);
        $row = $stmt->fetch();

        if ($row) {
            $plan = self::enrichPlan($row);
            $expiresAt = (string)($row['subscription_expires_at'] ?? '');
            $daysRemaining = self::daysUntil($expiresAt);
            $plan['subscription'] = [
                'id' => (int)$row['subscription_id'],
                'started_at' => $row['subscription_started_at'] ?? null,
                'expires_at' => $expiresAt,
                'days_remaining' => $daysRemaining,
                'status' => $daysRemaining <= 7 ? 'expiring' : 'active',
            ];
            $plan['usage'] = $usage;
            $plan['tier'] = 'member';
            $plan['is_member'] = true;
            return $plan;
        }

        $memberQuota = (int)Config::get('limits.member_quota_mb', 2048);
        $memberFiles = (int)Config::get('limits.member_max_files', 200);
        $freeQuota = (int)Config::get('limits.free_quota_mb', $memberQuota);
        $freeStmt = $pdo->prepare('SELECT * FROM plans WHERE code = "free" AND is_active = 1 LIMIT 1');
        $freeStmt->execute();
        $freeRow = $freeStmt->fetch();
        if ($freeRow) {
            $plan = self::enrichPlan($freeRow);
        } else {
            $plan = self::enrichPlan([
                'id' => 0,
                'code' => 'free',
                'name' => '免费版',
                'description' => '适合个人体验与轻量设计',
                'price_cents' => 0,
                'quota_mb' => $freeQuota,
                'max_files' => $memberFiles,
                'duration_days' => 0,
                'features' => '[]',
                'sort_order' => 0,
                'is_recommended' => 0,
                'is_active' => 1,
            ]);
        }
        $plan['subscription'] = [
            'id' => null,
            'started_at' => null,
            'expires_at' => null,
            'days_remaining' => null,
            'status' => 'free',
        ];
        $plan['usage'] = $usage;
        $plan['tier'] = 'free';
        $plan['is_member'] = false;
        return $plan;
    }

    public static function isActiveMember(int $userId): bool
    {
        $stmt = Db::pdo()->prepare(
            'SELECT 1 FROM subscriptions s JOIN plans p ON p.id = s.plan_id '
            . 'WHERE s.user_id = :u AND s.status = "active" AND s.expires_at > NOW() '
            . 'AND p.code <> "free" AND p.price_cents > 0 LIMIT 1'
        );
        $stmt->execute(['u' => $userId]);
        return (bool)$stmt->fetchColumn();
    }

    public static function requireActiveMember(int $userId): void
    {
        if (!self::isActiveMember($userId)) {
            Json::fail('membership_required', '此功能需要订阅后使用', 403);
        }
    }

    /** @return array<int, array<string, mixed>> */
    public static function recentOrders(int $userId, int $limit = 8): array
    {
        return self::listOrders($userId, 1, $limit)['items'];
    }

    /**
     * @return array{items: array<int, array<string, mixed>>, total: int, page: int, size: int}
     */
    public static function listOrders(int $userId, int $page = 1, int $size = 8): array
    {
        $page = max(1, $page);
        $size = max(1, min(50, $size));
        $offset = ($page - 1) * $size;
        $pdo = Db::pdo();
        $countStmt = $pdo->prepare('SELECT COUNT(*) FROM pay_orders WHERE user_id = :u');
        $countStmt->execute(['u' => $userId]);
        $total = (int)$countStmt->fetchColumn();
        $stmt = $pdo->prepare(
            'SELECT o.order_no, o.plan_id, o.amount_cents, o.status, o.channel, o.refund_status, '
            . 'o.created_at, o.paid_at, p.name AS plan_name, p.code AS plan_code '
            . 'FROM pay_orders o JOIN plans p ON p.id = o.plan_id '
            . 'WHERE o.user_id = :u ORDER BY o.id DESC LIMIT :lim OFFSET :off'
        );
        $stmt->bindValue('u', $userId, \PDO::PARAM_INT);
        $stmt->bindValue('lim', $size, \PDO::PARAM_INT);
        $stmt->bindValue('off', $offset, \PDO::PARAM_INT);
        $stmt->execute();
        $items = [];
        foreach ($stmt->fetchAll() as $row) {
            $items[] = [
                'order_no' => $row['order_no'],
                'plan_id' => (int)$row['plan_id'],
                'plan_name' => $row['plan_name'],
                'plan_code' => $row['plan_code'],
                'amount_cents' => (int)$row['amount_cents'],
                'status' => $row['status'],
                'refund_status' => $row['refund_status'] ?? 'none',
                'channel' => $row['channel'],
                'created_at' => $row['created_at'],
                'paid_at' => $row['paid_at'],
            ];
        }
        return ['items' => $items, 'total' => $total, 'page' => $page, 'size' => $size];
    }

    public static function previewAllowed(int $userId): bool
    {
        return self::isActiveMember($userId);
    }

    public static function settings(): array
    {
        $stmt = Db::pdo()->query('SELECT `key`, `value` FROM settings');
        $out = [];
        foreach ($stmt->fetchAll() as $row) {
            $out[$row['key']] = $row['value'];
        }
        return $out;
    }

    public static function maxFilesLimit(int $userId): int
    {
        $plan = self::currentPlan($userId);
        $limit = (int)($plan['max_files'] ?? 0);
        return $limit > 0 ? $limit : 10;
    }

    /** @param array<string, mixed> $row */
    public static function enrichPlanForAdmin(array $row): array
    {
        $plan = self::enrichPlan($row);
        $plan['is_active'] = (int)($row['is_active'] ?? 1);
        return $plan;
    }

    /**
     * 由套餐数值字段生成权益说明（与 FileService / 订阅逻辑一致，可执行）。
     * @param array<string, mixed> $row
     * @return list<string>
     */
    /** @return list<string> */
    public static function sanitizeFeatureLines(mixed $input): array
    {
        if (!is_array($input)) {
            return [];
        }
        $out = [];
        foreach ($input as $line) {
            if (!is_string($line)) {
                continue;
            }
            $t = trim($line);
            if ($t === '') {
                continue;
            }
            if (mb_strlen($t) > 200) {
                $t = mb_substr($t, 0, 200);
            }
            $out[] = $t;
        }
        return array_values(array_unique($out));
    }

    /** @return list<string>|null */
    public static function parseStoredFeatures(mixed $raw): ?array
    {
        if (is_array($raw)) {
            $lines = self::sanitizeFeatureLines($raw);
            return $lines === [] ? null : $lines;
        }
        if (!is_string($raw) || trim($raw) === '') {
            return null;
        }
        $decoded = json_decode($raw, true);
        if (!is_array($decoded)) {
            return null;
        }
        $lines = self::sanitizeFeatureLines($decoded);
        return $lines === [] ? null : $lines;
    }

    /**
     * @param list<string> $coreLines
     * @return list<string>
     */
    public static function buildPlanFeatures(string $code, int $durationDays, array $coreLines): array
    {
        $core = self::sanitizeFeatureLines($coreLines);
        if ($code === 'free') {
            return $core !== [] ? $core : self::planFeatureLines(['code' => 'free']);
        }
        $core = array_values(array_filter($core, static function (string $l): bool {
            return strpos($l, '订阅有效期') === false
                && strpos($l, '订阅周期') === false
                && strpos($l, '到期后') === false
                && strpos($l, '到期') === false;
        }));
        if ($core === []) {
            $core = self::memberBenefitLines();
        }
        if ($durationDays > 0) {
            $core[] = '订阅周期：' . self::periodLabel($durationDays);
        }
        return $core;
    }

    public static function planFeatureLines(array $row): array
    {
        $code = (string)($row['code'] ?? '');
        if ($code === 'free') {
            return ['设计与编辑工具免费使用'];
        }
        $days = (int)($row['duration_days'] ?? 0);
        return self::buildPlanFeatures($code, $days, self::memberBenefitLines());
    }

    public static function resolveFeatures(array $row): array
    {
        $stored = self::parseStoredFeatures($row['features'] ?? null);
        if ($stored !== null) {
            return $stored;
        }
        return self::planFeatureLines($row);
    }

    /** @return list<string> */
    public static function memberBenefitLines(): array
    {
        return [
            '高清预览',
            '成品打印',
            '云端保存',
            '导出设计文件',
        ];
    }

    /** @return list<string> */
    public static function coreFeatureLines(array $features): array
    {
        return array_values(array_filter($features, static function (string $l): bool {
            return strpos($l, '订阅有效期') === false
                && strpos($l, '订阅周期') === false
                && strpos($l, '到期后') === false
                && strpos($l, '到期') === false;
        }));
    }

    /** @param array<string, mixed> $row */
    private static function enrichPlan(array $row): array
    {
        $quotaMb = (int)($row['quota_mb'] ?? 0);
        $durationDays = (int)($row['duration_days'] ?? 0);
        $priceCents = (int)($row['price_cents'] ?? 0);
        $maxFiles = (int)($row['max_files'] ?? 0);
        return [
            'id' => (int)($row['id'] ?? 0),
            'code' => (string)($row['code'] ?? ''),
            'name' => (string)($row['name'] ?? ''),
            'description' => (string)($row['description'] ?? ''),
            'price_cents' => $priceCents,
            'price_display' => number_format($priceCents / 100, 2, '.', ''),
            'quota_mb' => $quotaMb,
            'quota_display' => self::formatQuota($quotaMb),
            'max_files' => $maxFiles,
            'duration_days' => $durationDays,
            'period_label' => self::periodLabel($durationDays),
            'features' => self::resolveFeatures($row),
            'limits' => [
                'quota_mb' => $quotaMb,
                'max_files' => $maxFiles,
                'duration_days' => $durationDays,
            ],
            'sort_order' => (int)($row['sort_order'] ?? 0),
            'is_recommended' => (int)($row['is_recommended'] ?? 0) === 1,
            'is_active' => (int)($row['is_active'] ?? 1) === 1,
        ];
    }

    /** @return array<string, int|float> */
    private static function usageStats(int $userId): array
    {
        $pdo = Db::pdo();
        $fileStmt = $pdo->prepare(
            'SELECT COUNT(*) AS files_count, COALESCE(SUM(size), 0) AS storage_bytes '
            . 'FROM soon_files WHERE user_id = :u AND deleted_at IS NULL'
        );
        $fileStmt->execute(['u' => $userId]);
        $row = $fileStmt->fetch() ?: ['files_count' => 0, 'storage_bytes' => 0];
        $bytes = (int)$row['storage_bytes'];
        $usedMb = $bytes > 0 ? round($bytes / 1024 / 1024, 2) : 0;
        return [
            'files_count' => (int)$row['files_count'],
            'storage_bytes' => $bytes,
            'used_mb' => $usedMb,
            'used_display' => self::formatQuota(max(1, $usedMb)) !== '0 MB' ? self::formatBytes($bytes) : '0 MB',
        ];
    }

    private static function formatQuota(int $mb): string
    {
        if ($mb <= 0) {
            return '0 MB';
        }
        if ($mb >= 1024) {
            $gb = $mb / 1024;
            return ($gb >= 10 ? (string)(int)round($gb) : rtrim(rtrim(number_format($gb, 1, '.', ''), '0'), '.')) . ' GB';
        }
        return $mb . ' MB';
    }

    private static function formatBytes(int $bytes): string
    {
        if ($bytes < 1024) {
            return $bytes . ' B';
        }
        if ($bytes < 1024 * 1024) {
            return round($bytes / 1024, 1) . ' KB';
        }
        return round($bytes / (1024 * 1024), 2) . ' MB';
    }

    private static function periodLabel(int $days): string
    {
        if ($days <= 0) {
            return '永久有效';
        }
        if ($days >= 365) {
            return '1 年';
        }
        if ($days === 90) {
            return '1 季';
        }
        if ($days >= 30 && $days % 30 === 0) {
            $months = (int)($days / 30);
            return $months . ' 个月';
        }
        return $days . ' 天';
    }

    private static function daysUntil(string $expiresAt): ?int
    {
        if ($expiresAt === '') {
            return null;
        }
        $ts = strtotime($expiresAt);
        if ($ts === false) {
            return null;
        }
        return max(0, (int)ceil(($ts - time()) / 86400));
    }
}