<?php

namespace App\Module\ThirdParty\Events;

use App\Module\ThirdParty\Models\ThirdPartyService;
use App\Module\ThirdParty\Models\ThirdPartyQuota;
use App\Module\ThirdParty\Enums\QUOTA_TYPE;
use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;

/**
 * 配额告警事件
 * 
 * 当第三方服务配额达到告警阈值时触发此事件
 */
class QuotaAlertEvent
{
    use Dispatchable, SerializesModels;

    /**
     * 第三方服务实例
     *
     * @var ThirdPartyService
     */
    public ThirdPartyService $service;

    /**
     * 配额实例
     *
     * @var ThirdPartyQuota
     */
    public ThirdPartyQuota $quota;

    /**
     * 告警类型
     *
     * @var string
     */
    public string $alertType;

    /**
     * 当前使用量
     *
     * @var int
     */
    public int $currentUsage;

    /**
     * 配额限制
     *
     * @var int
     */
    public int $quotaLimit;

    /**
     * 使用百分比
     *
     * @var float
     */
    public float $usagePercentage;

    /**
     * 告警阈值
     *
     * @var float
     */
    public float $alertThreshold;

    /**
     * 告警时间
     *
     * @var \Carbon\Carbon
     */
    public \Carbon\Carbon $alertTime;

    /**
     * 额外数据
     *
     * @var array
     */
    public array $metadata;

    // 告警类型常量
    public const ALERT_TYPE_WARNING = 'warning';      // 警告：达到警告阈值
    public const ALERT_TYPE_CRITICAL = 'critical';    // 严重：达到严重阈值
    public const ALERT_TYPE_EXHAUSTED = 'exhausted';  // 耗尽：配额用完

    /**
     * 创建事件实例
     *
     * @param ThirdPartyService $service
     * @param ThirdPartyQuota $quota
     * @param string $alertType
     * @param int $currentUsage
     * @param int $quotaLimit
     * @param float $usagePercentage
     * @param float $alertThreshold
     * @param array $metadata
     */
    public function __construct(
        ThirdPartyService $service,
        ThirdPartyQuota $quota,
        string $alertType,
        int $currentUsage,
        int $quotaLimit,
        float $usagePercentage,
        float $alertThreshold,
        array $metadata = []
    ) {
        $this->service = $service;
        $this->quota = $quota;
        $this->alertType = $alertType;
        $this->currentUsage = $currentUsage;
        $this->quotaLimit = $quotaLimit;
        $this->usagePercentage = $usagePercentage;
        $this->alertThreshold = $alertThreshold;
        $this->alertTime = now();
        $this->metadata = $metadata;
    }

    /**
     * 获取事件数据数组
     *
     * @return array
     */
    public function toArray(): array
    {
        return [
            'service_id' => $this->service->id,
            'service_code' => $this->service->code,
            'service_name' => $this->service->name,
            'quota_id' => $this->quota->id,
            'quota_type' => $this->quota->quota_type,
            'quota_type_label' => QUOTA_TYPE::from($this->quota->quota_type)->getLabel(),
            'alert_type' => $this->alertType,
            'current_usage' => $this->currentUsage,
            'quota_limit' => $this->quotaLimit,
            'usage_percentage' => $this->usagePercentage,
            'alert_threshold' => $this->alertThreshold,
            'alert_time' => $this->alertTime->toISOString(),
            'metadata' => $this->metadata,
        ];
    }

    /**
     * 获取告警级别
     *
     * @return string
     */
    public function getAlertLevel(): string
    {
        return match ($this->alertType) {
            self::ALERT_TYPE_WARNING => 'WARNING',
            self::ALERT_TYPE_CRITICAL => 'CRITICAL',
            self::ALERT_TYPE_EXHAUSTED => 'CRITICAL',
            default => 'INFO',
        };
    }

    /**
     * 获取告警消息
     *
     * @return string
     */
    public function getAlertMessage(): string
    {
        $serviceName = $this->service->name;
        $quotaTypeLabel = QUOTA_TYPE::from($this->quota->quota_type)->getLabel();
        $percentage = number_format($this->usagePercentage, 1);

        return match ($this->alertType) {
            self::ALERT_TYPE_WARNING => "第三方服务 [{$serviceName}] 的 {$quotaTypeLabel} 配额使用率已达到 {$percentage}%，请注意监控",
            self::ALERT_TYPE_CRITICAL => "第三方服务 [{$serviceName}] 的 {$quotaTypeLabel} 配额使用率已达到 {$percentage}%，即将耗尽",
            self::ALERT_TYPE_EXHAUSTED => "第三方服务 [{$serviceName}] 的 {$quotaTypeLabel} 配额已耗尽，服务调用将被限制",
            default => "第三方服务 [{$serviceName}] 配额状态更新",
        };
    }

    /**
     * 获取剩余配额
     *
     * @return int
     */
    public function getRemainingQuota(): int
    {
        return max(0, $this->quotaLimit - $this->currentUsage);
    }

    /**
     * 判断是否为严重告警
     *
     * @return bool
     */
    public function isCritical(): bool
    {
        return in_array($this->alertType, [self::ALERT_TYPE_CRITICAL, self::ALERT_TYPE_EXHAUSTED]);
    }

    /**
     * 获取预计耗尽时间
     *
     * @return \Carbon\Carbon|null
     */
    public function getEstimatedExhaustionTime(): ?\Carbon\Carbon
    {
        if ($this->alertType === self::ALERT_TYPE_EXHAUSTED) {
            return null; // 已经耗尽
        }

        // 基于当前使用率估算耗尽时间
        $quotaType = QUOTA_TYPE::from($this->quota->quota_type);
        $windowStart = \Carbon\Carbon::instance($quotaType->getCurrentWindowStart());
        $windowEnd = \Carbon\Carbon::instance($quotaType->getCurrentWindowEnd());

        $elapsedTime = now()->diffInMinutes($windowStart);
        
        if ($elapsedTime <= 0 || $this->currentUsage <= 0) {
            return null;
        }

        $usageRate = $this->currentUsage / $elapsedTime; // 每分钟使用量
        $remainingQuota = $this->getRemainingQuota();
        
        if ($usageRate <= 0) {
            return null;
        }

        $minutesToExhaustion = $remainingQuota / $usageRate;
        
        return now()->addMinutes($minutesToExhaustion);
    }

    /**
     * 获取建议操作
     *
     * @return array
     */
    public function getSuggestedActions(): array
    {
        $actions = [];

        switch ($this->alertType) {
            case self::ALERT_TYPE_WARNING:
                $actions[] = '监控配额使用情况';
                $actions[] = '检查是否有异常调用';
                $actions[] = '考虑优化调用频率';
                break;

            case self::ALERT_TYPE_CRITICAL:
                $actions[] = '立即检查调用情况';
                $actions[] = '暂停非必要的API调用';
                $actions[] = '联系服务提供商增加配额';
                $actions[] = '启用备用服务（如有）';
                break;

            case self::ALERT_TYPE_EXHAUSTED:
                $actions[] = '停止所有API调用';
                $actions[] = '等待配额重置';
                $actions[] = '切换到备用服务';
                $actions[] = '联系服务提供商紧急增加配额';
                break;
        }

        return $actions;
    }
}