'use client';

import * as React from 'react';
import { useCallback, useEffect, useState } from 'react';
import { toast } from 'sonner';
import { HardDrive, RefreshCw, Trash2 } from 'lucide-react';

import {
  Card,
  CardContent,
  CardDescription,
  CardHeader,
  CardTitle,
} from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Skeleton } from '@/components/ui/skeleton';
import { Label } from '@/components/ui/label';
import { Input } from '@/components/ui/input';
import { Switch } from '@/components/ui/switch';
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from '@/components/ui/dialog';
import type { CacheStatus } from '@/lib/services/admin';
import services from '@/lib/services';

/**
 * 格式化字节大小
 */
const formatBytes = (bytes: number) => {
  if (bytes === 0) return '0 Bytes';
  const k = 1024;
  const sizes = ['Bytes', 'KB', 'MB', 'GB', 'TB'];
  const i = Math.floor(Math.log(bytes) / Math.log(k));
  return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i];
};

/**
 * 格式化数字，每3位加逗号
 */
const formatNumber = (num: number | string) => {
  if (num === undefined || num === null) return '0';
  return num.toString().replace(/\B(?=(\d{3})+(?!\B))/g, ',');
};

interface CacheManagerProps {
  refreshTrigger: number;
}

export function CacheManager({ refreshTrigger }: CacheManagerProps) {
  const [cacheStatus, setCacheStatus] = useState<CacheStatus | null>(null);
  const [loadingCache, setLoadingCache] = useState<boolean>(true);
  const [savingConfig, setSavingConfig] = useState<boolean>(false);
  const [clearingCache, setClearingCache] = useState<boolean>(false);
  const [showClearConfirm, setShowClearConfirm] = useState<boolean>(false);

  // 策略配置表单状态
  const [maxSizeMB, setMaxSizeMB] = useState<string>('100');
  const [ttlMinutes, setTtlMinutes] = useState<string>('60');
  const [lruEnabled, setLruEnabled] = useState<boolean>(true);

  // 获取磁盘缓存状态
  const fetchCacheStatus = useCallback(async (isSilent = false) => {
    if (!isSilent) setLoadingCache(true);
    try {
      const data = await services.adminCache.getCacheStatus();
      setCacheStatus(data);
      setMaxSizeMB(data.max_size_mb.toString());
      setTtlMinutes(data.ttl_minutes.toString());
      setLruEnabled(data.lru_enabled);
    } catch (err) {
      toast.error('获取磁盘缓存状态失败', {
        description: err instanceof Error ? err.message : '未知错误',
      });
    } finally {
      setLoadingCache(false);
    }
  }, []);

  // 保存配置
  const handleSaveConfig = async (e: React.FormEvent) => {
    e.preventDefault();
    const size = parseInt(maxSizeMB, 10);
    const ttl = parseInt(ttlMinutes, 10);
    if (isNaN(size) || size < 1) {
      toast.error('保存失败', {
        description: '最大容量限制必须是大于等于 1 的整数',
      });
      return;
    }
    if (isNaN(ttl) || ttl < 0) {
      toast.error('保存失败', {
        description: '默认过期时间必须是大于等于 0 的整数',
      });
      return;
    }
    setSavingConfig(true);
    try {
      await services.adminCache.updateCacheConfig({
        max_size_mb: size,
        ttl_minutes: ttl,
        lru_enabled: lruEnabled,
      });
      toast.success('保存成功', { description: '磁盘缓存策略已热更新' });
      await fetchCacheStatus(true);
    } catch (err) {
      toast.error('保存配置失败', {
        description: err instanceof Error ? err.message : '未知错误',
      });
    } finally {
      setSavingConfig(false);
    }
  };

  // 清空磁盘缓存数据
  const handleClearCache = async () => {
    setClearingCache(true);
    try {
      await services.adminCache.clearCache();
      toast.success('清空成功', { description: '缓存数据已全部清除' });
      setShowClearConfirm(false);
      await fetchCacheStatus(true);
    } catch (err) {
      toast.error('清空缓存失败', {
        description: err instanceof Error ? err.message : '未知错误',
      });
    } finally {
      setClearingCache(false);
    }
  };

  // 初始化拉取
  useEffect(() => {
    fetchCacheStatus();
  }, [fetchCacheStatus]);

  // 当外部刷新触发器改变时自动刷新
  useEffect(() => {
    fetchCacheStatus(true);
  }, [refreshTrigger, fetchCacheStatus]);

  return (
    <Card className='border-border/40 bg-card/50 backdrop-blur-sm shadow-sm'>
      <CardHeader className='pb-3 border-b border-dashed flex flex-col md:flex-row md:items-center md:justify-between gap-4'>
        <div className='space-y-0.5'>
          <div className='flex items-center gap-2'>
            <HardDrive className='size-4 text-primary animate-pulse' />
            <CardTitle className='text-sm font-semibold'>缓存管理</CardTitle>
          </div>
          <CardDescription className='text-[11px]'>
            管理和监控系统级磁盘缓存的资源占用、生命周期及淘汰策略
          </CardDescription>
        </div>

        <Button
          size='sm'
          variant='secondary'
          className='h-8 gap-1.5 text-xs self-start md:self-auto'
          onClick={() => fetchCacheStatus(true)}
          disabled={loadingCache}
        >
          <RefreshCw
            className={`size-3 ${loadingCache ? 'animate-spin' : ''}`}
          />
          刷新状态
        </Button>
      </CardHeader>
      <CardContent className='pt-4'>
        {loadingCache && !cacheStatus ? (
          <div className='space-y-3 py-6'>
            <Skeleton className='h-6 w-full' />
            <Skeleton className='h-10 w-full' />
            <Skeleton className='h-10 w-full' />
          </div>
        ) : cacheStatus ? (
          <div className='grid grid-cols-1 lg:grid-cols-5 gap-6'>
            {/* 左边：状态区 (2/5 cols) */}
            <div className='lg:col-span-2 space-y-4'>
              <h4 className='text-xs font-semibold text-muted-foreground uppercase tracking-wider'>
                运行状态
              </h4>
              <div className='grid grid-cols-1 sm:grid-cols-2 gap-4'>
                {/* 已占空间 */}
                <div className='p-4 rounded-xl border border-border/40 bg-background/30 backdrop-blur-xs hover:border-primary/20 transition-all duration-300'>
                  <p className='text-[10px] text-muted-foreground font-medium mb-1'>
                    已用空间
                  </p>
                  <p className='text-xl font-bold tracking-tight text-foreground'>
                    {formatBytes(cacheStatus.total_size)}
                  </p>
                </div>
                {/* Key数量 */}
                <div className='p-4 rounded-xl border border-border/40 bg-background/30 backdrop-blur-xs hover:border-primary/20 transition-all duration-300'>
                  <p className='text-[10px] text-muted-foreground font-medium mb-1'>
                    缓存键数量
                  </p>
                  <p className='text-xl font-bold tracking-tight text-foreground'>
                    {formatNumber(cacheStatus.keys_count)}{' '}
                    <span className='text-xs text-muted-foreground font-normal'>
                      个文件
                    </span>
                  </p>
                </div>
              </div>

              {/* 存储路径 */}
              <div className='p-4 rounded-xl border border-border/40 bg-background/30 backdrop-blur-xs hover:border-primary/20 transition-all duration-300'>
                <p className='text-[10px] text-muted-foreground font-medium mb-1.5'>
                  缓存基准目录
                </p>
                <code
                  className='text-xs font-mono bg-muted/60 px-2 py-1 rounded-md block truncate'
                  title={cacheStatus.base_path}
                >
                  {cacheStatus.base_path}
                </code>
              </div>
              <Button
                variant='secondary'
                size='sm'
                className='h-8 text-xs font-medium w-full'
                onClick={() => setShowClearConfirm(true)}
              >
                立即清空缓存
              </Button>
            </div>

            {/* 右边：配置区 (3/5 cols) */}
            <div className='lg:col-span-3 border-t lg:border-t-0 lg:border-l border-border/40 pt-6 lg:pt-0 lg:pl-6 space-y-4'>
              <h4 className='text-xs font-semibold text-muted-foreground uppercase tracking-wider'>
                策略配置
              </h4>
              <form onSubmit={handleSaveConfig} className='space-y-4'>
                <div className='grid grid-cols-1 sm:grid-cols-2 gap-4'>
                  <div className='space-y-1.5'>
                    <Label htmlFor='maxSizeMB' className='text-xs font-medium'>
                      最大容量限制 (MB)
                    </Label>
                    <Input
                      id='maxSizeMB'
                      type='number'
                      min='1'
                      value={maxSizeMB}
                      onChange={(e) => setMaxSizeMB(e.target.value)}
                      className='h-8 text-xs bg-background/50 border-border/40'
                      placeholder='例如 100'
                      required
                    />
                    <p className='text-[9px] text-muted-foreground'>
                      当总大小超出该值时，自动触发淘汰算法
                    </p>
                  </div>

                  <div className='space-y-1.5'>
                    <Label htmlFor='ttlMinutes' className='text-xs font-medium'>
                      生存时间限制 (分钟)
                    </Label>
                    <Input
                      id='ttlMinutes'
                      type='number'
                      min='0'
                      value={ttlMinutes}
                      onChange={(e) => setTtlMinutes(e.target.value)}
                      className='h-8 text-xs bg-background/50 border-border/40'
                      placeholder='例如 60，0 表示永不过期'
                      required
                    />
                    <p className='text-[9px] text-muted-foreground'>
                      缓存项的最长存活时间，超期后将失效被清理
                    </p>
                  </div>
                </div>

                <div className='flex items-start justify-between p-4 rounded-xl border border-border/40 bg-background/20'>
                  <div className='space-y-1 pr-4'>
                    <Label
                      htmlFor='lruEnabled'
                      className='text-xs font-semibold block cursor-pointer'
                    >
                      启用 LRU 淘汰机制
                    </Label>
                    <span className='text-[10px] text-muted-foreground block'>
                      在到达最大容量限制时，自动移除最久未被访问的缓存项。关闭该功能仅清理过期项。
                    </span>
                  </div>
                  <Switch
                    id='lruEnabled'
                    checked={lruEnabled}
                    onCheckedChange={setLruEnabled}
                  />
                </div>

                <div className='flex justify-end pt-2'>
                  <Button
                    type='submit'
                    disabled={savingConfig}
                    className='h-8 text-xs px-4'
                  >
                    {savingConfig ? '正在保存...' : '保存设置'}
                  </Button>
                </div>
              </form>
            </div>
          </div>
        ) : (
          <div className='flex flex-col items-center justify-center py-10 text-muted-foreground'>
            <HardDrive className='size-8 opacity-45 mb-2' />
            <span className='text-xs'>未加载到缓存状态信息</span>
          </div>
        )}
      </CardContent>

      {/* 清除缓存确认对话框 */}
      <Dialog open={showClearConfirm} onOpenChange={setShowClearConfirm}>
        <DialogContent className='sm:max-w-md'>
          <DialogHeader>
            <DialogTitle className='text-sm font-semibold flex items-center gap-2 text-destructive'>
              <Trash2 className='size-4' />
              确认清空所有缓存？
            </DialogTitle>
            <DialogDescription className='text-xs text-muted-foreground pt-1'>
              该操作将彻底清空磁盘目录下的全部缓存文件（包含临时解压、处理后的图片及各种块文件），重置键数量统计为
              0。此操作不可撤销，且可能导致用户拉取资源时出现一过性的响应变慢。
            </DialogDescription>
          </DialogHeader>
          <DialogFooter className='flex gap-2 justify-end mt-4'>
            <Button
              variant='outline'
              size='sm'
              className='h-8 text-xs'
              onClick={() => setShowClearConfirm(false)}
              disabled={clearingCache}
            >
              取消
            </Button>
            <Button
              variant='destructive'
              size='sm'
              className='h-8 text-xs'
              onClick={handleClearCache}
              disabled={clearingCache}
            >
              {clearingCache ? '清理中...' : '确认清空'}
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </Card>
  );
}