'use client'

import { useState } from 'react'
import {
  Card,
  CardContent,
  CardDescription,
  CardHeader,
  CardTitle,
} from '@/components/ui/card'
import { Button } from '@/components/ui/button'
import {
  Loader2,
  Activity,
  Cpu,
  HardDrive,
  Network,
  Download,
  Upload,
  RefreshCw,
  ExternalLink,
} from 'lucide-react'
import Link from 'next/link'
import { useServerMetrics } from '@/hooks/use-netcup'

interface ServerMetricsPanelProps {
  netcupServerId: string
  serverName?: string
}

function formatBytes(bytes: number): string {
  if (bytes === 0) return '0 B'
  if (!Number.isFinite(bytes) || bytes < 0) return '0 B'
  const k = 1024
  const sizes = ['B', 'KB', 'MB', 'GB', 'TB']
  const i = Math.max(0, Math.min(Math.floor(Math.log(bytes) / Math.log(k)), sizes.length - 1))
  return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + ' ' + sizes[i]
}

function formatBytesPerSec(bps: number): string {
  return formatBytes(bps) + '/s'
}

function MetricsBar({ value, max = 100, gradient }: {
  value: number
  max?: number
  gradient?: string
}) {
  const percentage = Math.min((value / max) * 100, 100)

  const getThresholdColor = () => {
    if (percentage > 90) return 'bg-gradient-to-r from-red-500 to-red-600'
    if (percentage > 75) return 'bg-gradient-to-r from-amber-500 to-orange-500'
    return gradient || 'bg-gradient-to-r from-blue-500 to-blue-600'
  }

  return (
    <div className="h-1.5 bg-muted/60 rounded-full overflow-hidden ring-1 ring-inset ring-black/5">
      <div
        className={`h-full ${getThresholdColor()} transition-all duration-500 ease-out rounded-full`}
        style={{ width: `${percentage}%` }}
      />
    </div>
  )
}

export function ServerMetricsPanel({ netcupServerId, serverName }: ServerMetricsPanelProps) {
  const [hours, setHours] = useState(24)
  const { data: metrics, isLoading, isFetching, error, refetch } = useServerMetrics(netcupServerId, hours, !!netcupServerId)

  if (!netcupServerId) {
    return null
  }

  const isInitialLoading = isLoading && !metrics

  if (error && !metrics) {
    return (
      <Card>
        <CardHeader className="pb-3">
          <div className="flex items-center justify-between">
            <div className="flex items-center gap-3">
              <div className="p-2 rounded-lg bg-blue-100 dark:bg-blue-900/30">
                <Activity className="h-4 w-4 text-blue-600 dark:text-blue-400" />
              </div>
              <div>
                <CardTitle className="text-lg">Server Metrics</CardTitle>
                <CardDescription>Performance monitoring</CardDescription>
              </div>
            </div>
          </div>
        </CardHeader>
        <CardContent>
          <div className="rounded-lg border border-destructive/20 bg-destructive/5 py-6 text-center">
            <p className="text-muted-foreground text-sm mb-2">Failed to load metrics</p>
            <Button variant="outline" size="sm" onClick={() => refetch()} className="gap-2">
              <RefreshCw className="h-4 w-4" />
              Retry
            </Button>
          </div>
        </CardContent>
      </Card>
    )
  }

  return (
    <Card>
      <CardHeader className="pb-3">
        <div className="flex items-center justify-between">
          <div className="flex items-center gap-3">
            <div className="p-2 rounded-lg bg-blue-100 dark:bg-blue-900/30">
              <Activity className="h-4 w-4 text-blue-600 dark:text-blue-400" />
            </div>
            <div>
              <CardTitle className="text-lg">Server Metrics</CardTitle>
              <CardDescription className="flex items-center gap-1">
                Performance monitoring
                {serverName && (
                  <Link
                    href={`/admin/servers/netcup/${netcupServerId}`}
                    className="text-xs text-primary hover:underline ml-2 inline-flex items-center gap-1"
                  >
                    View full details
                    <ExternalLink className="h-3 w-3" />
                  </Link>
                )}
              </CardDescription>
            </div>
          </div>
          <div className="flex items-center gap-2">
            {/* Period selector */}
            <div className="flex items-center gap-0.5 p-0.5 bg-muted/50 rounded-lg">
              {[1, 6, 24, 168].map((h) => (
                <Button
                  key={h}
                  variant={hours === h ? 'default' : 'ghost'}
                  size="sm"
                  className={`h-7 px-2 text-xs font-medium transition-all ${
                    hours === h ? 'shadow-sm' : 'hover:bg-muted'
                  }`}
                  onClick={() => setHours(h)}
                  disabled={isFetching}
                >
                  {h === 168 ? '7d' : `${h}h`}
                </Button>
              ))}
            </div>
            <Button
              variant="ghost"
              size="sm"
              className="h-7 w-7 p-0"
              onClick={() => refetch()}
              disabled={isFetching}
            >
              <RefreshCw className={`h-3.5 w-3.5 ${isFetching ? 'animate-spin' : ''}`} />
            </Button>
          </div>
        </div>
      </CardHeader>
      <CardContent>
        {isInitialLoading ? (
          <div className="grid gap-4 md:grid-cols-3">
            {[
              { icon: Cpu, label: 'CPU', color: 'text-blue-500 bg-blue-100 dark:bg-blue-900/30' },
              { icon: HardDrive, label: 'Disk I/O', color: 'text-emerald-500 bg-emerald-100 dark:bg-emerald-900/30' },
              { icon: Network, label: 'Network', color: 'text-violet-500 bg-violet-100 dark:bg-violet-900/30' },
            ].map(({ icon: Icon, label, color }) => (
              <div key={label} className="rounded-lg border bg-card p-4">
                <div className="flex items-center gap-2 mb-3">
                  <div className={`p-1.5 rounded-md ${color}`}>
                    <Icon className="h-3.5 w-3.5" />
                  </div>
                  <span className="text-sm font-medium">{label}</span>
                </div>
                <div className="flex items-center justify-center py-4">
                  <Loader2 className="h-4 w-4 animate-spin text-muted-foreground" />
                </div>
              </div>
            ))}
          </div>
        ) : !metrics ? (
          <div className="rounded-lg border bg-muted/20 py-8 text-center">
            <Activity className="h-8 w-8 mx-auto text-muted-foreground/50 mb-2" />
            <p className="text-muted-foreground text-sm">No metrics data available</p>
            <p className="text-xs text-muted-foreground/70 mt-1">
              Metrics will appear once the server is running
            </p>
          </div>
        ) : (
          <div className={`grid gap-4 md:grid-cols-3 transition-opacity duration-200 ${isFetching ? 'opacity-60' : ''}`}>
            {/* CPU metrics */}
            <div className="rounded-lg border bg-gradient-to-br from-card to-blue-50/30 dark:to-blue-950/10 p-4 space-y-3">
              <div className="flex items-center justify-between">
                <div className="flex items-center gap-2">
                  <div className="p-1.5 rounded-md bg-blue-100 dark:bg-blue-900/30">
                    <Cpu className="h-3.5 w-3.5 text-blue-600 dark:text-blue-400" />
                  </div>
                  <span className="text-sm font-medium">CPU</span>
                </div>
                <span className="text-xl font-bold tabular-nums text-blue-600 dark:text-blue-400">
                  {metrics.cpu.average}%
                </span>
              </div>
              <MetricsBar
                value={metrics.cpu.average}
                gradient="bg-gradient-to-r from-blue-500 to-blue-600"
              />
              <div className="flex items-center justify-between text-xs text-muted-foreground">
                <span>Peak: {metrics.cpu.max}%</span>
                <span>{metrics.cpu.dataPoints.length} samples</span>
              </div>
            </div>

            {/* Disk I/O metrics */}
            {metrics.disk && (metrics.disk.readBps.length > 0 || metrics.disk.writeBps.length > 0) ? (
              <div className="rounded-lg border bg-gradient-to-br from-card to-emerald-50/30 dark:to-emerald-950/10 p-4 space-y-3">
                <div className="flex items-center gap-2">
                  <div className="p-1.5 rounded-md bg-emerald-100 dark:bg-emerald-900/30">
                    <HardDrive className="h-3.5 w-3.5 text-emerald-600 dark:text-emerald-400" />
                  </div>
                  <span className="text-sm font-medium">Disk I/O</span>
                </div>
                <div className="grid grid-cols-2 gap-3">
                  <div className="space-y-1">
                    <div className="flex items-center gap-1 text-xs text-muted-foreground">
                      <Download className="h-2.5 w-2.5" />
                      Read
                    </div>
                    <p className="text-sm font-semibold tabular-nums">
                      {metrics.disk.readBps.length > 0
                        ? formatBytesPerSec(metrics.disk.readBps[metrics.disk.readBps.length - 1]?.value || 0)
                        : 'N/A'}
                    </p>
                  </div>
                  <div className="space-y-1">
                    <div className="flex items-center gap-1 text-xs text-muted-foreground">
                      <Upload className="h-2.5 w-2.5" />
                      Write
                    </div>
                    <p className="text-sm font-semibold tabular-nums">
                      {metrics.disk.writeBps.length > 0
                        ? formatBytesPerSec(metrics.disk.writeBps[metrics.disk.writeBps.length - 1]?.value || 0)
                        : 'N/A'}
                    </p>
                  </div>
                </div>
              </div>
            ) : (
              <div className="rounded-lg border bg-gradient-to-br from-card to-emerald-50/30 dark:to-emerald-950/10 p-4">
                <div className="flex items-center gap-2 mb-3">
                  <div className="p-1.5 rounded-md bg-emerald-100 dark:bg-emerald-900/30">
                    <HardDrive className="h-3.5 w-3.5 text-emerald-600 dark:text-emerald-400" />
                  </div>
                  <span className="text-sm font-medium">Disk I/O</span>
                </div>
                <p className="text-xs text-muted-foreground text-center py-2">No data</p>
              </div>
            )}

            {/* Network metrics */}
            {metrics.network && (metrics.network.rxBps.length > 0 || metrics.network.txBps.length > 0) ? (
              <div className="rounded-lg border bg-gradient-to-br from-card to-violet-50/30 dark:to-violet-950/10 p-4 space-y-3">
                <div className="flex items-center gap-2">
                  <div className="p-1.5 rounded-md bg-violet-100 dark:bg-violet-900/30">
                    <Network className="h-3.5 w-3.5 text-violet-600 dark:text-violet-400" />
                  </div>
                  <span className="text-sm font-medium">Network</span>
                </div>
                <div className="grid grid-cols-2 gap-3">
                  <div className="space-y-1">
                    <div className="flex items-center gap-1 text-xs text-muted-foreground">
                      <Download className="h-2.5 w-2.5" />
                      RX
                    </div>
                    <p className="text-sm font-semibold tabular-nums">
                      {metrics.network.rxBps.length > 0
                        ? formatBytesPerSec(metrics.network.rxBps[metrics.network.rxBps.length - 1]?.value || 0)
                        : 'N/A'}
                    </p>
                  </div>
                  <div className="space-y-1">
                    <div className="flex items-center gap-1 text-xs text-muted-foreground">
                      <Upload className="h-2.5 w-2.5" />
                      TX
                    </div>
                    <p className="text-sm font-semibold tabular-nums">
                      {metrics.network.txBps.length > 0
                        ? formatBytesPerSec(metrics.network.txBps[metrics.network.txBps.length - 1]?.value || 0)
                        : 'N/A'}
                    </p>
                  </div>
                </div>
              </div>
            ) : (
              <div className="rounded-lg border bg-gradient-to-br from-card to-violet-50/30 dark:to-violet-950/10 p-4">
                <div className="flex items-center gap-2 mb-3">
                  <div className="p-1.5 rounded-md bg-violet-100 dark:bg-violet-900/30">
                    <Network className="h-3.5 w-3.5 text-violet-600 dark:text-violet-400" />
                  </div>
                  <span className="text-sm font-medium">Network</span>
                </div>
                <p className="text-xs text-muted-foreground text-center py-2">No data</p>
              </div>
            )}
          </div>
        )}
      </CardContent>
    </Card>
  )
}