import { useState, useEffect } from 'react';
import { toast } from 'sonner';
import { Button } from '@/components/ui/button';
import { Card, CardContent } from '@/components/ui/card';
import { Badge } from '@/components/ui/badge';
import { Input } from '@/components/ui/input';
import {
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
  DialogDescription,
  DialogFooter,
} from '@/components/ui/dialog';
import {
  Download,
  Upload,
  FileSpreadsheet,
  Check,
  X,
  AlertCircle,
  ChevronRight,
  ChevronLeft,
  Loader2,
} from 'lucide-react';
import { regionApi, serverApi, credentialApi } from '@/services/api';

interface RegionOption {
  id: string;
  name: string;
  code: string;
}

interface ExcelServerImportProps {
  open: boolean;
  onClose: () => void;
}

type PreviewRow = {
  row: number; hostname: string; ip: string; port: number;
  username: string; os: string; cpu: number; memory: number; disk: number; tags: string;
  status: string; message: string;
};

// 解析单行 CSV（支持引号包裹与转义） // Logan.Li
function parseCSVLine(line: string): string[] {
  const result: string[] = [];
  let current = '';
  let inQuotes = false;
  for (let i = 0; i < line.length; i++) {
    const ch = line[i];
    if (inQuotes) {
      if (ch === '"') {
        if (line[i + 1] === '"') { current += '"'; i++; }
        else inQuotes = false;
      } else {
        current += ch;
      }
    } else if (ch === '"') {
      inQuotes = true;
    } else if (ch === ',') {
      result.push(current);
      current = '';
    } else {
      current += ch;
    }
  }
  result.push(current);
  return result.map((s) => s.trim());
}

// 解析整个 CSV 文本为对象数组（首行为表头） // Logan.Li
function parseCSV(text: string): Record<string, string>[] {
  const lines = text.replace(/\r\n/g, '\n').replace(/\r/g, '\n').split('\n').filter((l) => l.trim());
  if (lines.length < 2) return [];
  const headers = parseCSVLine(lines[0]).map((h) => h.toLowerCase());
  const rows: Record<string, string>[] = [];
  for (let i = 1; i < lines.length; i++) {
    const cols = parseCSVLine(lines[i]);
    const row: Record<string, string> = {};
    headers.forEach((h, idx) => { row[h] = cols[idx] ?? ''; });
    rows.push(row);
  }
  return rows;
}

// IPv4 格式校验 // Logan.Li
function isValidIP(ip: string): boolean {
  return /^(\d{1,3}\.){3}\d{1,3}$/.test(ip) && ip.split('.').every((o) => Number(o) >= 0 && Number(o) <= 255);
}

// 下载 CSV 导入模板 — 主机名+IP+端口(默认22)，账号root，Agent 安装后自动补全 // Logan.Li
function downloadTemplate() {
  const csv = [
    'hostname,ip,port',
    'web-01,192.168.1.10,22',
    'db-01,192.168.1.20,22',
    'cache-01,192.168.1.30,2222',
  ].join('\n');
  const blob = new Blob(['\ufeff' + csv], { type: 'text/csv;charset=utf-8;' });
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = 'servers-template.csv';
  a.click();
  URL.revokeObjectURL(url);
}

export function ExcelServerImport({ open, onClose }: ExcelServerImportProps) {
  const [step, setStep] = useState(1);
  const [selectedRegion, setSelectedRegion] = useState<string>('');
  const [connectionMethod, setConnectionMethod] = useState<string>('password');
  const [selectedFile, setSelectedFile] = useState<File | null>(null);
  const [isUploading, setIsUploading] = useState(false);
  const [previewData, setPreviewData] = useState<PreviewRow[]>([]);
  const [regions, setRegions] = useState<RegionOption[]>([]);
  const [isImporting, setIsImporting] = useState(false);
  // 凭据选择 // Logan.Li
  const [credentials, setCredentials] = useState<any[]>([]);
  const [selectedCredentialId, setSelectedCredentialId] = useState<string>('');
  const [defaultSshPort, setDefaultSshPort] = useState('22');

  // 对话框打开时拉取区域列表 + 凭据列表 // Logan.Li
  useEffect(() => {
    if (!open) return;
    let cancelled = false;
    (async () => {
      try {
        const [regionResp, credResp] = await Promise.all([
          regionApi.list(),
          credentialApi.list(),
        ]);
        if (cancelled) return;
        const list = regionResp?.list ?? [];
        setRegions(list.map((r: any) => ({
          id: String(r.id ?? ''),
          name: r.name ?? '',
          code: r.code ?? '',
        })));
        setCredentials(credResp?.list ?? []);
      } catch {
        if (!cancelled) {
          setRegions([]);
          setCredentials([]);
        }
      }
    })();
    return () => { cancelled = true; };
  }, [open]);

  const handleNext = async () => {
    if (step === 2 && selectedFile) {
      setIsUploading(true);
      try {
        const text = await selectedFile.text();
        const rows = parseCSV(text);
        if (rows.length === 0) {
          toast.error('文件无有效数据，请使用模板格式（首行为表头）');
          setIsUploading(false);
          return;
        }
        const seen = new Set<string>();
        const preview: PreviewRow[] = rows.map((r, idx) => {
          const hostname = (r.hostname ?? '').trim();
          const ip = (r.ip ?? '').trim();
          const row: PreviewRow = {
            row: idx + 2,
            hostname,
            ip,
            port: Number(r.port) || 22,
            username: (r.username ?? '').trim() || 'root',
            os: r.os ?? '',
            cpu: Number(r.cpu) || 0,
            memory: Number(r.memory) || 0,
            disk: Number(r.disk) || 0,
            tags: r.tags ?? '',
            status: 'valid',
            message: '有效',
          };
          const errs: string[] = [];
          if (!hostname) errs.push('主机名缺失');
          if (!ip) errs.push('IP缺失');
          else if (!isValidIP(ip)) errs.push('IP格式错误');
          const key = `${hostname}|${ip}`;
          if (hostname && ip && seen.has(key)) errs.push('重复行');
          else seen.add(key);
          if (errs.length > 0) {
            row.status = 'error';
            row.message = errs.join('、');
          }
          return row;
        });
        setPreviewData(preview);
        setStep(step + 1);
      } catch {
        toast.error('文件解析失败，请确认是 CSV 格式');
      } finally {
        setIsUploading(false);
      }
    } else {
      setStep(step + 1);
    }
  };

  const handleBack = () => {
    if (step > 1) {
      setStep(step - 1);
    }
  };

  const handleFileChange = (e: React.ChangeEvent<HTMLInputElement>) => {
    if (e.target.files && e.target.files[0]) {
      setSelectedFile(e.target.files[0]);
    }
  };

  const resetState = () => {
    setStep(1);
    setSelectedRegion('');
    setDefaultSshPort('22');
    setSelectedCredentialId('');
    setSelectedFile(null);
    setPreviewData([]);
  };

  const handleImport = async () => {
    const valid = previewData.filter((d) => d.status === 'valid');
    if (valid.length === 0) return;
    setIsImporting(true);
    try {
      const servers = valid.map((d) => ({
        hostname: d.hostname,
        ip: d.ip,
        port: d.port,
        username: d.username,
        os: d.os,
        cpu: d.cpu,
        memory: d.memory,
        disk: d.disk,
        tags: d.tags,
      }));
      const resp: any = await serverApi.batchCreate({
        servers,
        region_id: selectedRegion || undefined,
        credential_id: selectedCredentialId ? Number(selectedCredentialId) : undefined,
        default_port: Number(defaultSshPort) || 22,
      });
      const r = resp ?? {};
      const success = r.success ?? 0;
      const skipped = r.skipped ?? 0;
      const failed = r.failed ?? 0;
      toast.success(`导入完成：成功 ${success}，跳过 ${skipped}，失败 ${failed}`);
      resetState();
      onClose();
    } catch (e: any) {
      toast.error(e?.message || '导入失败，请重试');
    } finally {
      setIsImporting(false);
    }
  };

  const handleClose = () => {
    onClose();
    resetState();
  };

  const validCount = previewData.filter(d => d.status === 'valid').length;
  const warningCount = previewData.filter(d => d.status === 'warning').length;
  const errorCount = previewData.filter(d => d.status === 'error').length;

  const steps = [
    { id: 1, title: '配置' },
    { id: 2, title: '上传' },
    { id: 3, title: '确认' },
  ];

  return (
    <Dialog open={open} onOpenChange={handleClose}>
      <DialogContent className="max-w-3xl bg-[var(--dg-bg-primary)] border-[var(--dg-border)] text-[var(--dg-text-primary)]">
        <DialogHeader>
          <DialogTitle className="text-xl">CSV 批量导入服务器</DialogTitle>
          <DialogDescription className="sr-only">通过 CSV 文件批量导入服务器资产</DialogDescription>
        </DialogHeader>

        {/* Step Indicator */}
        <div className="flex items-center justify-center mb-6">
          {steps.map((s, index) => (
            <div key={s.id} className="flex items-center">
              <div className={`flex items-center justify-center w-8 h-8 rounded-full ${
                step === s.id
                  ? 'bg-blue-600 text-white'
                  : step > s.id
                    ? 'bg-emerald-600 text-white'
                    : 'bg-[var(--dg-bg-secondary)] text-[var(--dg-text-muted)]'
              }`}>
                {step > s.id ? <Check className="h-4 w-4" /> : s.id}
              </div>
              <span className={`ml-2 text-sm ${step === s.id ? 'text-[var(--dg-text-primary)]' : 'text-[var(--dg-text-muted)]'}`}>
                {s.title}
              </span>
              {index < steps.length - 1 && (
                <div className="w-12 h-0.5 bg-[var(--dg-border)] mx-3" />
              )}
            </div>
          ))}
        </div>

        {/* Step 1: Configuration */}
        {step === 1 && (
          <div className="space-y-6">
            {/* Download Template */}
            <Card className="bg-[var(--dg-bg-secondary)] border-[var(--dg-border)]">
              <CardContent className="p-4">
                <div className="flex items-center justify-between">
                  <div className="flex items-center gap-3">
                    <div className="w-10 h-10 rounded-lg bg-emerald-500/20 flex items-center justify-center">
                      <FileSpreadsheet className="h-5 w-5 text-emerald-400" />
                    </div>
                    <div>
                      <p className="font-medium text-[var(--dg-text-primary)]">主机导入模板</p>
                      <p className="text-xs text-[var(--dg-text-muted)]">下载 CSV 模板，只需填主机名、IP和端口（默认22），Agent安装后自动补全</p>
                    </div>
                  </div>
                  <Button variant="outline" className="border-[var(--dg-border)] text-[var(--dg-text-secondary)]" onClick={downloadTemplate}>
                    <Download className="h-4 w-4 mr-2" />
                    下载模板
                  </Button>
                </div>
              </CardContent>
            </Card>

            {/* Region Selection */}
            <div>
              <label className="block text-sm font-medium text-[var(--dg-text-secondary)] mb-2">选择区域</label>
              <select
                value={selectedRegion}
                onChange={(e) => setSelectedRegion(e.target.value)}
                className="w-full px-3 py-2 bg-[var(--dg-bg-secondary)] border border-[var(--dg-border)] rounded-md text-[var(--dg-text-primary)] text-sm"
              >
                <option value="">请选择区域</option>
                {regions.map((region) => (
                  <option key={region.id} value={region.id}>
                    {region.name} ({region.code})
                  </option>
                ))}
              </select>
            </div>

            {/* 凭据选择（SSH密钥/密码） — 选中后自动关联到导入的每台服务器 // Logan.Li */}
            <div>
              <label className="block text-sm font-medium text-[var(--dg-text-secondary)] mb-2">
                选择凭据
                <span className="text-xs text-[var(--dg-text-muted)] ml-1">（可选，用于SSH连接）</span>
              </label>
              {credentials.length === 0 ? (
                <p className="text-xs text-[var(--dg-text-muted)] py-2">
                  暂无凭据，先去「凭证配置」添加 SSH 密钥或密码
                </p>
              ) : (
                <select
                  value={selectedCredentialId}
                  onChange={(e) => setSelectedCredentialId(e.target.value)}
                  className="w-full px-3 py-2 bg-[var(--dg-bg-secondary)] border border-[var(--dg-border)] rounded-md text-[var(--dg-text-primary)] text-sm"
                >
                  <option value="">不使用凭据（后续手动配置）</option>
                  {credentials.map((c: any) => (
                    <option key={c.id} value={String(c.id)}>
                      {c.type === 'ssh_key' ? '🔑' : c.type === 'api_token' ? '🌐' : '🔒'} {c.name} ({c.type === 'ssh_key' ? 'SSH密钥' : c.type === 'api_token' ? 'API Token' : '密码'})
                    </option>
                  ))}
                </select>
              )}
            </div>

            {/* SSH 端口配置 */}
            <div>
              <label className="block text-sm font-medium text-[var(--dg-text-secondary)] mb-2">
                SSH 端口
                <span className="text-xs text-[var(--dg-text-muted)] ml-1">（导入时统一设置，可在服务器管理页单独修改）</span>
              </label>
              <Input
                type="number"
                placeholder="22"
                value={defaultSshPort}
                onChange={(e) => setDefaultSshPort(e.target.value)}
                className="w-32 bg-[var(--dg-bg-secondary)] border-[var(--dg-border)] text-[var(--dg-text-primary)]"
              />
            </div>
          </div>
        )}

        {/* Step 2: Upload */}
        {step === 2 && (
          <div className="space-y-6">
            <div
              className="border-2 border-dashed border-[var(--dg-border)] rounded-lg p-8 text-center hover:border-blue-500/50 transition-colors"
            >
              <Upload className="h-12 w-12 mx-auto mb-4 text-[var(--dg-text-muted)]" />
              <p className="text-[var(--dg-text-secondary)] mb-2">点击或拖拽文件到此处上传</p>
              <p className="text-xs text-[var(--dg-text-muted)] mb-4">支持 CSV 格式文件（可点击左侧"下载模板"获取）</p>
              <Input
                type="file"
                accept=".csv,text/csv"
                onChange={handleFileChange}
                className="hidden"
                id="excel-upload"
              />
              <label htmlFor="excel-upload">
                <Button variant="outline" className="border-[var(--dg-border)] text-[var(--dg-text-secondary)]" asChild>
                  <span>选择文件</span>
                </Button>
              </label>
            </div>

            {selectedFile && (
              <Card className="bg-[var(--dg-bg-secondary)] border-[var(--dg-border)]">
                <CardContent className="p-3 flex items-center justify-between">
                  <div className="flex items-center gap-3">
                    <FileSpreadsheet className="h-8 w-8 text-emerald-400" />
                    <div>
                      <p className="text-sm text-[var(--dg-text-primary)]">{selectedFile.name}</p>
                      <p className="text-xs text-[var(--dg-text-muted)]">{(selectedFile.size / 1024).toFixed(2)} KB</p>
                    </div>
                  </div>
                  <Button
                    variant="ghost"
                    size="icon"
                    className="text-[var(--dg-text-muted)] hover:text-red-400"
                    onClick={() => setSelectedFile(null)}
                  >
                    <X className="h-4 w-4" />
                  </Button>
                </CardContent>
              </Card>
            )}

            {isUploading && (
              <div className="text-center py-4">
                <div className="w-8 h-8 border-2 border-blue-500 border-t-transparent rounded-full animate-spin mx-auto mb-2" />
                <p className="text-[var(--dg-text-secondary)] text-sm">正在解析文件...</p>
              </div>
            )}
          </div>
        )}

        {/* Step 3: Preview & Confirm */}
        {step === 3 && (
          <div className="space-y-4">
            <div className="flex items-center justify-between">
              <p className="text-[var(--dg-text-secondary)] text-sm">数据预览</p>
              <div className="flex items-center gap-2">
                <Badge className="bg-emerald-500/20 text-emerald-400 border-0">
                  <Check className="h-3 w-3 mr-1" />
                  {validCount} 有效
                </Badge>
                {warningCount > 0 && (
                  <Badge className="bg-amber-500/20 text-amber-400 border-0">
                    <AlertCircle className="h-3 w-3 mr-1" />
                    {warningCount} 警告
                  </Badge>
                )}
                {errorCount > 0 && (
                  <Badge className="bg-red-500/20 text-red-400 border-0">
                    <X className="h-3 w-3 mr-1" />
                    {errorCount} 错误
                  </Badge>
                )}
              </div>
            </div>

            <div className="border rounded-lg border-[var(--dg-border)] overflow-hidden max-h-[350px] overflow-y-auto">
              <table className="w-full">
                <thead className="bg-[var(--dg-bg-secondary)] sticky top-0">
                  <tr>
                    <th className="px-3 py-2 text-left text-xs font-medium text-[var(--dg-text-secondary)]">行号</th>
                    <th className="px-3 py-2 text-left text-xs font-medium text-[var(--dg-text-secondary)]">主机名</th>
                    <th className="px-3 py-2 text-left text-xs font-medium text-[var(--dg-text-secondary)]">IP地址</th>
                    <th className="px-3 py-2 text-left text-xs font-medium text-[var(--dg-text-secondary)]">状态</th>
                  </tr>
                </thead>
                <tbody className="divide-y divide-[var(--dg-border)]">
                  {previewData.map((row) => (
                    <tr key={row.row} className="hover:bg-[var(--dg-bg-hover)]">
                      <td className="px-3 py-2 text-sm text-[var(--dg-text-muted)]">{row.row}</td>
                      <td className="px-3 py-2 text-sm text-[var(--dg-text-primary)]">{row.hostname || '-'}</td>
                      <td className="px-3 py-2 text-sm text-[var(--dg-text-secondary)]">{row.ip}</td>
                      <td className="px-3 py-2">
                        <div className="flex items-center gap-1">
                          {row.status === 'valid' && (
                            <Badge className="bg-emerald-500/20 text-emerald-400 border-0 text-xs">
                              <Check className="h-3 w-3 mr-1" />
                              {row.message}
                            </Badge>
                          )}
                          {row.status === 'warning' && (
                            <Badge className="bg-amber-500/20 text-amber-400 border-0 text-xs">
                              <AlertCircle className="h-3 w-3 mr-1" />
                              {row.message}
                            </Badge>
                          )}
                          {row.status === 'error' && (
                            <Badge className="bg-red-500/20 text-red-400 border-0 text-xs">
                              <X className="h-3 w-3 mr-1" />
                              {row.message}
                            </Badge>
                          )}
                        </div>
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>

            {errorCount > 0 && (
              <div className="p-3 rounded-lg bg-red-500/10 border border-red-500/30">
                <div className="flex items-center gap-2 text-red-400">
                  <AlertCircle className="h-4 w-4" />
                  <span className="text-sm">存在 {errorCount} 条错误数据，请修正后重新上传</span>
                </div>
              </div>
            )}
          </div>
        )}

        {/* Footer */}
        <DialogFooter className="flex justify-between items-center">
          <div>
            {step > 1 && (
              <Button variant="outline" onClick={handleBack} className="border-[var(--dg-border)] text-[var(--dg-text-secondary)]">
                <ChevronLeft className="h-4 w-4 mr-1" />
                上一步
              </Button>
            )}
          </div>
          <div className="flex gap-2">
            <Button variant="outline" onClick={handleClose} className="border-[var(--dg-border)] text-[var(--dg-text-secondary)]">
              取消
            </Button>
            {step < 3 ? (
              <Button
                onClick={handleNext}
                disabled={(step === 1 && !selectedRegion) || (step === 2 && !selectedFile)}
                className="bg-blue-600 hover:bg-blue-700"
              >
                下一步
                <ChevronRight className="h-4 w-4 ml-1" />
              </Button>
            ) : (
              <Button
                onClick={handleImport}
                disabled={isImporting || errorCount > 0 || validCount === 0}
                className="bg-emerald-600 hover:bg-emerald-700"
              >
                {isImporting ? (
                  <Loader2 className="h-4 w-4 mr-1 animate-spin" />
                ) : (
                  <Check className="h-4 w-4 mr-1" />
                )}
                {isImporting ? '导入中...' : `确认导入 (${validCount})`}
              </Button>
            )}
          </div>
        </DialogFooter>
      </DialogContent>
    </Dialog>
  );
}