'use client';

import { useEffect, useState, useCallback } from 'react';
import Link from 'next/link';
import { useRouter } from 'next/navigation';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { StatusBadge, StatusDot } from '@/components/status-badge';
import { ProgressRing } from '@/components/progress-ring';
import { useUser } from '@/components/user-context';
import { Input } from '@/components/ui/input';
import { Textarea } from '@/components/ui/textarea';
import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogTrigger, DialogFooter } from '@/components/ui/dialog';
import { AlertDialog, AlertDialogAction, AlertDialogCancel, AlertDialogContent, AlertDialogDescription, AlertDialogFooter, AlertDialogHeader, AlertDialogTitle, AlertDialogTrigger } from '@/components/ui/alert-dialog';
import { Label } from '@/components/ui/label';
import { calculateProgress, getDaysRemaining, formatDateRange, isKRActive } from '@/lib/kr-utils';
import { REASON_CODES, PERIOD_TYPES } from '@/lib/constants';
import type { Project, User, Objective, KR } from '@/types/database';
import { toast } from 'sonner';
import {
  ArrowLeft,
  Plus,
  Target,
  Calendar,
  Users,
  AlertTriangle,
  Clock,
  Pencil,
  Trash2,
  Loader2
} from 'lucide-react';

interface ProjectWithRelations extends Project {
  owner: User | null;
  pm: User | null;
  members: { user_id: string; users: User }[];
}

interface KRWithRelations extends KR {
  owner: User | null;
}

export default function ProjectDetailPage({ projectId }: { projectId: string }) {
  // Force re-compile
  const { currentUser } = useUser();
  const router = useRouter();

  const [project, setProject] = useState<ProjectWithRelations | null>(null);
  const [objectives, setObjectives] = useState<Objective[]>([]);
  const [krs, setKRs] = useState<KRWithRelations[]>([]);
  const [isLoading, setIsLoading] = useState(true);
  const [isDeleting, setIsDeleting] = useState(false);
  const [isEditing, setIsEditing] = useState(false);
  const [isObjectiveDialogOpen, setIsObjectiveDialogOpen] = useState(false);
  const [editingObjective, setEditingObjective] = useState<Objective | null>(null);

  const fetchData = useCallback(async () => {
    try {
      const [projectRes, objectivesRes, krsRes] = await Promise.all([
        fetch(`/api/projects/${projectId}`),
        fetch(`/api/objectives?project_id=${projectId}`),
        fetch(`/api/krs?project_id=${projectId}`),
      ]);

      if (projectRes.ok) {
        const projectData = await projectRes.json();
        setProject(projectData);
      }

      if (objectivesRes.ok) {
        const objectivesData = await objectivesRes.json();
        setObjectives(objectivesData);
      }

      if (krsRes.ok) {
        const krsData = await krsRes.json();
        setKRs(krsData);
      }
    } catch (error) {
      console.error('Failed to fetch project data:', error);
    } finally {
      setIsLoading(false);
    }
  }, [projectId]);

  useEffect(() => {
    fetchData();
  }, [fetchData]);

  const canEdit = currentUser?.role === 'owner' || currentUser?.id === project?.pm_id;

  const handleDeleteProject = async () => {
    setIsDeleting(true);
    try {
      const res = await fetch(`/api/projects/${projectId}`, { method: 'DELETE' });
      if (!res.ok) throw new Error('删除失败');
      toast.success('项目已删除');
      router.push('/projects');
    } catch (error) {
      toast.error('删除失败');
    } finally {
      setIsDeleting(false);
    }
  };

  const handleEditProject = async (e: React.FormEvent<HTMLFormElement>) => {
    e.preventDefault();
    setIsEditing(true);
    const formData = new FormData(e.currentTarget);
    
    try {
      const res = await fetch(`/api/projects/${projectId}`, {
        method: 'PATCH',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          name: formData.get('name'),
          description: formData.get('description'),
        }),
      });

      if (!res.ok) throw new Error('更新失败');
      
      toast.success('项目已更新');
      fetchData();
    } catch (error) {
      toast.error('更新失败');
    } finally {
      setIsEditing(false);
    }
  };

  const handleDeleteObjective = async (objectiveId: string) => {
    if (!confirm('确定要删除此目标吗？关联的 KR 也会被解除关联。')) return;
    
    try {
      const res = await fetch(`/api/objectives/${objectiveId}`, { method: 'DELETE' });
      if (!res.ok) throw new Error('删除失败');
      toast.success('目标已删除');
      fetchData();
    } catch (error) {
      toast.error('删除失败');
    }
  };

  const handleEditObjective = async (e: React.FormEvent<HTMLFormElement>) => {
    e.preventDefault();
    if (!editingObjective) return;

    setIsEditing(true);
    const formData = new FormData(e.currentTarget);
    
    try {
      const res = await fetch(`/api/objectives/${editingObjective.id}`, {
        method: 'PATCH',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          title: formData.get('title'),
          description: formData.get('description'),
          period_start: formData.get('period_start'),
          period_end: formData.get('period_end'),
        }),
      });

      if (!res.ok) throw new Error('更新失败');
      
      toast.success('目标已更新');
      setIsObjectiveDialogOpen(false);
      setEditingObjective(null);
      fetchData();
    } catch (error) {
      toast.error('更新失败');
    } finally {
      setIsEditing(false);
    }
  };

  const activeKRs = krs.filter(isKRActive);
  const completedKRs = activeKRs.filter(kr => calculateProgress(kr) >= 1);

  if (isLoading) {
    return (
      <div className="max-w-7xl mx-auto px-4 py-8">
        <div className="animate-pulse space-y-6">
          <div className="h-6 bg-slate-200 rounded w-24" />
          <div className="h-8 bg-slate-200 rounded w-64" />
          <div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
            <div className="lg:col-span-2 space-y-4">
              {[1, 2, 3].map(i => (
                <div key={i} className="h-32 bg-slate-200 rounded-lg" />
              ))}
            </div>
            <div className="h-64 bg-slate-200 rounded-lg" />
          </div>
        </div>
      </div>
    );
  }

  if (!project) {
    return (
      <div className="max-w-7xl mx-auto px-4 py-8 text-center">
        <p className="text-muted-foreground">项目不存在</p>
        <Button asChild className="mt-4" variant="outline">
          <Link href="/projects">返回项目列表</Link>
        </Button>
      </div>
    );
  }

  return (
    <div className="max-w-7xl mx-auto px-4 py-8">
      <div className="mb-6">
        <Link
          href="/projects"
          className="inline-flex items-center text-sm text-muted-foreground hover:text-slate-800 mb-4"
        >
          <ArrowLeft className="h-4 w-4 mr-1" />
          返回项目列表
        </Link>

        <div className="flex items-start justify-between">
          <div>
            <div className="flex items-center gap-3">
              <h1 className="text-2xl font-bold text-slate-800">{project.name}</h1>
              <StatusBadge status={project.status} />
            </div>
            {project.description && (
              <p className="text-muted-foreground mt-2">{project.description}</p>
            )}
          </div>

          {canEdit && (
            <div className="flex gap-2">
              {currentUser?.role === 'owner' && (
                <>
                  <Dialog>
                    <DialogTrigger asChild>
                      <Button variant="ghost" size="sm">
                        <Pencil className="h-4 w-4" />
                      </Button>
                    </DialogTrigger>
                    <DialogContent>
                      <DialogHeader>
                        <DialogTitle>编辑项目</DialogTitle>
                      </DialogHeader>
                      <form onSubmit={handleEditProject} className="space-y-4">
                        <div>
                          <Label htmlFor="name">项目名称</Label>
                          <Input id="name" name="name" defaultValue={project.name} required />
                        </div>
                        <div>
                          <Label htmlFor="description">项目描述</Label>
                          <Textarea id="description" name="description" defaultValue={project.description || ''} />
                        </div>
                        <Button type="submit" disabled={isEditing} className="w-full">
                          {isEditing && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
                          保存修改
                        </Button>
                      </form>
                    </DialogContent>
                  </Dialog>

                  <AlertDialog>
                    <AlertDialogTrigger asChild>
                      <Button variant="ghost" size="sm" className="text-rose-500 hover:text-rose-600">
                        <Trash2 className="h-4 w-4" />
                      </Button>
                    </AlertDialogTrigger>
                    <AlertDialogContent>
                      <AlertDialogHeader>
                        <AlertDialogTitle>确定要删除项目吗？</AlertDialogTitle>
                        <AlertDialogDescription>
                          此操作无法撤销。这将永久删除项目及其所有关联的目标、KR 和打卡记录。
                        </AlertDialogDescription>
                      </AlertDialogHeader>
                      <AlertDialogFooter>
                        <AlertDialogCancel>取消</AlertDialogCancel>
                        <AlertDialogAction
                          onClick={handleDeleteProject}
                          className="bg-rose-600 hover:bg-rose-700"
                          disabled={isDeleting}
                        >
                          {isDeleting && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
                          删除
                        </AlertDialogAction>
                      </AlertDialogFooter>
                    </AlertDialogContent>
                  </AlertDialog>
                </>
              )}
              <Button asChild variant="outline">
                <Link href={`/projects/${projectId}/objectives/new`}>
                  <Plus className="h-4 w-4 mr-2" />
                  新建目标
                </Link>
              </Button>
              <Button asChild className="bg-teal-600 hover:bg-teal-700">
                <Link href={`/projects/${projectId}/krs/new`}>
                  <Plus className="h-4 w-4 mr-2" />
                  新建 KR
                </Link>
              </Button>
            </div>
          )}
        </div>
      </div>

      <div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
        <Dialog open={isObjectiveDialogOpen} onOpenChange={setIsObjectiveDialogOpen}>
          <DialogContent>
            <DialogHeader>
              <DialogTitle>编辑目标</DialogTitle>
            </DialogHeader>
            {editingObjective && (
              <form onSubmit={handleEditObjective} className="space-y-4">
                <div>
                  <Label htmlFor="obj-title">目标标题</Label>
                  <Input id="obj-title" name="title" defaultValue={editingObjective.title} required />
                </div>
                <div>
                  <Label htmlFor="obj-desc">描述</Label>
                  <Textarea id="obj-desc" name="description" defaultValue={editingObjective.description || ''} />
                </div>
                <div className="grid grid-cols-2 gap-4">
                  <div>
                    <Label htmlFor="obj-start">开始日期</Label>
                    <Input type="date" id="obj-start" name="period_start" defaultValue={editingObjective.period_start} required />
                  </div>
                  <div>
                    <Label htmlFor="obj-end">结束日期</Label>
                    <Input type="date" id="obj-end" name="period_end" defaultValue={editingObjective.period_end} required />
                  </div>
                </div>
                <Button type="submit" disabled={isEditing} className="w-full">
                  {isEditing && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
                  保存修改
                </Button>
              </form>
            )}
          </DialogContent>
        </Dialog>

        <div className="lg:col-span-2 space-y-6">
          <div className="grid grid-cols-3 gap-4">
            <Card>
              <CardContent className="pt-6 text-center">
                <p className="text-3xl font-bold text-slate-800">{activeKRs.length}</p>
                <p className="text-sm text-muted-foreground">进行中 KR</p>
              </CardContent>
            </Card>
            <Card>
              <CardContent className="pt-6 text-center">
                <p className="text-3xl font-bold text-emerald-600">{completedKRs.length}</p>
                <p className="text-sm text-muted-foreground">已达标</p>
              </CardContent>
            </Card>
            <Card>
              <CardContent className="pt-6 text-center">
                <p className="text-3xl font-bold text-rose-600">
                  {activeKRs.filter(kr => kr.status === 'red').length}
                </p>
                <p className="text-sm text-muted-foreground">风险 KR</p>
              </CardContent>
            </Card>
          </div>

          {objectives.length > 0 && (
            <Card>
              <CardHeader>
                <CardTitle className="text-lg flex items-center gap-2">
                  <Target className="h-5 w-5 text-teal-600" />
                  阶段目标 (Objectives)
                </CardTitle>
              </CardHeader>
              <CardContent className="space-y-4">
                {objectives.map(obj => {
                  const objKRs = krs.filter(kr => kr.objective_id === obj.id);
                  return (
                    <div key={obj.id} className="p-4 bg-slate-50 rounded-lg">
                      <div className="flex items-start justify-between mb-2">
                        <h3 className="font-medium text-slate-800">{obj.title}</h3>
                        <div className="flex items-center gap-2">
                          <span className="text-xs text-muted-foreground flex items-center gap-1">
                            <Calendar className="h-3 w-3" />
                            {formatDateRange(obj.period_start, obj.period_end)}
                          </span>
                          {currentUser?.role === 'owner' && (
                            <div className="flex items-center">
                              <Button
                                variant="ghost"
                                size="sm"
                                className="h-6 w-6 p-0"
                                onClick={() => {
                                  setEditingObjective(obj);
                                  setIsObjectiveDialogOpen(true);
                                }}
                              >
                                <Pencil className="h-3 w-3" />
                              </Button>
                              <Button
                                variant="ghost"
                                size="sm"
                                className="h-6 w-6 p-0 text-rose-500 hover:text-rose-600"
                                onClick={() => handleDeleteObjective(obj.id)}
                              >
                                <Trash2 className="h-3 w-3" />
                              </Button>
                            </div>
                          )}
                        </div>
                      </div>
                      {obj.description && (
                        <p className="text-sm text-muted-foreground mb-3">{obj.description}</p>
                      )}
                      <div className="text-xs text-muted-foreground">
                        关联 {objKRs.length} 个 KR
                      </div>
                    </div>
                  );
                })}
              </CardContent>
            </Card>
          )}

          <Card>
            <CardHeader>
              <CardTitle className="text-lg">执行目标 (Key Results)</CardTitle>
            </CardHeader>
            <CardContent className="space-y-3">
              {krs.length === 0 ? (
                <p className="text-center text-muted-foreground py-8">暂无 KR</p>
              ) : (
                krs.map(kr => {
                  const progress = calculateProgress(kr);
                  const daysLeft = getDaysRemaining(kr.period_end);
                  const isActive = isKRActive(kr);

                  return (
                    <Link key={kr.id} href={`/krs/${kr.id}`} className="block">
                      <div className={`flex items-center gap-4 p-4 rounded-lg border hover:bg-slate-50 transition-colors ${!isActive ? 'opacity-60' : ''}`}>
                        <ProgressRing progress={progress} status={kr.status} size={56} />
                        <div className="flex-1 min-w-0">
                          <div className="flex items-center gap-2 mb-1">
                            <p className="font-medium text-slate-800 truncate">{kr.title}</p>
                            {!isActive && (
                              <span className="text-xs bg-slate-200 text-slate-600 px-2 py-0.5 rounded">已结束</span>
                            )}
                          </div>
                          <div className="flex items-center gap-3 text-sm text-muted-foreground">
                            <span>{kr.owner?.name || '未分配'}</span>
                            <span className="text-xs bg-slate-100 px-2 py-0.5 rounded">
                              {PERIOD_TYPES[kr.period_type]}
                            </span>
                            <span>{formatDateRange(kr.period_start, kr.period_end)}</span>
                          </div>
                          {kr.reason_code && kr.status !== 'green' && (
                            <div className="flex items-center gap-1 mt-1 text-xs text-amber-600">
                              <AlertTriangle className="h-3 w-3" />
                              {REASON_CODES[kr.reason_code]}
                            </div>
                          )}
                        </div>
                        <div className="text-right">
                          <p className="text-sm font-medium">
                            {kr.current_value}/{kr.target_value} {kr.unit}
                          </p>
                          {isActive && (
                            <p className={`text-xs ${daysLeft <= 3 ? 'text-amber-600' : 'text-muted-foreground'}`}>
                              <Clock className="h-3 w-3 inline mr-1" />
                              剩余 {daysLeft} 天
                            </p>
                          )}
                        </div>
                      </div>
                    </Link>
                  );
                })
              )}
            </CardContent>
          </Card>
        </div>

        <div className="space-y-6">
          <Card>
            <CardHeader>
              <CardTitle className="text-lg">项目信息</CardTitle>
            </CardHeader>
            <CardContent className="space-y-4">
              <div>
                <p className="text-sm text-muted-foreground">项目类型</p>
                <p className="font-medium">{project.project_type || '通用'}</p>
              </div>
              <div>
                <p className="text-sm text-muted-foreground">负责人</p>
                <p className="font-medium">{project.owner?.name || '未指定'}</p>
              </div>
              <div>
                <p className="text-sm text-muted-foreground">项目经理</p>
                <p className="font-medium">{project.pm?.name || '未指定'}</p>
              </div>
            </CardContent>
          </Card>

          <Card>
            <CardHeader>
              <CardTitle className="text-lg flex items-center gap-2">
                <Users className="h-5 w-5" />
                团队成员
              </CardTitle>
            </CardHeader>
            <CardContent>
              {project.members && project.members.length > 0 ? (
                <div className="space-y-2">
                  {project.members.map(m => (
                    <div key={m.user_id} className="flex items-center gap-2 p-2 rounded bg-slate-50">
                      <div className="w-8 h-8 rounded-full bg-slate-200 flex items-center justify-center text-sm font-medium">
                        {m.users.name.charAt(0)}
                      </div>
                      <span className="text-sm">{m.users.name}</span>
                    </div>
                  ))}
                </div>
              ) : (
                <p className="text-sm text-muted-foreground">暂无成员</p>
              )}
            </CardContent>
          </Card>

          <Card>
            <CardHeader>
              <CardTitle className="text-lg">快速操作</CardTitle>
            </CardHeader>
            <CardContent className="space-y-2">
              <Button asChild variant="outline" className="w-full justify-start">
                <Link href={`/meeting?project_id=${projectId}`}>
                  <Calendar className="h-4 w-4 mr-2" />
                  发起例会
                </Link>
              </Button>
            </CardContent>
          </Card>
        </div>
      </div>
    </div>
  );
}