/**
 * ProjectDetailView Component
 * 
 * Displays project details and associated tasks.
 * Requirements: 1.5, 1.6
 */
import React, { useEffect, useState } from 'react';
import { useParams, useNavigate } from 'react-router-dom';
import { useAtom } from 'jotai';
import {
  Button,
  IconArrowLeft,
  IconEdit,
  IconPlus,
  DataTable,
  type ExtendedDataTableColumnDef,
  Badge,
  Dialog,
  DialogContent,
  DialogHeader,
  DialogTitle,
} from '@humansignal/ui';
import { getProject, getProjectTasks, createTask } from '../services/api';
import { currentProjectAtom, projectLoadingAtom, projectErrorAtom } from '../atoms/project-atoms';
import { tasksAtom, type Task } from '../atoms/task-atoms';
import { TaskForm, type TaskFormData } from '../components';

export const ProjectDetailView: React.FC = () => {
  const { id } = useParams<{ id: string }>();
  const navigate = useNavigate();
  
  const [currentProject, setCurrentProject] = useAtom(currentProjectAtom);
  const [loading, setLoading] = useAtom(projectLoadingAtom);
  const [error, setError] = useAtom(projectErrorAtom);
  const [tasks, setTasks] = useAtom(tasksAtom);
  const [tasksLoading, setTasksLoading] = useState(false);
  const [isCreateTaskDialogOpen, setIsCreateTaskDialogOpen] = useState(false);
  const [isCreatingTask, setIsCreatingTask] = useState(false);

  // Load project details and tasks
  useEffect(() => {
    if (!id) return;

    const loadProjectData = async () => {
      try {
        setLoading(true);
        setError(null);
        
        // Load project details
        const projectData = await getProject(id);
        setCurrentProject(projectData);
        
        // Load project tasks
        setTasksLoading(true);
        const tasksData = await getProjectTasks(id);
        setTasks(tasksData);
      } catch (err: any) {
        setError(err.message || '加载项目详情失败');
      } finally {
        setLoading(false);
        setTasksLoading(false);
      }
    };

    loadProjectData();
  }, [id]);

  const handleEditProject = () => {
    navigate(`/projects/${id}/edit`);
  };

  const handleCreateTask = () => {
    setIsCreateTaskDialogOpen(true);
  };

  const handleTaskFormSubmit = async (data: TaskFormData) => {
    try {
      setIsCreatingTask(true);
      
      // Create task via API
      const newTask = await createTask({
        project_id: data.project_id,
        name: data.name,
        data: data.data,
        assigned_to: data.assigned_to || null,
      });
      
      // Add new task to tasks list
      setTasks((prevTasks) => [...prevTasks, newTask]);
      
      // Update project task count
      if (currentProject) {
        setCurrentProject({
          ...currentProject,
          task_count: currentProject.task_count + 1,
        });
      }
      
      // Close dialog
      setIsCreateTaskDialogOpen(false);
    } catch (err: any) {
      throw new Error(err.message || '创建任务失败');
    } finally {
      setIsCreatingTask(false);
    }
  };

  const handleTaskFormCancel = () => {
    setIsCreateTaskDialogOpen(false);
  };

  // Define task table columns
  const taskColumns: ExtendedDataTableColumnDef<Task>[] = [
    {
      accessorKey: 'name',
      header: '任务名称',
      enableSorting: true,
      cell: ({ row }) => (
        <span className="text-body-medium text-primary-foreground font-semibold">
          {row.original.name}
        </span>
      ),
      size: 300,
      minSize: 200,
    },
    {
      accessorKey: 'status',
      header: '状态',
      enableSorting: true,
      cell: ({ row }) => {
        const statusMap = {
          pending: { label: '待处理', variant: 'secondary' as const },
          in_progress: { label: '进行中', variant: 'info' as const },
          completed: { label: '已完成', variant: 'success' as const },
        };
        const status = statusMap[row.original.status];
        return <Badge variant={status.variant}>{status.label}</Badge>;
      },
      size: 120,
      minSize: 100,
      maxSize: 150,
    },
    {
      accessorKey: 'progress',
      header: '进度',
      enableSorting: true,
      cell: ({ row }) => (
        <span className="text-body-medium text-primary-foreground">
          {row.original.progress}%
        </span>
      ),
      size: 100,
      minSize: 80,
      maxSize: 120,
    },
    {
      accessorKey: 'assigned_to',
      header: '分配给',
      enableSorting: true,
      cell: ({ row }) => (
        <span className="text-body-medium text-secondary-foreground">
          {row.original.assigned_to || '未分配'}
        </span>
      ),
      size: 150,
      minSize: 120,
      maxSize: 180,
    },
    {
      accessorKey: 'created_at',
      header: '创建时间',
      enableSorting: true,
      cell: ({ row }) => {
        const date = new Date(row.original.created_at);
        return (
          <span className="text-body-medium text-secondary-foreground">
            {date.toLocaleDateString('zh-CN', {
              year: 'numeric',
              month: '2-digit',
              day: '2-digit',
            })}
          </span>
        );
      },
      size: 150,
      minSize: 120,
      maxSize: 180,
    },
  ];

  if (loading) {
    return (
      <div className="flex items-center justify-center h-full">
        <div className="text-center">
          <p className="text-body-medium text-secondary-foreground">加载中...</p>
        </div>
      </div>
    );
  }

  if (error) {
    return (
      <div className="flex flex-col gap-comfortable h-full">
        <div className="flex items-center gap-comfortable pb-comfortable border-b border-neutral-border">
          <Button
            variant="neutral"
            look="string"
            size="small"
            onClick={() => navigate('/projects')}
            leading={<IconArrowLeft className="size-4" />}
          >
            返回
          </Button>
        </div>
        <div className="flex-1 flex items-center justify-center">
          <div className="bg-error-background text-error-foreground p-comfortable rounded-lg border border-error-border max-w-md">
            <div className="flex flex-col gap-tight">
              <span className="text-body-medium font-semibold">加载失败</span>
              <span className="text-body-medium">{error}</span>
            </div>
          </div>
        </div>
      </div>
    );
  }

  if (!currentProject) {
    return (
      <div className="flex items-center justify-center h-full">
        <div className="text-center">
          <p className="text-body-medium text-secondary-foreground">项目不存在</p>
        </div>
      </div>
    );
  }

  return (
    <div className="flex flex-col gap-comfortable h-full">
      {/* Header */}
      <div className="flex items-center justify-between pb-comfortable border-b border-neutral-border">
        <div className="flex items-center gap-comfortable">
          <Button
            variant="neutral"
            look="string"
            size="small"
            onClick={() => navigate('/projects')}
            leading={<IconArrowLeft className="size-4" />}
          >
            返回
          </Button>
          <div>
            <h1 className="text-heading-large font-bold text-primary-foreground">
              {currentProject.name}
            </h1>
            <p className="text-body-medium text-secondary-foreground mt-tighter">
              {currentProject.description}
            </p>
          </div>
        </div>
        <Button
          variant="neutral"
          size="medium"
          onClick={handleEditProject}
          leading={<IconEdit className="size-4" />}
        >
          编辑项目
        </Button>
      </div>

      {/* Project Info */}
      <div className="bg-primary-background border border-neutral-border rounded-lg p-comfortable">
        <h2 className="text-heading-small font-semibold text-primary-foreground mb-comfortable">
          项目信息
        </h2>
        <div className="grid grid-cols-2 gap-comfortable">
          <div>
            <span className="text-body-small text-secondary-foreground">创建时间</span>
            <p className="text-body-medium text-primary-foreground mt-tighter">
              {new Date(currentProject.created_at).toLocaleString('zh-CN', {
                year: 'numeric',
                month: '2-digit',
                day: '2-digit',
                hour: '2-digit',
                minute: '2-digit',
              })}
            </p>
          </div>
          <div>
            <span className="text-body-small text-secondary-foreground">任务数量</span>
            <p className="text-body-medium text-primary-foreground mt-tighter">
              {currentProject.task_count} 个任务
            </p>
          </div>
          <div className="col-span-2">
            <span className="text-body-small text-secondary-foreground">标注配置</span>
            <pre className="text-body-small font-mono text-primary-foreground mt-tighter bg-secondary-background p-tight rounded border border-neutral-border overflow-x-auto">
              {currentProject.config}
            </pre>
          </div>
        </div>
      </div>

      {/* Tasks Section */}
      <div className="flex-1 flex flex-col gap-comfortable overflow-hidden">
        <div className="flex items-center justify-between">
          <h2 className="text-heading-small font-semibold text-primary-foreground">
            关联任务
          </h2>
          <Button
            variant="primary"
            size="medium"
            onClick={handleCreateTask}
            leading={<IconPlus className="size-4" />}
          >
            创建任务
          </Button>
        </div>

        <div className="flex-1 overflow-hidden">
          <DataTable
            data={tasks}
            columns={taskColumns}
            isLoading={tasksLoading}
            loadingRows={5}
            enableSorting={true}
            emptyState={{
              title: '暂无任务',
              description: '点击"创建任务"按钮为此项目创建第一个任务',
              actions: (
                <Button
                  variant="primary"
                  size="medium"
                  onClick={handleCreateTask}
                  leading={<IconPlus className="size-4" />}
                >
                  创建任务
                </Button>
              ),
            }}
          />
        </div>
      </div>

      {/* Create Task Dialog */}
      <Dialog open={isCreateTaskDialogOpen} onOpenChange={setIsCreateTaskDialogOpen}>
        <DialogContent className="max-w-2xl">
          <DialogHeader>
            <DialogTitle>创建任务</DialogTitle>
          </DialogHeader>
          <TaskForm
            projectId={id}
            onSubmit={handleTaskFormSubmit}
            onCancel={handleTaskFormCancel}
            submitLabel="创建任务"
            isSubmitting={isCreatingTask}
          />
        </DialogContent>
      </Dialog>
    </div>
  );
};