import { useState } from 'react';
import { Crown, Database, Code, Eye, Shield, ChevronRight, Check, Save } from 'lucide-react';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { roles, permissionTreeData } from '@/lib/mock';
import type { Role } from '@/types';

const iconMap: Record<string, React.ElementType> = { Crown, Database, Code, Eye };

export default function RolesPage() {
  const [selectedRole, setSelectedRole] = useState<Role | null>(roles[0]);
  const [checkedKeys, setCheckedKeys] = useState<Set<string>>(new Set(roles[0]?.permissions || []));

  const handleRoleSelect = (role: Role) => {
    setSelectedRole(role);
    setCheckedKeys(new Set(role.permissions));
  };

  const togglePermission = (id: string) => {
    const next = new Set(checkedKeys);
    if (next.has(id)) next.delete(id);
    else next.add(id);
    setCheckedKeys(next);
  };

  const toggleChildren = (node: typeof permissionTreeData[0], checked: boolean) => {
    const next = new Set(checkedKeys);
    const toggleNode = (n: typeof node) => {
      if (checked) next.add(n.id);
      else next.delete(n.id);
      n.children?.forEach(toggleNode);
    };
    toggleNode(node);
    setCheckedKeys(next);
  };

  return (
    <div className="space-y-5">
      <div className="flex items-center justify-between">
        <div>
          <h1 className="text-2xl font-semibold">角色权限管理</h1>
          <p className="text-sm text-[var(--dg-text-secondary)] mt-1">配置 RBAC 角色权限，控制用户对系统功能和数据的访问</p>
        </div>
        <button className="flex items-center gap-2 px-4 py-2.5 bg-gradient-to-r from-blue-500 to-purple-600 rounded-lg text-sm font-medium text-white hover:opacity-90 transition-opacity">
          <Shield className="w-4 h-4" /> 新建角色
        </button>
      </div>

      {/* 角色卡片 */}
      <div className="grid grid-cols-4 gap-4">
        {roles.map(role => {
          const Icon = iconMap[role.icon] || Eye;
          return (
            <div
              key={role.id}
              onClick={() => handleRoleSelect(role)}
              className={`dg-card p-5 cursor-pointer transition-all ${selectedRole?.id === role.id ? 'border-blue-500/50 bg-blue-500/5' : 'dg-card-hover'}`}
            >
              <div className="flex items-center gap-3 mb-3">
                <div className={`w-10 h-10 rounded-xl flex items-center justify-center ${role.iconClass}`}>
                  <Icon className="w-5 h-5" />
                </div>
                <div className="flex-1 min-w-0">
                  <div className="text-base font-semibold truncate">{role.name}</div>
                  <div className="text-xs text-[var(--dg-text-muted)] truncate">{role.description}</div>
                </div>
              </div>
              <div className="flex gap-4 pt-3 border-t border-[var(--dg-border)]">
                <div className="text-xs text-[var(--dg-text-secondary)]"><span className="text-[var(--dg-text-primary)] font-semibold">{role.userCount}</span> 用户</div>
                <div className="text-xs text-[var(--dg-text-secondary)]"><span className="text-[var(--dg-text-primary)] font-semibold">{role.permissionCount}</span> 权限</div>
              </div>
            </div>
          );
        })}
      </div>

      {/* 权限配置 */}
      {selectedRole && (
        <Card className="dg-card">
          <CardHeader className="border-b border-[var(--dg-border)] flex flex-row items-center justify-between">
            <CardTitle className="text-[15px] font-semibold">{selectedRole.name} - 权限配置</CardTitle>
            <button className="flex items-center gap-2 px-4 py-2 bg-blue-500/15 border border-blue-500/30 rounded-lg text-sm font-medium text-blue-400 hover:bg-blue-500/25 transition-all">
              <Save className="w-4 h-4" /> 保存权限
            </button>
          </CardHeader>
          <CardContent className="p-5">
            <div className="space-y-2">
              {permissionTreeData.map(node => (
                <PermissionNodeComponent
                  key={node.id}
                  node={node}
                  checkedKeys={checkedKeys}
                  onToggle={togglePermission}
                  onToggleChildren={toggleChildren}
                  depth={0}
                />
              ))}
            </div>
          </CardContent>
        </Card>
      )}
    </div>
  );
}

function PermissionNodeComponent({
  node, checkedKeys, onToggle, onToggleChildren, depth
}: {
  node: typeof permissionTreeData[0];
  checkedKeys: Set<string>;
  onToggle: (id: string) => void;
  onToggleChildren: (node: typeof permissionTreeData[0], checked: boolean) => void;
  depth: number;
}) {
  const [expanded, setExpanded] = useState(true);
  const isChecked = checkedKeys.has(node.id);
  const hasChildren = node.children && node.children.length > 0;
  const allChildrenChecked = hasChildren && node.children!.every(c => checkedKeys.has(c.id));
  const someChildrenChecked = hasChildren && node.children!.some(c => checkedKeys.has(c.id));

  return (
    <div>
      <div
        className="flex items-center gap-2 py-2 px-3 rounded-lg hover:bg-[var(--dg-bg-hover)] transition-colors cursor-pointer"
        style={{ paddingLeft: `${depth * 20 + 12}px` }}
        onClick={() => { if (hasChildren) setExpanded(!expanded); }}
      >
        {hasChildren && (
          <ChevronRight className={`w-4 h-4 text-[var(--dg-text-muted)] transition-transform ${expanded ? 'rotate-90' : ''}`} />
        )}
        {!hasChildren && <div className="w-4" />}
        <div
          className={`w-4 h-4 rounded border flex items-center justify-center transition-all ${isChecked || allChildrenChecked ? 'bg-blue-500 border-blue-500' : someChildrenChecked ? 'bg-blue-500/50 border-blue-500' : 'border-[var(--dg-text-muted)]'}`}
          onClick={e => {
            e.stopPropagation();
            if (hasChildren) onToggleChildren(node, !allChildrenChecked);
            else onToggle(node.id);
          }}
        >
          {(isChecked || allChildrenChecked || someChildrenChecked) && <Check className="w-3 h-3 text-white" />}
        </div>
        <span className="text-sm">{node.label}</span>
      </div>
      {hasChildren && expanded && (
        <div>
          {node.children!.map(child => (
            <PermissionNodeComponent
              key={child.id}
              node={child}
              checkedKeys={checkedKeys}
              onToggle={onToggle}
              onToggleChildren={onToggleChildren}
              depth={depth + 1}
            />
          ))}
        </div>
      )}
    </div>
  );
}