x-server-mobile/backend/app/Model/BusinessTrip.php

<?php

namespace App\Model;

use Illuminate\Database\Eloquent\Model;

class BusinessTrip extends Model
{
    protected $table = 'business_trip';

    protected $fillable = [
        'user_id',
        'reason',
        'start_date',
        'end_date',
        'destination',
        'estimated_cost',
        'status',
        'approval_order_id',
    ];

    protected $casts = [
        'user_id' => 'integer',
        'estimated_cost' => 'decimal:2',
        'created_at' => 'datetime',
        'updated_at' => 'datetime',
    ];

    /**
     * 状态常量
     */
    const STATUS_DRAFT = 'draft';         // 草稿
    const STATUS_PENDING = 'pending';     // 审批中
    const STATUS_APPROVED = 'approved';   // 已通过
    const STATUS_REJECTED = 'rejected';   // 已拒绝
    const STATUS_CANCELLED = 'cancelled'; // 已撤销

    /**
     * 关联用户
     */
    public function user()
    {
        return $this->belongsTo(User::class, 'user_id');
    }

    /**
     * 关联行程明细
     */
    public function itineraries()
    {
        return $this->hasMany(BusinessTripItinerary::class, 'business_trip_id');
    }

    /**
     * 关联审批单
     */
    public function approvalOrder()
    {
        return $this->belongsTo(ApprovalOrder::class, 'approval_order_id');
    }

    /**
     * 计算总天数
     */
    public function getDurationDays(): int
    {
        if (!$this->start_date || !$this->end_date) {
            return 0;
        }
        $start = \DateTime::createFromFormat('Y-m-d', $this->start_date);
        $end = \DateTime::createFromFormat('Y-m-d', $this->end_date);
        if (!$start || !$end) {
            return 0;
        }
        return $end->diff($start)->days + 1;
    }

    /**
     * 判断是否可以编辑
     */
    public function canEdit(): bool
    {
        return $this->status === self::STATUS_DRAFT;
    }

    /**
     * 判断是否可以提交
     */
    public function canSubmit(): bool
    {
        return $this->status === self::STATUS_DRAFT;
    }

    /**
     * 判断是否可以取消
     */
    public function canCancel(): bool
    {
        return $this->status === self::STATUS_PENDING;
    }
}