from app.extensions import db, beijing_time
from app.models.system import SysUser
from datetime import datetime
import json


class BorrowApproval(db.Model):
    """
    借库审批单模型
    用于管理借库申请的多级审批流程
    """
    __tablename__ = 'borrow_approval'

    id = db.Column(db.Integer, primary_key=True)
    # 审批单号
    request_no = db.Column(db.String(100), unique=True, nullable=False, index=True)
    # 申请人ID
    applicant_id = db.Column(db.Integer, nullable=False, index=True)
    # 申请说明
    remark = db.Column(db.Text)
    # 状态: 0-待审批, 1-已通过, 2-已驳回, 3-已完成(已借出)
    status = db.Column(db.Integer, default=0, nullable=False)
    # 允许审批的人员列表 (JSON格式)
    allowed_approvers = db.Column(db.Text)
    # 实际审批人ID
    actual_approver_id = db.Column(db.Integer, index=True)
    # 审批时间
    approved_at = db.Column(db.DateTime)
    # 驳回原因
    reject_reason = db.Column(db.Text)
    # 借库人姓名（申请时填写，审批通过后流转至 TransBorrow）
    borrower_name = db.Column(db.String(100))

    # 明细快照 (存储借库物品的名称、规格、库位、数量等信息)
    items_json = db.Column(db.Text, nullable=False)

    # 创建时间和更新时间
    created_at = db.Column(db.DateTime, default=beijing_time, nullable=False)
    updated_at = db.Column(db.DateTime, default=beijing_time, onupdate=beijing_time, nullable=False)

    def _safe_parse_json(self, value):
        if value is None:
            return []
        if isinstance(value, (list, dict)):
            return value
        if isinstance(value, str):
            val = value.strip()
            if not val:
                return []
            try:
                parsed = json.loads(val)
                return parsed if isinstance(parsed, list) else []
            except (json.JSONDecodeError, TypeError, ValueError):
                return []
        return []

    def get_items(self):
        return self._safe_parse_json(self.items_json)

    def set_items(self, items):
        self.items_json = json.dumps(items, ensure_ascii=False) if items else '[]'

    def get_allowed_approvers(self):
        return self._safe_parse_json(self.allowed_approvers)

    def set_allowed_approvers(self, approvers):
        self.allowed_approvers = json.dumps(approvers, ensure_ascii=False) if approvers else '[]'

    def to_dict(self):
        return {
            'id': self.id,
            'request_no': self.request_no,
            'applicant_id': self.applicant_id,
            'applicant_name': self._get_user_name(self.applicant_id),
            'remark': self.remark,
            'status': self.status,
            'status_text': ['待审批', '已通过', '已驳回', '已完成'][self.status] if self.status in [0, 1, 2, 3] else '未知',
            'allowed_approvers': self.get_allowed_approvers(),
            'actual_approver_id': self.actual_approver_id,
            'approver_name': self._get_user_name(self.actual_approver_id) if self.actual_approver_id else None,
            'approved_at': self.approved_at.strftime('%Y-%m-%d %H:%M:%S') if self.approved_at else None,
            'reject_reason': self.reject_reason,
            'borrower_name': self.borrower_name,
            'items': self.get_items(),
            'created_at': self.created_at.strftime('%Y-%m-%d %H:%M:%S') if self.created_at else None,
            'updated_at': self.updated_at.strftime('%Y-%m-%d %H:%M:%S') if self.updated_at else None,
        }

    def _get_user_name(self, user_id):
        if not user_id:
            return ""
        try:
            user = SysUser.query.get(user_id)
            return user.username if user else f"未知用户({user_id})"
        except Exception:
            return f"用户({user_id})"