from app.extensions import db, beijing_time
import json


def _beijing_now():
    """
    统一时间口径：naive 北京时间，与 created_at / OutboundApproval / BorrowApproval 一致。

    ★ 原先返回 tz-aware 时间，配合 timestamptz 列才正确；现已将该表列类型统一为
      timestamp without time zone（见 db_migrations/unify_approval_timezone.sql），
      故此处必须返回 naive 值，否则存库会被当 UTC 处理而早 8 小时。
    """
    return beijing_time()


class ScrapApproval(db.Model):
    """
    报废申请/审批单（镜像 BorrowApproval / OutboundApproval）

    与出/借库的关键差异：items_json 里每条明细必须携带
    source_table + stock_id（精准定位到某条实物库存记录），
    因为报废从“申请那一刻”就要求指明具体要报废的东西。
    """
    __tablename__ = 'scrap_approval'

    id = db.Column(db.Integer, primary_key=True)
    request_no = db.Column(db.String(100), unique=True, nullable=False, index=True)

    applicant_id = db.Column(db.Integer, nullable=False, index=True)
    remark = db.Column(db.Text)  # 报废原因

    # 状态: 0-待审批, 1-已通过(待执行), 2-已驳回, 3-已执行(已报废)
    status = db.Column(db.Integer, default=0, nullable=False, index=True)

    allowed_approvers = db.Column(db.Text)       # JSON: [{"type":"user","value":123}, ...]
    actual_approver_id = db.Column(db.Integer, index=True)
    approved_at = db.Column(db.DateTime)
    reject_reason = db.Column(db.Text)

    # 明细快照: [{"source_table","stock_id","sku","name","spec_model","location","batch_number","scrap_qty"}]
    items_json = db.Column(db.Text, nullable=False)

    # 执行信息
    executed_at = db.Column(db.DateTime)
    executor_name = db.Column(db.String(100))

    created_at = db.Column(db.DateTime, default=_beijing_now, nullable=False)
    updated_at = db.Column(db.DateTime, default=_beijing_now, onupdate=_beijing_now, nullable=False)

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

    def get_items(self):
        try:
            return json.loads(self.items_json) if self.items_json else []
        except Exception:
            return []

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

    def get_allowed_approvers(self):
        try:
            return json.loads(self.allowed_approvers) if self.allowed_approvers else []
        except Exception:
            return []

    @staticmethod
    def _user_name(user_id):
        if not user_id:
            return ''
        try:
            from app.models.system import SysUser
            u = SysUser.query.get(user_id)
            return u.username if u else ''
        except Exception:
            return ''

    def to_dict(self):
        return {
            'id': self.id,
            'request_no': self.request_no,
            'applicant_id': self.applicant_id,
            'applicant_name': self._user_name(self.applicant_id),
            'remark': self.remark or '',
            'status': self.status,
            'allowed_approvers': self.get_allowed_approvers(),
            'actual_approver_id': self.actual_approver_id,
            'actual_approver_name': self._user_name(self.actual_approver_id),
            'approved_at': self.approved_at.strftime('%Y-%m-%d %H:%M:%S') if self.approved_at else None,
            'reject_reason': self.reject_reason or '',
            'items': self.get_items(),
            'executed_at': self.executed_at.strftime('%Y-%m-%d %H:%M:%S') if self.executed_at else None,
            'executor_name': self.executor_name or '',
            'created_at': self.created_at.strftime('%Y-%m-%d %H:%M:%S') if self.created_at else None,
        }