定义对应model

internal/infra/models/pig.go

@@ -1,5 +1,74 @@
 package models
 
+import (
+	"time"
+
+	"gorm.io/gorm"
+)
+
 /*
-	和猪只本身相关的模型
+	和猪只、猪群本身相关的模型
 */
+
+// PigBatchStatus 定义了猪批次所处的不同阶段或状态
+type PigBatchStatus string
+
+const (
+	BatchStatusWeaning   PigBatchStatus = "保育" // 从断奶到保育结束
+	BatchStatusGrowing   PigBatchStatus = "生长" // 生长育肥阶段
+	BatchStatusFinishing PigBatchStatus = "育肥" // 最后的育肥阶段
+	BatchStatusForSale   PigBatchStatus = "待售" // 达到出栏标准
+	BatchStatusSold      PigBatchStatus = "已出售"
+	BatchStatusArchived  PigBatchStatus = "已归档" // 批次结束（如全群淘汰等）
+)
+
+// PigBatchOriginType 定义了猪批次的来源
+type PigBatchOriginType string
+
+const (
+	OriginTypeSelfFarrowed PigBatchOriginType = "自繁"
+	OriginTypePurchased    PigBatchOriginType = "外购"
+)
+
+// PigBatch 是猪批次的核心模型，代表了一群被共同管理的猪
+type PigBatch struct {
+	gorm.Model
+	BatchNumber      string             `gorm:"size:50;not null;uniqueIndex;comment:批次编号,如 2024-W25-A01"`
+	OriginType       PigBatchOriginType `gorm:"size:20;not null;comment:批次来源 (自繁, 外购)"`
+	StartDate        time.Time          `gorm:"not null;comment:批次开始日期 (如转入日或购买日)"`
+	InitialCount     int                `gorm:"not null;comment:初始数量"`
+	CurrentCount     int                `gorm:"not null;comment:当前存栏数量"`
+	CurrentSickCount int                `gorm:"not null;default:0;comment:当前病猪数量"`
+	AverageWeight    float64            `gorm:"comment:平均体重 (kg)"`
+	Status           PigBatchStatus     `gorm:"size:20;not null;index;comment:批次状态"`
+	Pens             []Pen              `gorm:"foreignKey:PigBatchID;comment:所在圈舍ID"`
+}
+
+// LogChangeType 定义了猪批次数量变更的类型
+type LogChangeType string
+
+const (
+	ChangeTypeDeath       LogChangeType = "死亡"
+	ChangeTypeCull        LogChangeType = "淘汰"
+	ChangeTypeSale        LogChangeType = "销售"
+	ChangeTypeTransferIn  LogChangeType = "转入"
+	ChangeTypeTransferOut LogChangeType = "转出"
+	ChangeTypeTreatment   LogChangeType = "治疗" // 仅改变健康状态，不改变总数
+	ChangeTypeRecovering  LogChangeType = "康复" // 仅改变健康状态，不改变总数
+	ChangeTypeCorrection  LogChangeType = "盘点校正"
+)
+
+// PigBatchLog 记录了猪批次数量或状态的每一次变更
+type PigBatchLog struct {
+	gorm.Model
+	PigBatchID      uint          `gorm:"not null;index;comment:关联的猪批次ID"`
+	ChangeType      LogChangeType `gorm:"size:20;not null;comment:变更类型"`
+	ChangeCount     int           `gorm:"not null;comment:数量变化,负数表示减少"`
+	Reason          string        `gorm:"size:255;comment:变更原因描述"`
+	BeforeCount     int           `gorm:"not null;comment:变更前总数"`
+	AfterCount      int           `gorm:"not null;comment:变更后总数"`
+	BeforeSickCount int           `gorm:"not null;comment:变更前病猪数"`
+	AfterSickCount  int           `gorm:"not null;comment:变更后病猪数"`
+	Operator        string        `gorm:"size:50;comment:操作员"`
+	HappenedAt      time.Time     `gorm:"not null;default:CURRENT_TIMESTAMP;comment:事件发生时间"`
+}