package model

import (
	"fmt"
	"time"

	"github.com/shopspring/decimal"
)

// Material represents a material in the warehouse
type Material struct {
	ID                int64     `json:"id"`
	OrganizationID    int64     `json:"organization_id"`
	MaterialCode      string    `json:"material_code"`
	Name              string    `json:"name"`
	MaterialImage     *string   `json:"material_image,omitempty"`
	Spec              string    `json:"spec,omitempty"`
	ManufacturerModel *string   `json:"manufacturer_model,omitempty"`
	CategoryID        *int64    `json:"category_id,omitempty"`
	BaseUnitID        *int64    `json:"base_unit_id,omitempty"`
	Unit              string    `json:"unit,omitempty"`
	Status            string    `json:"status"`
	Version           int       `json:"version"`
	CreatedAt         time.Time `json:"created_at"`
	UpdatedAt         time.Time `json:"updated_at"`
}

// Tag represents a tag associated with a material
type Tag struct {
	ID         int64     `json:"id"`
	MaterialID int64     `json:"material_id"`
	TagCode    string    `json:"tag_code"`
	CreatedAt  time.Time `json:"created_at"`
}

// ApplyOrder represents a material application/requisition order
type ApplyOrder struct {
	ID              int64     `json:"id"`
	Applicant       string    `json:"applicant"`
	ApplyDate       time.Time `json:"apply_date"`
	Status          string    `json:"status"`
	ApprovalComment string    `json:"approval_comment,omitempty"`
	CreatedAt       time.Time `json:"created_at"`
	UpdatedAt       time.Time `json:"updated_at"`
}

// ApplyItem represents an item in an application order
type ApplyItem struct {
	ID           int64  `json:"id"`
	ApplyOrderID int64  `json:"apply_order_id"`
	MaterialID   int64  `json:"material_id"`
	Quantity     int    `json:"quantity"`
	Purpose      string `json:"purpose,omitempty"`
}

// InboundOrder represents an inbound order
type InboundOrder struct {
	ID          int64         `json:"id"`
	InboundNo   string        `json:"inbound_no"`
	Operator    string        `json:"operator"`
	InboundDate time.Time     `json:"inbound_date"`
	Handler     string        `json:"handler"`
	Supplier    string        `json:"supplier"`
	Remark      string        `json:"remark"`
	CreatedAt   time.Time     `json:"created_at"`
	UpdatedAt   time.Time     `json:"updated_at,omitempty"`
	Status      string        `json:"status,omitempty"`
	Items       []InboundItem `json:"items,omitempty"`
}

// InboundItem represents an item in an inbound order
type InboundItem struct {
	ID             int64  `json:"id"`
	InboundOrderID int64  `json:"inbound_order_id"`
	MaterialID     int64  `json:"material_id"`
	Quantity       int    `json:"quantity"`
	MaterialCode   string `json:"material_code,omitempty"`
	MaterialName   string `json:"material_name,omitempty"`
	MaterialStatus string `json:"material_status,omitempty"`
}

// OutboundOrder represents an outbound order
type OutboundOrder struct {
	ID           int64          `json:"id"`
	OutboundNo   string         `json:"outbound_no"`
	Operator     string         `json:"operator"`
	OutboundDate time.Time      `json:"outbound_date"`
	Handler      string         `json:"handler"`
	Receiver     string         `json:"receiver"`
	Remark       string         `json:"remark"`
	CreatedAt    time.Time      `json:"created_at"`
	UpdatedAt    time.Time      `json:"updated_at,omitempty"`
	Status       string         `json:"status,omitempty"`
	Items        []OutboundItem `json:"items,omitempty"`
}

// OutboundItem represents an item in an outbound order
type OutboundItem struct {
	ID              int64  `json:"id"`
	OutboundOrderID int64  `json:"outbound_order_id"`
	MaterialID      int64  `json:"material_id"`
	Quantity        int    `json:"quantity"`
	MaterialCode    string `json:"material_code,omitempty"`
	MaterialName    string `json:"material_name,omitempty"`
	MaterialStatus  string `json:"material_status,omitempty"`
}

// OrderNo returns the stable display number used by inbound and outbound
// documents. It derives from the database ID, so it remains unique and does
// not change when the document is edited.
func OrderNo(prefix string, id int64) string {
	return fmt.Sprintf("%s-%08d", prefix, id)
}

// StockLog represents a stock change log
type StockLog struct {
	ID               int64           `json:"id"`
	MaterialID       int64           `json:"material_id"`
	Type             string          `json:"type"`
	Quantity         int             `json:"quantity"`
	RelatedOrderType string          `json:"related_order_type"`
	RelatedOrderID   int64           `json:"related_order_id"`
	CreatedAt        time.Time       `json:"created_at"`
	RunningBalance   decimal.Decimal `json:"running_balance,omitempty"`
}

// Stock represents stock information with material details
type Stock struct {
	MaterialID     int64           `json:"material_id"`
	MaterialCode   string          `json:"material_code"`
	Name           string          `json:"name"`
	Spec           string          `json:"spec,omitempty"`
	Unit           string          `json:"unit,omitempty"`
	MajorCategory  string          `json:"major_category"`
	MinorCategory  string          `json:"minor_category"`
	TotalOnHand    decimal.Decimal `json:"total_on_hand"`
	WarningStock   decimal.Decimal `json:"warning_stock"`
	WarningEnabled bool            `json:"warning_enabled"`
	// WarningConfigured 表示该物料到底配没配过预警规则。"从没配过"和"配过但被手动
	// 关闭"都会被 WarningEnabled 报成 false，仅靠它无法区分；前端预填时需要知道是哪
	// 一种，才能决定默认勾选还是默认不勾选。它只服务于这个用途，不参与任何判定。
	WarningConfigured bool   `json:"warning_configured"`
	StockStatus       string `json:"stock_status"`
}

// Stock.StockStatus 的取值。只要预警处于启用状态、并且现存量已经触达阈值就是 low，
// 其余一律为 normal。阈值为 0 是合法配置，含义是"库存降到 0 时预警"，不会被排除。
const (
	StockStatusLow    = "low"
	StockStatusNormal = "normal"
)

// InventoryBalanceDetail represents detailed inventory balance
type InventoryBalanceDetail struct {
	ID             int64           `json:"id"`
	OrganizationID int64           `json:"organization_id"`
	Organization   string          `json:"organization"`
	WarehouseID    int64           `json:"warehouse_id"`
	Warehouse      string          `json:"warehouse"`
	LocationID     int64           `json:"location_id"`
	Location       string          `json:"location"`
	MaterialID     int64           `json:"material_id"`
	OnHand         decimal.Decimal `json:"on_hand"`
	Reserved       decimal.Decimal `json:"reserved"`
	Locked         decimal.Decimal `json:"locked"`
	InTransit      decimal.Decimal `json:"in_transit"`
	UpdatedAt      string          `json:"updated_at"`
}

// StockLogResponse represents a stock log with computed balance
type StockLogResponse struct {
	ID             int64           `json:"id"`
	MaterialID     int64           `json:"material_id"`
	ChangeType     string          `json:"change_type"`
	ChangeQuantity decimal.Decimal `json:"change_quantity"`
	BeforeQuantity decimal.Decimal `json:"before_quantity"`
	AfterQuantity  decimal.Decimal `json:"after_quantity"`
	ReferenceID    int64           `json:"reference_id"`
	ReferenceType  string          `json:"reference_type"`
	CreatedAt      time.Time       `json:"created_at"`
}

// InboundRecord represents inbound records for a specific material
type InboundRecord struct {
	ID        int64     `json:"id"`
	InboundID int64     `json:"inbound_id"`
	Handler   string    `json:"handler"`
	Supplier  string    `json:"supplier"`
	Quantity  int       `json:"quantity"`
	CreatedAt time.Time `json:"created_at"`
}

// OutboundRecord represents outbound records for a specific material
type OutboundRecord struct {
	ID         int64     `json:"id"`
	OutboundID int64     `json:"outbound_id"`
	Handler    string    `json:"handler"`
	Receiver   string    `json:"receiver"`
	Quantity   int       `json:"quantity"`
	CreatedAt  time.Time `json:"created_at"`
}

// ============= Request DTOs =============

// CreateMaterialRequest represents the request to create a material
type CreateMaterialRequest struct {
	OrganizationID    int64   `json:"organization_id"`
	MaterialCode      string  `json:"material_code" binding:"required"`
	Name              string  `json:"name" binding:"required"`
	MaterialImage     *string `json:"material_image"`
	Spec              string  `json:"spec"`
	ManufacturerModel *string `json:"manufacturer_model"`
	CategoryID        *int64  `json:"category_id" binding:"required,gt=0"`
	BaseUnitID        *int64  `json:"base_unit_id"`
	Unit              string  `json:"unit"`
}

// UpdateMaterialRequest represents the request to update a material
type UpdateMaterialRequest struct {
	MaterialCode      string  `json:"material_code"`
	Name              string  `json:"name"`
	MaterialImage     *string `json:"material_image"`
	Spec              string  `json:"spec"`
	ManufacturerModel *string `json:"manufacturer_model"`
	CategoryID        *int64  `json:"category_id" binding:"required,gt=0"`
	BaseUnitID        *int64  `json:"base_unit_id"`
	Unit              string  `json:"unit"`
	Status            string  `json:"status"`
}

// CreateInboundRequest represents the request to create an inbound order
type CreateInboundRequest struct {
	Handler  string `json:"handler" binding:"required"`
	Supplier string `json:"supplier" binding:"required"`
	Remark   string `json:"remark"`
	Items    []struct {
		MaterialID int64 `json:"material_id" binding:"required"`
		Quantity   int   `json:"quantity" binding:"required,gt=0"`
		// WarningStock 可选，为 nil 表示本次不改动已存的预警阈值。
		WarningStock *decimal.Decimal `json:"warning_stock"`
		// WarningEnabled 可选，为 nil 表示本次不改动预警的启用状态。仅在 WarningStock
		// 非 nil 时生效，用来表达"启用还是关闭预警"。
		WarningEnabled *bool `json:"warning_enabled"`
	} `json:"items" binding:"required,min=1"`
}

// CreateOutboundRequest represents the request to create an outbound order
type CreateOutboundRequest struct {
	// Handler is retained for API compatibility but is ignored. The server
	// always records the authenticated user's username as the operator.
	Handler  string `json:"handler"`
	Receiver string `json:"receiver" binding:"required"`
	Remark   string `json:"remark"`
	Items    []struct {
		MaterialID int64 `json:"material_id" binding:"required"`
		Quantity   int   `json:"quantity" binding:"required,gt=0"`
	} `json:"items" binding:"required,min=1"`
}

// UpdateInboundRequest represents the request to update an inbound order
type UpdateInboundRequest struct {
	Handler  string `json:"handler"`
	Supplier string `json:"supplier"`
	Remark   string `json:"remark"`
	Items    []struct {
		MaterialID int64 `json:"material_id" binding:"required"`
		Quantity   int   `json:"quantity" binding:"required,gt=0"`
		// WarningStock 可选，为 nil 表示本次不改动已存的预警阈值。
		WarningStock *decimal.Decimal `json:"warning_stock"`
		// WarningEnabled 可选，为 nil 表示本次不改动预警的启用状态。仅在 WarningStock
		// 非 nil 时生效，用来表达"启用还是关闭预警"。
		WarningEnabled *bool `json:"warning_enabled"`
	} `json:"items" binding:"required,min=1"`
}

// UpdateOutboundRequest represents the request to update an outbound order
type UpdateOutboundRequest struct {
	Handler  string `json:"handler"`
	Operator string `json:"-"`
	Receiver string `json:"receiver"`
	Remark   string `json:"remark"`
	Items    []struct {
		MaterialID int64 `json:"material_id" binding:"required"`
		Quantity   int   `json:"quantity" binding:"required,gt=0"`
	} `json:"items" binding:"required,min=1"`
}

// MaterialLog represents a material change log
type MaterialLog struct {
	ID            int64     `json:"id"`
	OperationType string    `json:"operation_type"`
	MaterialID    int64     `json:"material_id"`
	OldValue      string    `json:"old_value,omitempty"`
	NewValue      string    `json:"new_value,omitempty"`
	Operator      string    `json:"operator,omitempty"`
	Description   string    `json:"description,omitempty"`
	CreatedAt     time.Time `json:"created_at"`
}

// User represents a system user
type User struct {
	ID          int64     `json:"id"`
	Username    string    `json:"username"`
	Password    string    `json:"-"`
	Role        string    `json:"role"`
	Roles       []Role    `json:"roles"`
	Description string    `json:"description"`
	CreatedAt   time.Time `json:"created_at"`
}

// LoginRequest represents login request
type LoginRequest struct {
	Username string `json:"username" binding:"required"`
	Password string `json:"password" binding:"required"`
}

// LoginResponse represents login response
type LoginResponse struct {
	Token string `json:"token"`
	User  User   `json:"user"`
}

// ApplicationStatus constants
const (
	ApplicationStatusPending   = "pending"
	ApplicationStatusApproved  = "approved"
	ApplicationStatusRejected  = "rejected"
	ApplicationStatusCancelled = "cancelled"
)

// MaterialApplication represents a material application record
type MaterialApplication struct {
	ID              int64             `json:"id"`
	UserID          int64             `json:"user_id"`
	Username        string            `json:"username"`
	Purpose         string            `json:"purpose,omitempty"`
	Status          string            `json:"status"`
	RejectionReason string            `json:"rejection_reason,omitempty"`
	ApprovedBy      int64             `json:"approved_by,omitempty"`
	ApproverName    string            `json:"approver_name,omitempty"`
	CreatedAt       time.Time         `json:"created_at"`
	UpdatedAt       time.Time         `json:"updated_at"`
	Items           []ApplicationItem `json:"items,omitempty"`
}

// CreateApplicationRequest represents request to create application
type CreateApplicationRequest struct {
	Purpose string `json:"purpose"`
	Items   []struct {
		MaterialID int64 `json:"material_id" binding:"required"`
		Quantity   int   `json:"quantity" binding:"required,gt=0"`
	} `json:"items" binding:"required,min=1"`
}

// ApplicationItem represents an item in a material application
type ApplicationItem struct {
	ID            int64  `json:"id"`
	ApplicationID int64  `json:"application_id"`
	MaterialID    int64  `json:"material_id"`
	MaterialCode  string `json:"material_code"`
	MaterialName  string `json:"material_name"`
	Quantity      int    `json:"quantity"`
}

// ApproveApplicationRequest represents request to approve application
type ApproveApplicationRequest struct {
	AutoOutbound bool `json:"auto_outbound"`
}

// RejectApplicationRequest represents request to reject application
type RejectApplicationRequest struct {
	Reason string `json:"reason" binding:"required"`
}