### Implementing Authentication in Go

Source: https://context7.com/qor/admin/llms.txt

Provides an example of implementing the Auth interface to integrate custom authentication and authorization into the QOR admin panel. This involves defining methods for getting the current user, and providing login and logout URLs.

```go
// Auth interface
type Auth interface {
    GetCurrentUser(*Context) qor.CurrentUser
    LoginURL(*Context) string
    LogoutURL(*Context) string
}

// Custom auth implementation
type AdminAuth struct{}

func (auth AdminAuth) GetCurrentUser(context *admin.Context) qor.CurrentUser {
    // Get user from session
    session := context.Request.Context().Value("session").(*Session)
    if session == nil || session.UserID == 0 {
        return nil
    }

    var user User
    if err := context.GetDB().First(&user, session.UserID).Error; err != nil {
        return nil
    }
    return &user
}

func (auth AdminAuth) LoginURL(context *admin.Context) string {
    return "/admin/login"
}

func (auth AdminAuth) LogoutURL(context *admin.Context) string {
    return "/admin/logout"
}

// User must implement qor.CurrentUser interface
type User struct {
    gorm.Model
    Email string
    Role  string
}

func (u *User) DisplayName() string {
    return u.Email
}

// Set auth on admin
Admin.SetAuth(AdminAuth{})
```

--------------------------------

### Implement AssignVersionName for Versioned Structs (Go)

Source: https://github.com/qor/admin/blob/master/README.md

Provides an example of implementing the 'AssignVersionName' method on a versioned struct (e.g., 'Factory'). This method is required to assign a unique version name to an object when creating a new version, ensuring proper version management.

```go
func (fac *Factory) AssignVersionName(db *gorm.DB) {
	var count int
	name := time.Now().Format("2006-01-02")
	if err := db.Model(&CollectionWithVersion{}).Where("id = ? AND version_name like ?", fac.ID, name+"%" ).Count(&count).Error; err != nil {
    panic(err)
  }
	fac.VersionName = fmt.Sprintf("%s-v%v", name, count+1)
}
```

--------------------------------

### Initialize QOR Admin Interface

Source: https://github.com/qor/admin/blob/master/README.md

Demonstrates how to set up a basic QOR Admin instance, register GORM models, and mount the interface to an HTTP server.

```go
package main

import (
  "fmt"
  "net/http"
  "github.com/jinzhu/gorm"
  _ "github.com/mattn/go-sqlite3"
  "github.com/qor/admin"
)

type User struct {
  gorm.Model
  Name string
}

type Product struct {
  gorm.Model
  Name        string
  Description string
}

func main() {
  DB, _ := gorm.Open("sqlite3", "demo.db")
  DB.AutoMigrate(&User{}, &Product{})

  Admin := admin.New(&admin.AdminConfig{DB: DB})

  Admin.AddResource(&User{})
  Admin.AddResource(&Product{})

  mux := http.NewServeMux()
  Admin.MountTo("/admin", mux)

  fmt.Println("Listening on: 9000")
  http.ListenAndServe(":9000", mux)
}
```

--------------------------------

### Initialize QOR Admin Instance

Source: https://context7.com/qor/admin/llms.txt

Demonstrates how to initialize the Admin struct with a database connection, register GORM models as resources, and mount the interface to an HTTP server.

```go
package main

import (
    "fmt"
    "net/http"

    "github.com/jinzhu/gorm"
    _ "github.com/mattn/go-sqlite3"
    "github.com/qor/admin"
)

type User struct {
    gorm.Model
    Name  string
    Email string
}

type Product struct {
    gorm.Model
    Name        string
    Description string `gorm:"type:text"`
    Price       float64
}

func main() {
    DB, _ := gorm.Open("sqlite3", "demo.db")
    DB.AutoMigrate(&User{}, &Product{})

    // Create admin with database configuration
    Admin := admin.New(&admin.AdminConfig{
        DB:       DB,
        SiteName: "My Admin Panel",
    })

    // Add resources to admin
    Admin.AddResource(&User{})
    Admin.AddResource(&Product{})

    // Mount admin to HTTP server
    mux := http.NewServeMux()
    Admin.MountTo("/admin", mux)

    fmt.Println("Admin running at http://localhost:9000/admin")
    http.ListenAndServe(":9000", mux)
}
```

--------------------------------

### Register and Configure Admin Resources

Source: https://context7.com/qor/admin/llms.txt

Shows how to register database models with custom configurations such as menu hierarchy, icons, permissions, and singleton status.

```go
// Add resource with custom configuration
userResource := Admin.AddResource(&User{}, &admin.Config{
    Name:      "Members",
    IconName:  "person",
    Menu:      []string{"User Management"},
    Priority:  1,
    PageCount: 25,
})

// Add singleton resource (single record, e.g., site settings)
Admin.AddResource(&SiteSettings{}, &admin.Config{
    Name:      "Site Settings",
    Singleton: true,
})

// Get existing resource by name
res := Admin.GetResource("Members")

// Get all registered resources
resources := Admin.GetResources()
```

--------------------------------

### Querying Data with Searcher and Pagination

Source: https://context7.com/qor/admin/llms.txt

Demonstrates how to configure default pagination settings and use the Searcher API to perform programmatic data queries, apply scopes, and retrieve pagination metadata.

```go
admin.PaginationPageCount = 25

productResource := Admin.AddResource(&Product{}, &admin.Config{
    PageCount: 50,
})

func customHandler(context *admin.Context) {
    searcher := &admin.Searcher{Context: context}
    searcher.Page(1).PerPage(10)
    searcher = searcher.Scope("Published")
    results, err := searcher.FindMany()
    result, err := searcher.FindOne()
    pagination := searcher.Pagination
    fmt.Printf("Total: %d, Pages: %d, Current: %d\n",
        pagination.Total,
        pagination.Pages,
        pagination.CurrentPage,
    )
}
```

--------------------------------

### Configuring Global Search Resources

Source: https://context7.com/qor/admin/llms.txt

Shows how to register models into the global search center and define searchable attributes to enable cross-model search functionality.

```go
Admin.AddSearchResource(
    Admin.GetResource("Product"),
    Admin.GetResource("User"),
    Admin.GetResource("Order"),
)

productResource.SearchAttrs("Name", "Description", "SKU")
userResource.SearchAttrs("Name", "Email")
orderResource.SearchAttrs("ID", "User.Name", "User.Email")
```

--------------------------------

### Applying and Managing Themes for Resources in Go

Source: https://context7.com/qor/admin/llms.txt

Allows customization of the visual appearance and behavior of QOR Admin resources by applying themes. It supports using built-in themes, creating custom themes by implementing the `ThemeInterface`, and retrieving the currently applied theme from a resource. Custom themes require defining their name, view paths, and configuration logic.

```go
package main

import (
    "github.com/qor/admin"
)

// Theme interface
type ThemeInterface interface {
    GetName() string
    GetViewPaths() []string
    ConfigAdminTheme(*Resource)
}

// Use built-in theme
productResource.UseTheme("slideout")

// Create custom theme
type DarkTheme struct {
    admin.Theme
}

func (t DarkTheme) GetName() string {
    return "dark"
}

func (t DarkTheme) GetViewPaths() []string {
    return []string{"themes/dark/views"}
}

func (t DarkTheme) ConfigAdminTheme(res *admin.Resource) {
    // Configure resource for dark theme
}

// Apply custom theme
productResource.UseTheme(&DarkTheme{})

// Get theme from resource
theme := productResource.GetTheme("dark")
```

--------------------------------

### Defining Data Scopes for Filtering

Source: https://context7.com/qor/admin/llms.txt

Demonstrates how to create reusable database filters (scopes) for index pages. Scopes can be grouped, set as defaults, or restricted based on user context.

```go
type Scope struct {
    Name    string
    Label   string
    Group   string
    Visible func(context *Context) bool
    Handler func(*gorm.DB, *qor.Context) *gorm.DB
    Default bool
}

productResource.Scope(&admin.Scope{
    Name:  "Published",
    Label: "Published Products",
    Handler: func(db *gorm.DB, context *qor.Context) *gorm.DB {
        return db.Where("status = ?", "published")
    },
})
```

--------------------------------

### Managing Context for Rendering and Responses

Source: https://context7.com/qor/admin/llms.txt

Explains the use of admin.Context methods to handle template rendering, JSON responses, flash messages, and resource URL generation within custom handlers.

```go
func customHandler(context *admin.Context) {
    context.Execute("custom_template", data)
    html := context.Render("partial_name", data)
    context.JSON("show", map[string]interface{}{
        "status": "success",
        "data":   result,
    })
    context.Flash("Operation successful", "success")
    context.Set("key", "value")
    user := context.CurrentUser
    url := context.URLFor(product, productResource)
}
```

--------------------------------

### Print All Registered Routes (Go)

Source: https://github.com/qor/admin/blob/master/README.md

Demonstrates how to print all registered routes within a QOR admin instance. This utility function is helpful for debugging and understanding the routing configuration of the admin interface.

```go
// adm is a QOR admin instance
adm.GetRouter().PrintRoutes()
```

--------------------------------

### Configure Resource Attributes and Views

Source: https://context7.com/qor/admin/llms.txt

Configures which attributes are displayed on index, new, edit, and show pages, including support for sections, sorting, and search functionality.

```go
// Set attributes for index page (list view)
productResource.IndexAttrs("ID", "Name", "Price", "CreatedAt")

// Exclude specific attributes with minus prefix
productResource.IndexAttrs("-Description", "-UpdatedAt")

// Set attributes for new record form
productResource.NewAttrs("Name", "Description", "Price", "Category")

// Set attributes for edit form with sections
productResource.EditAttrs(
    &admin.Section{
        Title: "Basic Information",
        Rows: [][]string{
            {"Name"},
            {"Code", "Price"},
        },
    },
    &admin.Section{
        Title: "Details",
        Rows: [][]string{
            {"Category", "Brand"},
            {"Description"},
        },
    },
)

// Set attributes for show page
productResource.ShowAttrs("Name", "Description", "Price", "Category", "CreatedAt")

// Set sortable columns for index page
productResource.SortableAttrs("Name", "Price", "CreatedAt")

// Set searchable attributes
productResource.SearchAttrs("Name", "Code", "Category.Name", "Brand.Name")
```

--------------------------------

### Configure Factory Resource with Manager SelectOne (Go)

Source: https://github.com/qor/admin/blob/master/README.md

Configures the 'Manager' meta within the 'Factory' resource to use a 'SelectOne' input type. It utilizes the previously generated 'managerSelector' to provide a dropdown for selecting a related Manager, supporting composite primary keys.

```go
managerSelector := generateRemoteManagerSelector(adm)
factoryRes.Meta(&admin.Meta{
	Name: "Manager",
	Config: &admin.SelectOneConfig{
		RemoteDataResource: managerSelector,
	},
})
```

--------------------------------

### Adding Sidebar Menus in Go

Source: https://context7.com/qor/admin/llms.txt

Demonstrates how to customize the admin sidebar by adding main menus, submenus, and external links. The Menu struct allows for defining name, icon, link, priority, and permissions for each menu item.

```go
// Menu struct definition
type Menu struct {
    Name         string
    IconName     string
    Link         string
    RelativePath string
    Priority     int  // Higher = appears first, negative = appears last
    Ancestors    []string
    Permissioner HasPermissioner
    Permission   *roles.Permission
}

// Add custom menu with external link
Admin.AddMenu(&admin.Menu{
    Name:     "Dashboard",
    IconName: "dashboard",
    Link:     "/admin",
    Priority: 100,
})

// Add menu with submenu hierarchy
Admin.AddMenu(&admin.Menu{
    Name:      "Products",
    Ancestors: []string{"Store"},
    IconName:  "shopping_cart",
    Priority:  10,
})

Admin.AddMenu(&admin.Menu{
    Name:      "Orders",
    Ancestors: []string{"Store"},
    IconName:  "receipt",
    Priority:  9,
})

// Add external link menu
Admin.AddMenu(&admin.Menu{
    Name:     "View Site",
    Link:     "/",
    IconName: "open_in_new",
    Priority: -1,  // Appears at bottom
})

// Get menu and submenus
storeMenu := Admin.GetMenu("Store")
subMenus := storeMenu.GetSubMenus()
```

--------------------------------

### Configure Select One Fields in Go

Source: https://context7.com/qor/admin/llms.txt

Shows how to configure 'select_one' meta fields in QOR Admin for single-choice selections. This includes using static string arrays, key-value pairs, dynamic collections fetched from a database, and remote data resources for asynchronous loading.

```go
// SelectOneConfig for single selection fields
productResource.Meta(&admin.Meta{
    Name: "Category",
    Config: &admin.SelectOneConfig{
        Collection: []string{"Electronics", "Clothing", "Books", "Home"},
        Placeholder: "Select a category",
        AllowBlank:  true,
    },
})

// SelectOneConfig with key-value pairs
productResource.Meta(&admin.Meta{
    Name: "Status",
    Config: &admin.SelectOneConfig{
        Collection: [][]string{
            {"draft", "Draft"},
            {"published", "Published"},
            {"archived", "Archived"},
        },
    },
})

// SelectOneConfig with dynamic collection
productResource.Meta(&admin.Meta{
    Name: "Author",
    Config: &admin.SelectOneConfig{
        Collection: func(record interface{}, context *qor.Context) [][]string {
            var authors []Author
            context.GetDB().Find(&authors)
            var results [][]string
            for _, author := range authors {
                results = append(results, []string{
                    fmt.Sprint(author.ID),
                    author.Name,
                })
            }
            return results
        },
    },
})

// SelectOneConfig with remote data resource (async loading)
productResource.Meta(&admin.Meta{
    Name: "Brand",
    Config: &admin.SelectOneConfig{
        RemoteDataResource: Admin.GetResource("Brand"),
        SelectMode:         "select_async", // or "bottom_sheet"
    },
})
```

--------------------------------

### Configure Remote Selector for Versioned Relationships

Source: https://github.com/qor/admin/blob/master/README.md

Shows how to implement a remote resource selector for models using publish2.Version. This requires defining a CompositePrimaryKeyField and configuring the ID meta to handle composite keys.

```go
type Factory struct {
	gorm.Model
	Name string

	publish2.Version
	Items       []Item `gorm:"many2many:factory_items;association_autoupdate:false"`
	ItemsSorter sorting.SortableCollection
}

type Item struct {
	gorm.Model
	Name string
	publish2.Version

	resource.CompositePrimaryKeyField // Required
}

func generateRemoteItemSelector(adm *admin.Admin) (res *admin.Resource) {
	res = adm.AddResource(&Item{}, &admin.Config{Name: "ItemSelector"})
	res.IndexAttrs("ID", "Name")

	res.Meta(&admin.Meta{
	Name: "ID",
	Valuer: func(value interface{}, ctx *qor.Context) interface{} {
		if r, ok := value.(*Item); ok {
			return resource.GenCompositePrimaryKey(r.ID, r.GetVersionName())
		}
		return ""
	},
	})

	return res
}

itemSelector := generateRemoteItemSelector(adm)
factoryRes.Meta(&admin.Meta{
	Name: "Items",
	Config: &admin.SelectManyConfig{
	RemoteDataResource: itemSelector,
	},
})
```

--------------------------------

### Registering Custom Actions in QOR Admin

Source: https://context7.com/qor/admin/llms.txt

Defines how to create custom actions for records, including batch operations, visibility logic, and external URL redirection. It utilizes the Action struct to define handlers, permissions, and optional input resources.

```go
type Action struct {
    Name        string
    Label       string
    Method      string
    URL         func(record interface{}, context *Context) string
    URLOpenType string
    Visible     func(record interface{}, context *Context) bool
    Handler     func(argument *ActionArgument) error
    Modes       []string
    Resource    *Resource
    Permission  *roles.Permission
}

productResource.Action(&admin.Action{
    Name:  "Publish",
    Label: "Publish Product",
    Handler: func(arg *admin.ActionArgument) error {
        for _, record := range arg.FindSelectedRecords() {
            product := record.(*Product)
            product.Status = "published"
            arg.Context.GetDB().Save(product)
        }
        return nil
    },
    Modes: []string{"batch", "menu_item"},
})
```

--------------------------------

### Configure Select Many Fields in Go

Source: https://context7.com/qor/admin/llms.txt

Illustrates how to configure 'select_many' meta fields in QOR Admin for multiple-choice selections. This covers using static string arrays and fetching data from remote resources with asynchronous loading capabilities.

```go
// SelectManyConfig for multiple selections
productResource.Meta(&admin.Meta{
    Name: "Tags",
    Config: &admin.SelectManyConfig{
        Collection: []string{"Featured", "Sale", "New Arrival", "Best Seller"},
        SelectMode: "select",
    },
})

// SelectManyConfig with remote data
productResource.Meta(&admin.Meta{
    Name: "Categories",
    Config: &admin.SelectManyConfig{
        RemoteDataResource: Admin.GetResource("Category"),
        SelectMode:         "select_async",
    },
})
```

--------------------------------

### Generate Remote Manager Selector for Composite Primary Key (Go)

Source: https://github.com/qor/admin/blob/master/README.md

Generates a remote resource selector for the 'Manager' model, specifically configuring the 'ID' meta to support composite primary keys. This is essential for correctly handling relationships with versioned resources.

```go
func generateRemoteManagerSelector(adm *admin.Admin) (res *admin.Resource) {
	res = adm.AddResource(&Manager{}, &admin.Config{Name: "ManagerSelector"})
	res.IndexAttrs("ID", "Name")

	// Required. Convert single ID into composite primary key
	res.Meta(&admin.Meta{
		Name: "ID",
		Valuer: func(value interface{}, ctx *qor.Context) interface{} {
			if r, ok := value.(*Manager); ok {
				// github.com/qor/qor/resource
				return resource.GenCompositePrimaryKey(r.ID, r.GetVersionName())
			}
			return ""
		},
	})

	return res
}
```

--------------------------------

### Define Custom Meta Fields in Go

Source: https://context7.com/qor/admin/llms.txt

Demonstrates how to define custom meta fields for QOR Admin resources. This includes setting basic attributes like Name, Label, and Type, as well as implementing custom logic for data retrieval (Valuer) and data saving (Setter). It also shows how to use FormattedValuer for custom display and how to configure specialized field types like 'rich_editor'.

```go
// Meta struct definition
type Meta struct {
    Name            string
    FieldName       string
    Label           string
    Type            string  // string, text, number, checkbox, select_one, select_many, etc.
    Setter          func(record interface{}, metaValue *resource.MetaValue, context *qor.Context)
    Valuer          func(record interface{}, context *qor.Context) interface{}
    FormattedValuer func(record interface{}, context *qor.Context) interface{}
    Permission      *roles.Permission
    Config          MetaConfigInterface
    Collection      interface{}
    Resource        *Resource
}

// Register custom meta for a field
productResource.Meta(&admin.Meta{
    Name:  "Price",
    Label: "Product Price ($)",
    Type:  "number",
})

// Meta with custom valuer and setter
productResource.Meta(&admin.Meta{
    Name:  "FullName",
    Label: "Full Name",
    Valuer: func(record interface{}, context *qor.Context) interface{} {
        user := record.(*User)
        return user.FirstName + " " + user.LastName
    },
    Setter: func(record interface{}, metaValue *resource.MetaValue, context *qor.Context) {
        // Custom setter logic
    },
})

// Meta with formatted valuer for display
productResource.Meta(&admin.Meta{
    Name: "Price",
    FormattedValuer: func(record interface{}, context *qor.Context) interface{} {
        product := record.(*Product)
        return fmt.Sprintf("$%.2f", product.Price)
    },
})

// Rich text editor meta
productResource.Meta(&admin.Meta{
    Name: "Description",
    Type: "rich_editor",
})
```

--------------------------------

### Overwrite Collection for SelectMany with Composite Primary Key (Go)

Source: https://github.com/qor/admin/blob/master/README.md

Demonstrates how to overwrite the 'Collection' function for a 'SelectMany' meta (e.g., 'Items') in the 'Factory' resource. It ensures that composite primary keys are used when returning associated items, which is necessary for versioned associations.

```go
factoryRes.Meta(&admin.Meta{
  Name: "Items",
  Config: &admin.SelectManyConfig{
	Collection: func(value interface{}, ctx *qor.Context) (results [][]string) {
		if c, ok := value.(*Factory); ok {
		var items []Item
		ctx.GetDB().Model(c).Related(&items, "Items")

		for _, p := range items {
		// The first element must be the composite primary key instead of ID
		results = append(results, []string{resource.GenCompositePrimaryKey(p.ID, p.GetVersionName()), p.Name})
		}
		}
		return
	},
	RemoteDataResource: itemSelector,
  },
})
```

--------------------------------

### Define Factory and Manager Models for Has-One Relationship (Go)

Source: https://github.com/qor/admin/blob/master/README.md

Defines the 'Factory' and 'Manager' structs for a has-one relationship. The 'Manager' struct includes 'resource.CompositePrimaryKeyField' to support composite primary keys, which is crucial for versioned resources.

```go
type Factory struct {
	gorm.Model
	Name string
	publish2.Version

	ManagerID          uint
	ManagerVersionName string // Required. in "xxxVersionName" format.
	Manager            Manager
}

type Manager struct {
	gorm.Model
	Name string
	publish2.Version

	// github.com/qor/qor/resource
	resource.CompositePrimaryKeyField // Required
}
```

--------------------------------

### Registering Custom Routes for Extended Functionality in Go

Source: https://context7.com/qor/admin/llms.txt

Extends QOR Admin functionality by registering custom routes beyond standard CRUD operations. This allows for implementing specific actions like data export or bulk imports. It uses the `RegisterRoute` method on a resource, accepting HTTP methods, paths, handler functions, and optional route configurations for permissions.

```go
package main

import (
    "encoding/csv"
    "fmt"
    "net/http"

    "github.com/qor/admin"
    "github.com/qor/roles"
)

// Assuming Product struct and parseFloat function are defined elsewhere

// Register custom GET route
productResource.RegisterRoute("GET", "/export", func(context *admin.Context) {
    products, _ := context.FindMany()

    // Generate CSV
    context.Writer.Header().Set("Content-Type", "text/csv")
    context.Writer.Header().Set("Content-Disposition", "attachment; filename=products.csv")

    writer := csv.NewWriter(context.Writer)
    writer.Write([]string{"ID", "Name", "Price"})

    for _, p := range products.([]*Product) {
        writer.Write([]string{
            fmt.Sprint(p.ID),
            p.Name,
            fmt.Sprintf("%.2f", p.Price),
        })
    }
    writer.Flush()
}, &admin.RouteConfig{
    PermissionMode: roles.Read,
})

// Register custom POST route
productResource.RegisterRoute("POST", "/bulk-import", func(context *admin.Context) {
    file, _, _ := context.Request.FormFile("file")
    defer file.Close()

    // Process import
    reader := csv.NewReader(file)
    records, _ := reader.ReadAll()

    for _, record := range records[1:] { // Skip header
        product := &Product{
            Name:  record[0],
            Price: parseFloat(record[1]),
        }
        context.GetDB().Create(product)
    }

    context.Flash("Import completed successfully", "success")
    http.Redirect(context.Writer, context.Request,
        context.URLFor(&Product{}, productResource), http.StatusFound)
}, &admin.RouteConfig{
    PermissionMode: roles.Create,
})
```

--------------------------------

### Registering Middleware for Request Processing in Go

Source: https://context7.com/qor/admin/llms.txt

Adds middleware functions to the QOR Admin router for request processing, logging, or custom authorization. Middleware can intercept requests and responses, modify context, or perform actions before or after the main request handler. Dependencies include the 'time' and 'log' packages.

```go
package main

import (
    "log"
    "net/http"
    "time"

    "github.com/qor/admin"
    "github.com/qor/roles"
)

// Middleware struct
type Middleware struct {
    Name    string
    Handler func(*Context, *Middleware)
}

// Get router and register middleware
router := Admin.GetRouter()

// Logging middleware
router.Use(&admin.Middleware{
    Name: "logger",
    Handler: func(context *admin.Context, middleware *admin.Middleware) {
        start := time.Now()

        // Call next middleware
        middleware.Next(context)

        // Log after request
        log.Printf("[%s] %s - %v",
            context.Request.Method,
            context.Request.URL.Path,
            time.Since(start),
        )
    },
})

// Authorization middleware
router.Use(&admin.Middleware{
    Name: "authorization",
    Handler: func(context *admin.Context, middleware *admin.Middleware) {
        user := context.CurrentUser
        if user != nil && context.Resource != nil {
            // Check custom permissions
            if !hasPermission(user, context.Resource.Name, context.Request.Method) {
                context.Writer.WriteHeader(http.StatusForbidden)
                context.Writer.Write([]byte("Access denied"))
                return
            }
        }
        middleware.Next(context)
    },
})

// Print all registered routes
router.PrintRoutes()
```

--------------------------------

### Registering Filters for Advanced Filtering in Go

Source: https://context7.com/qor/admin/llms.txt

Defines and registers various types of filters (text, number, select, custom) for advanced data filtering within the QOR admin panel. It utilizes a Filter struct and allows for custom handlers to define complex filtering logic.

```go
// Filter struct definition
type Filter struct {
    Name       string
    Label      string
    Type       string
    Operations []string  // eq, cont, gt, gteq, lt, lteq, present, blank
    Resource   *Resource
    Visible    func(context *Context) bool
    Handler    func(*gorm.DB, *FilterArgument) *gorm.DB
    Config     FilterConfigInterface
}

// Basic text filter
productResource.Filter(&admin.Filter{
    Name:       "Name",
    Label:      "Product Name",
    Operations: []string{"contains", "eq"},
})

// Number filter with operations
productResource.Filter(&admin.Filter{
    Name:       "Price",
    Type:       "number",
    Operations: []string{"eq", "gt", "lt", "gteq", "lteq"},
})

// Select one filter
productResource.Filter(&admin.Filter{
    Name: "Status",
    Config: &admin.SelectOneConfig{
        Collection: [][]string{
            {"draft", "Draft"},
            {"published", "Published"},
            {"archived", "Archived"},
        },
    },
})

// Select many filter
productResource.Filter(&admin.Filter{
    Name: "Categories",
    Config: &admin.SelectManyConfig{
        RemoteDataResource: Admin.GetResource("Category"),
    },
})

// Custom filter handler
productResource.Filter(&admin.Filter{
    Name:  "PriceRange",
    Label: "Price Range",
    Type:  "string",
    Handler: func(db *gorm.DB, arg *admin.FilterArgument) *gorm.DB {
        if value := arg.Value.Get("Value"); value != nil {
            switch value.Value.(string) {
            case "low":
                return db.Where("price < ?", 50)
            case "medium":
                return db.Where("price >= ? AND price < ?", 50, 200)
            case "high":
                return db.Where("price >= ?", 200)
            }
        }
        return db
    },
})
```

--------------------------------

### Adding Sub-Resources for Nested Relationships in Go

Source: https://context7.com/qor/admin/llms.txt

Registers nested resources within the QOR Admin interface to manage relationships, such as has-many associations. This allows for hierarchical data management and navigation. It requires defining GORM models for the main and sub-resources and using the `AddSubResource` method on the parent resource.

```go
package main

import (
    "github.com/jinzhu/gorm"
    "github.com/qor/admin"
)

type Order struct {
    gorm.Model
    UserID     uint
    TotalPrice float64
    Items      []OrderItem
}

type OrderItem struct {
    gorm.Model
    OrderID   uint
    ProductID uint
    Quantity  int
    Price     float64
}

// Register main resource
orderResource := Admin.AddResource(&Order{})

// Add sub-resource for order items
itemResource, err := orderResource.AddSubResource("Items", &admin.Config{
    Name: "Order Items",
})

if err == nil {
    itemResource.IndexAttrs("Product", "Quantity", "Price")
    itemResource.EditAttrs("Product", "Quantity", "Price")
}

// Sub-resources are accessible via nested routes:
// GET /admin/orders/:order_id/order_items
// GET /admin/orders/:order_id/order_items/:order_item_id
// POST /admin/orders/:order_id/order_items
// PUT /admin/orders/:order_id/order_items/:order_item_id
// DELETE /admin/orders/:order_id/order_items/:order_item_id
```

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