package types

import (

"database/sql/driver"

"encoding/json"

"fmt"

)

// JSONMap defines a map that is safe for json and db read/write.

type JSONMap[T any] map[string]T

// MarshalJSON implements the [json.Marshaler] interface.

func (m JSONMap[T]) MarshalJSON() ([]byte, error) {

type alias JSONMap[T] // prevent recursion

// initialize an empty map to ensure that `{}` is returned as json

if m == nil {

m = JSONMap[T]{}

}

return json.Marshal(alias(m))

}

// String returns the string representation of the current json map.

func (m JSONMap[T]) String() string {

v, _ := m.MarshalJSON()

return string(v)

}

// Get retrieves a single value from the current JSONMap[T].

//

// This helper was added primarily to assist the goja integration since custom map types

// don't have direct access to the map keys (https://pkg.go.dev/github.com/dop251/goja#hdr-Maps_with_methods).

func (m JSONMap[T]) Get(key string) T {

return m[key]

}

// Set sets a single value in the current JSONMap[T].

//

// This helper was added primarily to assist the goja integration since custom map types

// don't have direct access to the map keys (https://pkg.go.dev/github.com/dop251/goja#hdr-Maps_with_methods).

func (m JSONMap[T]) Set(key string, value T) {

m[key] = value

}

// Value implements the [driver.Valuer] interface.

func (m JSONMap[T]) Value() (driver.Value, error) {

data, err := json.Marshal(m)

return string(data), err

}

// Scan implements [sql.Scanner] interface to scan the provided value

// into the current JSONMap[T] instance.

func (m *JSONMap[T]) Scan(value any) error {

var data []byte

switch v := value.(type) {

case nil:

// no cast needed

case []byte:

data = v

case string:

data = []byte(v)

default:

return fmt.Errorf("failed to unmarshal JSONMap[T] value: %q", value)

}

if len(data) == 0 {

data = []byte("{}")

}

return json.Unmarshal(data, m)

}