package main

import (
	"encoding/json"
	"errors"
	"database/sql/driver"
	"fmt"
	"github.com/jmoiron/sqlx"
	_ "github.com/lib/pq"
	"log"
)

var schema = `
CREATE TABLE person (
    first_name text,
    last_name text,
    contact JSON
);`

type PersonContact map[string]interface{};

func (pc *PersonContact) Scan(val interface{}) error {
	switch v := val.(type){
	case []byte:
		json.Unmarshal(v, &pc)
		return nil
	case string:
		json.Unmarshal([]byte(v), &pc)
		return nil	
	default:
		return errors.New(fmt.Sprintf("Unsupported type: %T", v))
	}
}
func (pc *PersonContact) Value() (driver.Value, error) {
	return json.Marshal(pc)
}

 
type Person struct {
	FirstName string            `db:"first_name"`
	LastName  string            `db:"last_name"`
	Contact   PersonContact `db:"contact"`
}

func main() {
	db, err := sqlx.Connect("postgres", "user=test dbname=test password=test")
	if err != nil {
		log.Fatalln(err)
	}
	defer db.Close()

	// exec the schema or fail
	db.MustExec("DROP TABLE IF EXISTS person;")
	db.MustExec(schema)

	var person Person
	contact := map[string]string{"email": "jmoiron@jmoiron.net"}
	contact_json, _ := json.Marshal(contact)

	db.MustExec("INSERT INTO person (first_name, last_name, contact) VALUES ($1, $2, $3)", "Jason", "Moiron", contact_json)

	row := db.QueryRowx("SELECT first_name, last_name, contact FROM person LIMIT 1")
	err = row.StructScan(&person)
	if err != nil {
		panic(err)
	}
	fmt.Printf("=> %v\n", person)
}