package db

import (
	"database/sql/driver"
	"encoding/json"
	"errors"
	"strings"
)

const separator = "\x1f"

type VSC []string

// MarshalJSON replaces `nil` with `[]` for hygiene.
func (vs VSC) MarshalJSON() ([]byte, error) {
	if vs == nil {
		vs = VSC{}
	}
	return json.Marshal([]string(vs)) //nolint: wrapcheck // Passthrough
}

func (vs VSC) Value() (driver.Value, error) {
	fields := make([]string, len(vs))
	for i, v := range vs {
		fields[i] = strings.ReplaceAll(v, separator, "")
	}
	return strings.Join(fields, separator), nil
}

var ErrWrongVSCType = errors.New("incompatible DB type for VSC")

func (vs *VSC) Scan(src any) error {
	var s string
	switch v := src.(type) {
	case string:
		s = v
	case []byte:
		s = string(v)
	case nil:
		*vs = nil
		return nil
	default:
		return ErrWrongVSCType
	}
	if s == "" {
		*vs = VSC{}
		return nil
	}
	*vs = strings.Split(s, separator)
	return nil
}