package utils

import (
	"database/sql"

	jsoniter "github.com/json-iterator/go"
)

// UnmarshalSQLRows unmarshals sql rows to json
//
// This function provides a way to unmarshal arbitrary sql rows
// to json.
func UnmarshalSQLRows(rows *sql.Rows) ([]byte, error) {
	columnTypes, err := rows.ColumnTypes()
	if err != nil {
		return nil, err
	}

	count := len(columnTypes)
	finalRows := []interface{}{}

	for rows.Next() {

		scanArgs := make([]interface{}, count)

		for i, v := range columnTypes {

			switch v.DatabaseTypeName() {
			case "VARCHAR", "TEXT", "UUID", "TIMESTAMP":
				scanArgs[i] = new(sql.NullString)
			case "BOOL":
				scanArgs[i] = new(sql.NullBool)
			case "INT4":
				scanArgs[i] = new(sql.NullInt64)
			default:
				scanArgs[i] = new(sql.NullString)
			}
		}

		err := rows.Scan(scanArgs...)

		if err != nil {
			return nil, err
		}

		masterData := map[string]interface{}{}

		for i, v := range columnTypes {

			if z, ok := (scanArgs[i]).(*sql.NullBool); ok {
				masterData[v.Name()] = z.Bool
				continue
			}

			if z, ok := (scanArgs[i]).(*sql.NullString); ok {
				masterData[v.Name()] = z.String
				continue
			}

			if z, ok := (scanArgs[i]).(*sql.NullInt64); ok {
				masterData[v.Name()] = z.Int64
				continue
			}

			if z, ok := (scanArgs[i]).(*sql.NullFloat64); ok {
				masterData[v.Name()] = z.Float64
				continue
			}

			if z, ok := (scanArgs[i]).(*sql.NullInt32); ok {
				masterData[v.Name()] = z.Int32
				continue
			}

			masterData[v.Name()] = scanArgs[i]
		}

		finalRows = append(finalRows, masterData)
	}
	return jsoniter.Marshal(finalRows)
}