package convx

import (
	"errors"
	"math/big"
)

// interface 转 int64
func ToInt64(val interface{}) (i int64, err error) {
	if val == nil {
		return 0, errors.New("value is nil")
	}

	switch v := val.(type) {
	case int:
		return int64(v), nil
	case int8:
		return int64(v), nil
	case int16:
		return int64(v), nil
	case int32:
		return int64(v), nil
	case int64:
		return v, nil
	case uint:
		return int64(v), nil
	case uint8:
		return int64(v), nil
	case uint16:
		return int64(v), nil
	case uint32:
		return int64(v), nil
	case uint64:
		return int64(v), nil
	case float32:
		return int64(v), nil
	case float64:
		return int64(v), nil
	case string:
		num := new(big.Float)
		_, ok := num.SetString(v)
		if !ok {
			return 0, errors.New("convx.ToInt64: out of range")
		}

		i, _ := num.Int64()
		// fmt.Println(val, i, b)
		return i, nil
	case bool:
		if v {
			return 1, nil
		} else {
			return 0, nil
		}
	}
	return 0, errors.New("convx.ToInt64: unknown type")
}