package cli

import (
	"fmt"

	"git.maximhutz.com/max/lambda/pkg/codec"
)

type Conversion interface {
	InType() string
	OutType() string

	Run(Repr) (Repr, error)
}

type forwardCodec[T, U any] struct {
	codec           codec.Codec[T, U]
	inType, outType string
}

func (c forwardCodec[T, U]) Run(r Repr) (Repr, error) {
	t, ok := r.Data().(T)
	if !ok {
		return nil, fmt.Errorf("could not parse '%v' as '%s'", t, c.inType)
	}

	u, err := c.codec.Encode(t)
	if err != nil {
		return nil, err
	}

	return NewRepr(c.outType, u), nil
}

func (c forwardCodec[T, U]) InType() string { return c.inType }

func (c forwardCodec[T, U]) OutType() string { return c.outType }

type backwardCodec[T, U any] struct {
	codec           codec.Codec[T, U]
	inType, outType string
}

func (c backwardCodec[T, U]) Run(r Repr) (Repr, error) {
	u, ok := r.Data().(U)
	if !ok {
		return nil, fmt.Errorf("could not parse '%v' as '%s'", r, c.outType)
	}

	t, err := c.codec.Decode(u)
	if err != nil {
		return nil, err
	}

	return NewRepr(c.inType, t), nil
}

func (c backwardCodec[T, U]) InType() string { return c.outType }

func (c backwardCodec[T, U]) OutType() string { return c.inType }

func ConvertCodec[T, U any](e codec.Codec[T, U], inType, outType string) []Conversion {
	return []Conversion{
		forwardCodec[T, U]{e, inType, outType},
		backwardCodec[T, U]{e, inType, outType},
	}
}