package inject

import (
	"context"
	"errors"
	"strings"
)

type Backend interface {
	Inject(ctx context.Context, text string) error
}

type ClipboardWriter interface {
	WriteClipboard(ctx context.Context, text string) error
}

type ClipboardWriterFunc func(ctx context.Context, text string) error

func (f ClipboardWriterFunc) WriteClipboard(ctx context.Context, text string) error {
	return f(ctx, text)
}

type Paster interface {
	Paste(ctx context.Context) error
}

type Typer interface {
	TypeText(ctx context.Context, text string) error
}

type Deps struct {
	Clipboard ClipboardWriter
	Paster    Paster
	Typer     Typer
}

type ClipboardBackend struct {
	Writer ClipboardWriter
	Paster Paster
}

func (b ClipboardBackend) Inject(ctx context.Context, text string) error {
	if b.Writer == nil || b.Paster == nil {
		return errors.New("clipboard backend missing dependencies")
	}
	if err := b.Writer.WriteClipboard(ctx, text); err != nil {
		return err
	}
	return b.Paster.Paste(ctx)
}

type InjectionBackend struct {
	Typer Typer
}

func (b InjectionBackend) Inject(ctx context.Context, text string) error {
	if b.Typer == nil {
		return errors.New("injection backend missing dependencies")
	}
	return b.Typer.TypeText(ctx, text)
}

func NewBackend(name string, deps Deps) (Backend, error) {
	switch strings.ToLower(strings.TrimSpace(name)) {
	case "", "clipboard":
		return ClipboardBackend{Writer: deps.Clipboard, Paster: deps.Paster}, nil
	case "injection":
		return InjectionBackend{Typer: deps.Typer}, nil
	default:
		return nil, errors.New("unknown injection backend")
	}
}