package imagegen

import "context"

// UpscaleRequest asks a super-resolution backend to enlarge an image. Zero
// values mean "backend default", mirroring EditRequest (ADR-0020).
type UpscaleRequest struct {
	// Image is the image to upscale. Required.
	Image Image

	// Scale is the enlargement factor (2 or 4 on the reference backend);
	// 0 = backend default.
	Scale int
}

// UpscaleOption mutates an UpscaleRequest before it is sent.
type UpscaleOption func(*UpscaleRequest)

// WithUpscaleScale sets the enlargement factor.
func WithUpscaleScale(s int) UpscaleOption { return func(r *UpscaleRequest) { r.Scale = s } }

// Apply returns a copy of the request with all options applied.
func (r UpscaleRequest) Apply(opts ...UpscaleOption) UpscaleRequest {
	for _, opt := range opts {
		opt(&r)
	}
	return r
}

// Upscaler enlarges images with a super-resolution model. It is its own
// small interface (not a method on Model) because upscalers are not
// diffusion models — they bind to a different backend id entirely.
type Upscaler interface {
	// Upscale returns the enlarged image (a one-image Result).
	Upscale(ctx context.Context, req UpscaleRequest, opts ...UpscaleOption) (*Result, error)
}

// UpscaleModelOption configures an Upscaler at construction time. Reserved
// for future per-model settings (mirrors ModelOption).
type UpscaleModelOption func(*UpscaleModelConfig)

// UpscaleModelConfig carries per-model construction settings.
type UpscaleModelConfig struct{}

// ApplyUpscaleModelOptions folds options into a config.
func ApplyUpscaleModelOptions(opts []UpscaleModelOption) UpscaleModelConfig {
	var cfg UpscaleModelConfig
	for _, opt := range opts {
		opt(&cfg)
	}
	return cfg
}

// UpscaleProvider mints Upscalers bound to one backend.
type UpscaleProvider interface {
	// Name is the registry identifier for the provider.
	Name() string

	// UpscaleModel returns an Upscaler bound to the given id (passed through
	// to the backend verbatim; no catalog validation).
	UpscaleModel(id string, opts ...UpscaleModelOption) (Upscaler, error)
}