package llm

// Part is one piece of message content: text, an image, or future media
// kinds. The set of implementations is closed (sealed by the unexported
// method) so providers can switch exhaustively over content kinds.
//
// Why: providers need a finite, known content vocabulary to serialize into
// their wire formats; an open interface would silently drop unknown content.
type Part interface {
	isPart()
}

// TextPart is plain text content.
type TextPart struct {
	Text string
}

func (TextPart) isPart() {}

// ImagePart is image content carried as raw bytes plus a MIME type.
//
// Why bytes-only (no URL form): the media pipeline must be able to inspect,
// downscale, and re-encode every image to fit the target's capabilities, and
// that requires the bytes. Callers with a URL fetch it themselves; majordomo
// does not download remote content on a caller's behalf.
type ImagePart struct {
	// MIME is the image content type, e.g. "image/png" or "image/jpeg".
	MIME string
	// Data is the raw, unencoded image bytes (providers base64 as needed).
	Data []byte
}

func (ImagePart) isPart() {}

// Text constructs a text content part.
func Text(s string) Part { return TextPart{Text: s} }

// Image constructs an image content part from raw bytes.
func Image(mime string, data []byte) Part { return ImagePart{MIME: mime, Data: data} }