package adapter

// Capabilities declares what a concrete platform adapter supports, so the
// runtime can degrade gracefully and the channel layer can enforce limits.
type Capabilities struct {
	// MaxMessageLength is the maximum message length the platform accepts.
	// Zero means "derive a sensible default".
	MaxMessageLength int
	// Markdown reports whether the platform renders markdown in outgoing text.
	Markdown bool
	// Image reports whether the platform supports sending images.
	Image bool
	// Voice reports whether the platform supports sending voice/audio.
	Voice bool
	// Reaction reports whether the platform supports reactions.
	Reaction bool
	// TypingHint reports whether the platform supports typing indicators.
	TypingHint bool
	// RecommendBurstMax is the recommended maximum number of messages in one
	// burst. Zero means "derive a sensible default".
	RecommendBurstMax int
	// Proactive reports whether the platform allows push without a recent
	// inbound message (e.g. weixin-ilink has a 24h window; OneBot needs rate
	// limiting). See design/08 section 3.
	Proactive bool
}

const (
	// defaultMaxMessageLength is used when an adapter declares no limit.
	defaultMaxMessageLength = 4000
	// defaultRecommendBurstMax avoids flooding a channel by default.
	defaultRecommendBurstMax = 1
)

// Normalize fills zero-valued numeric fields with sensible defaults so a
// partially declared Capabilities is still usable. Boolean fields are left
// untouched because an unset bool already means "not supported".
func (c Capabilities) Normalize() Capabilities {
	if c.MaxMessageLength <= 0 {
		c.MaxMessageLength = defaultMaxMessageLength
	}
	if c.RecommendBurstMax <= 0 {
		c.RecommendBurstMax = defaultRecommendBurstMax
	}
	return c
}

// DefaultCapabilities returns a conservative baseline for adapters that only
// speak plain text and basic images, leaving richer features off by default.
func DefaultCapabilities() Capabilities {
	return Capabilities{
		MaxMessageLength:  defaultMaxMessageLength,
		Markdown:          true,
		Image:             true,
		Voice:             false,
		Reaction:          false,
		TypingHint:        false,
		RecommendBurstMax: defaultRecommendBurstMax,
		Proactive:         false,
	}
}