smsg

type ABRBandwidthEstimator struct {
	// contains filtered or unexported fields
}

type ABRManifest struct {
	Version    string    `json:"version"`    // "abr-v1"
	Title      string    `json:"title"`      // Content title
	Duration   int       `json:"duration"`   // Total duration in seconds
	Variants   []Variant `json:"variants"`   // Quality variants (sorted by bandwidth, ascending)
	DefaultIdx int       `json:"defaultIdx"` // Default variant index (typically 720p)
	Password   string    `json:"-"`          // Shared password for all variants (not serialized)
}

type Attachment struct {
	Name     string `json:"name"`
	Content  string `json:"content,omitempty"` // base64-encoded (v1) or empty (v2, populated on decrypt)
	MimeType string `json:"mime,omitempty"`
	Size     int    `json:"size,omitempty"` // binary size in bytes
}

type Cadence string

type ChunkInfo struct {
	Offset int `json:"offset"` // byte offset in payload
	Size   int `json:"size"`   // encrypted chunk size (includes nonce + tag)
}

type ChunkedInfo struct {
	ChunkSize   int         `json:"chunkSize"`   // size of each chunk before encryption
	TotalChunks int         `json:"totalChunks"` // number of chunks
	TotalSize   int64       `json:"totalSize"`   // total unencrypted size
	Index       []ChunkInfo `json:"index"`       // chunk locations for seeking
}

type Header struct {
	Version     string    `json:"version"`
	Algorithm   string    `json:"algorithm"`
	Format      string    `json:"format,omitempty"`      // v2 for binary, v3 for streaming, empty for v1 (base64)
	Compression string    `json:"compression,omitempty"` // gzip, zstd, or empty for none
	Hint        string    `json:"hint,omitempty"`        // optional password hint
	Manifest    *Manifest `json:"manifest,omitempty"`    // public metadata for discovery

	// V3 streaming fields
	KeyMethod   string       `json:"keyMethod,omitempty"`   // lthn-rolling for v3
	Cadence     Cadence      `json:"cadence,omitempty"`     // key rotation frequency (daily, 12h, 6h, 1h)
	WrappedKeys []WrappedKey `json:"wrappedKeys,omitempty"` // CEK wrapped with rolling keys

	// V3 chunked streaming (optional - enables decrypt-while-downloading)
	Chunked *ChunkedInfo `json:"chunked,omitempty"` // chunk index for seeking/range requests
}

type Manifest struct {
	// Content identification
	Title  string `json:"title,omitempty"`
	Artist string `json:"artist,omitempty"`
	Album  string `json:"album,omitempty"`
	Genre  string `json:"genre,omitempty"`
	Year   int    `json:"year,omitempty"`

	// Release info
	ReleaseType string `json:"release_type,omitempty"` // single, album, ep, mix
	Duration    int    `json:"duration,omitempty"`     // total duration in seconds
	Format      string `json:"format,omitempty"`       // dapp.fm/v1, etc.

	// License expiration (for streaming/rental models)
	ExpiresAt   int64  `json:"expires_at,omitempty"`   // Unix timestamp when license expires (0 = never)
	IssuedAt    int64  `json:"issued_at,omitempty"`    // Unix timestamp when license was issued
	LicenseType string `json:"license_type,omitempty"` // perpetual, rental, stream, preview

	// Track list (like CD master)
	Tracks []Track `json:"tracks,omitempty"`

	// Artist links - direct to artist, skip the middlemen
	Links map[string]string `json:"links,omitempty"` // platform -> URL (bandcamp, soundcloud, website, etc.)

	// Custom metadata
	Tags  []string          `json:"tags,omitempty"`
	Extra map[string]string `json:"extra,omitempty"`
}

type Message struct {
	// Core message content
	Subject string `json:"subject,omitempty"`
	Body    string `json:"body"`

	// Optional attachments
	Attachments []Attachment `json:"attachments,omitempty"`

	// PKI for authenticated replies
	ReplyKey *PKIInfo `json:"reply_key,omitempty"`

	// Metadata
	From      string            `json:"from,omitempty"`
	Timestamp int64             `json:"timestamp,omitempty"`
	Meta      map[string]string `json:"meta,omitempty"`
}

type PKIInfo struct {
	PublicKey   string `json:"public_key"`            // base64-encoded X25519 public key
	KeyID       string `json:"key_id,omitempty"`      // optional key identifier
	Algorithm   string `json:"algorithm,omitempty"`   // e.g., "x25519"
	Fingerprint string `json:"fingerprint,omitempty"` // SHA256 fingerprint of public key
}

type StreamParams struct {
	License     string  // User's license identifier
	Fingerprint string  // Device/session fingerprint
	Cadence     Cadence // Key rotation cadence (default: daily)
	ChunkSize   int     // Optional: chunk size for decrypt-while-downloading (0 = no chunking)
}

type Track struct {
	Title    string  `json:"title"`
	Start    float64 `json:"start"`               // start time in seconds
	End      float64 `json:"end,omitempty"`       // end time in seconds (0 = until next track)
	Type     string  `json:"type,omitempty"`      // intro, verse, chorus, drop, outro, etc.
	TrackNum int     `json:"track_num,omitempty"` // track number for multi-track releases
}

type Variant struct {
	Name       string `json:"name"`       // Human-readable name: "1080p", "720p", etc.
	Bandwidth  int    `json:"bandwidth"`  // Required bandwidth in bits per second
	Width      int    `json:"width"`      // Video width in pixels
	Height     int    `json:"height"`     // Video height in pixels
	Codecs     string `json:"codecs"`     // Codec string: "avc1.640028,mp4a.40.2"
	URL        string `json:"url"`        // Relative path to .smsg file
	ChunkCount int    `json:"chunkCount"` // Number of chunks (for progress calculation)
	FileSize   int64  `json:"fileSize"`   // File size in bytes
}

type WrappedKey struct {
	Date    string `json:"date"`    // ISO date "YYYY-MM-DD" for key derivation
	Wrapped string `json:"wrapped"` // base64([nonce][ChaCha(CEK, streamKey)])
}