letter

type Envelope struct {

	// ID is the hash of the Marshaled Letter + the Public key of Sender
	ID string `json:"id"`
	// Timestamp is the time at which the envelope was created
	Timestamp time.Time `json:"timestamp"`
	// Sender is public key of the sender
	Sender    keypair.KeyPair `json:"sender"`
	SenderRaw string          `json:"sender_raw"`
	// Signature is the public key of the sender encrypted by
	// the Sender private key, against the public Region key
	// to authenticate sender. I.e., Sender == Decrypt(Signature) must be true.
	// A valid Signature is also used to prevent the Envelope from being deleted.
	// I.e., if a Region key is not able to decrypt it, then it is meant for another Region
	// and would be deleted.
	Signature string `json:"signature"`
	// SealedRecipients is list of encypted passphrase (used to encrypt the Content)
	// encrypted against each of the public keys of the recipients.
	SealedRecipients []string `json:"sealed_recipients"`

	// SealedLetter contains the encryoted and compressed letter, encoded as base64 string
	SealedLetter string `json:"sealed_letter,omitempty"`

	// Letter is the unsealed letter. Once a Envelope is "unsealed", then this
	// variable is set and the SealedLetter is set to "" (deleted). This will
	// then be saved in a bucket for unsealed letters. When the letter remains
	// sealed then this Letter is set to nil.
	Letter Letter `json:"letter,omitempty"`

	// Opened is a variable set to true if the Letter is opened, to make
	// it easier to index the opened/unopened letters in the database.false
	Opened bool `json:"opened"`
}

type Letter struct {
	// Purpose specifies the purpose of letter. Currently the purposes are:
	// "action-X" - used to action public data for reputation purposes (likes, follows, channel subscriptions, settting profile images and text and names)
	// "share-X" - used to share content either "post" or "image/png"/"image/jpg"
	Purpose string `json:"purpose,omitempty"`

	// To is a list of who the letter is addressed to: "public", "friends", "self" or the public key of any person
	To []string `json:"to,omitempty"`

	// Content is is the content of the letter (base64 encoded image, text, or HTML)
	Content string `json:"content,omitempty"`

	// FirstID is the first ID for chains of edits, which must be constant
	FirstID string `json:"first_id,omitempty"`

	// ReplyTo is the ID of the post being responded to
	ReplyTo string `json:"reply_to,omitempty"`
}