# -*- encoding: utf-8 -*-
# frozen_string_literal: true

class Oydid

    # DIDComm Plain Message ---------------------
    def self.dcpm(payload, options)
        dcDoc = {}
        dcDoc["id"] = SecureRandom.random_number(10e14).to_i
        dcDoc["type"] = options[:didcomm_type]
        if !options[:didcomm_from_did].nil?
            dcDoc["from"] = options[:didcomm_from_did]
        end
        dcDoc["to"] = [options[:didcomm_to_did]]
        dcDoc["created_time"] = Time.now.utc.to_i
        dcDoc["body"] = payload
        return [dcDoc, ""]

    end

    # signing -----------------------------------
    def self.msg_encrypt(payload, private_key_encoded)
        error = ""
        code, length, digest = decode(private_key_encoded).unpack('SCa*')
        case Multicodecs[code].name
        when 'ed25519-priv'
            private_key = RbNaCl::Signatures::Ed25519::SigningKey.new(digest)
            token = JWT.encode payload, private_key, 'ED25519'
        else
            token = nil
            error = "unsupported key codec"
        end
        return [token, error]
    end

    def self.msg_decrypt(token, public_key_encoded)
        error = ""
        code, length, digest = Oydid.decode(public_key_encoded).unpack('CCa*')
        case Multicodecs[code].name
        when 'ed25519-pub'
            public_key = RbNaCl::Signatures::Ed25519::VerifyKey.new(digest)
            payload = JWT.decode token.to_s, public_key, true, { algorithm: 'ED25519' }
        else
            payload = nil
            error = "unsupported key codec"
        end
        return [payload, error]
    end

end