/*
	This file describes Protocol buffers messages for bitcoin hardware wallet devices.
	
	Author: Marek Palatinus <slush@satoshilabs.com>
	
	Version: 0.5
*/

import "google/protobuf/descriptor.proto";

/*
	Mapping between Trezor wire identifier (int) and protobuf message
*/
enum MessageType {
    MessageType_Initialize = 0;
    MessageType_Ping = 1;
    MessageType_Success = 2;
    MessageType_Failure = 3;
    MessageType_ChangePin = 4;
    MessageType_WipeDevice = 5;
    MessageType_GetEntropy = 9;
    MessageType_Entropy = 10;
    MessageType_GetMasterPublicKey = 11;
    MessageType_MasterPublicKey = 12;
    MessageType_LoadDevice = 13;
    MessageType_ResetDevice = 14;
    MessageType_SignTx = 15;
    MessageType_SimpleSignTx = 16;
    MessageType_Features = 17;
    MessageType_PinMatrixRequest = 18;
    MessageType_PinMatrixAck = 19;
    MessageType_PinMatrixCancel = 20;
    MessageType_TxRequest = 21;
    MessageType_TxInput = 23;
    MessageType_TxOutput = 24;
    MessageType_ApplySettings = 25;
    MessageType_ButtonRequest = 26;
    MessageType_ButtonAck = 27;
    MessageType_ButtonCancel = 28;
    MessageType_GetAddress = 29;
    MessageType_Address = 30;
    MessageType_SettingsType = 31;
    MessageType_XprvType = 32;
    MessageType_CoinType = 33;
    MessageType_XpubType = 34;
    MessageType_EntropyRequest = 35;
    MessageType_EntropyAck = 36;
    MessageType_DebugLinkDecision = 100;
    MessageType_DebugLinkGetState = 101;
    MessageType_DebugLinkState = 102;
    MessageType_DebugLinkStop = 103;
}

// Such option indicates that the message field has binary payload
extend google.protobuf.FieldOptions {
	optional bool binary = 50001;
}


// ****************************************************************************
//
// Definition of custom field types
//

// Specifies which script will be used for given transaction output. 
enum ScriptType {
    PAYTOADDRESS = 0;
    PAYTOSCRIPTHASH = 1;
} 

// Specifies which kind of information is required by transaction signing process
enum RequestType {
    TXINPUT = 0;
    TXOUTPUT = 1;
}

// Structure for BIP32-encoded node
// Used for imports into the device
message XprvType {
	required uint32 version = 1;
	required uint32 depth = 2;
	required uint32 fingerprint = 3;
	required uint32 child_num = 4;
	required bytes chain_code = 5 [(binary) = true];
	required bytes private_key = 6 [(binary) = true];
}

// Structure returned by GetMasterPublicKey
message XpubType {
	required uint32 version = 1;
	required uint32 depth = 2;
	required uint32 fingerprint = 3;
	required uint32 child_num = 4;
	required bytes chain_code = 5 [(binary) = true];
	required bytes public_key = 6 [(binary) = true];
}

message CoinType {
	optional bytes coin_name = 1;
	optional bytes coin_shortcut = 2;
	optional uint32 address_type = 3;
	optional uint64 maxfee_kb = 4;
}

message SettingsType {
	optional bytes language = 1;	// Trezor uses 'english' as default
	optional CoinType coin = 2;
	optional bytes label = 3;		// Human readable wallet name
}

// ****************************************************************************
//
// Basic message
//

// Reset device to default state and ask for device details
//
// Response: Features
message Initialize {
}

// Response object for Initialize.
message Features {
    optional bytes vendor = 1;	// Name of the manufacturer, e.g. "trezor" 
    optional uint32 major_version = 2; // Major version of the device, e.g. 1
    optional uint32 minor_version = 3;  // Minor version of the device, e.g. 0
    optional SettingsType settings = 4;	// User-level settings of the device
    optional bytes device_id = 5 [(binary) = true];	// Device's unique identifier
    optional bytes mpk_hash = 6 [(binary) = true];	// Hash of master public key (sha256(XpubType.public_key).digest())
    optional bool pin_protection = 7;   // True if Trezor is covered by PIN
}

// Overwrites only filled fields of the structure
message ApplySettings {
	optional bytes language = 1;
	optional bytes coin_shortcut = 2;
	optional bytes label = 3;
}

// Starts workflow for setting/changing the PIN
// Response: ButtonRequest, PinMatrixRequest
message ChangePin {
    optional bool remove = 1;	// Set True if want to remove PIN protection
}

// Test if device is live, device will send back the message on success
//
// Response: None or Success
message Ping {
    optional bytes message = 1;	// Message will be sent back in Success message
}

// Response object defining success of the previous request
message Success {
    optional bytes message = 1;	//	May contain human readable description of the action or request-specific payload
}

// Response object defining failure of the previous request
message Failure {
    optional int32 code = 1;		// May contain computer-readable definition of the error state
    optional bytes message = 2;		// May contain human-readable message of the error state
}

// Message can be sent by the *device* as a resopnse to any request.
// Device is waiting for HW button press. No action is required from computer
// Computer should respond with ButtonAck message or ButtonCancel to cancel
// the original request.
message ButtonRequest {
}

// Computer agrees to wait for HW button press.
message ButtonAck {
}

// Computer want to cancel current action (don't wait to HW button press)
message ButtonCancel {
}
 
// Message can be sent by the *device* as a response to any request.
// Message asks computer to send back PinMatrixAck with the password encoded in pin matrix scheme.
//
// Response: PinMatrixAck, PinMatrixCancel
message PinMatrixRequest {
   optional bytes message = 1;	// Human readable message
}

// Message is sent by the computer as a response to PinMatrixRequest previously sent by the device.
message PinMatrixAck {
    required bytes pin = 1;	// User must write down the password for accessing the device.
}

// Message is sent as a response to PinMatrixRequest by the computer, asking the device to cancel
// pending action and reset to the default state.
message PinMatrixCancel {
}

// Request a sample of random data generated by hardware RNG. May be used
// for tests of internal RNG.
//
// Response: PinMatrixRequest, Entropy, Failure
message GetEntropy {
    required uint32 size = 1;	// Size of randomly generated buffer
}

// Response to GetEntropy request contains random data generated by internal HRNG.
message Entropy {
    required bytes entropy = 1 [(binary) = true];	// Stream of generated bytes
}

// Ask device for it's current master public key. This may be used for generating
// public keys on the computer independently to the device. API doesn't provide
// any other way how to get bitcoin addresses from the device.
//
// Response: MasterPublicKey, Failure
message GetMasterPublicKey {
}

// Contains master public key derived from device's seed.
message MasterPublicKey {
    required XpubType mpk = 1;	// BIP32 node public key + chaincode
}

message GetAddress {
    repeated uint32 address_n = 1;	// Parameter for address generation algorithm to derive the address from the master public key 
}

message Address {
    required bytes address = 1; // Bitcoin address in base58 encoding corresponding to GetAddress(n) call
}

// Request device to wipe all sensitive data and settings.
// Device will be turned to uninitialized state.
//
// Response: ButtonRequest
message WipeDevice {
}

// Load seed and related internal settings from computer to the device. Existing seed is overwritten.
//
// Response: Success, ButtonRequest, PinMatrixRequest, Failure
message LoadDevice {
    optional bytes seed = 1;	// Seed encoded as a mnemonic (12 english words)
    optional XprvType xprv = 2;
    optional bytes pin = 3;				// Set PIN protection for important actions
}

// Request device to do full-reset, to generate new seed
// and ask user for new settings (PIN).
// Workflow is splitted into ResetDevice/EntropyRequest to be sure
// that entropy provided by device isn't calculated on base of computer provided
// entropy. 
//
// 
// Response: EntropyRequest, PinMatrixRequest, Failure
message ResetDevice {
	optional bool display_random = 1; // If set, displays entropy generated by the device used
									  // for generating the seed *before* asking for additional entropy from computer
}

// Asks for additional Entropy from host computer
message EntropyRequest {
}

// Provide additional entropy for seed generation function.
message EntropyAck {
	optional bytes entropy = 1 [(binary) = true];	// Recommended to provide 256 bytes of random data.
}

// ****************************************************************************
//
// Messages related to transaction signing
//

// Request the device to sign the transaction
//
// Response: TxRequest, PinMatrixRequest, Failure
message SignTx {
    required uint32 outputs_count = 3;		// Count of outputs of the transaction 
    required uint32 inputs_count = 5; // Count of inputs of the transaction
}

// Request a simplified workflow of signing.
// This method doesn't support streaming,
// so there may be hardware limits
// in number of inputs and outputs.
// 
// This simplified workflow should not be used
// in production, it is designed mainly for debug purposes.
//
// When everything is fine, Success.message contains
// serialized transaction.
//
// Response: Success, PinMatrixRequest, Failure
message SimpleSignTx {
    repeated TxInput inputs = 1;
    repeated TxOutput outputs = 2;
}

// Sent by the device as a response for SignTx. Device asks for information for signing transaction.
// If request_index is set, device asks for TxInput/TxOutput message (depends on request_type)
// with details of index's input.
// If signed_index is set, 'signature' contains signed input of signed_index's input. 
message TxRequest {
	optional int32 request_index = 1;	// If >=0, device expects TxInput/TxOutput message from the computer
	optional RequestType request_type = 2; // Ask for TxInput or TxOutput?
	optional int32 signed_index = 3;	// If >=0, 'signature' contains signed input of this input
	optional bytes signature = 4 [(binary) = true];		// If signed_index>=0, represent signature of the signed_index input
	optional bytes serialized_tx = 5 [(binary) = true];   // Part of serialized and signed transaction
}

// Transaction onput for SignTx workflow. It is response to TxRequest message sent by device.
//
// Response: TxRequest, Failure
message TxInput {
	required uint32 index = 1;		// Position of input in proposed transaction
    repeated uint32 address_n = 2;	// Parameter for address generation algorithm to derive the address from the master public key
    required uint64 amount = 3;		// Amount to spend in satoshis. The rest will be used for transaction fees
    required bytes prev_hash = 4 [(binary) = true];	// Hash of previous transaction output to spend by this input
    required uint32 prev_index = 5;	// Index of previous output to spend
    optional bytes script_sig = 6 [(binary) = true];	// Script signature
}

// Transaction output for SignTx workflow. It is response to TxRequest message sent by the device.
message TxOutput {
    required uint32 index = 1;			// Position of output in proposed transaction
    required bytes address = 2;			// Target bitcoin address in base58 encoding
    repeated uint32 address_n = 3;		// Has higher priority than "address". If the output is to myself, specify parameter for address generation algorithm.
    required uint64 amount = 4;			// Amount to send in satoshis
    required ScriptType script_type = 5;// Select output script type
    repeated bytes script_args = 6 [(binary) = true];		// Provide additional parameters for the script (its script-depended)
}

// ****************************************************************************
//
//	Debug* messages are used only on DebugLink interface (separated from USB HID)
//

// Virtually "press" the button on the device.
// Message is available only on debugging connection and device must support "debug_link" feature.
//
// Response: Success
message DebugLinkDecision {
	required bool yes_no = 1;	// True for "confirm", False for "cancel"
}

// When sent over debug link connection, computer asks for some internal information of the device.
//
// Response: DebugLinkState
message DebugLinkGetState {
	optional bool layout = 1;	// Request raw buffer of display
	optional bool pin = 2;		// Request current pin
	optional bool matrix = 3;	// Request current pin matrix
	optional bool seed = 4;		// Request current seed
//	optional bool state = 5;
}

// Response object reflecting device's current state. It can be received only over debug link connection.
message DebugLinkState {
	optional bytes layout = 1 [(binary) = true];	// Raw buffer of display
	optional bytes pin = 2;	// Current PIN, blank if PIN is not set/enabled
	optional bytes matrix = 3;	// Current PIN matrix
	optional bytes seed = 4;	// Current seed (in mnemonic format)
//	optional bytes state = 5 [(binary) = true];
}

// Ask device to shutdown/restart
message DebugLinkStop {
}