From ffc23c362bdda5fec5b12fe7bb630c77af78bc42 Mon Sep 17 00:00:00 2001
From: Savely Krendelhoff <alicecandyom@proton.me>
Date: Fri, 22 Aug 2025 21:03:42 +0700
Subject: [PATCH] Define presentation layer types

---
 internal/protocol/types.go | 64 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 internal/protocol/types.go

diff --git a/internal/protocol/types.go b/internal/protocol/types.go
new file mode 100644
index 0000000..4afd17f
--- /dev/null
+++ b/internal/protocol/types.go
@@ -0,0 +1,64 @@
+package protocol
+
+import (
+	"hash-of-wisdom/internal/pow/challenge"
+	"hash-of-wisdom/internal/quotes"
+)
+
+// MessageType represents the type of protocol message
+type MessageType byte
+
+const (
+	ChallengeRequest  MessageType = 0x01
+	ChallengeResponse MessageType = 0x02
+	SolutionRequest   MessageType = 0x03
+	QuoteResponse     MessageType = 0x04
+	ErrorResponse     MessageType = 0x05
+)
+
+// Message represents a protocol message with type and payload
+type Message struct {
+	Type    MessageType
+	Payload []byte
+}
+
+// ChallengeRequestPayload is empty (no payload for challenge requests)
+type ChallengeRequestPayload struct{}
+
+// ChallengeResponsePayload is the direct challenge object (not wrapped)
+type ChallengeResponsePayload challenge.Challenge
+
+// SolutionRequestPayload contains the client's solution attempt
+type SolutionRequestPayload struct {
+	Challenge challenge.Challenge `json:"challenge"`
+	Nonce     uint64              `json:"nonce"`
+}
+
+// QuoteResponsePayload is the direct quote object (not wrapped)
+type QuoteResponsePayload quotes.Quote
+
+// ErrorResponsePayload contains error information
+type ErrorResponsePayload struct {
+	Code       string            `json:"code"`
+	Message    string            `json:"message"`
+	RetryAfter int               `json:"retry_after,omitempty"`
+	Details    map[string]string `json:"details,omitempty"`
+}
+
+// Error codes as defined in protocol specification
+const (
+	ErrMalformedMessage    = "MALFORMED_MESSAGE"
+	ErrInvalidChallenge    = "INVALID_CHALLENGE"
+	ErrInvalidSolution     = "INVALID_SOLUTION"
+	ErrExpiredChallenge    = "EXPIRED_CHALLENGE"
+	ErrRateLimited         = "RATE_LIMITED"
+	ErrServerError         = "SERVER_ERROR"
+	ErrTooManyConnections  = "TOO_MANY_CONNECTIONS"
+	ErrDifficultyTooHigh   = "DIFFICULTY_TOO_HIGH"
+)
+
+// Protocol constants
+const (
+	MaxPayloadSize = 8 * 1024 // 8KB maximum payload size
+	HeaderSize     = 5        // 1 byte type + 4 bytes length
+)