structs.go

package main

import "encoding/json"

// --- Claude API Structs (Anthropic Format) ---

// ClaudeRequest represents the incoming request structure from the client
type ClaudeRequest struct {
	Model         string             `json:"model"`
	Messages      []ClaudeMessage    `json:"messages"`
	System        json.RawMessage    `json:"system,omitempty"` // Can be string or list of blocks
	MaxTokens     *int               `json:"max_tokens,omitempty"` // Use pointer for optional fields
	StopSequences []string           `json:"stop_sequences,omitempty"`
	Stream        bool               `json:"stream,omitempty"`
	Temperature   *float64           `json:"temperature,omitempty"`
	TopP          *float64           `json:"top_p,omitempty"`
	TopK          *int               `json:"top_k,omitempty"` 
}

// ClaudeMessage represents a message in the Claude request
type ClaudeMessage struct {
	Role    string            `json:"role"` // "user" or "assistant"
	Content json.RawMessage   `json:"content"` // Can be string or list of blocks
}

// ClaudeContentBlock represents a block within the content array
type ClaudeContentBlock struct {
	Type string `json:"type"`
	Text string `json:"text,omitempty"`
	// Add other block types if needed (e.g., image)
}

// ClaudeResponse represents the non-streaming response structure sent to the client
type ClaudeResponse struct {
	ID           string               `json:"id"`
	Type         string               `json:"type"` // e.g., "message"
	Role         string               `json:"role"` // e.g., "assistant"
	Content      []ClaudeContentBlock `json:"content"`
	Model        string               `json:"model"`
	StopReason   string               `json:"stop_reason"` // e.g., "end_turn", "max_tokens"
	StopSequence *string              `json:"stop_sequence"` // Usually null
	Usage        ClaudeUsage          `json:"usage"`
}

// ClaudeUsage represents the token usage information
type ClaudeUsage struct {
	InputTokens  int `json:"input_tokens"`
	OutputTokens int `json:"output_tokens"`
}

// ClaudeErrorResponse represents the error structure sent to the client
type ClaudeErrorResponse struct {
	Type  string        `json:"type"` // Always "error"
	Error ClaudeError `json:"error"`
}

// ClaudeError represents the detailed error information
type ClaudeError struct {
	Type    string `json:"type"`    // e.g., "invalid_request_error", "api_error"
	Message string `json:"message"`
}


// --- OpenAI API Structs ---

// OpenAIRequest represents the request structure sent to the upstream OpenAI API
type OpenAIRequest struct {
	Model       string          `json:"model"`
	Messages    []OpenAIMessage `json:"messages"`
	MaxTokens   *int            `json:"max_tokens,omitempty"`
	Temperature *float64        `json:"temperature,omitempty"`
	TopP        *float64        `json:"top_p,omitempty"`
	TopK        *int            `json:"top_k,omitempty"` 
	Stop        []string        `json:"stop,omitempty"`
	Stream      bool            `json:"stream,omitempty"`
}

// OpenAIMessage represents a message in the OpenAI request
type OpenAIMessage struct {
	Role    string `json:"role"` // "system", "user", or "assistant"
	Content string `json:"content"`
}

// OpenAIResponse represents the non-streaming response from the upstream OpenAI API
type OpenAIResponse struct {
	ID      string             `json:"id"`
	Object  string             `json:"object"` // e.g., "chat.completion"
	Created int64              `json:"created"`
	Model   string             `json:"model"`
	Choices []OpenAIChoice     `json:"choices"`
	Usage   *OpenAIUsage       `json:"usage,omitempty"` 
}

// OpenAIChoice represents a choice in the OpenAI response
type OpenAIChoice struct {
	Index        int             `json:"index"`
	Message      OpenAIMessage   `json:"message"`
	FinishReason *string         `json:"finish_reason"` 
}

// OpenAIUsage represents the token usage information from OpenAI
type OpenAIUsage struct {
	PromptTokens     int `json:"prompt_tokens"`
	CompletionTokens int `json:"completion_tokens"`
	TotalTokens      int `json:"total_tokens"`
}

// OpenAIStreamChoice represents a choice within an OpenAI SSE chunk
type OpenAIStreamChoice struct {
	Index        int                  `json:"index"`
	Delta        OpenAIStreamDelta    `json:"delta"`
	FinishReason *string              `json:"finish_reason"` 
}

// OpenAIStreamDelta represents the delta content within an OpenAI SSE chunk
type OpenAIStreamDelta struct {
	Role    *string `json:"role,omitempty"` 
	Content *string `json:"content,omitempty"` 
}

// OpenAIStreamChunk represents the structure of a data chunk in the OpenAI SSE stream
type OpenAIStreamChunk struct {
	ID      string               `json:"id"`
	Object  string               `json:"object"` // e.g., "chat.completion.chunk"
	Created int64                `json:"created"`
	Model   string               `json:"model"`
	Choices []OpenAIStreamChoice `json:"choices"`
	Usage   *OpenAIUsage         `json:"usage,omitempty"` 
}


// --- Claude SSE Structs (for sending back to client) ---

// ClaudeSSEEvent represents a generic Claude SSE event structure for easy marshaling
type ClaudeSSEEvent struct {
	Type         string                `json:"type"`
	Index        *int                  `json:"index,omitempty"` 
	Message      *ClaudeSSEMessage     `json:"message,omitempty"` 
	ContentBlock *ClaudeSSEContentBlock `json:"content_block,omitempty"` 
	Delta        *ClaudeSSEDelta       `json:"delta,omitempty"` 
	Usage        *ClaudeSSEUsage       `json:"usage,omitempty"` 
	Error        *ClaudeError          `json:"error,omitempty"` 
}

// ClaudeSSEMessage is nested within message_start
type ClaudeSSEMessage struct {
	ID           string               `json:"id"`
	Type         string               `json:"type"` // "message"
	Role         string               `json:"role"` // "assistant"
	Content      []ClaudeContentBlock `json:"content"` // Initially empty
	Model        string               `json:"model"`
	StopReason   *string              `json:"stop_reason"` // Initially null
	StopSequence *string              `json:"stop_sequence"` // Initially null
	Usage        ClaudeUsage          `json:"usage"` // Initial usage (input tokens)
}

// ClaudeSSEContentBlock is nested within content_block_start
type ClaudeSSEContentBlock struct {
	Type string `json:"type"` // "text"
	Text string `json:"text"` // Initially empty
}

// ClaudeSSEDelta is nested within content_block_delta and message_delta
type ClaudeSSEDelta struct {
	Type         string  `json:"type,omitempty"` // "text_delta" in content_block_delta
	Text         *string `json:"text,omitempty"` // Pointer for content_block_delta
	StopReason   *string `json:"stop_reason,omitempty"` // Pointer for message_delta
	StopSequence *string `json:"stop_sequence,omitempty"` // Pointer for message_delta (usually null)
}

// ClaudeSSEUsage is nested within message_delta (HACK) and message_stop
type ClaudeSSEUsage struct {
	InputTokens  *int `json:"input_tokens,omitempty"` // Only in message_stop
	OutputTokens int  `json:"output_tokens"` 
}