// Homelab AI service message contracts.
//
// This is the single source of truth for all NATS message types.
// Generated Go code lives in handler-base/gen/messagespb.
//
// Naming: field numbers are stable across versions — add new fields,
// never reuse or renumber existing ones.

syntax = "proto3";

package messages.v1;

option go_package = "git.daviestechlabs.io/daviestechlabs/handler-base/gen/messagespb";

// ─────────────────────────────────────────────────────────────────────────────
// Common
// ─────────────────────────────────────────────────────────────────────────────

// ErrorResponse is the standard error reply from any handler.
message ErrorResponse {
  bool   error   = 1;
  string message = 2;
  string type    = 3;
}

// ─────────────────────────────────────────────────────────────────────────────
// Chat (companions-frontend ↔ chat-handler)
// ─────────────────────────────────────────────────────────────────────────────

// LoginEvent is published when a user authenticates.
// Subject: ai.chat.user.{user_id}.login
message LoginEvent {
  string user_id   = 1;
  string username  = 2;
  string nickname  = 3;
  bool   premium   = 4;
  int64  timestamp = 5; // Unix seconds
}

// GreetingRequest asks the LLM to generate a personalised greeting.
// Subject: ai.chat.user.{user_id}.greeting.request
message GreetingRequest {
  string user_id  = 1;
  string username = 2;
  string nickname = 3;
  bool   premium  = 4;
}

// GreetingResponse carries the generated greeting text.
// Subject: ai.chat.user.{user_id}.greeting.response
message GreetingResponse {
  string user_id  = 1;
  string greeting = 2;
}

// ChatRequest is an incoming chat message routed via NATS.
// Subject: ai.chat.user.{user_id}.message
message ChatRequest {
  string request_id       = 1;
  string user_id          = 2;
  string username         = 3;
  string message          = 4;
  string query            = 5;  // alternative to message (EffectiveQuery picks first non-empty)
  bool   premium          = 6;
  bool   enable_rag       = 7;
  bool   enable_reranker  = 8;
  bool   enable_streaming = 9;
  int32  top_k            = 10;
  string collection       = 11;
  bool   enable_tts       = 12;
  string system_prompt    = 13;
  string response_subject = 14;
}

// ChatResponse is the full reply to a ChatRequest.
// Subject: ai.chat.response.{request_id}  (or ChatRequest.response_subject)
message ChatResponse {
  string         user_id       = 1;
  string         response      = 2;
  string         response_text = 3;
  bool           used_rag      = 4;
  repeated string rag_sources  = 5;
  bool           success       = 6;
  bytes          audio         = 7;
  string         error         = 8;
}

// ChatStreamChunk is one piece of a streaming LLM response.
// Subject: ai.chat.response.stream.{request_id}
message ChatStreamChunk {
  string request_id = 1;
  string type       = 2; // "chunk" | "done"
  string content    = 3;
  bool   done       = 4;
  int64  timestamp  = 5;
}

// ─────────────────────────────────────────────────────────────────────────────
// Voice Assistant
// ─────────────────────────────────────────────────────────────────────────────

// VoiceRequest is an incoming voice-to-voice request.
// Subject: ai.voice.request
message VoiceRequest {
  string request_id = 1;
  bytes  audio      = 2;
  string language   = 3;
  string collection = 4;
}

// DocumentSource is a single RAG search-result citation.
message DocumentSource {
  string text  = 1;
  double score = 2;
}

// VoiceResponse is the reply to a VoiceRequest.
// Subject: ai.voice.response.{request_id}
message VoiceResponse {
  string                   request_id    = 1;
  string                   response      = 2;
  bytes                    audio         = 3;
  string                   transcription = 4;
  repeated DocumentSource  sources       = 5;
  string                   error         = 6;
}

// ─────────────────────────────────────────────────────────────────────────────
// TTS Module
// ─────────────────────────────────────────────────────────────────────────────

// TTSRequest is a text-to-speech synthesis request.
// Subject: ai.voice.tts.request.{session_id}
message TTSRequest {
  string text            = 1;
  string speaker         = 2;
  string language        = 3;
  string speaker_wav_b64 = 4;
  bool   stream          = 5;
}

// TTSAudioChunk is a streamed audio chunk from TTS synthesis.
// Subject: ai.voice.tts.audio.{session_id}
message TTSAudioChunk {
  string session_id   = 1;
  int32  chunk_index  = 2;
  int32  total_chunks = 3;
  bytes  audio        = 4;
  bool   is_last      = 5;
  int64  timestamp    = 6;
  int32  sample_rate  = 7;
}

// TTSFullResponse is a non-streamed TTS response (whole audio blob).
// Subject: ai.voice.tts.audio.{session_id}
message TTSFullResponse {
  string session_id  = 1;
  bytes  audio       = 2;
  int64  timestamp   = 3;
  int32  sample_rate = 4;
}

// TTSStatus is a TTS processing status update.
// Subject: ai.voice.tts.status.{session_id}
message TTSStatus {
  string session_id = 1;
  string status     = 2;
  string message    = 3;
  int64  timestamp  = 4;
}

// TTSVoiceInfo is summary info about a custom voice.
message TTSVoiceInfo {
  string name       = 1;
  string language   = 2;
  string model_type = 3;
  string created_at = 4;
}

// TTSVoiceListResponse is the reply to a voice list request.
// Subject: ai.voice.tts.voices.list  (request-reply)
message TTSVoiceListResponse {
  string                  default_speaker = 1;
  repeated TTSVoiceInfo   custom_voices   = 2;
  int64                   last_refresh    = 3;
  int64                   timestamp       = 4;
}

// TTSVoiceRefreshResponse is the reply to a voice refresh request.
// Subject: ai.voice.tts.voices.refresh  (request-reply)
message TTSVoiceRefreshResponse {
  int32                   count         = 1;
  repeated TTSVoiceInfo   custom_voices = 2;
  int64                   timestamp     = 3;
}

// ─────────────────────────────────────────────────────────────────────────────
// STT Module
// ─────────────────────────────────────────────────────────────────────────────

// STTStreamMessage is any message on the ai.voice.stream.{session_id} subject.
message STTStreamMessage {
  string type       = 1; // "start" | "chunk" | "state_change" | "end"
  bytes  audio      = 2;
  string state      = 3;
  string speaker_id = 4;
}

// STTTranscription is the transcription result published by the STT module.
// Subject: ai.voice.transcription.{session_id}
message STTTranscription {
  string session_id         = 1;
  string transcript         = 2;
  int32  sequence           = 3;
  bool   is_partial         = 4;
  bool   is_final           = 5;
  int64  timestamp          = 6;
  string speaker_id         = 7;
  bool   has_voice_activity = 8;
  string state              = 9;
}

// STTInterrupt is published when the STT module detects a user interrupt.
// Subject: ai.voice.transcription.{session_id}
message STTInterrupt {
  string session_id = 1;
  string type       = 2; // "interrupt"
  int64  timestamp  = 3;
  string speaker_id = 4;
}

// ─────────────────────────────────────────────────────────────────────────────
// Pipeline Bridge
// ─────────────────────────────────────────────────────────────────────────────

// PipelineTrigger is the request to start a pipeline.
// Subject: ai.pipeline.trigger
message PipelineTrigger {
  string request_id = 1;
  string pipeline   = 2;
  // Protobuf Struct could be used here, but a simple string map covers
  // all current use-cases and avoids a google/protobuf import.
  map<string, string> parameters = 3;
}

// PipelineStatus is the response / status update for a pipeline run.
// Subject: ai.pipeline.status.{request_id}
message PipelineStatus {
  string          request_id          = 1;
  string          status              = 2;
  string          run_id              = 3;
  string          engine              = 4;
  string          pipeline            = 5;
  string          submitted_at        = 6;
  string          error               = 7;
  repeated string available_pipelines = 8;
}