// ABOUTME: Chat orchestration domain service for multi-step chat operations
// ABOUTME: Extracts conversation creation, message dispatch, and model validation from routes
//
// SPDX-License-Identifier: MIT OR Apache-2.0
// Copyright (c) 2025 Pierre Fitness Intelligence
use crate::config::LlmProviderType;
use crate::database::repositories::ChatRepository;
use crate::database::{ConversationRecord, MessageRecord};
use crate::database_plugins::factory::Database;
use crate::errors::{AppError, AppResult};
use crate::models::TenantId;
/// Result of creating a new conversation, including validated model
pub struct CreateConversationResult {
/// The created conversation record
pub conversation: ConversationRecord,
}
/// Result of persisting a user message
pub struct UserMessageResult {
/// The persisted user message
pub message: MessageRecord,
/// The conversation record (for model/`system_prompt` access)
pub conversation: ConversationRecord,
}
/// Validate the model and create a conversation.
///
/// Business rules:
/// - Uses requested model if provided
/// - Falls back to `PIERRE_LLM_MODEL` environment variable
/// - Fails if no model can be determined
///
/// # Errors
///
/// Returns `AppError::Config` if no model is specified and `PIERRE_LLM_MODEL` is not set.
/// Returns database errors on conversation creation failure.
pub async fn create_conversation(
database: &Database,
user_id: &str,
tenant_id: TenantId,
title: &str,
requested_model: Option<&str>,
system_prompt: Option<&str>,
) -> AppResult<CreateConversationResult> {
let model = match requested_model {
Some(m) => m.to_owned(),
None => LlmProviderType::model_from_env().ok_or_else(|| {
AppError::config("No model specified and PIERRE_LLM_MODEL environment variable not set")
})?,
};
let conversation = database
.create_conversation(user_id, tenant_id, title, &model, system_prompt)
.await?;
Ok(CreateConversationResult { conversation })
}
/// Verify conversation ownership and persist user message.
///
/// Business rules:
/// - Conversation must exist and belong to the user/tenant
/// - Message is persisted before LLM dispatch (crash-safe)
/// - Returns both message and conversation (for model/prompt access in LLM step)
///
/// # Errors
///
/// Returns `AppError::NotFound` if the conversation does not exist or belongs to another user.
/// Returns database errors on message persistence failure.
pub async fn persist_user_message(
database: &Database,
conversation_id: &str,
user_id: &str,
tenant_id: TenantId,
content: &str,
) -> AppResult<UserMessageResult> {
// Verify ownership and get conversation details
let conversation = database
.get_conversation(conversation_id, user_id, tenant_id)
.await?
.ok_or_else(|| AppError::not_found("Conversation not found"))?;
// Persist user message before LLM dispatch
let message = database
.add_message(conversation_id, user_id, "user", content, None, None)
.await?;
Ok(UserMessageResult {
message,
conversation,
})
}
/// Get conversation history for LLM context building.
///
/// Returns all messages in the conversation for the given user.
///
/// # Errors
///
/// Returns database errors on message retrieval failure.
pub async fn get_conversation_history(
database: &Database,
conversation_id: &str,
user_id: &str,
) -> AppResult<Vec<MessageRecord>> {
database
.get_messages(conversation_id, user_id)
.await
.map_err(AppError::from)
}
/// Persist the assistant's response message.
///
/// Called after LLM dispatch + tool execution completes.
/// Returns the persisted message record and updated conversation.
///
/// # Errors
///
/// Returns `AppError::Internal` if the conversation cannot be retrieved after saving.
/// Returns database errors on message persistence failure.
pub async fn persist_assistant_response(
database: &Database,
conversation_id: &str,
user_id: &str,
tenant_id: TenantId,
content: &str,
token_count: Option<u32>,
finish_reason: Option<&str>,
) -> AppResult<(MessageRecord, ConversationRecord)> {
let message = database
.add_message(
conversation_id,
user_id,
"assistant",
content,
token_count,
finish_reason,
)
.await?;
let conversation = database
.get_conversation(conversation_id, user_id, tenant_id)
.await?
.ok_or_else(|| AppError::internal("Failed to get updated conversation"))?;
Ok((message, conversation))
}
