mdmodels 0.2.9

/*
 * Copyright (c) 2025 Jan Range
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

//! This module provides functionality for extracting structured data from text using LLM APIs.
//! It handles the communication with OpenAI's API, formatting requests and parsing responses
//! according to a specified data model schema.

use std::env;

use openai_api_rs::v1::{api::OpenAIClient, chat_completion};
use serde_json::{json, Value};

use crate::{datamodel::DataModel, json::export::to_json_schema};

/// Queries the OpenAI API with a given prompt and pre-prompt, using a specified data model and root.
///
/// # Arguments
///
/// * `prompt` - The main prompt to send to the OpenAI API.
/// * `pre_prompt` - An additional pre-prompt to provide context or setup for the main prompt.
/// * `data_model` - The data model used to generate the JSON schema for the response format.
/// * `root` - The root name for the JSON schema.
/// * `model` - The OpenAI model to use for the chat completion.
/// * `multiple` - Whether to extract multiple objects.
/// * `api_key` - Optional API key for OpenAI. If None, will try to read from environment variable.
///
/// # Returns
///
/// A `Result` containing a `serde_json::Value` with the parsed JSON response from the OpenAI API, or an error if the operation fails.
///
/// # Errors
///
/// This function will return an error if:
/// - The JSON schema cannot be generated from the data model
/// - The OpenAI API key is not provided and not found in environment variables
/// - The API request fails
/// - The response cannot be parsed as valid JSON
pub async fn query_openai(
    prompt: &str,
    pre_prompt: &str,
    data_model: &DataModel,
    root: &str,
    model: &str,
    multiple: bool,
    api_key: Option<String>,
) -> Result<Value, Box<dyn std::error::Error>> {
    let response_format = prepare_response_format(data_model, root, multiple)?;
    let mut client = prepare_client(api_key)?;
    let messages = vec![create_chat_message(pre_prompt), create_chat_message(prompt)];
    let model_type = ModelType::from_str(model)?;

    let req = match model_type {
        ModelType::Reasoning => {
            chat_completion::ChatCompletionRequest::new(model.to_string(), messages)
                .response_format(response_format)
        }
        ModelType::Generation => {
            chat_completion::ChatCompletionRequest::new(model.to_string(), messages)
                .response_format(response_format)
                .temperature(0.0)
        }
    };

    let result = client.chat_completion(req).await?;
    let content = result
        .choices
        .first()
        .and_then(|choice| choice.message.content.as_ref())
        .ok_or_else(|| format!("No content in response from {model}"))?;

    Ok(serde_json::from_str(content)?)
}

/// Prepares the response format for the OpenAI API request based on the data model.
///
/// # Arguments
///
/// * `model` - The data model used to generate the JSON schema.
/// * `root` - The root name for the JSON schema.
/// * `multiple` - Whether to prepare a format for multiple objects (array) or a single object.
///
/// # Returns
///
/// A `Result` containing a `serde_json::Value` with the prepared response format, or an error if the operation fails.
fn prepare_response_format(
    model: &DataModel,
    root: &str,
    multiple: bool,
) -> Result<Value, Box<dyn std::error::Error>> {
    let mut schema = to_json_schema(model, root, true)?;

    if multiple {
        let definitions = schema.definitions.clone();
        schema.definitions.clear();

        Ok(json!(
            {
                "type": "json_schema",
                "json_schema": {
                    "strict": true,
                    "name": root,
                    "schema": {
                        "type": "object",
                        "additionalProperties": false,
                        "required": ["items"],
                        "properties": {
                            "items": {
                                "type": "array",
                                "items": schema
                            }
                        },
                        "$defs": definitions
                    }
                }
            }
        ))
    } else {
        Ok(json!(
                {
                    "type": "json_schema",
                    "json_schema": {
                        "name": root,
                        "strict": true,
                        "schema": schema
                    }
                }
        ))
    }
}

/// Prepares the OpenAI client with the provided API key or from environment variables.
///
/// # Arguments
///
/// * `api_key` - An optional API key for OpenAI. If None, will try to read from the OPENAI_API_KEY environment variable.
///
/// # Returns
///
/// A `Result` containing the configured `OpenAIClient`, or an error if the API key is not available.
fn prepare_client(api_key: Option<String>) -> Result<OpenAIClient, Box<dyn std::error::Error>> {
    let api_key = match api_key {
        Some(api_key) => api_key,
        None => env::var("OPENAI_API_KEY")?,
    };

    OpenAIClient::builder().with_api_key(api_key).build()
}

/// Creates a chat message for the OpenAI API with the specified content.
///
/// # Arguments
///
/// * `content` - The text content of the message.
///
/// # Returns
///
/// A `ChatCompletionMessage` configured with the user role and provided content.
fn create_chat_message(content: &str) -> chat_completion::ChatCompletionMessage {
    chat_completion::ChatCompletionMessage {
        role: chat_completion::MessageRole::user,
        content: chat_completion::Content::Text(content.to_string()),
        name: None,
        tool_calls: None,
        tool_call_id: None,
    }
}

/// Represents the type of OpenAI model being used, which affects request configuration.
enum ModelType {
    /// Models optimized for reasoning tasks (e.g., GPT-4o)
    Reasoning,
    /// Models optimized for text generation (e.g., GPT-3.5-turbo)
    Generation,
}

impl ModelType {
    /// Determines the model type from a model name string.
    ///
    /// # Arguments
    ///
    /// * `s` - The model name string to parse.
    ///
    /// # Returns
    ///
    /// A `Result` containing the determined `ModelType`, or an error if the model name is invalid.
    fn from_str(s: &str) -> Result<Self, String> {
        // Use a regex to check if the model is a reasoning model
        if regex::Regex::new(r"o\d*").unwrap().is_match(s) {
            Ok(ModelType::Reasoning)
        } else {
            Ok(ModelType::Generation)
        }
    }
}